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LT3022 1A, 0.9V to 10V, Very Low Dropout Linear Regulator FeaTures
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DescripTion
The LT(R)3022 is a very low dropout voltage (VLDOTM) linear regulator that operates from single input supplies down to 0.9V. The device supplies 1A output current with 145mV typical dropout voltage. The LT3022 is ideal for low input voltage to low output voltage applications, providing comparable electrical efficiency to a switching regulator. The regulator optimizes stability and transient response with low ESR ceramic output capacitors as small as 10F Other LT3022 features include 0.05% typical line . regulation and 0.05% typical load regulation. In shutdown, quiescent current typically drops to 7.5A. Internal protection circuitry includes reverse-battery protection, current limiting, thermal limiting with hysteresis and reverse-current protection. The LT3022 is available as an adjustable device with an output voltage range down to the 200mV reference. The LT3022 regulator is available in the thermally enhanced low profile (0.75mm) 16-lead (5mm x 3mm) DFN and MSOP packages.
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. VLDO is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners.
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VIN Range: 0.9V to 10V Dropout Voltage: 145mV Typical Output Current: 1A Adjustable Output (VREF = VOUT(MIN) = 200mV) Stable with Low ESR, Ceramic Output Capacitors (10F Minimum) 0.05% Typical Load Regulation from 1mA to 1A Quiescent Current: 400A Typical 7.5A Typical Quiescent Current in Shutdown Current Limit Protection Reverse-Battery Protection with No Reverse Current Thermal Limiting with Hysteresis 16-Lead (5mm x 3mm) DFN and MSOP Packages
applicaTions
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High Efficiency Linear Regulators Battery-Powered Systems Logic Supplies Post Regulator for Switching Supplies Wireless Modems FPGA Core Supplies
Typical applicaTion
Minimum Input Voltage
1.1
1.2V to 0.9V, 1A VLDO Regulator
MINIMUM INPUT VOLTAGE (V) VIN 1.2V IN 10F SHDN GND OUT LT3022 ADJ VOUT 0.9V 10F 1A
1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 -50 -25 50 25 0 75 TEMPERATURE (C)
IL = 1A
698 1% 200 1%
3022 TA01a
100
125
3022 TA01b
3022f
LT3022 absoluTe MaxiMuM raTings
(Note 1)
IN Pin Voltage ........................................................ 10V OUT Pin Voltage ..................................................... 10V Input-to-Output Differential Voltage ....................... 10V ADJ Pin Voltage ..................................................... 10V SHDN Pin Voltage .................................................. 10V Output Short-Circuit Duration ......................... Indefinite
Operating Junction Temperature Range E-, I-Grades (Notes 2, 3) ................... -40C to 125C Storage Temperature Range ................. -65C to 150C Lead Temperature (Soldering, 10 sec) MSOP Package ................................................ 300C
pin conFiguraTion
TOP VIEW NC NC OUT OUT ADJ AGND AGND NC 1 2 3 4 5 6 7 8 17 GND 16 NC 15 NC 14 IN 13 IN 12 IN 11 PGND 10 PGND 9 SHDN NC NC OUT OUT ADJ AGND AGND NC 1 2 3 4 5 6 7 8 TOP VIEW 16 15 14 13 12 11 10 9 NC NC IN IN IN PGND PGND SHDN
17 GND
MSE PACKAGE 16-LEAD PLASTIC MSOP TJMAX = 125C, JA = 38C/W*, JC = 5C/W TO 10C/W EXPOSED PAD (PIN 17) IS GND, MUST BE SOLDERED TO PCB *SEE THE APPLICATIONS INFORMATION SECTION
DHC PACKAGE 16-LEAD (5mm 3mm) PLASTIC DFN TJMAX = 125C, JA = 38C/W*, JC = 4C/W EXPOSED PAD (PIN 17) IS GND, MUST BE SOLDERED TO PCB *SEE THE APPLICATIONS INFORMATION SECTION
orDer inForMaTion
LEAD FREE FINISH LT3022EDHC#PBF LT3022IDHC#PBF LT3022EMSE#PBF LT3022IMSE#PBF LEAD BASED FINISH LT3022EDHC LT3022IDHC LT3022EMSE LT3022IMSE TAPE AND REEL LT3022EDHC#TRPBF LT3022IDHC#TRPBF LT3022EMSE#TRPBF LT3022IMSE#TRPBF TAPE AND REEL LT3022EDHC#TR LT3022IDHC#TR LT3022EMSE#TR LT3022IMSE#TR PART MARKING* 3022 3022 3022 3022 PART MARKING* 3022 3022 3022 3022 PACKAGE DESCRIPTION 16-Lead (5mm x 3mm) Plastic DFN 16-Lead (5mm x 3mm) Plastic DFN 16-Lead Plastic MSOP 16-Lead Plastic MSOP PACKAGE DESCRIPTION 16-Lead (5mm x 3mm) Plastic DFN 16-Lead (5mm x 3mm) Plastic DFN 16-Lead Plastic MSOP 16-Lead Plastic MSOP TEMPERATURE RANGE -40C to 125C -40C to 125C -40C to 125C -40C to 125C TEMPERATURE RANGE -40C to 125C -40C to 125C -40C to 125C -40C to 125C
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container. For more information on lead free part marking, go to: http://www.linear.com/leadfree/ For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/
3022f
LT3022 elecTrical characTerisTics
PARAMETER Minimum Input Voltage (Notes 4, 6) ADJ Pin Voltage (Notes 5, 6) Line Regulation (Note 7) Load Regulation (Note 7) Dropout Voltage (Notes 8, 9)
The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25C.
