AIC2951D-33CN [AIC]
Low Dropout Linear Regulator; 低压差线性稳压器
| 型号： | AIC2951D-33CN |
| 厂家： | 
ANALOG INTERGRATIONS CORPORATION |
| 描述： | Low Dropout Linear Regulator |
| 文件： | 总10页 (文件大小：156K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
AIC2951/2951D
Low Dropout Linear Regulator
n FEATURES
n DESCRIPTION
l Low Dropout Voltage of 130mV at 100mA Output
The AIC2951/ 2951D series is the enhanced
CMOS version of the LP2951. The superior char-
acteristics of the AIC2951/ 2951D series include
zero base current loss, very low dropout voltage,
and 1% accuracy output voltage. Typical ground
current remains approximately 55mA, from no
load to maximum loading conditions. Dropout
voltage at 100mA output current is significantly
lower than its bipolar counterpart: 130mV for the
AIC2951-50/2951D-50, 180mV for the AIC2951-
33/ 2951D-33, and 200mV for the AIC2951-30/
2951D-30. Output current limiting and thermal
limiting are built in to provide maximal protection
to the AIC2951/2951D series from fault condi-
tions.
Current (AIC2951/2951D-50).
l Guaranteed 150mA /300mA Output Current.
l Internal 1.3W P-MOSFET Draws no Base Current.
l Low Ground Current at 55mA.
l 1% Accuracy Output of 3V/3.3V/5V.
l Error Flag Warns of Output Dropout.
l 1mA Supply Current in Shutdown Mode.
l Output Programmable from 1.235V~11V.
l Fast Transient Response.
l Needs only 1mF for Stability.
l Current and Thermal Limiting.
n APPLICATIONS
l Voltage Regulator for PentiumÒ CPUs.
l Wireless Communication System.
l Battery Powered Systems.
An error flag output, indicating when output volt-
age drops out of regulation, often due to the
falling batteries on the input, can be used for a
power-on reset. A logic-controlled shutdown
input enables the regulator to be switched on and
off. The part may be configured for a fixed output
voltage or programmed from 1.235V to 11V with
an external pair of resistors. The part comes in 8-
pin DIP or SO packages.
n TYPICAL APPLICATION CIRCUIT
VOUT=1.235(1+R1/R2)
+
VIN
m
470 F
R3
390
C1
Q1
1
2
3
8
VOUT
SENSE
SHDN
GND
VIN
FB
D45H2A
VOUT
7
6
R4
33
R1
TAP
4
5
+
ERROR
1000mF
C2
R2
AIC2951
Pentium Processor Power Supply
Analog Integrations Corporation
4F, 9, Industry E. 9th Rd, Science Based Industrial Park, Hsinchu Taiwan, ROC
www.analog.com.tw
DS-2951-01 Mar 13, 00
TEL: 886-3-5772500 FAX: 886-3-5772510
1
AIC2951/2951D
Low Dropout Linear Regulator
n ORDERING INFORMATION
AIC2951 X-XXXX
ORDER NUMBER
PIN CONFIGURATION
PACKAGE TYPE
N: PLASTIC DIP
S: SMALL OUTLINE
AIC2951-30CN
AIC2951-33CN
AIC2951-50CN
AIC2951D-30CN
AIC2951D-33CN
AIC2951D-50CN
(PLASTIC DIP)
TOP VIEW
VOUT
VIN
TEMPERATURE RANGE
1
2
3
4
8
7
6
5
°
°
C: 0 C~+70 C
FB
SENSE
SHDN
GND
OUTPUT VOLTAGE
30 : 3.0V
TAP
ERROR
33 : 3.3V
50 : 5.0V
AIC2951-30CS
AIC2951-33CS
AIC2951-50CS
AIC2951D-30CS
AIC2951D-33CS
AIC2951D-50CS
(PLASTIC SO)
MAX. OUTPUT CURRENT
DEFAULT
:
150mA
D
: 300mA
n 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 .............………….......................... -40°C~125 °C
Storage Temperature Range ............................…………............................ -65°C~150 °C
n TEST CIRCUIT
VOUT
VOUT
VIN
FB
VIN
VREF
+
COUT
m
10 F
+
SENSE
SHDN
GND
CIN
m
1 F
TAP
SHUTDOWN
1mA
ERROR
AIC2951
2
AIC2951/2951D
n
ELECTRICAL CHARACTERISTICS (Ta=25°C, CIN=1mF, COUT=10mF, unless oth-
erwise specified.)
