AIC AIC1741CN

AIC1741
LOW DROPOUT ADJUSTABLE REGULATOR
SPEC NO: DS-1741-00
FEATURES
1% Accuracy 1.235V Voltage Reference.
Fast Transient Response.
Low Ground Current at 55µA.
Wide Output Current Range, 10µA~80mA.
Output Programmable from 1.235V~11V.
Low Temperature Coefficiency.
Error Flag Warns of Output Dropout.
DESCRIPTION
The AIC1741 is a low power precision adjustable
regulator with 80mA output capability. The device
can be used as a secondary regular to provide
feedback in a switching power supply.
The AIC1741 circuitry includes an internal wide
band amplifier, a precision bandgap reference,
and a PMOS output transistor. The feedback
input can be connected to an external resistor
APPLICATIONS
divider to program the sensed output voltage.
Voltage Regulator for Pentium® CPUs.
Wireless Communication System.
5V to 3.3V Regulator for VGA Cards.
Battery Powered Systems.
The
VOUT
pin
provides
loop
frequency
compensation when used as a part of a larger
servo system.
Although the device works as a stand-alone
regulator, it can also drive an NPN power
transistor to construct a high current low dropout
regulator, with only very minor current loss to
ground.
TYPICAL APPLICATION CIRCUIT
VIN
5V
1 VOUT
Q1
TIP31C
C3
10µF
+
R3
2K
R1
390
+
3 GND
C2
33µF
4
8
FB 7
2 NC
VOUT
3.3V/3 A
VIN
+
C1
10µF
FLAG 6
NC 5
NC
AIC1741
R2
1.2K
5V to 3.3V Regulator for VGA Cards.
ORDERING INFORMATION
AIC1741 XX
ORDER NUMBER
PACKAGE TYPE
N: PLASTIC DIP
S: SMALL OUTLINE
TEMPERATURE RANGE
C: 0°C~+70°C
AIC1741CN
(PLASTIC DIP)
AIC1741CS
(PLASTIC SO)
Pentium
®
PIN CONFIGURATION
TOP VIEW
VOUT
1
8
VIN
NC
2
7
FB
GND
3
6
FLAG
NC
4
5
NC
is a registered trademark of Intel Corporation
ANALOG INTEGRATIONS CORPORATION
www.analog.com.tw
4F, 9 Industry E. 9th Road, Science-based Industrial Park , Hsinchu, Taiwan, R.O.C.
TEL: (8863)577-2500 FAX:(8863)577-2510
1
AIC1741
LOW DROPOUT ADJUSTABLE REGULATOR
SPEC NO: DS-1741-00
ABSOLUTE MAXIMUM RATINGS
Input Supply Voltage
................……………...................................................... -0.3~12V
Feedback Input Voltage
.............……………...................................................... -0.3~12V
Shutdown Input Voltage
...........……………....................................................... -0.3~12V
Error Comparator Output
..........………….......................................................... -0.3~12V
Operating Junction Temperature Range
...............…………......................................... -65°C~150°C
Storage Temperature Range
……….......................................... -40°C~125°C
TEST CIRCUIT
8
VIN
+
CIN
1µF
1mA
7
VOUT
VIN
NC
FB
6 FLAG
5
1
VOUT
3.3V
2
COUT
10µF
GND 3
NC
NC
4
R1
2K
R2
1.2K
AIC1741
ELECTRICAL CHARACTERISTICS (Ta=25°°C, CIN=1µ
µF, COUT=10µµF, unless otherwise
specified. Test conditions are referred to TEST CIRCUIT.)
PARAMETER
TEST CONDITIONS
MIN.
TYP.
MAX.
UNIT
3.267
3.3
3.333
V
50
150
PPM/°C
Output Voltage
VIN=3.6~12V, No Load, VOUT=3.3V
Output Voltage Temperature
Coefficiency
(Note 1)
Line Regulation
VIN=3.6~12V, IL=1mA, VOUT=3.3V
3
10
mV
Load Regulation
VIN=7V, IL=0.1~80mA, VOUT=3.3V
4
10
mV
0.2
200
10
300
mV
(Note 3)
IL=0.1mA
IL=80mA, VOUT=3.3V
Ground Current
VIN=4~12V, IO=0.1mA~IMAX
55
80
µA
Flag Pin Off Leakage Current
VIN=7V
1
µA
Flag Pin Pull Low Voltage
IOL=1mA, VIN=2.9V
300
mV
(Note 2)
Dropout Voltage
100
Flag Pin Upper Threshold
40
60
mV
Voltage
Flag Pin Lower Threshold
68
88
mV
Voltage
Note 1:
Guaranteed by design.
