AS2951ACS-3.0 [ETC]
Analog IC ; 模拟IC\n
| 型号： | AS2951ACS-3.0 |
| 厂家： | 
ETC |
| 描述： | Analog IC
|
| 文件： | 总12页 (文件大小：248K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
AS2950/AS2951
150mA Low Dropout Voltage Regulators
FEATURES
APPLICATIONS
• 5.0V, 3.3V, and 3.0V Versions at 150mA Output
• Very Low Quiescent Current
• Battery Powered Systems
• Cordless Telephones
• Low Dropout Voltage
• Radio Control Systems
• Portable/Palm Top/Notebook Computers
• Portable Consumer Equipment
• Portable Instrumentation
• Avionics
• Extremely Tight Load and Line Regulation
• Very Low Temperature Coefficient
• Needs Only 1µF for Stability
• Current & Thermal Limiting
• Unregulated DC Input can Withstand -20V Reverse Battery
and +60V Positive Transients
• Automotive Electronics
• SMPS Post-Regulator
• Similar Replacement With Higher IOUT for LP2950/LP2951 Sockets
• Voltage Reference
AS2951 Versions Only
• Error Flag Warns of Output Dropout
• Logic-Controlled Electronic Shutdown
• Output Programmable From 1.24V to 29V
PRODUCT DESCRIPTION
The AS2950 and AS2951 are low power voltage regulators. These devices are an excellent choice for use in battery-powered
applications such as cordless telephones, radio control systems, and portable computers. The AS2950 and AS2951 feature very low
quiescent current and very low dropout voltage (Typ. 50mV at light load and 380mV at 100mA). This include a tight initial tolerance
of 0.5% typ., extremely good load and line regulation of 0.05% typ. and very low output temperature coefficient, making the
AS2950/AS2951 useful as a low-power voltage reference. Other key additional features of this device includes higher output current
(150mA), positive transient protection up to 60V (Load dump), and the ability to survive an unregulated input voltage transient of -
20V below ground (reverse battery).
The error flag output feature is used as power-on reset for warning of a low output voltage, due to falling voltage input of batteries.
Another feature is the logic-compatible shutdown input which enables the regulator to be switched ON and OFF. The AS2950 is
offered in a 3-Pin TO-92 package compatible with other 5V regulators. The AS2951 is also available in 8-Pin Plastic, SO-8 and
TO-99 metal can packages.
The regulator output voltage may be pin-strapped for a 5V, 3.3V and 3.0V or programmed from 1.24V to 29V with an external pair of
resistors. Look for AS2954 for 250mA and AS2955 for 350mA.
PIN CONNECTIONS
8-Pin Surface Mount
ORDERING INFORMATION
TO-92
3-PIN
SOIC
8-PIN
OPER. TEMP.
TO-92 (N)
RANGE
OUTPUT
SENSE
1
2
8
INPUT
1
2
3
AS2950ACN-X
AS2950CN-X
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
FEEDBACK
7
A
S
2
9
5
16
SHUTDOWN
3
4
5V or 3.3V TAP
ERROR
AS2951ACS-X
AS2951CS-X
GROUND
5
VIN
VOUT
GND
Top View
Bottom View
X= Output Voltages (3.0V, 3.3V and 5.0V)
Rev. 9/29/00
AS2950/AS2951
ABSOLUTE MAXIMUM RATINGS
Power Dissipation..........................................Internally Limited
Lead Temp. (Soldering, 5 Seconds) ................................ 260°C
Storage Temperature Range ......................... -65°C to +150°C
Operating Junction Temperature Range
Input Supply Voltage (Survival) .........................-20 to +60V
Feedback Input Voltage .....................................-1.5 to +30V
Shutdown Input Voltage.....................................-0.3 to +30V
Error Comparator Output...................................-0.3 to +30V
ESD Rating .............................................................2KV Min
AS2951.................................................. -55°C to +150°C
AS2950AC/AS2950C
AS2951AC/AS2951C............................ -40°C to +125°C
ELECTRICAL CHARACTERISTICS at VS=15V, TA=25°C, unless otherwise specified.