PARAMETER
TEST CONDITIONS
MIN. TYP. MAX. UNIT
Output Voltage
No Load
AIC2951/2951D-50
AIC2951/2951D-33
AIC2951/2951D-30
VIN=5.5~12V
VIN=3.6~12V
VIN=3.3~12V
4.950
3.267
2.970
5.0
3.3
3.0
50
5.050
3.333
3.030
150
V
Output Voltage Tempera- (Note 1)
ture Coefficiency
PPM/°C
mV
Line Regulation
IL=1mA
AIC2951/2951D-50
AIC2951/2951D-33
AIC2951/2951D-30
AIC2951-50
VIN=5.5~12V
VIN=3.6~12V
3
10
10
10
15
25
15
25
3
VIN=3.3~12V
3
Load Regulation
VIN=7V, IL=0.1~150mA
VIN=7V, IL=0.1~300mA
VIN=5V, IL=0.1~150mA
VIN=5V, IL=0.1~300mA
VIN=7V, VOUT=0V
VIN=5V, VOUT=0V
VIN=7V, VOUT=0V
VIN=5V, VOUT=0V
IL=0.1mA
7
(Note 2)
AIC2951D-50
7
mV
MA
AIC2951-30/ -33
AIC2951D-30/-33
AIC2951-50
7
7
Current Limit
220
220
440
440
0.2
200
270
300
400
540
600
(Note 3)
AIC2951-30/ -33
AIC2951D-50
AIC2951D-30/ -33
AIC2951/2951D
AIC2951-50
Dropout Voltage
10
(Note 4)
IL=150mA
300
370
400
500
640
700
AIC2951-33
IL=150mA
AIC2951-30
IL=150mA
mV
AIC2951D-50
IL=300mA
AIC2951D-33
IL=300mA
AIC2951D-30
IL=300mA
Ground Current
IO=0.1mA~IMAX
AIC2951/2951D-50
AIC2951/2951D-33
AIC2951/2951D-30
AIC2951-50
VIN=5.5~12V
VIN=4~12V
55
55
55
80
80
80
mA
VIN=4~12V
FB Reference Voltage
VIN=5.5~12V
VIN=3.6~12V
1.222 1.235 1.248
1.222 1.235 1.248
V
PPM/°C
NA
AIC2951-30/ -33
Reference Voltage Temp.
Coef. (Note 1)
50
150
60
1
FB Pin Current
AIC2951/2951D
AIC2951/2951D
VIN=7V
VIN=7V
20
Error Pin off Leakage
Current
mA
Error Pin Pull Low
Voltage
IOL=1mA
AIC2951/2951D-50
AIC2951/2951D-33
VIN=4.5V
VIN=2.9V
100
100
300
300
mV
3
AIC2951/2951D
AIC2951/2951D-30
VIN=2.7V
100
300
n ELECTRICAL CHARACTERISTICS (CONTINUED)
PARAMETER
TEST CONDITIONS
MIN. TYP. MAX.
UNIT
Output Voltage
No Load
AIC2951/2951D-50
AIC2951/2951D-33
AIC2951/2951D-30
VIN=5.5~12V
VIN=3.6~12V
VIN=3.3~12V
4.950
3.267
2.970
40
5.0
3.3
3.0
60
5.050
3.333
3.030
V
Error Pin Upper Thresh-
old Voltage
mV
MV
V
Error Pin Lower Threshold
Voltage
68
0.8
10
88
2
Shutdown Threshold
Voltage
AIC2951/2951D
AIC2951/2951D
AIC2951/2951D
VIN=7V
0.5
Shutdown Input Bias
Current
VIN=7V, VSHDN=2V
VIN=7V, VSHDN=2V
25
2
mA
mA
Shutdown Supply
Current
Note 1:
Note 2:
Note 3:
Note 4:
Guaranteed by design.
Regulation is measured at constant junction temperature, using pulse testing with a low ON time.
Current limit is measured by pulsing a short time.
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.
