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Global Mixed-mode Technology Inc.
G920
150mA Micro-power LDO Regulators
Features
Supply Current at No-Load is 55A Minimum Over-Current Limit: 150mA Dropout Voltage is 70mV @ 50mA Load Built-in Over-Temperature Protection Fixed: 3.3V Output Max. Supply Current in Shutdown Mode < 1A Output Noise is 210VRMS from 10Hz to 1MHz
General Description
The G920 is a low supply current, low dropout linear regulator that comes in a space saving SO-8 package. The supply current at no-load is 55A. In the shutdown mode, the maximum supply current is less than 1A. operating voltage range of the G920 is from 3.6V to 6.5V. The over-current protection limit is set at 250mA typical and 150mA minimum. An over-temperature protection circuit is built-in in the G920 to prevent thermal overload. These power saving features make the G920 ideal for use in the battery-powered applications such as notebook computers, cellular phones, and PDA's.
Applications
Notebook Computers Cellular Phones PDA Hand-Held Devices
Ordering Information
PART
G920
TEMP. RANGE
-40C~ +85C
PIN-PACKAGE
SOP- 8
Pin Configuration
Typical Operating Circuit
NC IN OUT EN
1 2
8 7
GND GND GND GND
VIN 5V CIN 1F
IN
OUT
VOUT 3.3V/150mA
G920
EN GND
G920
3 4 8 Pin SOP 6 5
COUT 1F
Fixed mode
Ver 0.0 Preliminary Mar 27, 2001
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Global Mixed-mode Technology Inc.
ABSOLUTE MAXIMUM RATINGS
VIN to GND.........................................-0.3V to +7V Output Short-Circuit Duration..........................Infinite ADJ to GND........................................-0.3V to +7V EN to GND.........................................-0.3V to +7V EN to IN.............................................-7V to +0.3V OUT to GND.............................-0.3V to (VIN + 0.3V) Continuous Power Dissipation (TA = +70C)
G920
SOT23-5 (derate 7.1mW/C above +70C)......571 mW Operating Temperature Range............-40C to +85C Junction Temperature..................................+150C JA......................................................140C/Watt Storage Temperature Range.............-65C to +160C Lead Temperature (soldering, 10sec)...............+300C
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.
Electrical Characteristics
(VIN = +3.6V, GND = 0V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C.) (Note 1) PARAMETER
Input Voltage (Note 2) Output Voltage Adjustable Output Voltage Range (Note 3) Maximum Output Current Current Limit (Note 4) Ground Pin Current
SYMBOL
VIN VOUT VOUT ILIM IQ ADJ = GND IOUT = 1mA
CONDITIONS
0mA IOUT 150mA, ADJ = GND
MIN
TYP MAX UNITS
V V V mA mA A
ILOAD = 0mA ILOAD = 50mA
3.6 6.5 3.234 3.300 3.366 VSET 6.5 150 250 55 120 145 2 70 230 0.1 0.011 0.006 210 190 2.8 120
Dropout Voltage (Note 5)
Line Regulation Load Regulation Output Voltage Noise SHUTDOWN EN Input Threshold EN Input Bias Current Shutdown Supply Current THERMAL PROTECTION Thermal Shutdown Temperature Thermal Shutdown Hysteresis
VLNR VLDR
IOUT = 50mA IOUT = 150mA VIN=2.5V to 6.5V, ADJ tied to OUT, IOUT = 1mA IOUT = 0mA to 150mA 10 Hz to 1MHz ADJ = GND ADJ tied to OUT COUT = 1F COUT = 100F
mV
%/V %/mA VRMS
VIH VIL IIH IIL
Regulator enabled Regulator shutdown VEN = VIN VOUT = 0V TA = +25C TA = TMAX TA = +25C TA = TMAX
3 5
0.4 100 1
V nA A
0.2 170 20
TSHDN TSHDN
C C
Note 1:Limits is 100% production tested at TA= +25C. Limits over the operating temperature range are guaranteed through correlation using Statistical Quality Control (SQC) Methods. Note 2:Guaranteed by line regulation test. Note 3:Adjustable mode only. Note 4:Not tested. For design purposes, the current limit should be considered 150mA minimum to 420mA maximum. Note 5:The dropout voltage is defined as (VIN - VOUT) when VOUT is 100mV below the value of VOUT for VIN = VOUT +2V.
Ver 0.0 Preliminary Mar 27, 2001
TEL: 886-3-5788833 http://www.gmt.com.tw
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Global Mixed-mode Technology Inc.
TYPICAL PERFORMANCE CHARACTERISTICS
(VIN=+3.6V, CIN=1F, COUT=1F, TA =25 C, unless otherwise noted.)
