|
|
PDF L4949EP Data sheet ( Hoja de datos )
| Número de pieza | L4949EP | |
| Descripción | MULTIFUNCTION VERY LOW DROP VOLTAGE REGULATOR | |
| Fabricantes | STMicroelectronics | |
| Logotipo |  |
|
Hay una vista previa y un enlace de descarga de L4949EP (archivo pdf) en la parte inferior de esta página. Total 10 Páginas | ||
|
No Preview Available !
® L4949E
MULTIFUNCTION VERY LOW DROP
VOLTAGE REGULATOR
OPERATING DC SUPPLY VOLTAGE RANGE
5V - 28V
TRANSIENT SUPPLY VOLTAGE UP TO 40V
EXTREMELY LOW QUIESCENT CURRENT
IN STANDBY MODE
HIGH PRECISION STANDBY OUTPUT VOLT-
AGE 5V±1%
OUTPUT CURRENT CAPABILITY UP TO
100mA
VERY LOW DROPOUT VOLTAGE LESS
THAN 0.5V
RESET CIRCUIT SENSING THE OUTPUT
VOLTAGE
PROGRAMMABLE RESET PULSE DELAY
WITH EXTERNAL CAPACITOR
VOLTAGE SENSE COMPARATOR
THERMAL SHUTDOWN AND SHORT CIR-
CUIT PROTECTIONS
Minidip
SO8
SO20W (12+4+4)
ORDERING NUMBERS: L4949E (Minidip)
L4949ED (SO8)
L4949EP (SO20W)
DESCRIPTION
The L4949E is a monolithic integrated 5V voltage
regulator with a very low dropout output and addi-
tional functions as power-on reset and input volt-
age sense. It is designed for supplying the micro-
computer controlled systems especially in
automotive applications.
BLOCK DIAGRAM
VZ VOUT
VS PREREGULATOR 5V
CT
REG
SI
REF
June 2000
2µ
+
RESET
VS
2V
1.23V
SENSE
1.23V
D96AT219
RES
SO
GND
1/10
1 page  
With this structure very low dropout voltage 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.
The typical curve showing the standby output
voltage as a function of the input supply voltage is
shown in Fig. 2. The current consumption of the
device (quiescent current) is less than 300µA.
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, the quiescent current as a function of the
supply input voltage is shown in Fig. 3.
Figure 2: Output Voltage vs. Input Voltage
40V
Figure 3: Quiescent Current vs. Supply Voltage
L4949E
Preregulator
To improve the transient immunity a preregulator
stabilized the internal supply voltage to 5V. This
internal voltage is present at Pin 3 (VZ). This volt-
age should not be used as an output because the
output capability is very small (≤10µA).
This output may be used as an option when a
better transient behaviour for supply voltages less
than 8V is required (see also application note).
In this case a capacitor (100nF - 1µF) must be
connected between Pin 3 and GND. If this feature
is not used Pin 3 must be left open.
Reset Circuit
The block circuit diagram of the reset circuit is
shown in Fig. 4. The reset circuit supervises the
output voltage.
The reset thereshold of 4.5V is defined with the
internal reference voltage and standby output
drivider.
The reset pulse delay time tRD, is defined with the
charge time of an external capacitor CT:
tRD
=
CT • 2V
2µA
The reaction time of the reset circuit originates
from the discharge time limitation of the reset ca-
pacitor CT and is proportional to the value of CT.
The reaction time of the reset circuit increases the
noise immunity. Standby output voltage drops be-
low the reset threshold only a bit longer than the
reaction time results in a shorter reset delay time.
The nominal reset delay time will be generated for
standby output voltage drops longer than approxi-
mately 50µs.
The typical reset output waveforms are shown in
Fig. 5.
Sense Comparator
The sense comparator compares an input signal
with an internal voltage reference of typical 1.23V.
The use of an external voltage divider makes this
comparator very flexible in the application.
It can be used to supervise the input voltage
either before or after the protection diode and to
give additional informations to the microprocessor
like low voltage warnings.
5/10
5 Page | ||
| Páginas | Total 10 Páginas | |
| PDF Descargar | [ Datasheet L4949EP.PDF ] | |
Hoja de datos destacado
| Número de pieza | Descripción | Fabricantes |
| L4949E | MULTIFUNCTION VERY LOW DROP VOLTAGE REGULATOR | STMicroelectronics |
| L4949ED | MULTIFUNCTION VERY LOW DROP VOLTAGE REGULATOR | STMicroelectronics |
| L4949ED-E | (L4949ED-E / L4949EP-E) Multifunction very low drop voltage regulator | STMicroelectronics |
| L4949EP | MULTIFUNCTION VERY LOW DROP VOLTAGE REGULATOR | STMicroelectronics |
| Número de pieza | Descripción | Fabricantes |
| SLA6805M | High Voltage 3 phase Motor Driver IC. |
 Sanken |
| SDC1742 | 12- and 14-Bit Hybrid Synchro / Resolver-to-Digital Converters. |
 Analog Devices |
|
DataSheet.es es una pagina web que funciona como un repositorio de manuales o hoja de datos de muchos de los productos más populares, |
| DataSheet.es | 2020 | Privacy Policy | Contacto | Buscar |