CONDITIONS ILOAD = 1A, TA > 0C ILOAD = 1A, TA 0C VIN = 1.5V, ILOAD = 1mA 1.15V < VIN < 10V, 1mA < ILOAD < 1A VIN = 1.15V to 10V, ILOAD = 1mA VIN = 1.15V, ILOAD = 1mA to 1A ILOAD = 10mA
l l l l
MIN
TYP 0.9 0.9
MAX 1.05 1.10 204 206 0.5 0.5 1.0 75 135 90 175 150 235 185 285 2.5 8.5 20 36
UNITS V V mV mV mV mV mV mV mV mV mV mV mV mV mV A mA mA mA mA VRMS
196 194 -1.5 -0.5 -1.0
200 200 -0.1 0.1 45 55
ILOAD = 100mA
l
ILOAD = 500mA
l
110 145
l
ILOAD = 1A GND Pin Current, VIN = VOUT(NOMINAL) + 0.4V (Notes 9, 10) ILOAD = 0mA ILOAD = 1mA ILOAD = 100mA ILOAD = 500mA ILOAD = 1A COUT = 10F ILOAD = 1A, BW = 10Hz to 100kHz, , VOUT = 1.2V VADJ = 0.2V, VIN = 1.5V VOUT = Off to On VOUT = On to Off VSHDN = 0V, VIN = 10V VSHDN = 10V, VIN = 10V VIN = 6V, VSHDN = 0V VIN - VOUT = 1V, VRIPPLE = 0.5VP-P , fRIPPLE = 120Hz, ILOAD = 1A VIN = 10V, VOUT = 0V VIN = VOUT(NOMINAL) + 0.5V, VOUT -5% VIN = -10V, VOUT = 0V VOUT = 1.2V, VIN = 0V VIN = 1.6V, VOUT = 1.2V
l l l l l l
l l l l
400 1.2 3.4 8.3 18 165 30 0.25 0.64 0.64 3 7.5 55 70 2.6 1.7 4 0.1 1
Output Voltage Noise ADJ Pin Bias Current (Notes 7, 11) Shutdown Threshold SHDN Pin Current (Note 12) Quiescent Current in Shutdown Ripple Rejection (Note 13) Current Limit (Note 9) Input Reverse Leakage Current (Note 14) Reverse Output Current (Notes 15, 16) Minimum Required Output Current
100 0.9 1 9.5 15
nA V V A A A dB A A
1.1
20 5
A A mA
Note 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliability and lifetime. Note 2: The LT3022 regulator is tested and specified under pulse load conditions such that TJ TA. The LT3022 is 100% tested at TA = 25C. Performance of the LT3022E over the full -40C and 125C operating junction temperature range is assured by design, characterization and correlation with statistical process controls. The LT3022I regulators are guaranteed over the full -40C to 125C operating junction temperature range. High junction temperatures degrade operating lifetime. Operating lifetime is derated at junction temperatures greater than 125C. Note 3: This IC includes overtemperature protection that is intended to protect the device during momentary overload conditions. Junction
temperature will exceed 125C when overtemperature protection is active. Continuous operation above the specified maximum operating junction temperature may impair device reliability. Note 4: Minimum input voltage is the voltage required by the LT3022 to regulate the output voltage and supply the rated 1A output current. This specification is tested at VOUT = 0.2V. For higher output voltages, the minimum input voltage required for regulation equals the regulated output voltage VOUT plus the dropout voltage or 1.1V, whichever is greater. Note 5: Maximum junction temperature limits operating conditions. The regulated output voltage specification does not apply for all possible combinations of input voltage and output current. Limit the output current range if operating at maximum input voltage. Limit the input-to-output voltage differential range if operating at maximum output current.
3022f
LT3022 elecTrical characTerisTics
Note 6: The LT3022 typically supplies 1A output current with a 0.9V input supply. The guaranteed minimum input voltage for 1A output current is 1.10V, especially if cold temperature operation is required. Note 7: The LT3022 is tested and specified for these conditions with ADJ tied to OUT. Note 8: Dropout voltage is the minimum input to output voltage differential needed to maintain regulation at a specified output current. In dropout the output voltage equals: (VIN - VDROPOUT). Note 9: The LT3022 is tested and specified for these conditions with an external resistor divider (3.92k and 19.6k) setting VOUT to 1.2V. The external resistor divider adds 50A of load current. Note 10: GND pin current is tested with VIN = VOUT(NOMINAL) + 0.4V and a current source load. GND pin current increases in dropout. See GND pin current curves in the Typical Performance Characteristics section. Note 11: Adjust pin bias current flows out of the ADJ pin. Note 12: Shutdown pin current flows into the SHDN pin. Note 13: The LT3022 is tested and specified for this condition with an external resistor divider (3.92k and 5.9k) setting VOUT to 0.5V. The external resistor divider adds 50A of load current. The specification refers to the change in the 0.2V reference voltage, not the 0.5V output voltage. Note 14: Input reverse leakage current flows out of the IN pin. Note 15: Reverse output current is tested with IN grounded and OUT forced to the rated output voltage. This current flows into the OUT pin and out of the GND pin. Note 16: Reverse current is higher for the case of (rated_output) < VOUT < VIN, because the no-load recovery circuitry is active in this region and is trying to restore the output voltage to its nominal value.