G920
Ground Current vs. Load Current
Ground Current vs. Load Current
210
Output Voltage vs. Load Current
Output voltage vs. Load Current
3.315
Ground Current ( A)
0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150
3.312
190 170 150 130 110 90 70 50
0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150
Output Voltage (V)
3.309 3.306 3.303 3.300 3.297 3.294 3.291
Load Current (mA)
Load Current (mA)
Output Voltage vs. Input Voltage
Output voltage vs. Load Current
3.5 3.0
Supply Current vs. Input Voltage
Supply Current vs. Input Voltage
130 120 110 100 90 80 70 60 50 40 30 20 10 0
0 1 2 3 4
ILOAD = 50mA
Output Voltage (V)
2.5 2.0 1.5 1.0 0.5 0.0 0 1 2 3 4
Supply Current ( A)
No Load
ILOAD = 0A
5
6
Input Voltage (V)
Input Voltage (V)
5
6
7
Dropout Voltage vs. Load Current
Dropout Voltage vs. Load Current
240 220 200 180 160 140 120 100 80 60 40 20 0
0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150
Output Noise 10HZ to 1MHZ
Dropout Voltage (mV)
Load Current (mA)
Ver 0.0 Preliminary Mar 27, 2001
TEL: 886-3-5788833 http://www.gmt.com.tw
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Global Mixed-mode Technology Inc.
TYPICAL PERFORMANCE CHARACTERISTICS (continue)
Line Transient
G920
Load Transient
Load Transient
Load Transient
Ver 0.0 Preliminary Mar 27, 2001
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Global Mixed-mode Technology Inc.
Pin Description
PIN
1 2 3 4 5,6,7,8
G920
FUNCTION
NAME
NC IN OUT EN GND
This is a NC pin, should be left unconnected. Regulator Input. Supply voltage can range from +2.5V to +6.5V. Bypass with 1F to GND. Regulator Output. Sources up to 150mA. Bypass with a 1F, 0.2 typical ESR capacitor to GND. Active-High Enable Input. A logic low reduces the supply current to less than 1A. Connect to IN for normal operation. Ground. This pin also functions as a heatsink. Solder to large pads or the circuit board ground plane to maximize thermal dissipation.
Detailed Description
The block diagram of the G920 is shown in Figure 1. It consists of an error amplifier, 1.25V bandgap reference, PMOS output transistor, internal feedback voltage divider, shutdown logic, over current protection circuit, and over temperature protection circuit. The internal feedback voltage divider's central tap is connected to the non-inverting input of the error amplifier. The error amplifier compares non-inverting input with the 1.25V bandgap reference. If the feedback voltage is higher than 1.25V, the error amplifier's output becomes higher so that the PMOS output transistor has a smaller gate-to-source voltage (VGS). This reduces the current carrying capability of the PMOS
output transistor, as a result the output voltage decreases until the feedback v41oltage is equal to 1.25V. Similarly, when the feedback voltage is less than 1.25V, the error amplifier causes the output PMOS to conductor more current to pull the feedback voltage up to 1.25V. Thus, through this feedback action, the error amplifier, output PMOS, and the voltage divider effectively form a unity-gain amplifier with the feedback voltage force to be the same as the 1.25V bandgap reference. The output voltage, VOUT, is then given by the following equation: VOUT = 1.25 (1 + R1/R2). (1) For the G920, the pre-set output voltage is 3.3V.
IN EN
SHUTDOWN LOGIC ERROR AMP OVER CURRENT PROTECT & DYNAMIC FEEDBACK
OUT
R1
OVER TEMP. PROTECT 1.25V Vref
R2 GND
Figure 1. Functional Diagram
Ver 0.0 Preliminary Mar 27, 2001
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Global Mixed-mode Technology Inc.