Parameter
Conditions
AS2951
AS2950C/AS2951C AS2950C/AS2951C UNITS
Min Typ Max Min Typ Max Min Typ Max
3.0V Version
Output Voltage
V
TJ = 25°C
2.985
3.0
3.015 2.985
2.970
3.036 2.964
3.045 2.958
3.0
3.0
3.0
3.0
3.015 2.970
3.030 2.955
3.036 2.940
3.042 2.928
3.0
3.0
3.0
3.0
3.030
3.045
3.060
3.072
-25°C < TJ < 85°C
Full Operating Temperature
2.964
2.955
Output Voltage
100mA < IL < 150mA
TJ < TJMAX
V
V
3.0
3.3
3.3V Version
Output Voltage
TJ = 25°C
-25°C < TJ < 85°C
Full Operating Temperature
3.284
3.317 3.284
3.267
3.340 3.260
3.350 3.254
3.3
3.3
3.3
3.3
3.317 3.267
3.333 3.251
3.340 3.234
3.346 3.221
3.3
3.3
3.3
3.3
3.333
3.350
3.366
3.379
3.260
3.251
Output Voltage
100mA < IL < 150mA
TJ < TJMAX
V
V
3.3
5.0
5.0V Version
Output Voltage
TJ = 25°C
-25°C < TJ < 85°C
Full Operating Temperature
4.975
5.025 4.975
4.95
4.94
5.075 4.93
5.0
5.0
5.0
5.0
5.025 4.95
5.050 4.925
5.0
5.0
5.0
5.0
5.05
5.075
5.10
4.94
5.06
5.06
5.07
4.90
4.88
Output Voltage
V
100µA < IL < 150mA
4.925
5.0
20
5.12
TJ < TJMAX
All Voltage Options
Output Voltage Temperature
Coefficient
Line Regulation (Note 3)
Load Regulation (Note 3)
Dropout Voltage (Note 5)
(Note 1)
ppm/°
C
120
20
50
6V < VIN < 30V (Note 4)
100mA < IL < 150mA
%
0.03
0.04
50
380
450
150
3
5
130
0.05
430
160
100
0.1
0.1
80
450
500
170
6
8
0.03
0.04
50
0.1
0.1
80
0.04
0.1
50
0.2
0.2
80
%
mV
IL = 100µA
IL = 100mA
IL = 150mA
IL = 100µA
IL = 100mA
IL = 150mA
VOUT = 0
380
450
150
3
450
500
170
6
8
200
0.2
380
450
150
3
450
500
170
6
8
200
0.2
Ground Current
µA
mA
mA
5
5
Current Limit
Thermal Regulation
mA
%/W
µVrms
µVrms
µVrms
200
0.2
130
0.05
430
160
100
130
0.05
430
160
100
Output Noise,
CL = 1µF
10Hz to 100KHz
CL = 200µF
CL = 13.3µF
(bypass = 0.01µF pins 6 to 1
(AS2951))
8-Pin Version Only
AS2951
AS2951AC
AS2951C
Reference Voltage
V
V
1.22 1.235 1.25
1.22
1.19
1.235 1.25
1.27
1.21
1.18
1.23
1.26
1.28
Reference Voltage
Over Temperature (Note 6)
1.19
1.27
Rev. 9/29/00
AS2950/AS2951
AS2950AC
AS2951AC
Typ
AS2950C
PARAMETER
CONDITIONS
AS2951
Typ
AS2951C
(Note 2)
Min
Max
Min
Max
60
Min
Typ Max
UNITS
8-Pin Version only (Continued)
Feedback Pin Bias Current
40
20
60
40
20
40
50
60
nA
Reference Voltage Temperature
ppm/°
Coefficient
( Note 7 )
C
Feedback Pin Bias Current
0.1
0.1
0.1
nA/°C
Temperature Coefficient
Error Comparator
Output Leakage Current
V
OH = 30V
0.01
150
1
0.01
150
1
0.0
1
1
µA
Output Low Voltage
VIN = 4.5V
250
250
150 250
mV
I
OL = 400µA
Upper Threshold Voltage
Lower Threshold Voltage
Hysteresis
(Note 8)
(Note 8)
(Note 8)
40
2
60
75
15
40
60
75
15
40
2
60
75
15
mV
mV
mV
95
95
95
Shutdown Input
Input logic Voltage
Low (Regulator ON)
High (Regulator OFF)
VS = 2.4V
1.3
0.6
1.3
0.7
1.3
30
0.7
50
V
V
µA
µA
µA
2
Shut down Pin Input Current
30
50
30
50
VS = 30V
(Note 9)
675
800
675
800
675 800
Regulator Output Current in
Shutdown
3
10
3
10
3
10
Note 1: Output or reference voltage temperature coefficients defined as the worst case voltage change divided by the total temperature range.