Typical perForMance characTerisTics
Dropout Voltage
300 270 DROPOUT VOLTAGE (mV) 240 210 180 150 120 90 60 30 0 0 100 200 300 400 500 600 700 800 900 1000 OUTPUT CURRENT (mA)
3022 G01
Guaranteed Dropout Voltage
300 GUARANTEED DROPOUT VOLTAGE (mV) 270 240 210 180 150 120 90 60 30 0 0 100 200 300 400 500 600 700 800 900 1000 OUTPUT CURRENT (mA)
3022 G02
Dropout Voltage
300 270 DROPOUT VOLTAGE (mV) VOUT = 1.2V
VOUT = 1.2V
= TEST POINTS
TJ = 125C
240 210 180 150 120 90 60 30 0 -50 -25 IL = 100mA IL = 10mA 50 25 0 75 TEMPERATURE (C) 100 125 IL = 500mA IL = 1A
TJ = 125C TJ = 25C TJ = -40C
TJ = 25C
3022 G03
Minimum Input Voltage
1.1 1.0 MINIMUM INPUT VOLTAGE (V) 0.9 ADJ PIN VOLTAGE (mV) 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 -50 -25 50 25 0 75 TEMPERATURE (C) 100 125 IL = 1A 206 204 202 200 198 196
ADJ Pin Voltage
IL = 1mA
194 -50 -25
50 25 75 0 TEMPERATURE (C)
100
125
3022 G04
3022 G05
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LT3022 Typical perForMance characTerisTics
ADJ Pin Bias Current
100 90 ADJ PIN BIAS CURRENT (nA) QUIESCENT CURRENT (A) 80 70 60 50 40 30 20 10 0 -50 -25 50 25 0 75 TEMPERATURE (C) 100 125 1000 900 800 700 600 500 400 300 200 100 0 -50 -25 VSHDN = 0V 50 25 0 75 TEMPERATURE (C) 100 125 VSHDN = VIN
Quiescent Current
VIN = 6V VOUT = 1.2V IL = 0 5.0 4.5 QUIESCENT CURRENT (mA) 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0
Quiescent Current
VOUT = 1.2V IL = 0 TJ = 25C
VSHDN = VIN
VSHDN = 0V 0 1 2 34567 INPUT VOLTAGE (V) 8 9 10
3022 G06
3022 G07
3022 G08
Quiescent Current
5.0 4.5 QUIESCENT CURRENT (mA) 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0 0 1 2 VSHDN = 0V 34567 INPUT VOLTAGE (V) 8 9 10 VSHDN = VIN VOUT = 1.5V IL = 0 TJ = 25C 5.0 4.5 QUIESCENT CURRENT (mA) 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0
Quiescent Current
VOUT = 1.8V IL = 0 TJ = 25C GND PIN CURRENT (mA) 24 21 18 15 12 9 6 3 8 9 10 0
GND Pin Current
VOUT = 1.2V TJ = 25C RL = 1.2 IL = 1A
VSHDN = VIN
RL = 2.4 IL = 500mA RL = 120 IL = 10mA RL = 12 IL = 100mA
RL = 1.2k IL = 1mA
VSHDN = 0V 0 1 2 34567 INPUT VOLTAGE (V)
0
1
2
34567 INPUT VOLTAGE (V)
8
9
10
3022 G09
3022 G10
3022 G11
GND Pin Current
24 21 GND PIN CURRENT (mA) 18 15 12 9 6 3 0 0 1 RL = 1.5 IL = 1A VOUT = 1.5V TJ = 25C GND PIN CURRENT (mA) 24 21 18 15 12 9 6 3 8 9 10 0
GND Pin Current
VOUT = 1.8V TJ = 25C RL = 1.8 IL = 1A RL = 3.6 IL = 500mA
RL = 3 IL = 500mA RL = 15 IL = 100mA
RL = 150 R = 1.5k L IL = 10mA I = 1mA L
RL = 180 IL = 10mA
RL = 1.8k IL = 1mA
RL = 18 IL = 100mA
2
34567 INPUT VOLTAGE (V)
0
1
2
34567 INPUT VOLTAGE (V)
8
9
10
3022 G12
3022 G13
3022f
LT3022 Typical perForMance characTerisTics
24
GND Pin Current vs ILOAD
SHDN Pin Threshold
1.0 0.9 SHDN PIN THRESHOLD (V) 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 IL = 1mA SHDN PIN INPUT CURRENT (A) 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 -25 50 25 0 75 TEMPERATURE (C) 100 125 0
SHDN Pin Input Current
TJ = 25C
GND PIN CURRENT (mA)
VIN = 1.6V 21 VOUT = 1.2V VSHDN = 10V 18 TJ = 25C 15 12 9 6 3 0 0 100 200 300 400 500 600 700 800 900 1000 LOAD CURRENT (mA)
3022 G14
0 -50
0
1
2
345678 SHDN PIN VOLTAGE (V)
9
10
3022 G15
3022 G16
SHDN Pin Input Current
6 SHDN PIN INPUT CURRENT (A) 5 4 3 2 1 0 -50 -25 VIN = 10V VSHDN = 10V 3.0 2.7 2.4 CURRENT LIMIT (A) 2.1 1.8 1.5 1.2 0.9 0.6 0.3 50 25 75 0 TEMPERATURE (C) 100 125
Current Limit
VOUT = 0V VIN = 10V INPUT CURRENT (A) VIN = 1.7V 0 -2 -4 -6 -8 -10 -12 -14 -16 -18 -25 50 25 0 75 TEMPERATURE (C) 100 125 -20
Reverse Input Leakage Current
0 -50
VOUT = 0V VSHDN = 10V TJ = 25C 0 -1 -2 -3 -4 -5 -6 -7 -8 -9 -10 INPUT VOLTAGE (V)
3022 G19
3022 G17
3022 G18
Reverse Input Leakage Current
0 -2 REVERSE OUTPUT CURRENT (A) -4 INPUT CURRENT (A) -6 -8 -10 -12 -14 -16 -18 VIN = -10V VOUT = 0V VSHDN = 10V -25 50 25 0 75 TEMPERATURE (C) 100 125 100 80 60 40 20 120
Reverse Output Current
VIN = 0V VOUT = 1.2V IOUT FLOWS INTO OUT PIN IIN FLOWS OUT OF IN PIN 100 90 INPUT RIPPLE REJECTION (dB) 80 70 60 50 40 30 20 10 0
Input Ripple Rejection
VIN = 1.5V + 50mVRMS RIPPLE VOUT = 0.5V IL = 1A TJ = 25C COUT = 47F
COUT = 10F
IOUT 50 25 75 0 TEMPERATURE (C) 100
-20 -50
0 -50 -25
IIN 125
10
100
1k 10k 100k FREQUENCY (Hz)
1M
10M
3022 G22
3022 G20
3022 G21
3022f
LT3022 Typical perForMance characTerisTics
Input Ripple Rejection
