Ver 0.0 Preliminary
Mar 27, 2001
TEL: 886-3-5788833
http://www.gmt.com.tw
1
G920
Global Mixed-mode Technology Inc.
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 210V
RMS
from 10Hz to 1MHz
Applications
Notebook Computers
Cellular Phones
PDA
Hand-Held Devices
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 shut-
down 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-tem-
perature protection circuit is built-in in the G920 to
prevent thermal overload. These power saving
features make the G920 ideal for use in the bat-
tery-powered applications such as notebook com-
puters, cellular phones, and PDA's.
Ordering Information
PART TEMP.
RANGE PIN-PACKAGE
G920
-40C~ +85C
SOP- 8
Pin Configuration
Typical Operating Circuit
GND
GND
8 Pin SOP
G920
8
5
1
NC
2
4
IN
EN
IN
OUT
GND
EN
G920
C
IN
1F
C
OUT
1
F
Fixed mode
3
GND
6
GND
7
OUT
V
IN
5V
V
OUT
3.3V/150mA
GND
GND
8 Pin SOP
G920
8
5
1
NC
2
4
IN
EN
IN
OUT
GND
EN
G920
C
IN
1F
C
OUT
1
F
Fixed mode
3
GND
6
GND
7
OUT
V
IN
5V
V
OUT
3.3V/150mA
Ver 0.0 Preliminary
Mar 27, 2001
TEL: 886-3-5788833
http://www.gmt.com.tw
2
G920
Global Mixed-mode Technology Inc.
ABSOLUTE MAXIMUM RATINGS
V
IN
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 (V
IN
+ 0.3V)
Continuous Power Dissipation (T
A
= +70C)
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 rat-
ings 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
(V
IN
= +3.6V, GND = 0V, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25C.) (Note 1)
PARAMETER SYMBOL CONDITIONS MIN
TYP
MAX
UNITS
Input Voltage (Note 2)
V
IN
3.6
6.5
V
Output Voltage
V
OUT
0mA
I
OUT
150mA, ADJ = GND
3.234 3.300 3.366
V
Adjustable Output Voltage Range (Note 3)
V
OUT
V
SET
6.5 V
Maximum Output Current
150
mA
Current Limit (Note 4)
I
LIM
250 mA
I
LOAD
= 0mA
55
120
Ground Pin Current
I
Q
ADJ = GND
I
LOAD
= 50mA
145
A
I
OUT
= 1mA
2
I
OUT
= 50mA
70
120
Dropout Voltage (Note 5)
I
OUT
= 150mA
230
mV
Line Regulation
V
LNR
V
IN
=2.5V to 6.5V, ADJ tied to OUT,
I
OUT
= 1mA
0.1 %/V
ADJ = GND
0.011
Load Regulation
V
LDR
I
OUT
= 0mA to 150mA
ADJ tied to OUT
0.006
%/mA
C
OUT
= 1F
210
Output Voltage Noise
10 Hz to 1MHz
C
OUT
= 100F
190
V
RMS
SHUTDOWN
V
IH
Regulator
enabled
2.8
EN Input Threshold
V
IL
Regulator
shutdown
0.4
V
T
A
= +25C
3
100
EN Input Bias Current
I
IH
V
EN
= V
IN
T
A
= T
MAX
5
nA
T
A
= +25C
1
Shutdown Supply Current
I
IL
V
OUT
= 0V
T
A
= T
MAX
0.2
A
THERMAL PROTECTION
Thermal Shutdown Temperature
T
SHDN
170 C
Thermal Shutdown Hysteresis
T
SHDN
20 C
Note 1:Limits is 100% production tested at T
A
= +25C. Limits over the operating temperature range are guar-
anteed 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 (V
IN
- V
OUT
) when V
OUT
is 100mV below the value of V
OUT
for V
IN
= V
OUT
+2V.
Ver 0.0 Preliminary
Mar 27, 2001
TEL: 886-3-5788833
http://www.gmt.com.tw
3
G920
Global Mixed-mode Technology Inc.
TYPICAL PERFORMANCE CHARACTERISTICS
(VIN=+3.6V, CIN=1F, COUT=1F, TA =25 C, unless otherwise noted.)
Dropout Voltage vs. Load Current
Output Noise 10HZ to 1MHZ
Output Voltage vs. Load Current
Ground Current vs. Load Current
Output Voltage vs. Input Voltage
Supply Current vs. Input Voltage
Ground Current vs. Load Current
50
70
90
110
130
150
170
190
210
0
10 20 30 40 50 60 70 80 90 100 110 120 130 140 150
Load Current (mA)
Ground Current (
A)
I
LOAD
= 0A
I
LOAD
= 50mA
Supply Current vs. Input Voltage
0
10
20
30
40
50
60
70
80
90
100
110
120
130
0
1
2
3
4
5
6
7
Input Voltage (V)
Supply Current (
A)
Dropout Voltage vs. Load Current
0
20
40
60
80
100
120
140
160
180
200
220
240
0
10 20 30 40 50 60 70 80 90 100 110 120 130 140 150
Load Current (mA)
Dropout Voltage (mV)
Output voltage vs. Load Current
3.291
3.294
3.297
3.300
3.303
3.306
3.309
3.312
3.315
0
10 20 30 40 50 60 70 80 90 100 110 120 130 140 150
Load Current (mA)
Output Voltage (V)
Output voltage vs. Load Current
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
0
1
2
3
4
5
6
Input Voltage (V)
Output Voltage (V)
No Load
Ver 0.0 Preliminary
Mar 27, 2001
TEL: 886-3-5788833
http://www.gmt.com.tw
4
G920
Global Mixed-mode Technology Inc.