Over Current Protection The G920 use a current mirror to monitor the output current. A small portion of the PMOS output transistor's current is mirrored onto a resistor such that the voltage across this resistor is proportional to the output current. This voltage is compared against the 1.25V reference. Once the output current exceeds the limit, the PMOS output transistor is turned off. Once the output transistor is turned off, the current monitoring voltage decreases to zero, and the output PMOS is turned on again. If the over current condition persist, the over current protection circuit will be triggered again. Thus, when the output is shorted to ground, the output current will be alternating between 0 and the over current limit. The typical over current limit of the G920 is set to 250mA. Note that the input bypass capacitor of 1F must be used in this case to filter out the input voltage spike caused by the surge current due to the inductive effect of the package pin and the printed circuit board's routing wire. Otherwise, the actual voltage at the IN pin may exceed the absolute maximum rating. Dynamic Current Feedback The G920 is designed to work with both low and high ESR output capacitors. Since a PMOS transistor is used as the output transistor, an output capacitor greater than 1 F is needed to stabilize the feedback loop of the regulator. Due to the large value of the output capacitor, the dominant pole is the pole caused by the output node. The pole cause by the error amplifier's output node is the second pole. With a high ESR output capacitor, the zero caused by the ESR is typically near the second pole so that the second pole is cancelled by the zero, and the loop is stable. However, when the output capacitor has a low ESR, the zero will be much larger than the second pole. When the zero is near or larger than the unity-gain frequency, it can no longer cancel the phase shift caused by the second pole, and the loop becomes unstable. The G920 uses dynamic current feedback to stabilize the loop. The output impedence of the error amplifier is reduced when the output current increases. Thus, the second pole is pushed outward in accordance with the output current so that the second pole can be cancelled by the ESR's zero to maintain regulator stability. Over Temperature Protection To prevent abnormal temperature from occurring, the G920 has a built-in temperature monitoring circuit. When it detects the temperature is above 170oC, the output transistor is turned off. When the IC is cooled down to below 150oC, the output is turned on again. In this way, the G920 will be protected against abnormal junction temperature during operation. Shutdown Mode When the EN pin is connected a logic low voltage, the G920 enters shutdown mode. All the analog circuits are turned off completely, which reduces the current
Ver 0.0 Preliminary Mar 27, 2001
G920
consumption to only the leakage current. The output is disconnected from the input. When the output has no load at all, the output voltage will be discharged to ground through the internal resistor voltage divider. Operating Region and Power Dissipation Since the G920 is a linear regulator, its power dissipation is always given by P = IOUT (VIN - VOUT). The maximum power dissipation is given by: PMAX = (TJ - TA)/JA, Where (TJ - TA) is the temperature difference the G920 die and the ambient air, JA, is the thermal resistance of the chosen package to the ambient air. In the case of a SOT23-5 package, the thermal resistance is typically 140oC/Watt.
Applications Information
Capacitor Selection and Regulator Stability Normally, use a 1F capacitor on the input and a 1F capacitor on the output of the G920. Larger input capacitor values and lower ESR provide better supply-noise rejection and transient response. A higher-value input capacitor (10F) may be necessary if large, fast transients are anticipated and the device is located several inches from the power source. For stable operation over the full temperature range, with load currents up to 120mA, a minimum of 1F is recommended. Power-Supply Rejection and Operation from Sources Other than Batteries The G920 is designed to deliver low dropout voltages and low quiescent currents in battery powered systems. Power-supply rejection is 53dB at low frequencies as the frequency increases above 20kHz, the output capacitor is the major contributor to the rejection of power-supply noise. When operating from sources other than batteries, improve supply-noise rejection and transient response by increasing the values of the input and output capacitors, and using passive filtering techniques. Load Transient Considerations The G920 load-transient response graphs show two components of the output response: a DC shift of the output voltage due to the different load currents, and the transient response. Typical overshoot for step changes in the load current from 0mA to 100mA is 12mV. Increasing the output capacitor's value and decreasing its ESR attenuates transient spikes. Input-Output (Dropout) Voltage A regulator's minimum input-output voltage differential (or dropout voltage) determines the lowest usable supply voltage. In battery-powered systems, this will determine the useful end-of-life battery voltage. Because the G920 use a P-channel MOSFET pass transistor, their dropout voltage is a function of RDS(ON) multiplied by the load current.
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Global Mixed-mode Technology Inc.
Package Information
C
G920
E
H
L D 7 (4X)
A2 A1 e B
A
y
Note: 1. Package body sizes exclude mold flash and gate burrs 2. Dimension L is measured in gage plane 3. Tolerance 0.10mm unless otherwise specified 4. Controlling dimension is millimeter converted inch dimensions are not necessarily exact. SYMBOL
A A1 A2 B C D E e H L y
MIN.
1.35 0.10 ----0.33 0.19 4.80 3.80 ----5.80 0.40 ----0
DIMENSION IN MM NOM.
1.60 ----1.45 ----------------1.27 -----------------
MAX.
1.75 0.25 ----0.51 0.25 5.00 4.00 ----6.20 1.27 0.10 8
MIN.
0.053 0.004 ----0.013 0.007 0.189 0.150 ----0.228 0.016 ----0
DIMENSION IN INCH NOM.
0.063 ----0.057 ----------------0.050 -----------------
MAX.
0.069 0.010 ----0.020 0.010 0.197 0.157 ----0.244 0.050 0.004 8
Ver 0.0 Preliminary Mar 27, 2001
TEL: 886-3-5788833 http://www.gmt.com.tw
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