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MIC5255
Micrel
MIC5255
150mA Low Noise Cap CMOS LDO
General Description
The MIC5255 is an efficient, precise CMOS voltage regulator optimized for ultra-low-noise applications. It offers 1% initial accuracy, extremely-low dropout voltage (135mV at 150mA) and low ground current (typically 90A). The MIC5255 provides a very-low-noise output, ideal for RF applications where a clean voltage source is required. A noise bypass pin is also available for further reduction of output noise. Designed specifically for handheld and battery-powered devices, the MIC5255 provides a TTL-logic-compatible enable pin. When disabled, power consumption drops nearly to zero. The MIC5255 also works with low-ESR ceramic capacitors, reducing the amount of board space necessary for power applications, critical in handheld wireless devices. Key features include current limit, thermal shutdown, faster transient response, and an active clamp to speed up device turn-off. Available in the 6-pin 2mm x 2mm MLFTM package, the IttyBitty(R) SOT-23-5 package and the new Thin SOT-235, which offers the same footprint as the standard IttyBitty(R) SOT-23-5, but only 1mm tall. The MIC5255 offers a range of output voltages. All support documentation can be found on Micrel's web site at www.micrel.com.
Features
* * * * * * Input voltage range: 2.7V to 6.0V Thin SOT package: 1mm height SOT-23-5 Ultra-low output noise: 30V(rms) Stability with ceramic output capacitors Ultra-low dropout: 135mV @ 150mA High output accuracy: 1.0% initial accuracy 2.0% over temperature Low quiescent current: 90A Tight load and line regulation TTL-Logic-controlled enable input "Zero" off-mode current Thermal shutdown and current limit protection
* * * * *
Applications
* * * * * Cellular phones and pagers Cellular accessories Battery-powered equipment Laptop, notebook, and palmtop computers Consumer/personal electronics
Typical Application
MIC5255-x.xBM5
1 2 3 4 5
CIN = 1.0F Ceramic
Enable Shutdown
VIN
VOUT COUT = 1.0F Ceramic CBYP = 0.01F
ENABLE SHUTDOWN
VIN EN
MIC5255-x.xBML
1 2 3 6 5 4
VOUT CBYP
(optional)
COUT
EN
EN (pin 3) may be connected directly to IN (pin 1).
Ultra-Low-Noise Regulator Application
IttyBitty is a registered trademark of Micrel, Inc. MicroLeadFrame and MLF are trademarks of Amkor Technology. Micrel, Inc. * 1849 Fortune Drive * San Jose, CA 95131 * USA * tel + 1 (408) 944-0800 * fax + 1 (408) 474-1000* http://www.micrel.com
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Ordering Information
Standard Part Number Pb-Free MIC5255-2.5YM5 MIC5255-2.6YM5 MIC5255-2.7YM5 MIC5255-2.8YM5 MIC5255-2.8YML MIC5255-2.9YM5 MIC5255-3.0YM5 MIC5255-3.0YML MIC5255-3.1YM5 MIC5255-3.2YM5 MIC5255-3.3YM5 MIC5255-2.6YD5 MIC5255-2.7YD5 MIC5255-2.8YD5 MIC5255-2.9YD5 MIC5255-3.0YD5 MIC5255-3.3YD5 Marking Voltage Standard Pb-Free LW25 LW26 LW27 LW28 W28 LW2J LW29 LW30 W30 LW31 LW32 LW33 NW26 NW27 NW28 NW2J NW29 NW30 NW33 LW25 LW26 LW27 LW28 W28 LW2J LW29 LW30 W30 LW31 LW32 LW33 NW26 NW27 NW28 NW2J NW2J NW2J NW2J 2.5V 2.6V 2.7V 2.8V 2.8V 2.85V 2.9V 3.0V 3.0V 3.1V 3.2V 3.3V 2.6V 2.7V 2.8V 2.85V 2.9V 3.0V 3.3V Temperature Range -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C Package SOT-23-5 SOT-23-5 SOT-23-5 SOT-23-5 6-Pin 2x2 MLFTM SOT-23-5 SOT-23-5 SOT-23-5 6-Pin 2x2 MLFTM SOT-23-5 SOT-23-5 SOT-23-5 TSOT-23-5 TSOT-23-5 TSOT-23-5 TSOT-23-5 TSOT-23-5 TSOT-23-5 TSOT-23-5
