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Preliminary
RT9166/A
300/500mA, Ultra-Fast Transient Response LDO Regulator
General Description
The RT9166/A series are CMOS low dropout regulators optimized for ultra-fast transient response. The devices are capable of supplying 300mA or 500mA of output current with a dropout voltage of 230mV or 430mV respectively. The RT9166/A's performance is optimized for CD/DVD-ROM, CD/RW or wireless communication supply applications. The RT9166/A regulators are stable with output capacitors as low as 1F. The other features include ultra low dropout voltage, high output accuracy, current limiting protection, and high ripple rejection ratio. The devices are available in fixed output voltages range of 1.2V to 4.5V with 0.1V per step. The RT9166/A regulators are available in 3-lead SOT-23, SOT-89, SOT-223 and TO-92 packages.
Features
Low Quiescent Current (Typically 220A) Guaranteed 300/500mA Output Current Low Dropout Voltage: 230/430mV at 300/500mA Wide Operating Voltage Ranges: 3V~5.5V Ultra-Fast Transient Response Tight Load and Line Regulation Current Limiting Protection Thermal Shutdown Protection Only low-ESR Ceramic Capacitor Required for Stability Custom Voltage Available
Applications
CD/DVD-ROM, CD/RW Wireless LAN Card/Keyboard/Mouse Battery-Powered Equipment XDSL Router PCMCIA Card
Ordering Information
RT9166/APackage Type VL : SOT-23 X : SOT-89 XL : SOT-89 L type G : SOT-223 GL : SOT-223 L type Z : TO-92 Operating Temperature Range C: Commercial Standard Output Voltage 12 : 1.2V 13 : 1.3V : 45 : 4.5V 500mA Output Current 300mA Output Current
Marking Information
For marking information, contact our sales representative directly or through a RichTek distributor located in your area, otherwise visit our website for detail.
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RT9166/A
Pin Configurations
Part Number RT9166CVL (Plastic SOT-23)
1
Preliminary Typical Application Circuit
3
Pin Configurations
TOP VIEW 1. GND 2. VOUT 3. VIN TOP VIEW 1. VOUT 2. GND (TAB) 3. VIN TOP VIEW 1. GND 2. VIN (TAB) 3. VOUT TOP VIEW 1. VOUT 2. GND (TAB) 3. VIN TOP VIEW 1. GND 2. VIN (TAB) 3. VOUT TOP VIEW 1. VIN 2. GND 3. VOUT
VIN 1F C IN + _
RT9166/A
VIN GND VOUT VOUT + 1F _ C OUT
2
RT9166/ACG (Plastic SOT-223)
1 2 3
RT9166/ACGL (Plastic SOT-223)
1 2 3
RT9166/ACX (Plastic SOT-89)
1 2 3
Note: To prevent oscillation, a 1F minimum X7R or X5R ceramic is strongly recommended if ceramics are used as input/output capacitors. When using the Y5V ceramic, the minimum value of the input/output capacitance that can be used for stable over full operating temperature range is 3.3F. (see Application Information Section for further details)
Pin Description
Pin Name VIN VOUT GND Pin Function Supply Input Regulator Output Common Ground
RT9166/ACXL (Plastic SOT-89)
1 2 3
RT9166/ACZ (Plastic TO-92)
123
Function Block Diagram
VIN
VOUT
Current Limiting Sensor
Error Amp _+
Thermal Shutdown
1.2V Reference
GND
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Preliminary Absolute Maximum Ratings (Note 1)
Supply Input Voltage Power Dissipation, PD @ TA = 25C SOT-23 SOT-223 SOT-89 TO-92 Package Thermal Resistance SOT-23, JA SOT-223, JC SOT-223, JA SOT-89, JC SOT-89, JA TO-92, JA Lead Temperature (Soldering, 10 sec.) Junction Temperature Storage Temperature Range ESD Susceptibility (Note 2) HBM MM
RT9166/A
6.5V 0.25W 2W 0.5W 0.6W 250C/W 15C/W 60C/W 100C/W 180C/W 160C/W 260C 150C -65C to 150C 2kV 200V
Recommended Operating Conditions (Note 3)
Supply Input Voltage Junction Temperature Range 2.8V to 5.5V -40C to 125C
Electrical Characteristics
(VIN = VOUT + 1V or VIN = 2.8V whichever is greater, CIN = 1F, COUT = 1F, TA = 25C, unless otherwise specified) Parameter Output Voltage Accuracy Current Limit RT9166 RT9166A RT9166 RT9166A Symbol VOUT ILIM IQ VDROP VLINE VLOAD PSRR TSD TSD Test Conditions IOUT = 1mA RLOAD = 1 IOUT = 0mA IOUT = 300mA IOUT = 500mA VIN = (VOUT + 0.3V) to 5.5V, IOUT = 1mA 1mA < IOUT < 300mA 1mA < IOUT < 500mA f = 1kHz, COUT = 1F Min -1 300 500 ---------Typ ---220 230 430 0.2 15 25 -55 170 40 Max +3 --300 ---35 50 ---Units % mA A mV %/V mV dB C C
