l4947r STMicroelectronics, l4947r Datasheet - Page 3

• Manufacturer Part Number: l4947r
• Description: 5v-0.5a Very Low Drop Regulator With Reset
• Manufacturer: STMicroelectronics

ELECTRICAL CHARACTERISTICS (refer to the test circuit, V
R
(*) For a DC voltage 26 < V
FUNCTIONAL DESCRIPTION
The L4947/L4947R is a very low drop 5V/0.5A
voltage regulator provided with a reset function
and therefore particularly suited to meet the re-
quirements of supplying the microprocessor sys-
tems used in automotive and industrial applica-
tions.
The block diagram shows the basic structure of
the device : the reference, the error amplifier, the
p
Symbol
V
= 1K , R
V
V
V
V
SVR
RT peak
V
RT (off)
RT (on)
i
V
V
V
V
I
disch
T
V
I
Hyst
–V
I
I
V
V
sc
T
V
R
dH
q
d
R
o
d
d
i
o
o
o
o
L
Output Voltage
Operating Input Voltage
Line Regulation
Load Regulation
Dropout Voltage
Quiescent Current
Temperature Output Voltage
Drift
Supply Volt. Rej.
Output Short Circuit Current
Reset Output Saturation Voltage
Reset Output Leakage Current
Power On-Off Reset out Peak
Voltage
Power OFF V
Power ON V
Power ON-Off Hysteresis
Delay Comparator Threshold
Delay Comparator Hysteresis
Delay Capacitor Charging
Current
Delay Capacitor Discharge
Voltage
Power on Reset Delay Time
= 1K , –40 C
i
< 37V the device is not operating
Parameter
o
o
Threshold
Threshold
T
J
125 C, unless otherwise specified)
I
Over Full T Range
T
I
V
I
I
I
Over Full T Range
I
I
I
I
C
V
1.5V < V
I
3.0V < V
I
V
1K Reset Pull-up to V
25 C
T
L4947: V
Transition
L4947R: V
L Transition
V
Transition
V
V
Transition
V
Transition
V
V
C
o
o
o
o
o
o
o
o
o
R
R
J
J
i
o
i
O
o
RT (on)
d
d
d
o
d
= 0mA to 500mA
= 0mA to (*) 500mA
= 5mA
= 5mA to 500mA
= 500mA, T
= 0mA, T
= 0mA Over Full T
= 500mA Over Full T
= 350mA ; f = 120Hz
= 6V to 26V ;
= 12V
= 1.6mA
= 8mA
= 25 C
= 25 C
@ Reset Out L to H
@ Reset Out L to H
@ Reset Out H to L
= 3V, T
< V
= 100 F ;
in Regulation, V
= 100nF, T
RT (off)
Test Conditions
–V
o
o
o
< V
< V
RT (off)
5V
@ Reset Out H to L
o
J
J
@ Reset Out H to
= 25 C
driver, the power PNP, the protection and reset
functions.
The power stage is a Lateral PNP transistor
which allows a very low dropout voltage (typ.
400mV at T
temperature range @ I
curve of the dropout voltage as a function of the
junction temperature is shown in Fig. 1 : that is
the worst case, where I
= 25 C
pp
RT (off)
RT (off)
J
J
= 25 C
= 25 C
R
,
,
= 5V
i
= 14. 4V, C
o
, T
J
J
=
= 25 C, max. 750mV over the full
Min.
4.80
4.90
0.50
4.70
4.75
4.55
3.65
3.20
50
10
o
6
= 47 F, ESR < 10 ,
O
O
= 500mA.
Vo–0.15
Vo–0.30
= 500mA). The typical
V
+ 0.05
– 0.5
Typ.
5.00
5.00
0.40
0.80
0.50
0.05
4.00
3.55
0.45
0.55
110
RT (off)
6.5
15
60
20
20
2
5
L4947 - L4947R
Max.
5.20
5.10
0.55
0.75
1.50
0.40
0.40
0.80
V
0.04
4.35
3.90
1.20
180
26
10
60
10
13
50
30
o
–
mV/ C
Unit
mV
mV
mA
mA
mA
/ A
ms
dB
V
V
V
V
V
A
V
V
V
V
V
V
V
V
V
V
V
V
A
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