X4643 datasheet(4/22 Pages) XICOR

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X4643/5 – Preliminary Information

Characteristics subject to change without notice.

4 of 22

REV 1.26 4/30/02

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Setting the VTRIP Voltage

This procedure is used to set the VTRIP to a higher or

lower voltage value. It is necessary to reset the trip

point before setting the new value.

To set the new VTRIP voltage, start by setting the WEL

bit in the control register, then apply the desired VTRIP

threshold voltage to the VCC pin and the programming

voltage, VP, to the WP pin and 2 byte address and 1

byte of “00” data. The stop bit following a valid write

operation initiates the VTRIP programming sequence.

Bring WP LOW to complete the operation.

Resetting the VTRIP Voltage

This procedure is used to set the VTRIP to a “native”

voltage level. For example, if the current VTRIP is 4.4V

and the new VTRIP must be 4.0V, then the VTRIP must

be reset. When VTRIP is reset, the new VTRIP is some-

thing less than 1.7V. This procedure must be used to

set the voltage to a lower value.

To reset the new VTRIP voltage start by setting the

WEL bit in the control register, apply VCC and the pro-

gramming voltage, VP, to the WP pin and 2 byte

address and 1 byte of “00” data. The stop bit of a valid

write

operation

initiates

the VTRIP programming

sequence. Bring WP LOW to complete the operation.

Figure 2. Reset VTRIP Level Sequence (VCC > 3V. WP = 12-15V, WEL bit set)

Figure 3. Sample VTRIP Reset Circuit

012 345 67

SCL

SDA

A0h

012 345 67

00h

VP = 12-15V

012 345 67

03h

012 345 6 7

00h

X4643

VTRIP

Adj.

RESET

4.7K

SDA

SCL

µC

Adjust

Run

SOIC

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