Quiescent Current (Note 6) Dropout Voltage (Note 4) Line Regulation Load Regulation (Note 5) Power Supply Rejection Rate Thermal Shutdown Temperature Thermal Shutdown Hysteresis
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RT9166/A
Preliminary
Note 1. Stresses beyond those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Note 2. Devices are ESD sensitive. Handling precaution recommended. The human body model is a 100pF capacitor discharged through a 1.5K resistor into each pin. Note 3. The device is not guaranteed to function outside its operating conditions. Note 4. Dropout voltage is defined as the input to output differential at which the output voltage drops 1% below its nominal value measured at 1V differential. Dropout voltage does not apply to some lower voltage versions since the dropout voltage limited by input voltage range limitations. Note 5. Regulation is measured at constant junction temperature by using a 20mS current pulse. Devices are tested for load regulation in the load range from 1mA to 300mA and 500mA respectively. Note 6. Quiescent, or ground current, is the difference between input and output currents. It is defined by IQ = IIN - IOUT under no load condition (IOUT = 0mA). The total current drawn from the supply is the sum of the load current plus the ground pin current.
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Preliminary Typical Operating Characteristics
Dropout Voltage vs. Output Current
600 500 400 300 200 100 0 0 100 200 300 400 500
RT9166/A
Power Supply Rejection Ratio
Dropout Voltage (mV)
VIN = 5V CIN = 1F COUT = 1F TJ = +25C
0
TJ = +125C
-10 -20 -30 -40 -50 -60
VIN = 5V CIN = 1F COUT = 1F
PSRR (dB)
TJ = -40C
100mA 1mA
10 10
100 100
1k 1000
10k 10000
100k 100000
1M 1000000
Output Current (mA)
Frequency (Hz)
100
Range of Stable ESR
Output Noise Signal (V)
VIN = 5V CIN = 1F 400 200 0 -200 -400
Output Noise
ILOAD = 100mA COUT = 1F
Output Capacitor ESR ()
10
COUT = 10F Unstable Region
1
0.1
Stable Region COUT = 1F
0.01 0 100 200 300 400 500
f = 10Hz to 100kHz
Output Current (mA)
Time: 1mS/Div
Current Limit vs. Input voltage
900
Current Limit vs. Input voltage
900
Current Limit (mA)
Current Limit (mA)
850
850
800
800
750
VIN = 5V CIN = 1F COUT = 1F RL = 0.5
3 3.5 4 4.5
750
700
RT9166-33CX
5 5.5
VIN = 5V CIN = 1F COUT = 1F RL = 0.5
3 3.5 4 4.5
RT9166-33CVL
5 5.5
700
Input voltage (V)
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RT9166/A
Current Limit vs. Temperature
900
Preliminary
Current Limit vs. Temperature
900
Current Limit (mA)
800
Current Limit (mA)
850
850
800
750
VIN = 5V CIN = 1F COUT = 1F RL = 0.5
-25 0 25 50
750
700 -50 -40
RT9166-33CX
75 100 125
Temperature (C)
700 -40 -50
VIN = 5V CIN = 1F COUT = 1F RL = 0.5
-25 0 25 50
RT9166-33CVL
75 100 125
Temperature (C)
Quiescent Current vs. Temperature
260 240 220 200 180 160
Quiescent Current vs. Temperature
260 240 220 200 180 160
(A) Quiescent Current (uA)1
VIN = 5V CIN = 1F COUT = 1F
-25 0 25 50
(A) Quiescent Current (uA)1
140 -40 -50
RT9166-33CX
75 100 125
140 -40 -50
VIN = 5V CIN = 1F COUT = 1F
-25 0 25 50
RT9166-33CVL
75 100 125
Temperature (C)
Temperature (C)
Temperature Stability
3.4
Temperature Stability
3.4
Output Voltage (V)
3.3
Output Voltage (V)
VIN = 5V CIN = 1F COUT = 1F
-25 0 25 50
3.35
3.35
3.3
3.25
3.25
3.2 -40 -50
RT9166-33CX
75 100 125
3.2
VIN = 5V CIN = 1F COUT = 1F
-25 0 25 50
RT9166-33CVL
75 100 125
-50 -40
Temperature (C)
Temperature (C)
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Preliminary
RT9166/A
Load Transient Response Load Current (mA) Load Current (mA)
VIN = 5V ILOAD = 1 to 150mA CIN = COUT = 1F (Ceramic, X7R) 200 100 0
Load Transient Response
VIN = 5V ILOAD = 1 to 150mA 200 CIN = COUT = 1F (Ceramic, X7R) 100 0
Output Voltage Deviation (mV)
20 0 -20 RT9166-33CX
Output Voltage Deviation (mV)