Note 2:
Regulation is measured at constant junction temperature, using pulse testing with a low ON time.
Note 3:
Dropout voltage is defined as the input to output differential at which the output voltage drops 100mV
below the value measured with a 1V differential.
ANALOG INTEGRATIONS CORPORATION
www.analog.com.tw
4F, 9 Industry E. 9th Road, Science-based Industrial Park , Hsinchu, Taiwan, R.O.C.
TEL: (8863)577-2500 FAX:(8863)577-2510
2
AIC1741
LOW DROPOUT ADJUSTABLE REGULATOR
SPEC NO: DS-1741-00
TYPICAL PERFORMANCE CHARACTERISTICS
Reference Voltage vs. Temperature
Ground Current vs. Input Voltage
1.28
60
50
Ground Current (µA)
Reference Voltage (V)
1.26
VREF=1.244V
1.24
VREF=1.225V
1.22
VREF=1.225V
1.2
40
30
20
10
1.18
-50
-25
0
25
50
75
100
0
125
0
2
4
6
10
12
Dropout Voltage vs. Load Current
Ground Current vs. Temperature
60
200
VOUT=3.3V
Dropout Voltage (mV)
58
Ground Current (µA)
8
Input Voltage (V)
Temperature (°C)
IL=80mA
56
54
IL=0.1mA
150
100
50
52
0
50
-50
-25
0
25
50
75
100
0
125
20
40
Temperature(°C)
Dropout Voltage vs Temperature
100
Bias Current vs. Temperature
40
VOUT=3.3V
IL=80mA
Bias Current (nA)
250
Dropout Voltage(mV)
80
Load Current (mA)
300
200
150
100
50
0
60
30
20
IL=0.1mA
-50
-25
0
25
50
75
100
125
10
-50
-25
0
Temperature(°C)
25
50
75
100
125
Temperature (°C)
ANALOG INTEGRATIONS CORPORATION
www.analog.com.tw
4F, 9 Industry E. 9th Road, Science-based Industrial Park , Hsinchu, Taiwan, R.O.C.
TEL: (8863)577-2500 FAX:(8863)577-2510
3
AIC1741
LOW DROPOUT ADJUSTABLE REGULATOR
SPEC NO: DS-1741-00
TYPICAL PERFORMANCE CHARACTERISTICS
(CONTINUED)
Minimum Operating Voltage vs Temperature
Minimum Operating Voltage (V)
2.8
2.7
2.6
2.5
2.4
2.3
2.2
-50
-25
0
25
50
Temperature (°C)
75
100
125
BLOCK DIAGRAM
8
VIN
7
+
FB
1
VOUT
66mV
+
6
FLAG
1.235V, Reference
3
GND
PIN DESCRIPTIONS
PIN 1: VOUT - Output pin.
PIN 2: NC
-
PIN 3: GND
- Power GND.
PIN 4: NC
-
PIN 5: NC
-
PIN 6: FLAG - Open drain output of error flag
warns.
PIN 7: FB
- Error amplifier positive feedback
(see Block Diagram)
PIN 8: VIN
- Power supply input.
ANALOG INTEGRATIONS CORPORATION
www.analog.com.tw
4F, 9 Industry E. 9th Road, Science-based Industrial Park , Hsinchu, Taiwan, R.O.C.
TEL: (8863)577-2500 FAX:(8863)577-2510
4
AIC1741
LOW DROPOUT ADJUSTABLE REGULATOR
SPEC NO: DS-1741-00
APPLICATION INFORMATIONS
The AIC1741 has two major applications, one as a
low dropout linear regulator and another an error
amplifier for a switching power supply to provide
precision feedback control.
Use as a Linear Regulator
nearby noise sources can also upset the output. This
may especially be a problem when using high value
external resistors to set the output voltage. Adding a
100pF capacitor between output and feedback and
increasing the output capacitor to at least 3.3µF will
cure this problem.