MIC5255-2.5BM5 MIC5255-2.6BM5 MIC5255-2.7BM5 MIC5255-2.8BM5 MIC5255-2.8BML MIC5255-2.9BM5 MIC5255-3.0BM5 MIC5255-3.0BML MIC5255-3.1BM5 MIC5255-3.2BM5 MIC5255-3.3BM5 MIC5255-2.6BD5 MIC5255-2.7BD5 MIC5255-2.8BD5 MIC5255-2.9BD5 MIC5255-3.0BD5 MIC5255-3.3BD5
MIC5255-2.85BM5 MIC5255-2.85YM5
MIC5255-2.85BD5 MIC5255-2.85YD5
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Pin Configuration
EN GND IN
3 2 1
EN GND IN
3 2 1
EN GND IN
3 2 1
LWxx
4 5
KWxx
4 5 4
NWxx
5
BYP
OUT
BYP
OUT
BYP
OUT
MIC5255-x.xBM5 (SOT-23-5)
MIC5255-x.xYM5 (SOT-23-5)
MIC5255-x.xBD5 (TSOT-23-5)
EN 1 GND 2 IN 3
6 BYP 5 NC 4 OUT
MIC5255-x.xBML 6-Pin 2mm x 2mm MLFTM (ML) (Top View)
Pin Description
Pin Number SOT-23-5 TSOT-23-5 1 2 3 4 5 - - Pin Number 6-MLFTM 3 2 1 6 4 5 EP Pin Name Pin Function
IN GND EN BYP OUT NC GND
Supply Input. Ground. Enable/Shutdown (Input): CMOS compatible input. Logic high = enable; logic low = shutdown. Do not leave open. Reference Bypass: Connect external 0.01F CBYP 1.0F capacitor to GND to reduce output noise. May be left open. Regulator Output No internal connection. Ground: Internally connected to the exposed pad. Connect externally to GND pin.
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Absolute Maximum Ratings(1)
Supply Input Voltage (VIN) .................................. 0V to +7V Enable Input Voltage (VEN) ................................. 0V to +7V Power Dissipation (PD) ........................ Internally Limited(3) Junction Temperature (TJ) ....................... -40C to +125C Storage Temperature (TS) ....................... -65C to +150C Lead Temperature (soldering, 5 sec.) ....................... 260C ESD(4) .............................................................................................. 2kV Electrical Characteristics(5)
Symbol VO VLNR VLDR VIN - VOUT Parameter Output Voltage Accuracy Line Regulation Load Regulation Dropout Voltage(7) Conditions IOUT = 100A
Operating Ratings(2)
Input Voltage (VIN) ......................................... +2.7V to +6V Enable Input Voltage (VEN) .................................. 0V to VIN Junction Temperature (TJ) ....................... -40C to +125C Thermal Resistance SOT-23 (JA) .....................................................235C/W 2x2 MLFTM (JA) ..................................................90C/W
VIN = VOUT + 1V, VEN = VIN; IOUT = 100A; TJ = 25C, bold values indicate -40C TJ +125C; unless noted. Min -1 -2 0.02 1.5 0.1 90 135 0.2 90 117 60 60 50 160 425 30 Typical Max 1 2 0.05 2.5 5 150 200 250 1 150 Units % % %/V % mV mV mV mV A A A dB dB dB mA V(rms)
VIN = VOUT + 1V to 6V IOUT = 0.1mA to IOUT = 100A IOUT = 100mA IOUT = 150mA 150mA(6)
IQ IGND PSRR
Quiescent Current Ground Pin Current(8)
VEN 0.4V (shutdown) IOUT = 0mA IOUT = 150mA f = 10Hz, COUT = 1.0F, CBYP = 0.01F f = 100Hz, VIN = VOUT +1 f = 10kHz, VIN = VOUT +1
Ripple Rejection
