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Número de pieza | L4938EPD | |
Descripción | ADVANCED VOLTAGE REGULATOR | |
Fabricantes | STMicroelectronics | |
Logotipo | ||
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No Preview Available ! L4938ED
L4938EPD
Advanced voltage regulator
Features
■ Enable and sense inputs (EN, SI) protected
against negative transients down to -5 V
■ Reset threshold adjustable from 3.8 V to 4.7 V
■ Extremely low quiescent current, 65 µA (less
than 90 µA) in standby mode
■ Operating DC supply voltage range 5 V - 28 V
■ Operating transient supply voltage up to 40 V
■ High precision standby output voltage 5 V ± 1%
with 100 mA current capability
■ Output 2 voltage 5 V ± 2% with 400 mA current
capability (ADJ wired to VOUT2)
■ Output 2 voltage adjustable by external voltage
divider
■ Output 2 disable function for standby mode
SO-20
PowerSO-20
Description
The L4938ED and L4938EPD are monolithic
integrated dual voltage regulators with two very
low dropout outputs and additional functions such
as power-on reset and input voltage sense. They
are designed for supplying microcomputer
controlled systems especially in automotive
applications.
September 2013
Table 1. Device summary
Package
Order codes
Tube
Tape and reel
SO-20
L4938ED L4938ED013TR
PowerSO-20
L4938EPD L4938EPD13TR
Doc ID 17243 Rev 2
1/20
www.st.com
1
1 page L4938ED, L4938EPD
Block diagram and pin description
1 Block diagram and pin description
Figure 1. Block diagram
Figure 2. Configuration diagram (top view)
PR
CT
EN
GND
GND
GND
GND
RES
SO
OUT1
1 20
2 19
3 18
4 17
5 16
6 15
7 14
8 13
9 12
10 11
SO-20
SI
VS1
VS2
GND
GND
GND
GND
N.C.
OUT2
ADJ
GND
N.C.
VS2
VS1
SI
PR
CT
EN
N.C.
GND
1 20
2 19
3 18
4 17
5 16
6 15
7 14
8 13
9 12
10 11
PowerSO-20
GND
N.C.
OUT2
ADJ
OUT1
SO
RESET
N.C.
N.C.
GND
Doc ID 17243 Rev 2
5/20
5 Page L4938ED, L4938EPD
3 Application information
Figure 3. Application diagram
(See note 2)
Application information
(See note 1)
3.1
3.2
1. The leakage of CT must be less than 0.5 mA (2 V). If an external resistor between CT and VOUT1 is applied,
the leakage current may be increased. The external resistor should have more than 30 KΩ.
For stability: Cs ≥ 1 µF, C01 ≥ 10 µF, C02 ≥ 10 µF, ESR ≤ 5Ω (designed target).
2. For transients exceeding 20 V or -20 V external protection is required at the pins SI and EN as shown at
pin EN. The protection proposed provides proper function for transients in the range of ±200 V. If the zener
diode is omitted the external resistor should be raised to 200 KΩ to limit the current to 1 mA. Without the
zener diode, the function 20 V or -20 V can not be guaranteed.
Functional description
The L4938ED and L4938EPD are monolithic integrated dual voltage regulators, based on
the STM modulator voltage regulator approach. Several outstanding features and auxiliary
functions are implemented to meet the requirements of supplying microprocessor systems
in automotive applications. Nevertheless, it is suitable also in other applications where two
stabilized voltages are required. The modular approach of this device allows to get easy
also other features and functions when required.
Standby regulator
The standby regulator uses an isolated collector vertical PNP transistor as a regulating
element. With this structure very low dropout voltage at currents up to 100 mA is obtained.
The dropout operation of the standby regulator is maintained down to 3 V input supply
voltage. The output voltage is regulated up to the transient input supply voltage of 40 V. With
this feature no functional interruption due to overvoltage pulses is generated.
Doc ID 17243 Rev 2
11/20
11 Page |
Páginas | Total 20 Páginas | |
PDF Descargar | [ Datasheet L4938EPD.PDF ] |
Número de pieza | Descripción | Fabricantes |
L4938EPD | ADVANCED VOLTAGE REGULATOR | STMicroelectronics |
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