4
AIC2951/2951D
n TYPICAL PERFORMANCE CHARACTERISTICS
Reference Voltage vs Temperature
Ground Current vs. Input Voltage
1.28
1.26
1.24
1.22
1.2
60
50
40
30
20
10
VREF=1.244V
VREF=1.235V
VREF=1.225V
1.18
0
-50
-25
0
25
50
75
100
125
0
1
2
3
4
5
6
7
8
°
Input Voltage (V)
Temperature( C)
Dropout Voltage vs Load Current
Ground Current vs. Temperature
600
60
58
56
54
52
50
500
400
VOUT=3V
VOUT=3.3V
IL=300mA
300
200
100
0
IL=150mA
VOUT=5V
IL=0.1mA
300
0
100
150
250
125
50
200
0
25
50
75
100
-50
-25
°
Temperature( C)
Load Current (mA)
Short Circuit Current vs. Temperature
AIC2951D
Dropout Voltage vs Temperature
600
500
400
300
200
500
400
300
200
VOUT=5V
IL=300mA
IL=150mA
AIC2951
100
0
IL=0.1mA
-50
-25
0
25
50
75
100
125
-50
-25
0
25
50
75
100
125
°
Temperature ( C)
°
Temperature( C)
5
AIC2951/2951D
n
TYPICAL PERFORMANCE CHARACTERISTICS (CONTINUED)
Line Transient Response
Load Transient Response
100
50
m
COUT=1 F
100
0
VOUT=5V
0
m
COUT=1 F
-100
-50
IL=1mA
VOUT=5V
-200
150
0.1
8
6
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
Time (mS)
Time (mS)
Load Transient Response
Enable Transient
COUT=1mF
COUT=10mF
6
4
20
0
VOUT=5V
IL=10mA
VIN=8V
VOUT=5V
-20
2
0
m
COUT=10 F
-40
-60
2
0
150
0.1
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
Time (mS)
Time (mS)
FB Pin Bias Current vs. Temperature
Minmum Operating Voltage vs Temperature
40
30
20
10
2.8
2.7
2.6
2.5
2.4
2.3
2.2
-50
-25
0
25
50
75
100
125
-50
-25
0
25
50
75
100
125
°
°
Temperature ( C)
Temperature ( C)
6
AIC2951/2951D
n BLOCK DIAGRAM
FB
VOUT
VIN
8
7
1
2
6
SENSE
TAP
RF1
RF2
+
-
ERROR
AMP
3
SHDN
60mV
+
+
5
4
ERROR
GND
-
ERROR DETECTION
COMPARATOR
+
1.235V REFERENCE
n PIN DESCRIPTIONS
ERROR
PIN 1: VOUT - Output pin.
PIN 5:
- Open drain output of error flag warns.
PIN 2: SENSE -Remote sense input, connected
to internal resistor divider.
PIN 6: TAP
PIN 7: FB
PIN 8: VIN
- Center output of internal resistor di-
vider.
PIN 3: SHDN - Shutdown input.
PIN 4: GND - Power GND.
- Error amplifier positive feedback (see
Block Diagram)
- Power supply input
n APPLICATION INFORMATIONS
Output Filter Capacitors
A 1mF (or greater) capacitor is required between the AIC2951/AIC2951D output and ground for stability. Without
this capacitor the part will oscillate. Even though most types of capacitor may work, if Aluminum electrolytic type
is used, the equivalent series resistance (ESR) should be held to 5W or less. Many Aluminum electrolytics have
electrolytes that freeze at about -30°C, so solid tantalums are recommended for operation below -25°C. The value
of this capacitor may be increased without limit.
The output capacitance required for stability varies with output voltage (smaller for higher output voltage) and out-
put current (smaller for lower output currents). At the worst-case situation of a 150mA load at 1.235V output
(output shorted to FB pin) a 3.3 mF or greater capacitor should be used.
A 0.1mF capacitor should be placed from the AIC2951/2951D 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 AIC2951/2951D from nearby noise sources can also upset the output. This may especially
be a problem when using high value external resis-
Programming the Output Voltage
tors to set the output voltage. Adding a 100pF ca-
pacitor between output and feedback and increas-
ing the output capacitor to at least 3.3mF will cure
this problem.
