Global Mixed-mode Technology Inc.
G914
150mA Low-Dropout Linear Regulators
Features
Low, 52µA Ground Current
Guaranteed 150mA Output Current
Dropout Voltage is 100mV @ 50mA Load
Over-Temperature Protection and Short-Circuit
Protection
Adjustable Mode: from 2.5V to 5.5V
Max. Supply Current in Shutdown Mode < 1µA
Low Output Noise is 170 µV
RMS
General Description
The G914 is a low supply current, low dropout linear
regulator that comes in a space saving SOT23-5 pack-
age. The supply current at no-load is 52µA. In the
shutdown mode, the maximum supply current is less
than 1µA. Operating voltage range of the G914 is from
2.5V to 5.5V. The over-current protection limit is set at
370mA typical and 150mA minimum. An overtem-
perature protection circuit is built-in in the G914 to
prevent thermal overload. These power saving fea-
tures make the G914 ideal for use in the bat-
tery-powered applications such as notebook com-
puters, cellular phones, and PDA’s.
The G914 is a adjustable output version in a small
SOT 23-5 package.
Applications
Notebook Computers
Cellular Phones
PDAs
Digital still Camera and Video Recorders
Hand-Held Devices
Bar Code Scanners
Ordering Information
PART MARKING VOLTAGE
G914
14
Adjustable
TEMP.
RANGE
-40°C~ +85°C
PIN-
PACKAGE
SOT 23-5
Pin Configuration
IN
1
5
OUT
＋
IN
OUT
R1
OUTPUT
VOLTAGE
G914
BATTERY
C
IN
1µF
SHDN
GND
ADJ
R2
470pF
C
OUT
1µF
GND
2
G914
－
SHDN
3
4
ADJ
SOT23-5
Adjustable mode
V
OUT
=1.250 X ( R
2
/R
1
+1)
Ver 0.1 Preliminary
Nov 05, 2001
TEL: 886-3-5788833
http://www.gmt.com.tw
1
Global Mixed-mode Technology Inc.
Absolute Maximum Ratings
V
IN
to GND……………………………………-0.3V to +7V
Output Short-Circuit Duration………………….….Infinite
SET to GND.……………………………..…..-0.3V to +7V
SHDN to GND…………………..………….-0.3V to +7V
SHDN to IN….…………………..…………..-7V to +0.3V
OUT to GND…………………………-0.3V to (V
IN
+ 0.3V)
G914
Continuous Power Dissipation (T
A
= +25°C)
SOT23-5……………………………………...…..568 mW
Operating Temperature Range………...-40°C to +85°C
Junction Temperature……………………….……+150°C
θ
JA
….…..……………….…………….…..…..220°C/Watt
Storage Temperature Range………….-65°C to +160°C
Lead Temperature (soldering, 10sec)..…………+300°C
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
= V
OUT
+1V;
V
SHDN
= V
IN
; C
IN
= C
OUT
= 1µF = T
A
= T
J
= +25°C, unless otherwise noted.) (Note 1)
PARAMETER
SYMBOL CONDITIONS
MIN TYP MAX UNITS
Input Voltage (Note 2)
Output Voltage Accuracy
Adjustable Output Voltage Range (Note 3)
Maximum Output Current
Current Limit
Ground Pin Current
V
IN
V
OUT
V
OUT
I
LIM
I
Q
V
DROP
∆V
LNR
∆V
LDR
Variation from specified V
OUT
, I
OUT
=1mA
Note2
-2
2.5
150
370
52
2
100
340
0.1
30
40
192
170
2
0.4
T
A
= +25°C
T
A
= +25°C
T
A
= +25°C
0.007
0.06
5
150
15
0.1
1
20
C
ADJ
= 470pF
C
ADJ
= 10nF
80
5.5
2
5.5
V
%
V
mA
mA
µA
Dropout Voltage (Note 3)
Line Regulation
Load Regulation
Output Voltage Temperature Coefficient
Output Voltage Noise (10HZ to 100KHZ)
SHUTDOWN
SHDN
Input Threshold
SHDN
Input Bias Current
V
OUT
= 0V
I
LOAD
= 0mA
I
LOAD
= 150mA
I
OUT
= 1mA
I
OUT
= 50mA
I
OUT
=150mA
V
IN
=V
O
+0.1V to 5.5V, I
OUT
= 1mA
I
OUT
= 0mA to 150mA
mV
%/V
mV
ppm/°C
µV
RMS
∆V
O
/
∆T
I
OUT
= 40mA, T
J
= 25°C to 125°C
e
n
I
L
= 150mA
V
IH
V
IL
I
SHDN
I
QSHDN
I
ADJ
T
SHDN
∆T
SHDN
Regulator enabled
Regulator shutdown
V
SHDN
= V
IN
V
OUT
= 0V
V
ADJ
= 1.3V
V
µA
µA
nA
°C
°C
Shutdown Supply Current
ADJ INPUT
ADJ Input Leakage Current
THERMAL PROTECTION
Thermal Shutdown Temperature
Thermal Shutdown Hysteresis
Note 1: Limits is 100% production tested at T
A
= +25°C. Low duty pulse techniques are used during test to
maintain junction temperature as close to ambient as possible.
Note 2: V
IN (min)
= V
OUT
+V
DROP
.
Note 3: 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 0.1 Preliminary
Nov 05, 2001
TEL: 886-3-5788833
http://www.gmt.com.tw
2
Global Mixed-mode Technology Inc.
Pin Description
PIN
1
2
3
G914
NAME
IN
GND
SHDN
FUNCTION
Regulator Input. Supply voltage can range from +2.5V to +5.5V. Bypass with 1µF to GND
Ground. This pin also functions as a heatsink. Solder to large pads or the circuit board ground plane to
maximize thermal dissipation.