ILIM en Enable Input VIL VIH IEN
Current Limit Output Voltage Noise
VOUT = 0V COUT = 1.0F, CBYP = 0.01F, f = 10Hz to 100kHz
Enable Input Logic-Low Voltage Enable Input Logic-High Voltage Enable Input Current
VIN = 2.7V to 5.5V, regulator shutdown VIN = 2.7V to 5.5V, regulator enabled VIL 0.4V, regulator shutdown VIH 1.6V, regulator enabled 1.6 0.01 0.01 500
0.4
V V A A C C
Shutdown Resistance Discharge Thermal Protection Thermal Shutdown Temperature Thermal Shutdown Hysteresis
150 10
Notes: 1. Exceeding the absolute maximum rating may damage the device. 2. The device is not guaranteed to function outside its operating rating. 3. The maximum allowable power dissipation of any TA (ambient temperature) is PD(max) = (TJ(max)-TA)/JA. Exceeding the maximum allowable power dissipation will result in excessive die temperature, and the regulator will go into thermal shutdown. The JA of the MIC5255-x.xBM5 (all versions) is 235C/W on a PC board. See "Thermal Considerations" section for further details. 4. Devices are ESD sensitive. Handling precautions recommended. 5. Specification for packaged product only. 6. Regulation is measured at constant junction temperature using low duty cycle pulse testing. Parts are tested for load regulation in the load range from 0.1mA to 150mA. Changes in output voltage due to heating effects are covered by the thermal regulation specification. 7. Dropout Voltage is defined as the input-to-output differential at which the output voltage drops 2% below its nominal value measured at 1V differential. For outputs below 2.7V, dropout voltage is the input-to-output voltage differential with the minimum input voltage 2.7V. Minimum input operating voltage is 2.7V. 8. Ground pin current is the regulator quiescent current. The total current drawn from the supply is the sum of the load current plus the ground pin current.
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Typical Characteristics
Power Supply Rejection Ratio
70 60 50
PSRR (dB)
PSRR (dB)
Power Supply Rejection Ratio
70 60 50
PSRR (dB)
Power Supply Rejection Ratio
70 60 50 0F* 0.01F* 0.1F* 1.0F*
40 30 20
100A* 50mA* 100mA* 150mA*
40 30 20
100A* 50mA* 100mA* 150mA*
40 30 20
*ILOAD 10 COUT = 1F Ceramic
10 10000 1000 1000000 100 100000
* ILOAD 10 COUT = 4.7F Ceramic
10 10000 1000 1000000 100 100000
10
10000
1000
FRQUENCY (Hz)
FRQUENCY (Hz)
FRQUENCY (Hz)
PSRR vs. Voltage Drop
70 60 50 PSRR (dB)
PSRR (dB)
PSRR vs. Voltage Drop
80 ILOAD = 100A
GROUND CURRENT (A)
Ground Pin Current
130 125 120 115 110 105 100 0.1 VIN = VOUT + 1V 1 10 100 1000 OUTPUT CURRENT (mA)
ILOAD = 100A
70 60 ILOAD = 150mA 50 40 30 20 COUT = 1F CBYP = 0 10 0 0
40 30 20 10 0 0
ILOAD = 150mA COUT = 1F CBYP = 0.01F 200 400 600 800 1000 VOLTAGE DROP (mV)
200 400 600 800 1000 VOLTAGE DROP (mV)
Ground Pin Current
115 125 GROUND CURRENT (A)
Ground Pin Current
140 GROUND CURRENT (A) 120 100 80 60 40 20 120 115 110 105 100 95 -40 -20 0 20 40 60 80 100120140 TEMPERATURE (C) ILOAD = 150mA
Ground Pin Current
GROUND CURRENT (A)
113 111 109 107 105 103 101 99 97 95 -40 -20 0 20 40 60 80 100120140 TEMPERATURE (C) ILOAD = 100A
