L4938E STMicroelectronics, L4938E Datasheet - Page 5
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L4938E
Manufacturer Part Number
L4938E
Description
IC REG LDO DUAL 5V/ADV 16DIP
Manufacturer
STMicroelectronics
Datasheet
1.L4938E.pdf
(12 pages)
Specifications of L4938E
Regulator Topology
Positive Fixed and Adjustable
Voltage - Output
5V, 4.9 ~ 5.1 V
Voltage - Input
Up to 28V
Voltage - Dropout (typical)
0.2V @ 100mA, 0.3V @ 400mA
Number Of Regulators
2
Current - Output
100mA, 400mA
Current - Limit (min)
100mA, 450mA
Operating Temperature
-40°C ~ 150°C
Mounting Type
Through Hole
Package / Case
20-SOIC (7.5mm Width)
Polarity
Positive
Number Of Outputs
2
Output Type
Fixed
Output Voltage
5.1 V
Output Current
5 mA
Line Regulation
20 mV
Load Regulation
50 mV
Dropout Voltage (max)
0.2 V
Input Voltage Max
20 V
Maximum Operating Temperature
+ 150 C
Minimum Operating Temperature
- 40 C
Maximum Power Dissipation
875 mW
Mounting Style
Through Hole
Reference Voltage
1.23 V
Voltage Regulation Accuracy
2 %
Lead Free Status / RoHS Status
Contains lead / RoHS non-compliant
Other names
497-3355-5
497-3914-5
497-3914-5
497-3914-5
497-3914-5
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Company
Part Number
Manufacturer
Quantity
Price
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Manufacturer:
ST
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Part Number:
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Part Number:
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Part Number:
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Figure 1. Application Diagram.
FUNCTIONAL DESCRIPTION
The L4938E/ED/EPD is a monolithic integrated
dual voltage regulator, based on the STM modu-
lator voltage regulator approach. Several out-
standing features and auxiliary functions are im-
plemented to meet the requirements of supplying
microprocessor systems in automotive applica-
tions. Nevertheless, it is suitable also in other ap-
plications where two stabilized voltages are re-
quired. The modular approach of this device
allows to get easly also other features and func-
tions when required.
Standby Regulator
The standby regulator uses an Isolated collector
Vertical PNP transistor as a regulating element.
With this structure very low dropout volotage at
currents up to 100mA is obtained. The dropout
operation of the standby regulator is maintained
down to 3V input supply voltage. The output volt-
age is regulated up to the transient input supply
voltage of 40V. With this feature no functional in-
terruption due to overvoltage pulses is generated.
In the standby mode when the output 2 is dis-
abled, the current consumption of the device (qui-
escent current) is less than 90 A (14V supply
voltage).
for example
BZX97C15
(Note 8)
100K
15V
C
VS1
VS2
S
EN
PR
SI
1.23V
RESET
SENSE
REG1
REG2
1.23V
To reduce the quiescent current peak in the un-
dervoltage region and to improve the transient re-
sponse in this region, the dropout voltage is con-
trolled. A second regulation path will keep the
output voltage without load below 5.5V even at
high temperatures.
Output 2 Voltage
The output 2 regulator uses the same output
structure as the standby regulator but rated for
the output current of 400mA. The output voltage
is internally fixed to 5V if ADJ is connected to
V
The output 2 regulator can be switches OFF via
the enable input.
Figure 2.
OUT2
.
1.23V
1.23V
1.4V
1.23V
+
-
L4938E - L4938ED - L4938EPD
REFERENCE
R
R
1i
2i
total 100K
D94AT079A
typical
R
ADJ
OUT1
OUT2
GND
RES
ADJ
SO
CT
OUT2
ADJ
D94AT080
CT (Note 7)
V
OUT1
R
R
R
SO
C
C
1E
2E
5/12
O1
O2