100 90 INPUT RIPPLE REJECTION (dB) 80 70 60 50 40 30 20 10 VIN = 1.5V + 0.5VP-P RIPPLE AT 120Hz VOUT = 0.5V COUT = 10F IL = 1A -25 50 25 0 75 TEMPERATURE (C) 100 125 LINE REGULATION (mV) 0.5 0.3 0.1 -0.1 -0.3 -0.5 -0.7 -0.9 -1.1 -1.3 -1.5 -50 -25 50 25 0 75 TEMPERATURE (C) 100 125
Line Regulation
VIN = 1.15V TO 10V VOUT = 0.2V IL = 1mA LOAD REGULATION (mV) 1.0 0.8 0.6 0.4 0.2 0 -0.2 -0.4 -0.6 -0.8
Load Regulation
VIN = 1.15V VOUT = 0.5V IL = 1mA TO 1A LOAD REGULATION NUMBER REFERS TO CHANGE IN THE 200mV REFERENCE VOLTAGE
0 -50
-1.0 -50
-25
50 25 0 75 TEMPERATURE (C)
100
125
3022 G23
3022 G24
3022 G25
No-Load Recovery Threshold
30 25 OUTPUT OVERSHOOT (%) 20 15 10 5 0 TJ = 25C 12 10 8 6
No-Load Recovery Threshold
OUTPUT NOISE SPECTRAL DENSITY (V/Hz) 10
Output Noise Spectral Density
VOUT = 1.2V IL = 1A TJ = 25C
OUTPUT SINK CURRENT (mA)
1 COUT = 10F COUT = 47F
IOUT(SINK) = 5mA IOUT(SINK) = 1mA
0.1
4 2 0 -50 -25
0.01
0
5 10 15 OUTPUT OVERSHOOT (%)
20
3022 G26
50 25 75 0 TEMPERATURE (C)
100
125
0.001
10
100
1k 10k FREQUENCY (Hz)
100k
1M
3022 G28
3022 G27
RMS Output Noise vs Load Current (10Hz to 100kHz)
200 180 160 OUTPUT NOISE (VRMS) 140 120 100 80 60 40 20 0 0.01 0.1 1 10 100 LOAD CURRENT (mA) 1000
3022 G29
Start-Up from Shutdown
Transient Response
VOUT = 1.2V COUT = 10F TJ = 25C
VOUT 0.5V/DIV
VOUT 50mV/DIV
VSHDN 1V/DIV
IOUT 500mA/DIV
RL = 1.2 VIN = 1.5V VOUT = 1.2V COUT = 10F
50s/DIV
3022 G30
50s/DIV VIN = 1.5V VOUT = 1.2V IOUT = 100mA to 1A COUT = 22F tRISE = tFALL = 100ns
3022 G31
3022f
LT3022 pin FuncTions
NC (Pins 1, 2, 8, 15, 16): No Connect Pins. These pins have no connection to internal circuitry. These pins may be floated, tied to VIN or tied to GND for improved thermal performance. OUT (Pins 3, 4): These pins supply power to the load. Use a minimum output capacitor of 10F to prevent oscillations. Large load transient applications require larger output capacitors to limit peak voltage transients. See the Applications Information section for more information on output capacitance and reverse-output characteristics. The LT3022 requires a 1mA minimum load current to ensure proper regulation and stability. ADJ (Pin 5): This pin is the error amplifier inverting terminal. Its 30nA typical input bias current flows out of the pin (see curve of ADJ Pin Bias Current vs Temperature in the Typical Performance Characteristics). The ADJ pin reference voltage is 200mV (referred to AGND). AGND (Pins 6, 7): Analog Ground. Tie these pins directly to PGND (Pins 10, 11) and the exposed backside GND (Pin 17). Connect the bottom of the external resistor divider, setting output voltage, directly to AGND for optimum regulation. SHDN (Pin 9): Pulling the SHDN pin low puts the LT3022 into a low power state and turns the output off. Drive the SHDN pin with either logic or an open-collector/drain device with a pull-up resistor. The resistor supplies the pull-up current to the open collector/drain logic, normally several microamperes, and the SHDN pin current, typically 3A. If unused, connect the SHDN pin to VIN. The LT3022 does not function if the SHDN pin is not connected. PGND (Pins 10, 11): Power Ground. The majority of ground pin current flows out of PGND. Tie these pins directly to AGND (Pins 6, 7) and the exposed backside GND (Pin 17). IN (Pins 12, 13,14): These pins supply power to the device. The LT3022 requires a bypass capacitor at IN if located more than six inches from the main input filter capacitor. Include a bypass capacitor in battery-powered circuits as a battery's output impedance rises with frequency. A minimum bypass capacitor of 10F suffices. The LT3022 withstands reverse voltages on the IN pin with respect to ground and the OUT pin. In the case of a reversed input, which occurs if a battery is plugged in backwards, the LT3022 behaves as if a diode is in series with its input. No reverse current flows into the LT3022 and no reverse voltage appears at the load. The device protects itself and the load. GND (Pin 17): Exposed Pad. Tie this pin directly to AGND (Pins 6, 7), PGND (Pins 10, 11) and the PCB ground. This pin provides enhanced thermal performance with its connection to the PCB ground. See the Applications Information section for thermal considerations and calculating junction temperature.