ILOAD = 100A 0 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 INPUT VOLTAGE (V)
Ground Pin Current
140 3.5 OUTPUT VOLTAGE (V)
Dropout Characteristics
0.14 DROPOUT VOLTAGE (mV) 0.12 0.1 0.08 0.06 0.04 0.02 3 ILOAD = 100A 2.5 2 1.5 1 0.5 0 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 INPUT VOLTAGE (V) ILOAD = 150mA
Dropout Voltage
GROUND CURRENT (A)
120 100 80 60 40 20 ILOAD = 150mA 0 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 INPUT VOLTAGE (V)
I = 100A LOAD 0 -40 -20 0 20 40 60 80 100120140 TEMPERATURE (C)
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1000000
100
100000
0
0
* CBYP ILOAD = 50mA 10 VIN = VOUT + 0.5V = 1F Ceramic C 0 OUT
MIC5255
Micrel
ENABLE THRESHOLD VOLTAGE (V)
Short Circuit Current
SHORT CIRCUIT CURRENT (mA)
500 490 480 470 460 450 440 430 420 410 400 -40 -20 0 20 40 60 80 100120140 TEMPERATURE (C) VIN = VOUT + 1V 3.05
Output Voltage vs. Temperature
OUTPUT VOLTAGE (V)
3.04 3.03 3.02 3.01 3.00 2.99 2.98 2.97 2.96 ILOAD = 100A 2.95 -40 -20 0 20 40 60 80 100120140 TEMPERATURE (C)
Enable Threshold vs. Temperature
1.3 1.25 1.2 1.15 1.1 1.05 1 0.95 0.9 0.85 ILOAD = 100A 0.8 -40 -20 0 20 40 60 80 100120140 TEMPERATURE (C)
Turn-On Time vs. Bypass Capacitance
500 450 CIN = 1F Ceramic 400 COUT = 1F Ceramic = 100A I 350 LOAD
TIME (s)
300 250 200 150 100 50 Prop Delay 0 100
Rise Time
1000 10000 100000 1000000 BYPASS CAPACITANCE (pF)
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Functional Characteristics
Line Transient Response
Output Voltage (50mV/div)
Load Transient Response
Input Voltage (1V/div)
5V 4V
Output Voltage (50mV/div)
Output Current (100mA/div)
CIN = 1F Ceramic COUT = 1F Ceramic CBYP = 0.01F IOUT = 100A
CIN = 1F Ceramic COUT = 1F Ceramic CBYP = 0.01F VIN = 4V 150mA 100A
TIME (400s/div)
TIME (4s/div)
Enable Pin Delay
Enable Voltage (1V/div) Enable Voltage (1V/div)
Shutdown Delay
CIN = 1F Ceramic COUT = 1F Ceramic CBYP = 0.01F VIN = 4V
CIN = 1F Ceramic COUT = 1F Ceramic CBYP = 0.01F IOUT = 100A
Output Voltage (1V/div)
TIME (10s/div)
Output Voltage (1V/div)
TIME (400s/div)
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Block Diagram
IN Reference Voltage Startup/ Shutdown Control Quickstart/ Noise Cancellation BYP
EN
Thermal Sensor Undervoltage Lockout
FAULT
Error Amplifier
Current Amplifier
OUT
ACTIVE SHUTDOWN
GND
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No-Load Stability The MIC5255 will remain stable and in regulation with no load unlike many other voltage regulators. This is especially important in CMOS RAM keep-alive applications. Thermal Considerations The MIC5255 is designed to provide 150mA of continuous current in a very small package. Maximum power dissipation can be calculated based on the output current and the voltage drop across the part. To determine the maximum power dissipation of the package, use the junction-to-ambient thermal resistance of the device and the following basic equation: T (max) - TA PD (max) = J JA TJ(max) is the maximum junction temperature of the die, 125C, and TA is the ambient operating temperature. JA is layout dependent; Table 1 shows examples of junction-toambient thermal resistance for the MIC5255.