Active-Low Shutdown Input. A logic low reduces the supply current to less than 1µA. Connect to IN for normal
operation.
Adjust (Input): Adjustable regulator feedback input. It can connect to an external resistor divider for ad-
justable output voltage. It also must connect
≥470pF
ceramic capacitor from ADJ pin to GND for reduce
output noise.
Regulator Output. Fixed or adjustable from +2.5V to +5.5V. Sources up to 150mA. Bypass with a 1µF,
＜0.2Ω
typical ESR capacitor to GND.
4
ADJ
5
OUT
Detailed Description
The block diagram of the G914 is shown in Figure 1. It
consists of an error amplifier, 1.25V bandgap refer-
ence, PMOS output transistor, shutdown logic, over
current protection circuit, and over temperature protec-
tion circuit.
The G914 can be adjusted to a specific output voltage
by using two external resistors (Figure 2). The resis-
tors set the output voltage based on the following
equation:
R2
V
OUT
=1.250V X
+1
R1
This equation is correct due to the configuration of the
bandgap reference. The bandgap voltage is relative to
the output, as seen in the block diagram. Traditional
regulators normally have the reference voltage relative
to ground and have a different V
OUT
equation. Resistor
values are not critical because ADJ (adjust)has a high
input impedance, but for best results use resistors of
470kΩ or less. A capacitor from ADJ to ground pro-
vides greatly improved noise performance.
IN
SHDN
SHUTDOWN
LOGIC
ERROR
AMP.
＋
OVER TEMP. &
OVER CURRENT
PROTECTION
1.25V
ref
OUT
ADJ
GND
Figure 1. Functional Diagram
Ver 0.1 Preliminary
Nov 05, 2001
TEL: 886-3-5788833
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Global Mixed-mode Technology Inc.
IN
＋
－
BATTERY C
IN
1µF
G914
ADJ
SHDN
GND
R2
470pF
C
OUT
1µF
R
L
OUT
R1
OUTPUT
VOLTAGE
G914
of the chosen package to the ambient air. In the case
of a SOT23-5 package, the thermal resistance is typi-
cally 220
o
C/Watt.
The die attachment area of the G914’s lead frame is
connected to pin 2, which is the GND pin. Therefore,
the GND pin of G914 can carry away the heat of the
G914 die very effectively. To improve the power dis-
sipation, connect the GND pin to ground using a large
ground plane near the GND pin.
Applications Information
Figure 2. Adjustable Output Using External
Feedback Resistors
Over Current Protection
The G914 use a current mirror to monitor the output
current. A small portion of the PMOS output transis-
tor’s current is mirrored onto a resistor such that the
voltage across this resistor is proportional to the out-
put current. This voltage is compared against the ref-
erence voltage. Once the output current exceeds the
limit, the PMOS output transistor enters constant cur-
rent mode. The current is set to 370mA typically.
Over Temperature Protection
To prevent abnormal temperature from occurring, the
G914 has a built-in temperature monitoring circuit.
When it detects the temperature is above 150
o
C, the
output transistor is turned off. When the IC is cooled
down to below 135
o
C, the output is turned on again. In
this way, the G914 will be protected against abnormal
junction temperature during operation.
Shutdown Mode
When the
SHDN
pin is connected a logic low voltage,
the G914 enters shutdown mode. All the analog cir-
cuits are turned off completely, which reduces the
current consumption to only the leakage current. The
output is disconnected from the input. When the out-
put has no load at all, the output voltage will be dis-
charged to ground through the internal resistor voltage
divider.
Operating Region and Power Dissipation
Since the G914 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
D(MAX)
= (T
J
–T
A
)/θ
JA
,=150
o
C-25
o
C/220
o
C/W= 568mW
Where (T
J
–T
A
) is the temperature difference the G914
die and the ambient air,θ
JA
, is the thermal resistance
Capacitor Selection and Regulator Stability
Normally, use a 1µF capacitor on the input and a 1µF
capacitor on the output of the G914. Larger input ca-
pacitor values and lower ESR provide better sup-
ply-noise rejection and transient response. A higher-
value input capacitor (10µF) may be necessary if large,
fast transients are anticipated and the device is lo-
cated several inches from the power source.
Power-Supply Rejection and Operation from Sources
Other than Batteries
The G914 is designed to deliver low dropout voltages
and low quiescent currents in battery powered sys-
tems. Power-supply rejection is 42dB at low frequen-
cies.
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 G914 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 G914 use a P-channel MOSFET pass tran-
sistor, their dropout voltage is a function of R
DS(ON)
multiplied by the load current.
Ver 0.1 Preliminary
Nov 05, 2001
TEL: 886-3-5788833
http://www.gmt.com.tw
4
Global Mixed-mode Technology Inc.
Layout Guide
An input capacitance of
≅
1µF is required between the
G914 input pin and ground (the amount of the capaci-
tance may be increased without limit), This capacitor
must be located a distance of not more than 1cm from
the input and return to a clean analog ground.
Input capacitor can 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
G914
routing wire. Otherwise, the actual voltage at the IN
pin may exceed the absolute maximum rating.
The output capacitor also must be located a distance
of not more than 1cm from output to a clean analog
ground. Because it can filter out the output spike
caused by the surge current due to the inductive effect
of the package pin and the printed circuit board’s
routing wire. Figure 3 is suggested PCB layout of
G914.
Figure 3. Suggested PCB Layout
*Distance between pin & capacitor must no more than 1cm
Ver 0.1 Preliminary
Nov 05, 2001
TEL: 886-3-5788833
http://www.gmt.com.tw
5
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