The AIC2951/2951D series can be set to deliver
any output voltage from 1.235V to 11V by using an
external voltage divider. In addition, internal voltage
7
AIC2951/2951D
dividers are provided for 3.0V/3.3V/5.0V output ver-
sions. To use the internal voltage divider, connect
the SENSE pin to output and the TAP pin to the FB
pin. When using an external divider the SENSE and
TAP pins are left open, and the divider is installed
from the output to ground, with its center connected
to the FB pin (see Fig. 1). When using an external
voltage divider, resistance can be calculated from
the following formula:
R2. Using a 1.2MW resistor for R2, the bias current
will already cause a 2% shift in output voltage. For
better accuracy, choosing R2=100KW reduces this
error to 0.17% at the price of merely increasing the
resistor programming current to 12mA.
Reducing Output Noise
In reference applications it may be advantageous to
reduce the AC noise present at the output. One
method is to reduce the regulator bandwidth by in-
creasing the size of the output capacitor. Another,
noise can be reduced by bypassing the upper re-
sistor in the feedback divider with a small capacitor,
since the capacitor provides a more direct path for
AC feedback. The size of this capacitor can be cal-
culated from the formula:
R1
VOUT = VREF ´ (1+
) + IFB ´ R1
R2
V
OUT
+
V
IN
C2
3.3
m
F
+
R1
C1
C3
1
8
VOUT
VIN
0.01mF
2
3
4
7
FB
SENSE
×
×
R1 fCORNER)
CBYPASS 1/(2p
@
6
SHUTDOWN
TAP
SHDN
GND
Where R is the upper resistor of the feedback di-
R2
1
5
ERROR
vider and fCORNOR is the frequency above which the
increased AC feedback is to become active. The
reduction of the output noise at high frequency will
be proportional to the ratio of the two resistors in
the feedback divider, R2/(R1+R2). In order to main-
tain regulator stability when using a noise-reducing
bypass capacitor, it will also be necessary to in-
crease the size of the output filter capacitor by the
AIC2951
Fig. 1 Adjustable Regulator
Where VREF is the nominal 1.235V reference voltage
and IFB is the feedback pin bias current, nominally -
20nA. The minimum recommended load current of
1mA forces an upper limit of 1.2MW on the value of
same ratio.
n APPLICATION EXAMPLES
Load Transient Response
VOUT=3.3V
100
0
VOUT=1.235(1+R1/1K)
+
VIN
5V
m
1000 F
6.3V
R3
390
C1
1
8
Q1
-100
VOUT
VIN
FB
D45H2A
2
7
6
VOUT
SENSE
SHDN
GND
R4
33
3
4
R1
TAP
5
+
ERROR
5
0
m
C2
1000 Fx5
6.3V
R2
1K
AIC2951
1.0
0.8
0.9
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
Time (mS)
Fig. 2 PentiumÒ Processor Power Supply
8
AIC2951/2951D
n
APPLICATION EXAMPLES (CONTINUED)
L
I =1.235/R
LOAD
IN
V =2.5V-12V
1
8
@
VOUT VIN
VOUT
VIN
1
8
VOUT
SENSE
SHDN
GND
VIN
FB
VIN=2.5V-12V
+
2
3
7
C1
2
3
SENSE
SHDN
GND
7
6
FB
m
1 F
6
+
m
1 F
TAP
TAP
C1
4
5
4
5
R
ERROR
ERROR
AIC2951
AIC2951
Fig. 3 Current Limiter
Fig. 4 Precision Sink Current Source
n PHYSICAL DIMENSIONS
l 8 LEAD PLASTIC SO (unit: mm)
D
SYMBOL
MIN
1.35
0.10
0.33
0.19
4.80
3.80
MAX
A
A1
B
1.75
0.25
0.51
0.25
5.00
4.00
H
E
C
D
E
e
A
e
1.27(TYP)
C
H
L
5.80
0.40
6.20
1.27
B
L
l 8 LEAD PLASTIC DIP (unit: mm)
SYMBOL
MIN
0.381
2.92
0.35
0.20
9.01
7.62
6.09
MAX
—
D
A1
A2
b
4.96
0.56
0.36
10.16
8.26
7.12
E1
C
E
D
E
A2
A1
E1
e
C
L
2.54 (TYP)
10.92
3.81
eB
eB
L
—
b
e
2.92
9
AIC2951/2951D
10
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