X4643/5 – Preliminary Information
Setting the V
TRIP
Voltage
This procedure is used to set the V
TRIP
to a higher or
lower voltage value. It is necessary to reset the trip
point before setting the new value.
To set the new V
TRIP
voltage, start by setting the WEL
bit in the control register, then apply the desired V
TRIP
threshold voltage to the V
CC
pin and the programming
voltage, V
P
, to the WP pin and 2 byte address and 1
byte of “00” data. The stop bit following a valid write
operation initiates the V
TRIP
programming sequence.
Bring WP LOW to complete the operation.
Resetting the V
TRIP
Voltage
This procedure is used to set the V
TRIP
to a “native”
voltage level. For example, if the current V
TRIP
is 4.4V
and the new V
TRIP
must be 4.0V, then the V
TRIP
must
be reset. When V
TRIP
is reset, the new V
TRIP
is some-
thing less than 1.7V. This procedure must be used to
set the voltage to a lower value.
To reset the new V
TRIP
voltage start by setting the
WEL bit in the control register, apply V
CC
and the pro-
gramming voltage, V
P
, to the WP pin and 2 byte
address and 1 byte of “00” data. The stop bit of a valid
write operation initiates the V
TRIP
programming
sequence. Bring WP LOW to complete the operation.
Figure 2. Reset V
TRIP
Level Sequence (V
CC
> 3V. WP = 12-15V, WEL bit set)
WP
V
P
= 12-15V
0 1 2 3 4 5 6 7
SCL
0 1 2 3 4 5 6 7
0 1 2 3 4 5 6 7
0 1 2 3 4 5 6 7
SDA
A0h
00h
03h
00h
Figure 3. Sample V
TRIP
Reset Circuit
V
P
SOIC
4.7K
RESET
V
TRIP
Adj.
1
2
3
4
X4643
8
7
6
5
Run
SCL
SDA
Adjust
µC
REV 1.26 4/30/02
www.xicor.com
Characteristics subject to change without notice.
4 of 22
XICOR [ XICOR INC. ]
