ST L4925 User Manual
查询L4925供应商
VERY LOW DROP VOLTAGE REGULATOR
OPERATINGDC SUPPLY VOLTAGERANGE
6V TO 28V
TRANSIENTSUPPLYVOLTAGEUP TO 40V
EXTREMELY LOW QUIESCENTCURRENT
HIGHPRECISIONOUTPUT VOLTAGE
OUTPUT CURRENT CAPABILITY UP TO
500mA
VERY LOW DROPOUT VOLTAGE LESS
THAN 0.6V
RESET CIRCUIT SENSING THE OUTPUT
VOLTAGE
PROGRAMMABLE RESET PULSE DELAY
WITH EXTERNALCAPACITOR
THERMAL SHUTDOWN AND SHORT CIR-
CUIT PROTECTIONS
DESCRIPTION
The L4925 is a monolithic integrated 5V voltage
regulator with a very low dropoutoutput and addi-
L4925
Pentawatt
ORDERING NUMBERS:
tional functions such as power-on reset and programmable reset delay time. It is designed for
supplying microcomputer controlled systems especiallyin automotiveapplications.
PowerSO20
L4925 (Pentawatt)
L4925PD (PowerSO20)
BLOCK DIAGRAM
V
S
C
S
GND
PREREGULATOR
5V
+
-
Vz
VREF
1.23V
RESETREG
Vz
2µ
L4925N
2V
=
D95AT151
CT
RES
V
O
June 2000
This is advanced informationon a newproduct now in development or undergoing evaluation.Details are subject to change withoutnotice.
1/8
L4925
ABSOLUTE MAXIMUM RATINGS
Symbol Parameter Value Unit
V
SDC
V
STR
I
O
V
O
V
RES
I
RES
T
stg
T
j
T
j-SD
NOTE:
The circuit is ESD protected according to MIL-STD-883C. According to ISO/DIS 7637 the transients must be clamped with external circuitry
(see Application Circuit).
CONNECTIONDIAGRAM
DC Operating Supply Voltage 28 V
Transient Supply Voltage (t < 1s) 40 V
Output Current internally limited
Output Voltage 20 V
Output Voltage 20 V
Output Current 5 mA
Storage Temperature -55 to 150
C
°
Operating Junction Temperature -40 to 150 °C
Thermal Shutdown-Junction Temperature 165 °C
N.C.
N.C.
V
S
V
S
N.C.
N.C.
RES
N.C.
N.C. N.C.
GND N.C.
2
3
4
5
6
7
8
9
10
D95AT152
20
19
18
17
16
15
14
13
12
11
THERMAL DATA
Symbol Parameter Pentawatt SO 20 Unit
R
th j-amb
R
th j-case
Thermal resistance junction to ambient max.
Thermal resistance junction to case max.
60
3.5
77 to 97 °C/W
N.C.1
N.C.
N.C.
VOUT
VOUT
N.C.
CT
N.C.
°C/W
2/8
L4925
ELECTRICALCHARACTERISTICS
=14VTj=–40 to 125°C unless otherwise specified;
(V
S
Symbol Parameter Test Condition Min. Typ. Max. Unit
V
O
V
O
V
DP
V
IO
Output Voltage VI= 6 to28V; IO= 1 to 500mA 4.90 5 5.10 V
Output Voltage VI= 35V; T <1s;
I
= 1 to 500mA
O
Dropout Voltage IO= 100mA
I
= 500mA
O
Input to Output Voltage
V
= 4V; IO= 100mA 0.5 V
I
0.2
0.3
5.50 V
0.3
0.6
Difference in Undervoltage
Condition
V
I
V
I
LIM
QSE
OL
OLO
I
Q
Line Regulation VI = 6 to 28V; IO= 1 to1mA 10 mV
Load Regulation IO= 1 to 500mA 50 mV
Current Limit VO= 4.5V
VO= 0;Foldback characteristic
;
550 1000
250
1500 mA
Quiescent Current IO= 0.3mA 190 360 µA
Quiescent Current IO= 500mA 20 mA
RESET
Symbol Parameter Test Condition Min. Typ. Max. Unit
V
V
t
t
V
I
V
V
CTth hy
RT
RTH
RD
RR
RL
RH
CTth
Reset Threshold Voltage 4.5 5.2 V
Reset Threshold 50 100 200 mV
Reset Pulse Delay CT= 100nF; tR> 100µs 60 100 140 ms
Reset Reaction Time CT= 100nF; 5 30
Reset Output LOW Voltage R
Reset Output HIGH Leakage
= 10KΩ to VO;VS=> 3V 0.4 V
RES
V
=5V 1 µA
RES
Current
Delay Comparator Threshold 2 V
Delay Comparator Threshold
200 mV
Hysteresis
V
V
mA
µ
s
APPLICATIONCIRCUIT DIAGRAM
PREREGULATOR
5V
VBAT
For stability: C
Recommendedfor application:C
V
S
C
S
GND
>1µF; CO>10µF;ESR< 2.5Ωat 10KHz
S
S=CO
Vz
+
-
=10µF to100µF
VREF
1.23V
RESETREG
Vo
L4925N
Vz
2µ
2V
=
D95AT153
Co
CT
RES
Vout
RES
3/8
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