L6730 datasheet(15/52 Pages) STMICROELECTRONICS

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L6730 - L6730B

Device description

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5.4

Internal and external references

It is possible to set two internal references, 0.6V and 1.2V, or provide an external reference

from 0V to 2.5V. The maximum value of the external reference depends on the VCC : with VCC =

4V the clamp operates at about 2V (typ.), while with VCC greater than 5V the maximum external

reference is 2.5V (typ).

●

VEAREF from 0% to 80% of VCCDR −> External reference

●

VEAREF from 80% to 95% of VCCDR −> VREF = 1.2V

●

VEAREF from 95% to 100% of VCCDR −> VREF = 0.6V

Providing an external reference from 0V to 450mV the output voltage will be regulated but

some restrictions must be considered:

●

The minimum OVP threshold is set at 300mV.

●

The under-voltage-protection doesn’t work.

●

The PGOOD signal remains low.

To set the resistor divider it must be considered that a 100K pull-down resistor is integrated into

the device (see Figure 6.). Finally it must be taken into account that the voltage at the EAREF

pin is captured by the device at the start-up when Vcc is about 4V.

5.5

Error amplifier

Figure 6.

Error Amplifier Reference

2.5V

100K

EAREF

VCCDR

0.6V

1.2V

EXT

Error Amplifier Ref.

L6730 Arkusz danych(PDF) 15 Page - STMicroelectronics