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L4938E

P1-P3P4-P6P7-P9P10-P12
L4938E/ED
L4938EPD
ADVANCED VOLTAGE REGULATOR
ENABLE AND SENSE INPUTS (EN, SI) PRO-
TECTED AGAINST NEGATIVE TRANSIENTS
DOWN TO -5V
RESET THRESHOLD ADJUSTABLE FROM
3.8 TO 4.7V
EXTREMELY LOW QUIESCENT CURRENT,
65
µ
A (LESS THAN 90
µ
A) IN STANDBY
MODE
OPERATING DC SUPPLY VOLTAGE RANGE
5V - 28V
OPERATING TRANSIENT SUPPLY VOLT-
AGE UP TO 40V
HIGH PRECISION STANDBY OUTPUT VOLT-
AGE 5V
±
1% WITH 100mA CURRENT CA-
PABILITY
OUTPUT 2 VOLTAGE 5V
±
2% WITH 400mA
CURRENT CAPABILITY (ADJ WIRED TO
V
OUT2
)
OUTPUT 2 VOLTAGE ADJUSTABLE BY EX-
TERNAL VOLTAGE DIVIDER
OUTPUT 2 DISABLE FUNCTION FOR
STANDBY MODE
DESCRIPTION
The L4938E/ED/EPD is a monolithic integrated
dual voltage regulator with two very low dropout
outputs and additional functions as power-on re-
set and input voltage sense. It is designed for
supplying the microcomputer controlled systems
especially in automotive applications.
February 1999
®
PIN CONNECTIONS
DIP (12+2+2) SO20 (12+4+4) PowerSO20
ORDERING NUMBERS:
L4938E (DIP)
L4938ED (SO)
L4938EPD (PSO)
PR
CT
EN
GND
GND
SO
RES
1
3
2
4
5
6
7 OUT2
GND
N.C.
GND
VS2
VS1
SI16
15
14
13
12
10
11
D94AT075A
OUT1 8 ADJ9
DIP (12+2+2)
PR
CT
EN
GND
GND
GND
GND
RES
SO OUT2
N.C.
GND
GND
GND
GND
VS2
VS1
SI1
3
2
4
5
6
7
8
9
18
17
16
15
14
12
13
11
19
10
20
OUT1 ADJ
D94AT076A
SO (12+4+4)
GND
N.C.
N.C.
V
S2
V
S1
PR
SI
CT
EN
N.C.
GND 10
8
9
7
6
5
4
3
2
13
14
15
16
17
19
18
20
12
1
11
GND
L4938EPD
N.C.
RESET
OUT1
SO
ADJ
OUT2
N.C.
GND
PowerSO20
1/12
Obsolete Product(s) - Obsolete Product(s)
Obsolete Product(s) - Obsolete Product(s)
REG1
1.23V REFERENCE
REG2
1.23V
RESET
1.4V
1.23V
1.23V
SENSE
VS1
VS2
EN
PR
SI
SO
RES
CT
ADJ
OUT2
OUT1
GND
D94AT074A
BLOCK DIAGRAM
ABSOLUTE MAXIMUM RATINGS
Symbol Parameter Value Unit
V
INDC
DC Operating Supply Voltage 28 V
V
INTR
Transient Operating Supply Voltage (T < 400ms) -14 to 40 V
I
O
Output Current internally limited
V
SI
Sense Input Voltage (Voltage Forced) (note 2) -20 to 20 V
I
SI
Sense Input Current (Current Forced) (note 2) ±1mA
V
EN
Enable Input Voltage (Voltage Forced) (note 2) -20 to 20 V
I
EN
Sense Input Current (Current Forced) (note 2) ±1mA
V
RES
, V
SO
Output Voltages -0.3 to 20 V
I
RES
, I
SO
Output Currents (Output Low) 5 mA
P
O
Power Dissipation at T
amb
= 80°C (note 3)
Powerdip 12+2+2
875 mW
T
stg
Storage Temperature -65 to 150 °C
T
j
Operating Junction Temperature -40 to 150 °C
T
JSD
Thermal shutdown junction temperature Output 2 will shut-down
typically at Tj 10K lower than output 1
165 °C
Note 1: The circuit is ESD protected according to MIL-STD-883C