Package SOT-23-5 (M5 or D5) JA Recommended Minimum Footprint 235C/W JA 1" Square Copper Clad 185C/W JC 145C/W
Applications Information
Enable/Shutdown The MIC5255 comes with an active-high enable pin that allows the regulator to be disabled. Forcing the enable pin low disables the regulator and sends it into a "zero" off-modecurrent state. In this state, current consumed by the regulator goes nearly to zero. Forcing the enable pin high enables the output voltage. This part is CMOS and the enable pin cannot be left floating; a floating enable pin may cause an indeterminate state on the output. Input Capacitor The MIC5255 is a high performance, high bandwidth device. Therefore, it requires a well-bypassed input supply for optimal performance. A 1F capacitor is required from the input to ground to provide stability. Low-ESR ceramic capacitors provide optimal performance at a minimum of space. Additional high frequency capacitors, such as small valued NPO dielectric type capacitors, help filter out high frequency noise and are good practice in any RF-based circuit. Output Capacitor The MIC5255 requires an output capacitor for stability. The design requires 1F or greater on the output to maintain stability. The design is optimized for use with low-ESR ceramic chip capacitors. High ESR capacitors may cause high frequency oscillation. The maximum recommended ESR is 300m. The output capacitor can be increased, but performance has been optimized for a 1F ceramic output capacitor and does not improve significantly with larger capacitance. X7R/X5R dielectric-type ceramic capacitors are recommended because of their temperature performance. X7Rtype capacitors change capacitance by 15% over their operating temperature range and are the most stable type of ceramic capacitors. Z5U and Y5V dielectric capacitors change value by as much as 50% and 60%, respectively, over their operating temperature ranges. To use a ceramic chip capacitor with Y5V dielectric, the value must be much higher than an X7R ceramic capacitor to ensure the same minimum capacitance over the equivalent operating temperature range. Bypass Capacitor A capacitor can be placed from the noise bypass pin to ground to reduce output voltage noise. The capacitor bypasses the internal reference. A 0.01F capacitor is recommended for applications that require low-noise outputs. The bypass capacitor can be increased, further reducing noise and improving PSRR. Turn-on time increases slightly with respect to bypass capacitance. A unique quick-start circuit allows the MIC5255 to drive a large capacitor on the bypass pin without significantly slowing turn-on time. Refer to the "Typical Characteristics" section for performance with different bypass capacitors. Active Shutdown The MIC5255 also features an active shutdown clamp, which is an N-Channel MOSFET that turns on when the device is disabled. This allows the output capacitor and load to discharge, de-energizing the load. August, 2004 9
Table 1. SOT-23-5 Thermal Resistance The actual power dissipation of the regulator circuit can be determined using the equation: PD = (VIN - VOUT) IOUT + VIN IGND Substituting PD(max) for PD and solving for the operating conditions that are critical to the application will give the maximum operating conditions for the regulator circuit. For example, when operating the MIC5255-3.0BM5 at 50C with a minimum footprint layout, the maximum input voltage for a set output current can be determined as follows: 125C - 50C PD (max) = 235C/W PD(max) = 315mW The junction-to-ambient thermal resistance for the minimum footprint is 235C/W, from Table 1. The maximum power dissipation must not be exceeded for proper operation. Using the output voltage of 3.0V and an output current of 150mA, the maximum input voltage can be determined. Because this device is CMOS and the ground current is typically 100A over the load range, the power dissipation contributed by the ground current is < 1% and can be ignored for this calculation: 315mW = (VIN - 3.0V) 150mA 315mW = VIN x 150mA - 450mW 810mW = VIN x 150mA VIN(max) = 5.4V Therefore, a 3.0V application at 150mA of output current can accept a maximum input voltage of 5.4V in a SOT-23-5 package. For a full discussion of heat sinking and thermal effects on voltage regulators, refer to the "Regulator Thermals" section of Micrel's Designing with Low-Dropout Voltage Regulators handbook.
M0385-080204
MIC5255
Micrel
Package Information
1.90 (0.075) REF 0.95 (0.037) REF
1.75 (0.069) 1.50 (0.059)
3.00 (0.118) 2.60 (0.102)
DIMENSIONS: MM (INCH) 3.02 (0.119) 2.80 (0.110) 1.30 (0.051) 0.90 (0.035) 10 0 0.15 (0.006) 0.00 (0.000) 0.20 (0.008) 0.09 (0.004)
0.50 (0.020) 0.35 (0.014)
0.60 (0.024) 0.10 (0.004)
SOT-23-5 (M5)
4AL
TSOT-23-5 (D5)
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Package Information (continued)
TOP VIEW
BOTTOM VIEW
DIMENSIONS IN MILLIMETERS
SIDE VIEW
Rev. 02
6-Pin MLFTM (ML)
MICREL, INC. 1849 FORTUNE DRIVE SAN JOSE, CA 95131
TEL
USA
+ 1 (408) 944-0800
FAX
+ 1 (408) 944-0970
WEB
http://www.micrel.com
The information furnished by Micrel in this data sheet is believed to be accurate and reliable. However, no responsibility is assumed by Micrel for its use. Micrel reserves the right to change circuitry and specifications at any time without notification to the customer. Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a product can reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for surgical implant into the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significant injury to the user. A Purchaser's use or sale of Micrel Products for use in life support appliances, devices or systems is at Purchaser's own risk and Purchaser agrees to fully indemnify Micrel for any damages resulting from such use or sale. (c) 2004 Micrel, Incorporated.
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