ST L4909 User Manual
L4909
L4909
EXTERNALLY ADJUSTABLE MULTIFUNCTION REGULATOR
■3 OUTPUTS
-Vo1 : output voltage variable from 5 to 12 V; limit current : 1.2 A.
-Vo2 : output voltage variable from 5 to 12 V; limit current : 1.2 A.
-Vo3 : output voltage variable from 5 to 12 V; limit current : 1.2 A.
■ENABLE INPUT FOR EACH REGULATOR
■FEEDBACK INPUT FOR EACH REGULATOR
■SHORT CIRCUIT PROTECTION TO GROUND
■OVERCURRENT WARNING
■DRIVER FOR EXTERNAL SCR (CROWBAR PROTECTION)
■THERMAL SHUTDOWN
DESCRIPTION
It is a monolithic Multifunction Voltage Regulator; it contains 3 regulators, (REG1, REG2, REG3) each one with an enable input and a feedback input, to allow the voltage setting via external resistive divider.
BLOCK DIAGRAM
|
THERMAL |
REFERENCE |
|
SHUTDOWN |
GENERATOR |
6 |
|
REG1 |
EN1 |
|
|
7 |
ENABLE |
REG2 |
EN2 |
CONTROL |
|
9 |
|
|
EN3 |
|
REG3 |
|
+ |
+ |
5 |
|
|
OC |
OVER |
|
|
|
|
|
CURRENT |
|
|
CHECK |
|
4 |
|
|
TRIG |
|
|
8 |
|
|
GND |
|
|
MULTIWATT 15
Each regulator is current limited and furthermore an OR-ed warning signal is output (open collector, active low output) when the current in a regulator goes above an over-current threshold (1 A typ for any regulator).
When one output voltage is higher than 20% typ of its nominal value (for instance in case of input-to-output short circuit), the crowbar output pin is activated, triggering an external SCR (connected between input and ground) that blows the input line fuse.
REF
+ |
VINA, VINB |
|
REF+20% |
3,13 |
|
|
+ |
|
+ |
|
|
REG1 |
2 |
|
- |
||
- |
VO1 |
|
1 |
||
+ |
||
FB1 |
||
|
+ |
|
+ |
|
|
REG2 |
14 |
|
- |
||
- |
VO2 |
|
15 |
||
+ |
||
FB2 |
||
|
+ |
|
+ |
|
|
REG3 |
11 |
|
- |
||
- |
VO3 |
|
10 |
||
+ |
||
FB3 |
D00AU1171
May 2000 |
1/7 |
L4909
PIN CONNECTION
15 |
FB2 |
14 |
VO2 |
13 |
VINB |
12 |
N.C. |
11 |
VO3 |
10 |
FB3 |
9 |
EN3 |
8 |
GND |
7 |
EN2 |
6 |
EN1 |
5 |
OC |
4 |
TRIG |
3 |
VINA |
2 |
VO1 |
1 |
FB1 |
TAB CONNECTED TO PIN 8 |
D00AU1153 |
Table 1. Pin Description
No. Pin |
Name |
Function |
1 |
FB1 |
REG1 feedback voltage input |
2 |
Vo1 |
REG1 output voltage |
3 |
VinA |
Input DC supply voltage |
4 |
TRIG |
Trigger for external SCR (crowbar protection) |
5 |
OC |
Over current warning output |
6 |
EN1 |
REG1 enable input |
7 |
EN2 |
REG2 enable input |
8 |
GND |
Analog ground |
9 |
EN3 |
REG3 enable input |
10 |
FB3 |
REG3 feedback voltage input |
11 |
Vo3 |
REG3 output voltage |
12 |
N.C. |
Not Connected |
13 |
VinB |
Input DC supply voltage |
14 |
Vo2 |
REG2 output voltage |
15 |
FB2 |
REG2 feedback voltage input |
2/7
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|
|
L4909 |
ABSOLUTE MAXIMUM RATINGS |
|
|
|
Symbol |
Parameter |
Value |
Unit |
Vin |
VinA,VinB input DC supply voltage |
40 |
V |
Io |
Vo1, Vo2, Vo3 output currents |
internally limited |
|
Voc |
OC output voltage |
min (15, Vin) |
V |
VENx |
ENx input voltage |
15 |
V |
Top |
Operating temperature range |
0 to 70 |
o |
|
|
|
C |
Tstg |
Storage temperature |
- 40 to 150 |
oC |
THERMAL DATA |
|
|
|
Symbol |
Parameter |
Value |
Unit |
RTH j-case |
Thermal Resistance Junction to Case |
1.8 |
°C/W |
ELECTRICAL CHARACTERISTICS (Cout = 100nF; Vin -Vo = 5V; Io = 10mA; Tcase = 25°C unless otherwise specified
Symbol |
Parameter |
Test Condition |
Min. |
Typ. |
Max. |
Unit |
Vo1 |
REG1 output voltage range |
V(FB1) |
REG1 feedback voltage |
Ilim1 |
REG1 output current limit |
Vo1 |
line regulation |
------------- |
|
Vo1 |
|
Vo1 |
load regulation |
------------- |
|
Vo1 |
|
Vd1 |
REG1 drop out |
SVR1 |
REG1 supply voltage rejec. |
Vo2 |
REG2 output voltage range |
V(FB2) |
REG2 feedback voltage |
Ilim2 |
REG2 output current limit |
Vo2 |
line regulation |
------------- |
|
Vo2 |
|
Vo2 |
load regulation |
------------- |
|
Vo2 |
|
|
5 |
|
12 |
V |
EN1=ON; |
1.22 |
1.27 |
1.32 |
V |
EN1=ON; Vin-Vo1<12V |
1.20 |
1.70 |
|
A |
Io1=10mA; Vin-Vo1=3 to 25 V |
|
0.6 |
2 |
% |
Io1=10mA; Vin-Vo1=3 to 12 V |
|
0.1 |
|
|
Io1=10 mA to 1.2A |
|
0.5 |
2 |
% |
Io1=10 mA to 0.5A |
|
0.1 |
|
|
Io1=500mA |
|
|
2.20 |
V |
freq=120 Hz to 1KHz |
60 |
|
|
dB |
|
5 |
|
12 |
V |
EN2 = ON; |
1.22 |
1.27 |
1.32 |
V |
EN2=ON; Vin-Vo2<12V |
1.20 |
1.70 |
|
A |
Io2=10mA;Vin-Vo2=3 to 25 V |
|
0.6 |
2 |
% |
Io2=10mA;Vin-Vo2=3 to 12 V |
|
0.1 |
|
|
Io2=10 mA to 1.2A |
|
0.5 |
2 |
% |
Io2=10 mA to 0.5A |
|
0.1 |
|
|
Vd2 |
REG2 drop out |
Io2=500mA |
2.2 |
V |
3/7
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