Note 2: Current forced means voltage unlimited but current limited to the specified value
Voltage forced means voltage limited to the specified valueswhile the current is not limited
Note 3: Typical value soldered on a PC board with 8cm
2
copper ground plane (35mm thick).
L4938E - L4938ED - L4938EPD
2/12
Obsolete Product(s) - Obsolete Product(s)
ELECTRICAL CHARACTERISTICS
(V
S
= 14V; T
j
= -40 to 150
°
C unless otherwise specified.)
Symbol Parameter Test Condition Min. Typ. Max. Unit
OUT 1
V
O1
Supply Output Voltage V
S
= 6 to 28V;
I
O1
= 400µA to 100mA
4.955.1V
T
j
≤125°C; I
O1
= 50 to 400µA 4.8 5 5.2 V
V
DP1
Dropoutput Voltage 1 I
OUT1
= 10mA 0.1 0.2 V
I
OUT1
= 100mA; V
S
= 4.8V 0.2 0.4 V
V
OL01
Load Regulation 1 I
OUT1
= 1 to 100mA
(after regulation setting)
25 mV
V
LIM1
Current Limit 1 VOUT1 = 0.8 to 4.5V 100 200 400 mA
I
QSB
Quiescent Current in Standby
Mode
I
EN
≥ 2.4V (output 2 disabled)
I
O1
= 0.1mA; V
SI
> 1.3V
65 90 µA
T
J
< 85°C; R
PR
= 0 75 µA
OUT 2
V
O2
Output Voltage 2
ADJ connected to OUT 2
Enable = LOW; V
S
= 6 to 28V;
I
02
= 5 to 400mA
4.9 5.1 V
V
DP2
Dropoutput Voltage 2 I
OUT2
= 100mA 0.2 0.3 V
I
OUT2
= 400mA; V
S
= 4.8V 0.3 0.6 V
V
OL02
Load Regulation 2 I
OUT1
= 5 to 400mA
(after regulation setting)
50 mV
R
ADJ
Adjust Input Resistance 60 100 150 mA
I
LIM2
Current Limit 2 V02 = 0.8 to 4.5V 450 650 1300 mA
I
Q
Quiescent Current I
OUT1
= 100mA; I
OUT2
= 400mA 20 mA
OUT1, OUT 2
V
OLi 1,2
Line Regulation V
S
= 6 to 28V; I
O1
= 1mA,
I
O2
= 5mA,
(after regulation setting)
20 mV
PIN FUNCTIONS
PIN
(DIP 12+2+2)
PIN
(SO 12+4+4)
PIN
PowerSO20
Name Function
14 18 3 VS2 Supply Voltage (400mA Regulator)
15 19 4 VS1 Supply Voltage (100mA Regulator, Reset, Sense)
16 20 5 S1 Sense Input
1 1 6 PR Reset Theresold Programming
2 2 7 CT Reset Delay Capacitor
3 3 8 EN Enable (low will activate the 400mA regulator)
4, 5, 12, 13 4, 5, 6, 7, 14,
15, 16, 17
1,10,11,20 GND Ground
6 8 14 RES Reset Output
7 9 15 SO Sense Output
8 10 16 OUT 1 100mA Regulator Output
9 11 17 ADJ Feedback of 400mA Regulator
10 12 18 OUT 2 400mA Regulator Output
11 13 2,9,19 NC Not Connected
THERMAL DATA
Symbol Parameter DIP 12+2+2 SO 12+4+4 PowerSO20 Unit
R
th j-amb
Thermal Resistance Junction to ambient 40 50 - °C/W
R
th j-case
Thermal Resistance Junction to case - - <2 °C/W
Note 3: Typical value soldered on a PC board with 8cm
2
copper ground plane (35mm thick).
L4938E - L4938ED - L4938EPD
3/12
P1-P3P4-P6P7-P9P10-P12

L4938E

Mfr. #:
Buy L4938E
Manufacturer:
STMicroelectronics
Description:
LDO Voltage Regulators Dual 5V Very LDO
Lifecycle:
New from this manufacturer.
Delivery:
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