20 0 RT9166-33CVL
-20
Time: 100S/Div Line Transient Response Input Voltage Deviation (V)
VIN = 4 to 5V CIN = 1F COUT = 1F
Time: 100S/Div
5 4
Output Voltage Deviation (mV)
20 0 -20
Time: 1mS/Div
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RT9166/A
Application Information
Preliminary
NO LOAD STABILITY The device will remain stable and in regulation with no external load. This is specially important in CMOS RAM keep-alive applications. INPUT-OUTPUT (DROPOUT) VOLTAGE A regulator's minimum input-to-output voltage differential (dropout voltage) determines the lowest usable supply voltage. In battery-powered systems, this determines the useful end-of-life battery voltage. Because the device uses a PMOS, its dropout voltage is a function of drain-to-source on-resistance, RDS(ON), multiplied by the load current: VDROUPOUT = VIN - VOUT = RDS(ON) x IOUT CURRENT LIMIT The RT9166/A monitors and controls the PMOS' gate voltage, minimum limiting the output current to 300mA for RT9166 and 500mA for RT9166A. The output can be shorted to ground for an indefinite period of time without damaging the part. SHORT-CIRCUIT PROTECTION The device is short circuit protected and in the event of a peak over-current condition, the short-circuit control loop will rapidly drive the output PMOS pass element off. Once the power pass element shuts down, the control loop will rapidly cycle the output on and off until the average power dissipation causes the thermal shutdown circuit to respond to servo the on/off cycling to a lower frequency. Please refer to the section on thermal information for power dissipation calculations. CAPACITOR CHARACTERISTICS It is important to note that capacitance tolerance and variation with temperature must be taken into consideration when selecting a capacitor so that the minimum required amount of capacitance is provided over the full operating temperature range. In general, a good tantalum capacitor will show very little capacitance variation with temperature, but a ceramic may not be as good (depending on dielectric type).
Like any low-dropout regulator, the RT9166/A series requires input and output decoupling capacitors. These capacitors must be correctly selected for good performance (see Capacitor Characteristics Section). Please note that linear regulators with a low dropout voltage have high internal loop gains which require care in guarding against oscillation caused by insufficient decoupling capacitance. INPUT CAPACITOR An input capacitance of 1F is required between the device input pin and ground directly (the amount of the capacitance may be increased without limit). The input capacitor MUST be located less than 1 cm from the device to assure input stability (see PCB Layout Section). A lower ESR capacitor allows the use of less capacitance, while higher ESR type (like aluminum electrolytic) require more capacitance. Capacitor types (aluminum, ceramic and tantalum) can be mixed in parallel, but the total equivalent input capacitance/ESR must be defined as above to stable operation. There are no requirements for the ESR on the input capacitor, but tolerance and temperature coefficient must be considered when selecting the capacitor to ensure the capacitance will be 1F over the entire operating temperature range. OUTPUT CAPACITOR The RT9166/A is designed specifically to work with very small ceramic output capacitors. The recommended minimum capacitance (temperature characteristics X7R or X5R) is 1F to 4.7F range with 10m to 50m range ceramic capacitor between LDO output and GND for transient stability, but it may be increased without limit. Higher capacitance values help to improve transient. The output capacitor's ESR is critical because it forms a zero to provide phase lead which is required for loop stability. (When using the Y5V dielectric, the minimum value of the input/output capacitance that can be used for stable over full operating temperature range is 3.3F.)