Note 2: Unless otherwise specified all limits guaranteed for TJ = 25°C, VIN = 6V, IL = 100 µA and CL = 1 µF. Additional conditions for the 8-pin versions are
feedback tied to 5V Tap and output tied to output sense (VOUT = 5V) and VSHUTDOWN ≤ 0.8V.
Note 3: Regulation is measured at constant junction temperature, using pulse testing with a low duty cycle. Changes in output voltage due to heating effects are
covered under the specification for thermal regulation.
Note 4: Line regulation for the AS2951 is tested at 150°C for IL = 1 mA. For IL = 100 µA and TJ = 125°C, line regulation is guaranteed by design to 0.2%. See
typical performance characteristics for line regulation versus temperature and load current.
Note 5: Dropout voltage is defined as the input to output differential at which the output voltage drops 100 mV below its nominal value measured at 1V differential at
very low values of programmed output voltage, the minimum input supply voltage of 2V ( 2.3V over temperature) must be taken into account.
Note 6: VREF ≤VOUT ≤ (VIN - 1V), 2.3 ≤VIN≤30V, 100µA≤IL≤ 150 mA, TJ ≤ TJMAX
.
Note 7: Output or reference voltage temperature coefficient is defined as the worst case voltage change divided by the total temperature range.
Note 8: Comparator thresholds are expressed in terms of a voltage differential at the feedback terminal below the nominal reference voltage measured at 6V input. To
express these thresholds in terms of output voltage change, multiply by the error amplifier gain = VOUT/VREF = (R1 + R2)/R2. For example, at a programmed output
voltage of 5V, the Error output is guaranteed to go low when the output drops by 95 mV x 5V/1.235 = 384 mV. Thresholds remain constant as a percent of VOUT as
V
OUT is varied, with the dropout warning occurring at typically 5% below nominal, 7.5% guaranteed.
Note 9: VSHUTDOWN ≥ 2V, VIN ≤ 30V, VOUT =0, Feedback pin tied to 5V Tap.
Note 10: All typical values are not guaranteed. The value could vary from lot to lot.
UNREGULATED DC
5V @ 150mA
MAX
BLOCK DIAGRAM
1
7
8
+
INPUT
FEEDBACK
OUTPUT
2
SENSE
180k Ω ..
60k Ω ..
+
_
6
ERROR
3
FROM
AMPLIFIER
5V TAP
Ω
330k ..
CMOS OR
TTL
SHUTDOWN
+
5
1 µ F..
+
+
_
______
60 mV
ERROR
ERROR DETECTION
COMPARATOR
TO CMOS OR
TTL
1.23V
+
4
REFERENCE
GROUND
AS2950 and A2951 Block Diagram
Rev. 9/29/00
AS2950/AS2951
APPLICATION HINTS
EXTERNAL CAPACITORS
.
