MIC2950/2951
Micrel
+
6V
120kΩ
1.5kΩ**
SEALED
LEAD-
ACID
1N457
8
+V
IN
FB
BATTERY
SOURCE
LM385
1
2
V
OUT
–
MIC2951
SENSE
≈ 400kΩ*
FOR 5.5V
3
SD
100kΩ
+
GND
4
1µF
* Sets disconnect voltage
** Sets disconnect hysteresis
Low-Battery Disconnect
For values shown, Regulator shuts down when VIN < 5.5 V and turns on again at 6.0 V. Current drain in disconnected mode is 150µA.
+V
IN
8
10kΩ
+V
IN
5° PRE-SHUTDOWN FLAG
3
5
1
AUX. SHUTDOWN
INPUT
ERROR
MIC2951
SD
OFF
V
OUT
ON
EXTERNAL CIRCUIT
PROTECTED FROM
OVER TEMPERATURE
(V+ GOES OFF WHEN
TEMP.> 125°)
GND
4
FB
OR
+
7
TEMP. LM34 OR
RELAY
SENSOR
LM35
8.2kΩ
–
LM34 for 125°F Shutdown
LM35 for 125°C Shutdown
System Overtemperature Protection Circuit
Schematic Diagram
FEEDBACK
IN
R18
20kΩ
Q15A
100 x
Q15B
Q24
R27
Q26
Q25
OUT
Q9
R11
18
kΩ
Q3
Q4
Q7
SENSE
Q8
Q5
R17
12 kΩ
C1
20
pF
182 kΩ
Q14
R11
20.6
kΩ
Q6
Q17
Q16
5V TAP
Q1
10
R28
60 kΩ
Q2
Q20
R1
20 kΩ
Q22
R10
150
kΩ
Q42
R8
31.4 kΩ
Q21
Q23
C2
40 pF
R2
50 kΩ
R15
100 kΩ
R5
180
kΩ
R6
140
kΩ
R9
27.8 kΩ
R12
110
kΩ
R14
350
kΩ
R13
100
kΩ
R16
30 kΩ
Q40
Q13
Q12
R17
Q41
Q11
10 Ω
Q29
R30
30
Q18
Q19
Q28
kΩ
R3
50 kΩ
R4
13 kΩ
R21 8 Ω
50 kΩ
10 kΩ
Q30 Q31
SHDN
R23 60 kΩ
Q37
Q36
R22
150 kΩ
R24
50 kΩ
ERROR
Q38
Q34
R26
60 kΩ
DENOTES CONNECTION ON MIC2950 ONLY
R25
2.8 kΩ
GND
Q39
3-62
February 1999
MICREL [ MICREL SEMICONDUCTOR ]