When AIC1741 is connected as a low dropout linear
regulator, two external divider resistors are needed to
The AIC1741 can drive low cost NPN bipolar
set the output voltage (see Test Circuit). The output
transistor to deliver more output current. Typical
voltage can be calculated from the following formula:
application circuit is an example of 5V to 3.3V linear
VOUT=VREF(1+R1/R2)+IFBR1
regulator for VGA cards power supply. A 390Ω
resistor and 1µF capacitor are needed between
where VREF is the nominal 1.235V reference voltage
VOUT pin and ground for stability. The minimum
and IFB is the feedback pin bias current, nominally
dropout voltage between input to output is VBEQ1+VDS
-20nA. For better accuracy, the recommended
of AIC1741 output PMOSFET, typical 1V @ 3A
maximum value of R2 is 100KΩ.
output current.
A 1µF (or greater) capacitor is required between the
AIC1741 output and ground for stability. Without this
Use as an Error Amplifier
capacitor the part will oscillate. Even though most
Fig. 1 shows a popular application for the AIC1741 in
types of capacitor may work, if Aluminum electrolytic
switching power supply. The output voltage is sensed
type is used, the equivalent series resistance (ESR)
between FB pin and GND pin of the AIC1741 through
should be held to 5Ω. or less. Many Aluminum
the divider resistor. The VIN pin servos to control the
electrolytics have electrolytes that freeze at about
duty cycle of the pulse width modulator to stabilize
-30°C, so solid tantalums are recommended for
the output voltage at the set voltage. The FB pin and
operation below -25°C. The value of this capacitor
VIN pin are in same phase while the FB pin and
may be increased without limit.
VOUT pin are in opposite phases. Connecting a
capacitor from VOUT pin to FB pin provides
The output capacitance required for stability varies
frequency compensation for the control loop. The
with output voltage (smaller for higher output voltage)
AIC1741 provides output voltage remote sensing to
and output current (smaller for lower output currents).
improve precision and regulation specifications of the
At the worst-case situation of a 80mA load at 1.235V
output of the switching power supply.
output (output shorted to FB pin) a 3.3 µF or greater
capacitor should be used.
A 0.1µF capacitor should be placed from the
AIC1741 input to ground if the lead inductance
between the input and power source exceeds 500nH
(approximately 10 inches of trace). Noise injection
into the feedback terminal of the AIC1741 from
ANALOG INTEGRATIONS CORPORATION
www.analog.com.tw
4F, 9 Industry E. 9th Road, Science-based Industrial Park , Hsinchu, Taiwan, R.O.C.
TEL: (8863)577-2500 FAX:(8863)577-2510
5
AIC1741
LOW DROPOUT ADJUSTABLE REGULATOR
SPEC NO: DS-1741-00
APPLICATION EXAMPLES
C3
SC
+
AIC1562
TC
VCC
GND
FB
C1
47µF
Q2
C4
VOUT : 2.5V~3.5V/10A
L1
+
D1
C4
ZD1
C2
220pF
5.1V
R8
10K
VIN
5V
1000µF/6.3Vx2
C6
7.5µF
0.022µF
R2
24K
+
1000µF
12V
R1
1K
SE
BST
MTD20N03DH
Q1
2N2907A
D3
BYV118
D2
1N4148
VIN
1N4148
0.1µF
C10 C11
0.1µF 0.1µF
1000µF/6.3V
x2
x2
x5
+
C13
P5
MICROPROCESSOR
CPU
FB
R2*
GND VOUT
C11, C12: Ceramic Capacitor
L1: Iron Powder Core
VOUT= (1+R10/1K)x1.235V
AIC1741
Fig. 1
R10
R7 C5
470 0.1µF 1K
R3
1K
CPU Power Supply for P5 Mother Board
PHYSICAL DIMENSIONS
8 LEAD PLASTIC DIP
8 LEAD PLASTIC SO
4.80±0.20
9.3±0.3
6.0±0.2
3.8±0.2
6.2±0.2
8.0±0.5
0.6±0.3
2.5±0.1
10°max
8.5±1.0
0.5±0.1
2.54±0.10
0.45±0.10
0.2 ± 0.1
3.2±0.3
1.5±0.2
0.25±0.10
1.27±0.10
3.3±0.1
0.015X45°
8° max.
UNIT: mm
ANALOG INTEGRATIONS CORPORATION
www.analog.com.tw
4F, 9 Industry E. 9th Road, Science-based Industrial Park , Hsinchu, Taiwan, R.O.C.
TEL: (8863)577-2500 FAX:(8863)577-2510
6