The stability of the AS2950/AS2951 requires a 1.0µF or greater
capacitor between output and ground. Oscillation could occur
without this capacitor. Most types of tantalum or aluminum
electrolytic works fine here. For operations below -25°C solid
tantalum is recommended since many aluminum types have
electrolytes that freeze at about -30°C. The ESR of about 5Ω or
less and resonant frequency above 500kHz are the most
important parameters in the value of the capacitor. The capacitor
value can be increased without limit.
The error comparator has an open-collector output which requires an
external pull-up resistor. Depending on the system requirements the
resistor may be returned to 5V output or other supply voltage in
determining the value of this resistor, note that the output is rated to
sink 400µA, this value adds to battery drain in a low battery
condition. Suggested values range from 100K to 1MΩ. If the output
is unused this resistor is not required.
PROGRAMMING THE OUTPUT VOLTAGE OF AS2951
The AS2951 may be pin-strapped for 5V using its internal voltage
divider by tying Pin 1 (output) to Pin 2 (sense) and Pin 7 (feedback)
to Pin 6 (5V Tap). Also it may be programmed for any output voltage
between its 1.235V reference and its 30V maximum rating . As seen
in Figure 2, an external pair of resistors is required.
At lower values of output current, less output capacitance is
required for stability. For the currents below 10mA the value of
the capacitor can be reduced to 0.5µF and 0.15µF for 1mA. More
output capacitance is needed for the 8-pin version at voltages
below 5V since it runs the error amplifier at lower gain. At worst
case 5µF or greater must be used for the condition of 150mA
load at 1.23V output.
Refer to the below equation for the programming of the output
voltage.
The AS2950, unlike other low dropout regulators will remain
stable in regulation with no load in addition to the internal
V
OUT = VREF × ( 1 + R1/R2 )+ IFBR1
voltage divider.
This feature is especially important in
applications like CMOS RAM keep-alive. When setting the
output voltage of the AS2951 version with external resistors, a
minimum load of 1uA is recommended.
The VREF is 1.235 and IFB is the feedback bias current, nominally
-20 nA. The minimum recommended load current of 1µA forces an
upper limit of 1.2 MΩ on value of R2. If no load presented the IFB
produces an error of typically 2% in VOUT which may be eliminated at
room temperature by trimming R1. To improve the accuracy choose
the value of R2 = 100k this reduces the error by 0.17% and increases
the resistor program current by 12µA. Since the AS2951 typically
draws 60µA at no load with Pin 2 open-circuited this is a small price
to pay.
If there is more than 10 inches of wire between the input and the
AC filter capacitor or if a battery is used as the input then a 1µA
tantalum or aluminum electrolytic capacitor should be placed
from the input to the ground.
Instability can occur if there is stray capacitance to the AS2951
feedback terminal (pin 7). This could cause more problems when
using a higher value of external resistors to set the output voltage.
This problem can be fixed by adding a 100pF capacitor between
output and feedback and increasing the output capacitor to at
least 3.3µF.
REDUCING OUTPUT NOISE
It may be an advantage to reduce the AC noise present at the output.
One way is to reduce the regulator bandwidth by increasing the size of
the output capacitor. This is the only way that noise can be reduced
on the AS2950 but is relatively inefficient, as increasing the capacitor
from 1µF to 220 µF only decreases the noise from 430µV to
160µVRMS. for a 100kHz bandwidth at 5V output.
ERROR DETECTION COMPARATOR OUTPUT
The Comparator produces a logic low output whenever the
AS2951 output falls out of regulation by more than around 5%.
This is around 60mV offset divided by the 1.235 reference
voltage. This trip level remains 5% below normal regardless of
the programmed output voltage of the regulator. Figure 1 shows
the timing diagram depicting the ERROR signal and the regulator
output voltage as the AS2951 input is ramped up and down. The
ERROR signal becomes low at around 1.3V input, and goes high
around 5V input (input voltage at which VOUT = 4.75 ). Since the
AS2951’s dropout voltage is load dependent, the input voltage
trip point (around 5V) will vary with the load current. The
output voltage trip point (approx. 4.75V) does not vary with load.
