rc2951mt Fairchild Semiconductor, rc2951mt Datasheet - Page 8

• Manufacturer Part Number: rc2951mt
• Description: Adjustable Micropower Voltage Regulator
• Manufacturer: Fairchild Semiconductor

RC2951
Typical Applications
8
Figure 7. Regulator with Early Warning and Auxillary Output
• Early warning flag on low input voltage
• Main output latches of f at lower input voltages
• Battery backup on auxillary output
Operation Reg. #1’s V
flag becomes active when V
flag of Reg. #2 becomes active and via Q1 latches the main output off.
When V
warning signal rises unlatching Reg. #2 via D3.
Q
1
Figure 8. Latch Off When Error Flag Occurs
in
again exceeds 5.7V Reg. #1 is back in regulation and the early
Reset
2.7MΩ
6
6
7
7
3
470kΩ
470kΩ
V
V
FB
FB
SD
+V
+V
+V
TAP
TAP
IN
IN
IN
8
8
RC2951
RC2951
OUT
5
3
GND
GND
#1
#2
ERROR
D
SD
SENSE
SENSE
is programmed one diode drop above 5V. Its error
ERROR
ERROR
4
4
4
in
V
V
≤ 5.7V. WhenV
OUT
OUT
RC2951
2
27kΩ
2
+V
+V
GND
IN
IN
D
4
8
1
1
5
5
1
V
(continued)
D
OUT
FB
3
in
1
7
Main 5V Output
drops below 5.3V, the error
330kΩ
+
+
R
R
1µF
1
2
1µF
EARLY WARNING
D
2
+
V
5V Memory
OUT
V
RESET
Supply
DD
1µF
20
µP
3.6V
Nicad
Figure 11. Open Circuit Detector for 4mA to 20mA Current Loop
V
For 5V
*High input lowers V
OUT
Shutdown
Input
*Sleep
Input
Error
Output
2N3906
Current
Limit Section
20kΩ
680
Figure 10. 5V Regulator with 2.5V Sleep Function
4.7MΩ
= 1.23V
4
220
OUT
Figure 9. 2 Ampere Low Dropout Regulator
,use internal resistors. Wire pin 6 to 7, & wire pin 2 +V
0.1µF
1N
4001
.033
20mA
(
5
3
47kΩ
1 +
ERROR
SD
3
GND
R
R
OUT
SD
1
2
4
RC2951
GND
+V
)
+V
+V
to 2.5V.
RC2951
RC2951
4
IN
+V
GND
V
IN
IN
= V
8
IN
ERROR
IN
8
8
4
Min. Voltages ≈ 4V
470
V
V
FB
OUT
V
OUT
OUT
1N457
7
FB
OUT
FB
1
+5.0V
47
C-MOS
GATE
1
5
7
1
7
100
pF
10kΩ
Error
Flag
PRODUCT SPECIFICATION
2N3906
470kΩ
1
2
360
4.7kΩ
MJE2955
R
1%
R
0.05
1
2
+5V
REV. 1.0.1 4/8/02
200kΩ
1%
100kΩ
1%
100kΩ
+
* High for
I
L
+V
TANT.
< 3.5mA
5
Output*
+V
4
OUT
+
4.7
OUT
OUT
3.3µF
@ 2A
+
2950-13
Buss.
100
µF