TYPICAL PERFORMANCE CHARACTERISTICS
(continue)
Line Transient
Load Transient
Load Transient
Load Transient
Ver 0.0 Preliminary
Mar 27, 2001
TEL: 886-3-5788833
http://www.gmt.com.tw
5
G920
Global Mixed-mode Technology Inc.
Pin Description
PIN NAME
FUNCTION
1
NC
This is a NC pin, should be left unconnected.
2
IN
Regulator Input. Supply voltage can range from +2.5V to +6.5V. Bypass with 1F to GND.
3 OUT
Regulator Output. Sources up to 150mA. Bypass with a 1F,
0.2
typical ESR capacitor to
GND.
4 EN
Active-High Enable Input. A logic low reduces the supply current to less than 1
A. Connect to IN for
normal operation.
5,6,7,8 GND
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 refer-
ence, 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 ampli-
fier. 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 out-
put becomes higher so that the PMOS output transis-
tor has a smaller gate-to-source voltage (V
GS
). This
reduces the current carrying capability of the PMOS
output transistor, as a result the output voltage de-
creases 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 effec-
tively form a unity-gain amplifier with the feedback
voltage force to be the same as the 1.25V bandgap
reference. The output voltage, V
OUT
, is then given by
the following equation:
V
OUT
= 1.25 (1 + R1/R2).
(1)
For the G920, the pre-set output voltage is 3.3V.
Figure 1. Functional Diagram
EN
IN
OUT
SHUTDOWN
LOGIC
1.25V
Vref
ERROR
AMP
OVER CURRENT
PROTECT & DYNAMIC
FEEDBACK
GND
R1
R2
OVER TEMP.
PROTECT
EN
IN
OUT
SHUTDOWN
LOGIC
1.25V
Vref
ERROR
AMP
OVER CURRENT
PROTECT & DYNAMIC
FEEDBACK
GND
R1
R2
OVER TEMP.
PROTECT
Ver 0.0 Preliminary
Mar 27, 2001
TEL: 886-3-5788833
http://www.gmt.com.tw
6
G920
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 protec-
tion circuit will be triggered again. Thus, when the output
is shorted to ground, the output current will be alternat-
ing 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. Other-
wise, 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 out-
put capacitor, the dominant pole is the pole caused by
the output node. The pole cause by the error ampli-
fier's output node is the second pole. With a high ESR
output capacitor, the zero caused by the ESR is typi-
cally 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 170
o
C, the
output transistor is turned off. When the IC is cooled
down to below 150
o
C, 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
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 dissipa-
tion is always given by P = I
OUT
(V
IN
V
OUT
). The
maximum power dissipation is given by:
P
MAX
= (T
J
T
A
)/
JA
,
Where (T
J
T
A
) is the temperature difference the
G920 die and the ambient air,
JA
, is the thermal re-
sistance of the chosen package to the ambient air. In
the case of a SOT23-5 package, the thermal resis-
tance is typically 140
o
C/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 ca-
pacitor values and lower ESR provide better sup-
ply-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 sta-
ble operation over the full temperature range, with load
currents up to 120mA, a minimum of 1F is recom-
mended.
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 sys-
tems. Power-supply rejection is 53dB at low frequen-
cies as the frequency increases above 20kHz, the
output capacitor is the major contributor to the rejec-
tion 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 ca-
pacitors, 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. Be-
cause the G920 use a P-channel MOSFET pass tran-
sistor, their dropout voltage is a function of R
DS(ON)
multiplied by the load current.
Ver 0.0 Preliminary
Mar 27, 2001
TEL: 886-3-5788833
http://www.gmt.com.tw
7
G920
Global Mixed-mode Technology Inc.
Package Information
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.
DIMENSION IN MM
DIMENSION IN INCH
SYMBOL
MIN. NOM. MAX. MIN. NOM. MAX.
A 1.35 1.60 1.75 0.053 0.063 0.069
A1 0.10 ----- 0.25 0.004
----- 0.010
A2 ----- 1.45 ----- ----- 0.057
-----
B 0.33 ----- 0.51 0.013
----- 0.020
C 0.19 ----- 0.25 0.007
----- 0.010
D 4.80 ----- 5.00 0.189
----- 0.197
E 3.80 ----- 4.00 0.150
----- 0.157
e ----- 1.27 ----- ----- 0.050
-----
H 5.80 ----- 6.20 0.228
----- 0.244
L 0.40 ----- 1.27 0.016
----- 0.050
y ----- ----- 0.10 ----- ----- 0.004
0 ----- 8 0 ----- 8
D
E
H
7
(4X)
A1
A2
A
e
B
y
C
L
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