Noise could also be reduced fourfold by a bypass capacitor across R1,
since it reduces the high frequency gain from 4 to unity. Pick
C
BYPASS ≅ 1 / 2πR1 × 200 Hz
or choose 0.01µF. When doing this, the output capacitor must be
increased to 3.3µF to maintain stability. These changes reduce the
output noise from 430µV to 100µVRMS. for a 100kHz bandwidth at
5V output. With the bypass capacitor added, noise no longer scales
with output voltage so that improvements are more dramatic at higher
output voltages.
Rev. 9/29/00
AS2950/2951
TYPICAL PERFORMANCE CHARACTERISTICS
INPUT CURRENT
QUIESCENT CURRENT
DROPOUT CHARACTERISTICS
10
1
250
6
225
200
5
4
RL = 50k
Ω
175
150
RL=50k
Ω
125
3
2
RL=50k
Ω
RL
=
100
75
0.1
50
25
0
1
0
0.01
0.1
10
150
1
10
150
0
1
2
3
0
1
2
3
4
5
6
INPUT VOLTAGE (VOLTS)
LOAD CURRENT (mA)
INPUT VOLTAGE (VOLTS)
OUTPUT VOLTAGE VS. TEMP OF 3
REPRESENTATIVE UNITS
GROUND CURRENT
INPUT CURRENT
320
280
160
150
140
5.06
5.04
5.02
130
120
110
100
90
RL=50
Ω
240
200
160
IL= 1mA
IL= 0
80
5.0
70
60
120
80
50
4.98
40
30
0.2%
20
4.96
4.94
40
10
0
0
0
1
2
3
4
5
6
7
8
0
1
2
3
4
5
6
7
8
9 10
-75 -50 -25
0
25 50 75 100 125 150
INPUT VOLTAGE (VOLTS)
INPUT VOLTAGE (VOLTS)
TEMPERATURE (ºC)
GROUND CURRENT
QUIESCENT CURRENT
GROUND CURRENT
240
220
200
180
16
16
14
12
IL=100mA
12
10
8
VIN=6V
IL=100mA
VIN = 6V
I
L = 100mA
6
4
8
4
2
0
-75 -50 -25
0
25 50 75 100 125 150
0
2
3
4
5
6
7
8
1
-75 -50 -25
0
25 50 75 100 125 150
TEMPERATURE (ºC)
TEMPERATURE (ºC)
INPUT VOLTAGE
SHORT CIRCUIT CURRENT
DROP-OUT VOLTAGE
DROP-OUT VOLTAGE
170
160
150
140
130
120
110
500
400
300
600
IL = 100mA
500
400
300
100
~
~
200
TJ = 25ºC
100
0
50
0
IL = 100µA
110
-75 -50 -25
0
25 50 75 100 125 150
100µA
1mA
OUTPUT CURRENT
10mA
100mA
-75 -50 -25
0
25 50 75 100 125 150
TEMPERATURE (ºC)
TEMPERATURE (ºC)
Rev. 9/29/00
AS2950/AS2951
TYPICAL PERFORMANCE CHARACTERISTICS (continued)
AS2951
LINE TRANSIENT RESPONSE
ERROR COMPARATOR OUTPUT
COMPARATOR SINK CURRENT
2.5
2.0
100
8
6
mV
VOUT= 5V
TA = 125ºC
50
mV
0
1.5
1.0
4
TA = 25ºC
TA = -55ºC
CL = 1µF
IL = 1mA
VOUT = 5V
-50
HYSTERESIS
mV
~
~
2
8V
0
0.5
0.0
6V
4V
PULLUP RESISTOR TO
SEPARATE 5V SUPPLY
-2
0
1
2
3
4
5
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
0
200
400
600
800
INPUT VOLTAGE (V)
OUTPUT LOW VOLTAGE (V)
TIME(µs)
RIPPLE REJECTION
RIPPLE REJECTION
OUTPUT IMPEDANCE
10
90
90
80
70
60
50
40
30
20
IO = 100µA
IO = 1mA
5
2
80
70
60
50
40
CL= 1µF
VIN = 6V