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Preliminary
Aluminum electrolytics also typically have large temperature variation of capacitance value. Equally important to consider is a capacitor's ESR change with temperature: this is not an issue with ceramics, as their ESR is extremely low. However, it is very important in Tantalum and aluminum electrolytic capacitors. Both show increasing ESR at colder temperatures, but the increase in aluminum electrolytic capacitors is so severe they may not be feasible for some applications. Ceramic: For values of capacitance in the 10F to 100F range, ceramics are usually larger and more costly than tantalums but give superior AC performance for by-passing high frequency noise because of very low ESR (typically less than 10m). However, some dielectric types do not have good capacitance characteristics as a function of voltage and temperature. Z5U and Y5V dielectric ceramics have capacitance that drops severely with applied voltage. A typical Z5U or Y5V capacitor can lose 60% of its rated capacitance with half of the rated voltage applied to it. The Z5U and Y5V also exhibit a severe temperature effect, losing more than 50% of nominal capacitance at high and low limits of the temperature range. X7R and X5R dielectric ceramic capacitors are strongly recommended if ceramics are used, as they typically maintain a capacitance range within 20% of nominal over full operating ratings of temperature and voltage. Of course, they are typically larger and more costly than Z5U/Y5U types for a given voltage and capacitance. Tantalum: Solid tantalum capacitors are recommended for use on the output because their typical ESR is very close to the ideal value required for loop compensation. They also work well as input capacitors if selected to meet the ESR requirements previously listed.
RT9166/A
Tantalums also have good temperature stability: a good quality tantalum will typically show a capacitance value that varies less than 10~15% across the full temperature range of 125C to -40C. ESR will vary only about 2X going from the high to low temperature limits. The increasing ESR at lower temperatures can cause oscillations when marginal quality capacitors are used (if the ESR of the capacitor is near the upper limit of the stability range at room temperature). Aluminum: This capacitor type offers the most capacitance for the money. The disadvantages are that they are larger in physical size, not widely available in surface mount, and have poor AC performance (especially at higher frequencies) due to higher ESR and ESL. Compared by size, the ESR of an aluminum electrolytic is higher than either Tantalum or ceramic, and it also varies greatly with temperature. A typical aluminum electrolytic can exhibit an ESR increase of as much as 50X when going from 25C down to -40C. It should also be noted that many aluminum electrolytics only specify impedance at a frequency of 120Hz, which indicates they have poor high frequency performance. Only aluminum electrolytics that have an impedance specified at a higher frequency (between 20kHz and 100kHz) should be used for the device. Derating must be applied to the manufacturer's ESR specification, since it is typically only valid at room temperature. Any applications using aluminum electrolytics should be thoroughly tested at the lowest ambient operating temperature where ESR is maximum.
