CD00257532 datasheet(10/19 Pages) STMICROELECTRONICS

10 / 19 page

Application information

L4949ED-E, L4949EP-E

10/19

Doc ID 16823 Rev 1

Application information

Figure 3.

Application circuit(1)

For stability: CS ≥ 1µF, CO ≥ 4.7µF, ESR < 10Ω at 10KHz. Recommended for application: CS = CO = 10 µF to 100 µF

3.1

Supply voltage transient

High supply voltage transients can cause a reset output signal disturbance. For supply

voltages greater than 8V the circuit shows a high immunity of the reset output against supply

transients of more than 100V/µs. For supply voltages less than 8V supply transients of more

than 0.4V/µs can cause a reset signal disturbance.

To improve the transient behaviour for supply voltages less than 8V a capacitor at pin VZ can

be used.

This capacitor (C3

≤ 1 µF) reduces also the output noise.

3.2

Functional description

The L4949ED-E and L4949EP-E are monolithic integrated voltage regulator, based on the

STM modular 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 the

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