VOUT = 5V
IL = 10mA
IL = 0
IO = 100mA
1
0.5
0.2
VOUT = 5V
CL = 1µF
0.1
0.05
IL = 100µA
CL = 1µF
VIN = 6V
VOUT = 5V
30
20
0.02
0.01
IL = 10mA
104
103
101
102
103
FREQUENCY (Hz)
104
105
106
106
10
100
1K
FREQUENCY (Hz)
10K
100K
1M
101
102
105
FREQUENCY (Hz)
AS2951
FEEDBACK PIN CURRENT
AS2951
FEEDBACK BIAS CURRENT
AS2951
MINIMUM OPERATING VOLTAGE
10
1
20
10
50
0
PIN 7 DRIVEN BY EXTERNAL
SOURCE (REGULATOR RUN
OPEN LOOP)
-50
TA =1 25ºC
0
-100
-150
-200
-250
-10
-20
-30
0.1
TA = 25ºC
TA = 55ºC
0.01
-75 -50 -25
0
25 50 75 100 125 150
-75 -50 -25
0
25 50 75 100 125 150
-2.0 -1.5 -1.0 -0.5
0
0.5 1.0
TEMPEATURE (ºC)
FEEDBACK VOLTAGE (V)
TEMPERATURE
ENABLE TRANSIENT
LOAD TRANSIENT RESPONSE
LOAD TRANSIENT RESPONSE
80
60
40
250
200
150
7
6
5
4
20
0
-20
-40
-60
100
50
0
-50
-100
3
2
1
0
CL = 1µF
IL = 10mA
VIN = 8V
CL = 10µF VOUT = 5V
VOUT = 5V
CL = 1µF
VOUT = 5V
~
~
~
~
100
mA
2
0
100
µA
100
µA
100
µA
-2
0
1
2
3
4
5
0
4
8
12
16
20
-100
100 200 300 400 500 600 700
0
TIME (ms)
TIME (ms)
TIME
Rev. 9/29/00
AS2950/AS2951
TYPICAL PERFORMANCE CHARACTERISTICS (continued)
AS2950 MAXIUM RATED OUTPUT
AS2950 MAXIUM RATED OUTPUT
AS2951 DIVIDER RESISTANCE
CURRENT
120
400
300
200
120
8-PIN
MOLDED
DIP SOLDERED
TO PC BOARD
TJMAX = 125º C
VOUT = 5V
TA = 25ºC
TO-92 PACKAGE
0.25" LEADS SOLDERED
TO PC BOARD
100
100
80
80
TJMAX = 125 ºC
60
60
40
TA = 50ºC
40
20
0
TA=25 ºC
100
0
20
0
TA = 85ºC
TA = 85 ºC
0
5
10
15
20
25
30
0
5
10
INPUT VOLTAGE (V)
SHUTDOWN THRESHOLD VOLTAGE
15
20
25
30
-75 -50 -25
0
25 50 75 100 125 150
INPUT VOLTAGE (V)
OUTPUT NOISE
TEMPERATURE (ºC)
THERMAL RESPONSE
3.5
3.0
5
4
1.8
1.6
IL = 100mA
CL = 1µF
2.5
2.0
1.5
1.0
2
CL = 220µF
CL = 3.3µF
1.4
1.2
0
-2
1
~
~
1.0
0.8
0.6
1.25W
0.5
0.0
0
-1
-75 -50 -25
0
25 50 75 100 125 150
0
10
20
30
40
50
102
103
104
105
TEMPERATURE (ºC)
TIME (µs)
FREQUENCY (Hz)
LINE REGULATION
RIPPLE REJECTION
80
70
60
50
40
30
20
10
30
25
20
15
10
5
IL = 50µA
IL = 100µA
TJ = 150 ºC
IL = 100mA
IL = 1mA
0
~
~
CL = 1µF
VIN = 6V
VOUT = 5V
10
5
0
-5
-10
TJ = 125 ºC
IL = 100µA
101
102
103
FREQUENCY (Hz)
104
105
106
5
10
15
20
25
30
INPUT VOLTAGE (V)
Rev. 9/29/00
AS2950/AS2951
TYPICAL APPLICATIONS
+V
IN
4.75V
OUTPUT
100K
8
VOLTAGE
+V
______
IN
ERROR
5
ERROR
1.2 to 30V
1
OUTPUT
VOUT
_______
ERROR*
AS2951
+
3
R
1
SHUTDOWN
INPUT
3.3uF
SD
.01uF
FB
GND
7
4
1.23V
VREF
+
+
5.0V
R
2
INPUT
VOLTAGE
+
1.3V
+
Figure 2. Adjustable Regulator
* See Application Info.