3022f
LT3022 block DiagraM
9 SHDN IN SHUTDOWN THERMAL SHUTDOWN R3 D1 12, 13, 14
NO-LOAD RECOVERY
IDEAL DIODE
applicaTions inForMaTion
The LT3022 very low dropout linear regulator is capable of 0.9V input supply operation. It supplies 1A output current and dropout voltage is typically 145mV. Quiescent current is typically 400A and drops to 7.5A in shutdown. The LT3022 incorporates several protection features, making it ideal for use in battery-powered systems. The device protects itself against reverse-input and reverse-output voltages. If the output is held up by a backup battery when the input is pulled to ground in a battery backup application, the LT3022 behaves as if a diode is in series with its output, preventing reverse current flow. In dual supply applications where the regulator load is returned to a negative supply, pulling the output below ground by as much as 10V does not affect start-up or normal operation. Adjustable Operation The LT3022's output voltage range is 0.2V to 9.5V. Figure 1 shows that the external resistor ratio sets output voltage. The device regulates the output to maintain ADJ at 200mV referred to ground. R1's current equals 200mV/R1. R2's current is R1's current minus the ADJ pin bias current. The 30nA ADJ pin bias current flows out of the pin. Use Figure 1's formula to calculate output voltage. Given the LT3022's 1mA minimum load current requirement, Linear Technology recommends choosing resistor divider values to satisfy this requirement. A 200 R1 value sets a 1mA resistor divider current. In shutdown, the output is off and the divider current is zero. Curves of ADJ Pin Voltage vs Temperature and ADJ Pin Bias Current vs Temperature appear in the Typical Performance Characteristics section. Specifications for output voltages greater than 200mV are proportional to the ratio of desired output voltage to 200mV (VOUT/200mV). For example, load regulation for an output current change of 1mA to 1A is typically 0.1mV at VADJ = 200mV. At VOUT = 1.5V, load regulation is: 1.5V * 0.1mV = 750 V 200mV
+
VIN IN SHDN GND OUT LT3022 ADJ R1
3022 F01
+
-
200mV BIAS CURRENT AND REFERENCE GENERATOR 213mV
+
-
Q3 CURRENT GAIN Q1 PGND 10, 11 D2 OUT 3, 4
ERROR AMP
Q2
R2 ADJ R1 AGND 6, 7
3022 BD
25k NOTE: R1 AND R2 ARE EXTERNAL TIE PGND, AGND AND THE EXPOSED PAD TOGETHER
5
VOUT R2
VOUT: 200mV * (1 + R2/R1) - (IADJ * R2) VADJ: 200mV IADJ: 30nA AT 25C OUTPUT RANGE: 0.2V TO 9.5V
Figure 1. Adjustable Operation
3022f
LT3022 applicaTions inForMaTion
Table 1 shows 1% resistor divider values for some common output voltages with a resistor divider current equaling or about 1mA.
Table 1
VOUT (V) 0.9 1.0 1.2 1.5 1.8 2.5 3.3 R1 () 200 187 200 200 187 187 200 R2 () 698 750 1000 1300 1500 2150 3090
20 0 CHANGE IN VALUE (%) -20 -40 -60 -80 -100 BOTH CAPACITORS ARE 16V, 1210 CASE SIZE, 10F X5R
Y5V
0
2
4
8 6 10 12 DC BIAS VOLTAGE (V)
14
16
3022 F02
Figure 2. Ceramic Capacitor DC Bias Characteristics
Output Capacitance and Transient Response The LT3022's design is stable with a wide range of output capacitors, but is optimized for low ESR ceramic capacitors. The output capacitor's ESR affects stability, most notably with small value capacitors. Use a minimum output capacitor of 10F with an ESR of less than 0.1 to prevent oscillations. The LT3022 is a low voltage device and output load transient response is a function of output capacitance. Larger values of output capacitance decrease the peak deviations and provide improved transient response for large load current changes. Ceramic capacitors require extra consideration. Manufacturers make ceramic capacitors with a variety of dielectrics; each with a different behavior across temperature and applied voltage. The most common dielectrics are Z5U, Y5V, X5R and X7R. Z5U and Y5V dielectrics provide high C-V products in a small package at low cost, but exhibit strong voltage and temperature coefficients. X5R and X7R dielectrics yield highly stable characteristics and are more suitable for use as the output capacitor at fractionally increased cost. X5R and X7R dielectrics both exhibit excellent voltage coefficient characteristics. X7R works over a larger temperature range and exhibits better temperature stability whereas X5R is less expensive and is available in higher values. Figures 2 and 3 show voltage coefficient and temperature coefficient comparisons between Y5V and X5R material.
40 20 CHANGE IN VALUE (%) 0 -20 -40 -60 -80 Y5V X5R
BOTH CAPACITORS ARE 16V, 1210 CASE SIZE, 10F -100 50 25 75 -50 -25 0 TEMPERATURE (C)
100
125
3022 F03
Figure 3. Ceramic Capacitor Temperature Characteristics
Voltage and temperature coefficients are not the only sources of problems. Some ceramic capacitors have a piezoelectric response. A piezoelectric device generates voltage across its terminals due to mechanical stress, similar to the way a piezoelectric accelerometer or microphone works. For a ceramic capacitor, the stress can be induced by vibrations in the system or thermal transients. The resulting voltages produced can cause appreciable amounts of noise. A ceramic capacitor produced Figure 4's trace in response to light tapping from a pencil. Similar vibration induced behavior can masquerade as increased output voltage noise.
3022f
0
LT3022 applicaTions inForMaTion
If external circuitry forces the output above the no-load recovery circuit's threshold, the current sink turns on in an attempt to restore the output voltage to nominal. The current sink remains on until the external circuitry releases the output. However, if the external circuitry pulls the output voltage above the input voltage or the input falls below the output, the LT3022 turns the current sink off and shuts down the bias current/reference generator circuitry.