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RT9166/A
THERMAL CONSIDERATIONS
Preliminary
It should be noted that stability problems have been seen in applications where "vias" to an internal ground plane were used at the ground points of the device and the input and output capacitors. This was caused by varying ground potentials at these nodes resulting from current flowing through the ground plane. Using a single point ground technique for the regulator and it's capacitors fixed the problem. Since high current flows through the traces going into VIN and coming from VOUT, Kelvin connect the capacitor leads to these pins so there is no voltage drop in series with the input and output capacitors. Optimum performance can only be achieved when the device is mounted on a PC board according to the diagram below:
The RT9166/A series can deliver a current of up to 300/500mA over the full operating junction temperature range. However, the maximum output current must be derated at higher ambient temperature to ensure the junction temperature does not exceed 125C. With all possible conditions, the junction temperature must be within the range specified under operating conditions. Power dissipation can be calculated based on the output current and the voltage drop across regulator. PD = (VIN - VOUT) IOUT + VIN IGND The final operating junction temperature for any set of conditions can be estimated by the following thermal equation: PD (MAX) = ( TJ (MAX) - TA ) / JA Where TJ (MAX) is the maximum junction temperature of the die (125C) and TA is the maximum ambient temperature. The junction to ambient thermal resistance (JA) for SOT-23 package at recommended minimum footprint is 250C/W, 180C/W for SOT-89 package, 60C/W for SOT-223 package (JA is layout dependent), and 160C/W for TO-92 package. Visit our website in which "Recommended Footprints for Soldering Surface Mount Packages" for detail. PCB LAYOUT Good board layout practices must be used or instability can be induced because of ground loops and voltage drops. The input and output capacitors MUST be directly connected to the input, output, and ground pins of the device using traces which have no other currents flowing through them. The best way to do this is to layout CIN and COUT near the device with short traces to the VIN, VOUT, and ground pins. The regulator ground pin should be connected to the external circuit ground so that the regulator and its capacitors have a "single point ground".
IN
GND
VOUT
SOT-23 Board Layout
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Preliminary Package Information
RT9166/A
D
H L
C
B
e
A A1 b
Symbol A A1 B b C D e H L
Dimensions In Millimeters Min 0.889 -1.397 0.356 2.591 2.692 1.803 0.102 0.356 Max 1.295 0.152 1.803 0.508 2.997 3.099 2.007 0.254 0.610
Dimensions In Inches Min 0.035 -0.055 0.014 0.102 0.106 0.071 0.004 0.014 Max 0.051 0.006 0.071 0.020 0.118 0.122 0.079 0.010 0.024
SOT-23 Plastic Surface Mount
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RT9166/A
Preliminary
D D1
A
C
B
C1 e e H A b b
b1
Symbol A b B b1 C C1 D D1 e H
Dimensions In Millimeters Min 1.397 0.356 2.388 0.406 -0.787 4.394 1.397 1.448 0.355 Max 1.600 0.483 2.591 0.533 4.242 1.194 4.597 1.753 1.549 0.432
Dimensions In Inches Min 0.055 0.014 0.094 0.016 -0.031 0.173 0.055 0.057 0.014 Max 0.063 0.019 0.102 0.021 0.167 0.047 0.181 0.069 0.061 0.017
3-Lead SOT-89 Surface Mount
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Preliminary
RT9166/A
D D1
H
C
B
L e e
A b
A1
Symbol A b B C D D1 e H L
Dimensions In Millimeters Min -0.610 3.302 6.706 6.299 2.896 2.261 0.229 0.914 Max 1.803 0.787 3.708 7.290 6.706 3.150 2.362 0.330 --
Dimensions In Inches Min -0.024 0.130 0.264 0.248 0.114 0.089 0.009 0.036 Max 0.071 0.031 0.146 0.287 0.264 0.124 0.093 0.013 --
3-Lead SOT-223 Plastic Surface Mount
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RT9166/A
Preliminary
D
A
E
L
e D1
b
C
A1
Symbol A A1 b C D D1 E e L
Dimensions In Millimeters Min 3.175 1.143 0.406 0.406 4.445 3.429 4.318 1.143 12.700 Max 4.191 1.372 0.533 0.533 5.207 -5.334 1.397 -3-Lead TO-92 Package
Dimensions In Inches Min 0.125 0.045 0.016 0.016 0.175 0.135 0.170 0.045 0.500 Max 0.165 0.054 0.021 0.021 0.205 -0.210 0.055 --
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Preliminary
RT9166/A
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RT9166/A
Preliminary
RICHTEK TECHNOLOGY CORP.
Headquarter
5F, No. 20, Taiyuen Street, Chupei City Hsinchu, Taiwan, R.O.C. Tel: (8863)5526789 Fax: (8863)5526611
RICHTEK TECHNOLOGY CORP.
Taipei Office (Marketing)
8F-1, No. 137, Lane 235, Paochiao Road, Hsintien City Taipei County, Taiwan, R.O.C. Tel: (8862)89191466 Fax: (8862)89191465 Email: marketing@richtek.com
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