_______
Figure 1. ERROR Output Timing
+VIN
+VIN
470K
8
Ω ..
+VIN
______
5
8
VOUT
470KΩ .. ERROR
1
+VIN
VOUT
______
ERROR
ERROR
5
*VOUT = VIN
1
OUTPUT
VOUT
ALPHA
2951
2951
+
3
R1
1uF
SD
3
SHUTDOWN
INPUT
SD
FB
7
GND
4
FB
GND
7
4
*MINIMUM INPUT-OUTPUT VOLTAGE RANGES FROM 4mV TO 400mV.
DEPENDING ON LOAD CURRENT. CURRENT LIMIT IS TYPICALLY 160mA
R2
Wide Input Vltage Range Current Limiter
Latch Off When Error Flag Occurs
Rev. 9/29/00
AS2950/AS2951
TYPICAL APPLICATIONS (Continued)
+
6V
SEALED
LEAD-
ACID
1.5K
Ω ..
120K
FB
Ω ..
8
1N457
BATTERY
SOURCE
+VIN
1
2
MAIN V-
AS385
VOUT
2951
MEMORY V+
SENSE
400K
Ω ..
+
FOR 5.5 V
3
20K
Ω ..
1uF
SD
100K
Ω ..
GND
4
NI-CAD
BACKUP
BATTERY
Low Battery Disconnect
8
2
Ω
39k
SENSE
+V
ERROR
IN
+V OUT = 5V
5
3
1
7
V
OUT
RESET
+
µ
1
F
-
2951
C4
SD
FB
+
GND
4
TAP
6
Ω
39k
1%
Ω
100k
-
Ω
100k
C1
+
6V
Ω
1k
LEAD-
<5.8V**
<6.0V**
1%
1%
ACID
BATTERY
-
Ω
100k
C2
+
-
Ω
100k
Ω
1k
C3
+
<6.2V**
Ω
10k
R
3
*OPTIONAL LATCH OFF WHEN DROPOUT OCCURS.
ADJUST R3 FOR C2 SWITCHING VIN IS 6.0V.
**OUTPUTS GO LOW WHEN VIN DROPS BELOW
DESIGNATED THRESHOLDS.
1%
Ω
20k
Regulator with State-of-Charge Indicator
Rev. 9/29/00
AS2950/AS2951
TYPICAL APPLICATIONS (continued)
+
6V
1.5K
SEALED
LEAD-
ACID
Ω
..
120K
Ω
..
8
1N457
BATTERY
SOURCE
+VIN
FB
1
2
MAIN V-
AS385
VOUT
MEMORY V+
20K
2951
SENSE
400K
Ω
..
+
FOR 5.5 V
3
Ω
1uF
..
SD
100K
Ω
..
GND
4
NI-CAD
BACKUP
BATTERY
Low Battery Disconnect
8
2
Ω
39k ..
SENSE
VOUT
+VIN
______
ERROR
+VOUT = 5V
5
3
1
RESET
+
1uF
-
2951
C4
SD
7
FB
+
Ω
39k ..
GND
4
TAP
6
1%
1%
100kΩ
..