VOUT = 1.3V COUT = 10F ILOAD = 0 1ms/DIV
3022 F04
1mV/DIV
Thermal Considerations The LT3022's maximum rated junction temperature of 125C limits its power handling capability. Two components comprise the power dissipation of the device: 1. Output current multiplied by the input-to-output voltage differential: (ILOAD) * (VIN - VOUT) and 2. GND pin current multiplied by the input voltage: (IGND) * (VIN) GND pin current is found by examining the GND pin current curves in the Typical Performance Characteristics. Power dissipation equals the sum of the two components listed. The LT3022's internal thermal limiting (with hysteresis) protects the device during overload conditions. For normal continuous conditions, do not exceed the maximum junction temperature rating of 125C. Carefully consider all sources of thermal resistance from junction to ambient including other heat sources mounted in proximity to the LT3022. The underside of the LT3022 DHC and MSE packages has exposed metal from the lead frame to the die attachment. Heat transfers directly from the die junction to the printed circuit board metal, allowing maximum junction temperature control. The dual-in-line pin arrangement allows metal to extend beyond the ends of the package on the topside (component side) of a PCB. Connect this metal to GND on the PCB. The multiple IN and OUT pins of the LT3022 also assist in spreading heat to the PCB. Copper board stiffeners and plated throughholes can also be used to spread the heat generated by power devices.
Figure 4. Noise Resulting from Tapping on a Ceramic Capacitor
No-Load/Light-Load Recovery A possible transient load step that occurs is where the output current changes from its maximum level to zero current or a very small load current. The output voltage responds by overshooting until the regulator lowers the amount of current it delivers to the new level. The regulator loop response time and the amount of output capacitance control the amount of overshoot. Once the regulator has decreased its output current, the current provided by the resistor divider (which sets VOUT) is the only current remaining to discharge the output capacitor from the level to which it overshot. The amount of time it takes for the output voltage to recover easily extends to milliseconds with minimum divider current and many microfarads of output capacitance. To eliminate this problem, the LT3022 incorporates a no-load or light load recovery circuit. This circuit is a voltage-controlled current sink that significantly improves the light load transient response time by discharging the output capacitor quickly and then turning off. The current sink turns on when the output voltage exceeds 6.5% of the nominal output voltage. The current sink level is then proportional to the overdrive above the threshold up to a maximum of about 24mA. Consult the curve in the Typical Performance Characteristics for the No-Load Recovery Threshold.
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LT3022 applicaTions inForMaTion
The following tables list thermal resistance as a function of copper area in a fixed board size. All measurements are taken in still air on a 4-layer FR-4 board with 1oz solid internal planes, and 2oz external trace planes with a total board thickness of 1.6mm. For more information on thermal resistance and high thermal conductivity test boards, refer to JEDEC standard JESD51, notably JESD51-12 and JESD51-7. Achieving low thermal resistance necessitates attention to detail and careful PCB layout.
Table 2. Measured Thermal Resistance for DHC Package
COPPER AREA TOPSIDE* 2500mm2 1000mm2 225mm2 100mm2 BACKSIDE 2500mm2 2500mm2 2500mm2 2500mm2 BOARD AREA 2500mm2 2500mm2 2500mm2 2500mm2 THERMAL RESISTANCE (JUNCTION-TO-AMBIENT) 35C/W 37C/W 38C/W 40C/W
The thermal resistance is about 38C/W depending on the copper area. So the junction temperature rise above ambient is approximately equal to: 0.434W * (38C/W) = 16.5C The maximum junction temperature equals the maximum junction temperature rise above ambient plus the maximum ambient temperature or: TJMAX = 85C + 16.5C = 101.5C Protection Features The LT3022 incorporates several protection features that make it ideal for use in battery-powered circuits. In addition to the normal protection features associated with monolithic regulators, such as current limiting and thermal limiting, the device also protects against reverse-input voltages, reverse-output voltages and reverse output-toinput voltages. Current limit protection and thermal overload protection protect the device against current overload conditions at its output. For normal operation, do not exceed 125C junction temperature. The typical thermal shutdown temperature is 165C and the thermal shutdown circuit incorporates about 7C of hysteresis. The IN pins withstand reverse voltages of 10V. The LT3022 limits current flow to less than 1A and no negative voltage appears at OUT . The device protects both itself and the load against batteries that are plugged in backwards. The LT3022 incurs no damage if OUT is pulled below ground. If IN is left open-circuited or grounded, OUT can be pulled below ground by 10V. No current flows from the pass transistor connected to OUT. However, current flows in (but is limited by) the resistor divider that sets the output voltage. Current flows from the bottom resistor in the divider and from the ADJ pin's internal clamp through the top resistor in the divider to the external circuitry pulling OUT below ground. If IN is powered by a voltage source, OUT sources current equal to its current limit capability and the LT3022 protects itself by thermal limiting. In this case, grounding SHDN turns off the LT3022 and stops OUT from sourcing current.
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*Device is mounted on topside
Table 3. Measured Thermal Resistance for MSE Package
COPPER AREA TOPSIDE* 2500mm2 1000mm2 225mm2 100mm2 BACKSIDE 2500mm2 2500mm2 2500mm2 2500mm2 BOARD AREA 2500mm2 2500mm2 2500mm2 2500mm2 THERMAL RESISTANCE (JUNCTION-TO-AMBIENT) 35C/W 37C/W 38C/W 40C/W
*Device is mounted on topside.
Calculating Junction Temperature Example: Given an output voltage of 1.5V, an input voltage range of 1.7V to 1.9V, an output load current range of 1mA to 1A and a maximum ambient temperature of 85C, what is the maximum junction temperature for an application using the DHC package? The power dissipated by the device equals: ILOAD(MAX) * (VIN(MAX) - VOUT) + IGND * (VIN(MAX)) where: ILOAD(MAX) = 1A VIN(MAX) = 1.9V IGND at (ILOAD = 1A, VIN = 1.9V) = 18mA so: P = 1A * (1.9V - 1.5V) + 18mA * (1.9V) = 0.434W
LT3022 applicaTions inForMaTion
The LT3022 incurs no damage if the ADJ pin is pulled above or below ground by 10V. If IN is left open-circuited or grounded and ADJ is pulled above ground, ADJ acts like a 25k resistor in series with two diodes. ADJ acts like a 25k resistor if pulled below ground. If IN is powered by a voltage source and ADJ is pulled below its reference voltage, the LT3022 attempts to source its current limit capability at OUT. The output voltage increases to VIN - VDROPOUT with VDROPOUT set by whatever load current the LT3022 supports. This condition can potentially damage external circuitry powered by the LT3022 if the output voltage increases to an unregulated high voltage. If IN is powered by a voltage source and ADJ is pulled above its reference voltage, two situations can occur. If ADJ is pulled slightly above its reference voltage, the LT3022 turns off the pass transistor, no output current is sourced and the output voltage decreases to either the voltage at ADJ or less. If ADJ is pulled above its no-load recovery threshold, the no-load recovery circuitry turns on and attempts to sink current. OUT is actively pulled low and the output voltage clamps at a Schottky diode above ground. Please note that the behavior described above applies to the LT3022 only. If a resistor divider is connected under the same conditions, there will be additional V/R current. In circuits where a backup battery is required, several different input/output conditions can occur. The output voltage may be held up while the input is either pulled to ground, pulled to some intermediate voltage or is left open circuit. In the case where the input is grounded, there is less than 1A of reverse output current. If the LT3022 IN pin is forced below the OUT pin or the OUT pin is pulled above the IN pin, input current drops to less than 10A typically. This occurs if the LT3022 input is connected to a discharged (low voltage) battery and either a backup battery or a second regulator circuit holds up the output. The state of the SHDN pin has no effect on the reverse output current if OUT is pulled above IN. Input Capacitance and Stability The LT3022 design is stable with a minimum of 10F capacitor placed at the IN pin. Very low ESR ceramic capacitors may be used. However, in cases where long wires connect the power supply to the LT3022's input and ground, use of low value input capacitors combined with an output load current of greater than 20mA may result in instability. The resonant LC tank circuit formed by the wire inductance and the input capacitor is the cause and not a result of LT3022 instability. The self-inductance, or isolated inductance, of a wire is directly proportional to its length. However, the wire diameter has less influence on its self inductance. For example, the self-inductance of a 2-AWG isolated wire with a diameter of 0.26" is about half the inductance of a 30-AWG wire with a diameter of 0.01". One foot of 30-AWG wire has 465nH of self-inductance. Several methods exist to reduce a wire's self-inductance. One method divides the current flowing towards the LT3022 between two parallel conductors. In this case, placing the wires further apart reduces the inductance; up to a 50% reduction when placed only a few inches apart. Splitting the wires connects two equal inductors in parallel. However, when placed in close proximity to each other, mutual inductance adds to the overall self inductance of the wires. The most effective technique to reducing overall inductance is to place the forward and return current conductors (the input wire and the ground wire) in close proximity. Two 30-AWG wires separated by 0.02" reduce the overall self-inductance to about one-fifth of a single wire. If a battery, mounted in close proximity, powers the LT3022, a 10F input capacitor suffices for stability. However, if a distantly located supply powers the LT3022, use a larger value input capacitor. Use a rough guideline of 1F (in addition to the 10F minimum) per 8 inches of wire length. The minimum input capacitance needed to stabilize the application also varies with power supply output impedance variations. Placing additional capacitance on the LT3022's output also helps. However, this requires an order of magnitude more capacitance in comparison with additional LT3022 input bypassing. Series resistance between the supply and the LT3022 input also helps stabilize the application; as little as 0.1 to 0.5 suffices. This impedance dampens the LC tank circuit at the expense of dropout voltage. A better alternative is to use higher ESR tantalum or electrolytic capacitors at the LT3022 input in place of ceramic capacitors.
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LT3022 package DescripTion
DHC Package 16-Lead Plastic DFN (5mm x 3mm)