-
100k ..
Ω
C1
C2
+
6V
Ω
1k
..
LEAD-
<5.8V**
<6.0V**
<6.2V**
ACID
-
100kΩ
..
BATTERY
+
-
Ω
100k ..
1%
1kΩ
..
C3
+
10kΩ
..
R3
*OPTIONAL LATCH OFF WHEN DROPOUT OCCURS. ADJUST R3
FOR C2 SWITCHING VIN IS 6.0V.
**OUTPUTS GO LOW WHEN VIN DROPS BELOW DESIGNATED
THRESHOLDS.
1%
Ω
20k ..
Regulator with State-of-Charge Indicator
Rev. 9/29/00
AS2950/AS2951
TYPICAL APPLICATIONS (continued)
+VIN
8
10KΩ
..
+VIN
_______
ERROR
5
1
3
5 DEGREE SHUTDOWN
AUX SHUTDOW
SD
ON
OFF
2951
VOUT
FB
7
GND
4
EXTERNAL CIRCUIT
PROTECTED
OR
+
OVER
(V+ GOES OFF
TEMP
RELAY
TEMP > 125)
AS35
SENSOR
-
8.2KΩ
..
System Over Temperature Protection Circuit
+5V
4.7mA
4
20mA
UNREGULATED INPUT
8
OUTPUT
+VIN
5
1
7
330KΩ
..
IN
1
2
VOUT
2N5432
VOUT
1N4001
0.1uF
Ω
27K ..
2951
2951
FB
2
3
5V
VTAP
SENSE
GND
FB
7
GND
OUTPUT
+
Ω
..
360K
4
4.7uF
4
LOAD
50mA
TO
1N457
MIN VOLTAGE = 4V
300 mA
300 mA Regulator with 0.75 Dropout
Open Circuit Detector for 4mA to 20mA Current Loop
Rev. 9/29/00
AS2950/AS2951
SCHEMATIC DIAGRAM
Rev. 9/29/00
相关型号：
AS2951ACS-3.3
Fixed/Adjustable Positive LDO Regulator, 3.26V Min, 3.34V Max, 0.5V Dropout, BIPolar, PDSO8, 0.150 INCH, PLASTIC, SOIC-8
CALOGIC
AS2951ACS-5.0
Fixed/Adjustable Positive LDO Regulator, 4.94V Min, 5.06V Max, 0.5V Dropout, BIPolar, PDSO8, 0.150 INCH, PLASTIC, SOIC-8
CALOGIC
AS2951CP-3.0
Fixed/Adjustable Positive LDO Regulator, 2.94V Min, 3.06V Max, 0.5V Dropout, BIPolar, PDIP8, PLASTIC, DIP-8
CALOGIC
AS2951CP-3.3
Fixed/Adjustable Positive LDO Regulator, 3.23V Min, 3.366V Max, 0.5V Dropout, BIPolar, PDIP8, PLASTIC, DIP-8
CALOGIC
AS2951CP-5.0
Fixed/Adjustable Positive LDO Regulator, 4.9V Min, 5.1V Max, 0.5V Dropout, BIPolar, PDIP8, PLASTIC, DIP-8
CALOGIC
AS2951CS-3.0
Fixed/Adjustable Positive LDO Regulator, 2.94V Min, 3.06V Max, 0.5V Dropout, BIPolar, PDSO8, 0.150 INCH, PLASTIC, SOIC-8
CALOGIC
AS2951CS-3.3
Fixed/Adjustable Positive LDO Regulator, 3.23V Min, 3.366V Max, 0.5V Dropout, BIPolar, PDSO8, 0.150 INCH, PLASTIC, SOIC-8
CALOGIC
AS2951CS-5.0
Fixed/Adjustable Positive LDO Regulator, 4.9V Min, 5.1V Max, 0.5V Dropout, BIPolar, PDSO8, 0.150 INCH, PLASTIC, SOIC-8
CALOGIC
©2020 ICPDF网 联系我们和版权申明