(Reference LTC DWG # 05-08-1706)
0.65 0.05 3.50 0.05
1.65 0.05 2.20 0.05 (2 SIDES) PACKAGE OUTLINE 0.25 0.05 0.50 BSC 4.40 0.05 (2 SIDES) RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS 5.00 0.10 (2 SIDES) R = 0.20 TYP 3.00 0.10 (2 SIDES) PIN 1 TOP MARK (SEE NOTE 6) 8 0.200 REF 0.75 0.05 4.40 0.10 (2 SIDES) BOTTOM VIEW--EXPOSED PAD 1 0.25 0.05 0.50 BSC 1.65 0.10 (2 SIDES) PIN 1 NOTCH
(DHC16) DFN 1103
9
R = 0.115 TYP
0.40 16
0.10
0.00 - 0.05
NOTE: 1. DRAWING PROPOSED TO BE MADE VARIATION OF VERSION (WJED-1) IN JEDEC PACKAGE OUTLINE MO-229 2. DRAWING NOT TO SCALE 3. ALL DIMENSIONS ARE IN MILLIMETERS 4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE 5. EXPOSED PAD SHALL BE SOLDER PLATED 6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE TOP AND BOTTOM OF PACKAGE
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LT3022 package DescripTion
MSE Package 16-Lead Plastic MSOP Exposed Die Pad ,
(Reference LTC DWG # 05-08-1667 Rev A)
BOTTOM VIEW OF EXPOSED PAD OPTION 2.845 (.112 0.102 .004)
0.889 (.035
0.127 .005)
2.845 (.112 1
0.102 .004) 8 0.35 REF
5.23 (.206) MIN
1.651 (.065
0.102 3.20 - 3.45 .004) (.126 - .136)
0.305 0.038 (.0120 .0015) TYP
0.50 (.0197) BSC
16 4.039 0.102 (.159 .004) (NOTE 3)
DETAIL "B" CORNER TAIL IS PART OF DETAIL "B" THE LEADFRAME FEATURE. FOR REFERENCE ONLY 9 NO MEASUREMENT PURPOSE 0.280 0.076 (.011 .003) REF
1.651 (.065
0.102 .004)
0.12 REF
RECOMMENDED SOLDER PAD LAYOUT
DETAIL "A" 0 - 6 TYP
16151413121110 9
0.254 (.010)
GAUGE PLANE
4.90 0.152 (.193 .006)
3.00 0.102 (.118 .004) (NOTE 4)
0.53 0.152 (.021 .006)
DETAIL "A"
0.18 (.007)
1.10 (.043) MAX
12345678
0.86 (.034) REF
SEATING PLANE
NOTE: 1. DIMENSIONS IN MILLIMETER/(INCH) 2. DRAWING NOT TO SCALE 3. DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.152mm (.006") PER SIDE 4. DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS. INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.152mm (.006") PER SIDE 5. LEAD COPLANARITY (BOTTOM OF LEADS AFTER FORMING) SHALL BE 0.102mm (.004") MAX
0.17 - 0.27 (.007 - .011) TYP
0.50 (.0197) BSC
0.1016 (.004
0.0508 .002)
MSOP (MSE16) 0608 REV A
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Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
LT3022 Typical applicaTion
1.5V to 1.2V, 1A VLDO Regulator
VIN 1.5V IN 10F SHDN GND OUT LT3022 ADJ VOUT 1.2V 10F 1A 1k 1% 200 1%
3022 TA02
relaTeD parTs
PART NUMBER LT3020 DESCRIPTION 100mA, Low Voltage VLDO Linear Regulator COMMENTS VIN: 0.9V to 10V, VOUT : 0.2V to 9.5V, VDO = 0.15V, IQ = 120A, Noise: <250VRMS, Stable with 2.2F Ceramic Capacitors, DFN-8, MS8 Packages VIN: 0.9V to 10V, Dropout Voltage: 160mV Typical, Adjustable Output (VREF = VOUT(MIN) = 200mV), Fixed Output Voltages: 1.2V, 1.5V, 1.8V, Stable with Low ESR, Ceramic Output Capacitors, 16-Pin DFN (5mm x 5mm) and 8-Lead SO Packages VIN = 0.9V to 5.5V, Dropout Voltage: 45mV, Low Noise 80VRMS, Low IQ: 54A, 2mm x 2mm 6-Lead DFN Package VIN = 0.9V to 5.5V, Dropout Voltage: 75mV, Low Noise 80VRMS, Low IQ: 54A, Fixed Output: 1.2V (LTC3025-2), 1.5V (LTC3025-3), 1.8V (LTC3025-4); Adjustable Output Range: 0.4V to 3.6V (LTC3025-1), 2mm x 2mm 6-Lead DFN Package VIN: 1.14V to 3.5V (Boost Enabled), 1.14V to 5.5V (with External 5V), VDO = 0.1V, IQ = 950A, Stable with 10F Ceramic Capacitors, 10-Lead MSOP and DFN-10 Packages Output Current: 500mA per Channel, Low Dropout Voltage: 300mV Low Noise: 20VRMS (10Hz to 100kHz), Low Quiescent Current: 55A per Channel, Wide Input Voltage Range: 1.8V to 20V (Common or Independent Input Supply), Adjustable Output: 1.215V Reference, Very Low Quiescent Current in Shutdown: <1A per Channel Stable with 3.3F Minimum Output Capacitor, Stable with Ceramic, Tantalum or Aluminum Electrolytic Capacitors, ReverseBattery, Reverse-Output and Reverse Output-to-Input Protection, Thermally Enhanced 16-Lead MSOP and 16-Lead (4mm x 3mm) DFN Packages VIN = 1.7V to 5.5V, VOUT : 0.4V to 3.6V, Dropout Voltage: 45mV, IQ: 100A, 3mm x 2mm DFN-8 300mV Dropout Voltage (2-Supply Operation), Low Noise: 40VRMS, VIN: 1.2V to 36V, VOUT : 0V to 35.7V, Current-Based Reference with 1-Resistor VOUT Set; Directly Parallelable (No Op Amp Required), Stable with Ceramic Capacitors, TO-220, SOT-223, MSOP-8 and 3mm x 3mm DFN-8 Packages; LT3080-1 Has Integrated Internal Ballast Resistor 275mV Dropout Voltage (2-Supply Operation), Low Noise: 40VRMS, VIN: 1.2V to 36V, VOUT : 0V to 35.7V, Current-Based Reference with 1-Resistor VOUT Set; Directly Parallelable (No Op Amp Required), Stable with Ceramic Capacitors, MSOP-8 and 2mm x 3mm DFN-6 packages
LT3021
500mA, Low Voltage, VLDO Linear Regulator
LTC(R)3025 LTC3025-1/LTC3025-2/ LTC3025-3/LTC3025-4
300mA Micropower VLDO Linear Regulator 500mA Micropower VLDO Linear Regulator in 2mm x 2mm DFN
LTC3026
1.5A, Low Input Voltage VLDO Linear Regulator
LT3029
Dual 500mA/500mA, Low Dropout, Low Noise, Micropower Linear Regulator
LTC3035 LT3080/LT3080-1
300mA VLDO Linear Regulator with Charge Pump Bias Generator 1.1A, Parallelable, Low Noise, Low Dropout Linear Regulator
LT3085
500mA, Parallelable, Low Noise, Low Dropout Linear Regulator
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Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 FAX: (408) 434-0507
LT 0410 * PRINTED IN USA
www.linear.com
LINEAR TECHNOLOGY CORPORATION 2010

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