X40620 Datasheet, PDF (5/17 Pages) Xicor Inc. – Dual Voltage CPU Supervisor with 64K Serial EEPROM

X40620
Figure 5. Reset V2_TRIP Level Sequence (V_CC > 3V, WEL is set.)
V_{CC VTRIP}
RESET
V_P = 15V
0 1 23 4 56 7
01 23 4 56 7
01 23 4 56 7
01 23 4 56 7
SCL
SDA
D8h
00h
03h
00h
03h resets V_CC
V_CC AND V2MON THRESHOLD RESET PROCEDURE
The X40620 is shipped with standard V_TRIP and
V2_TRIP voltages. These values will not change over
normal operating and storage conditions. However, in
applications where the standard thresholds are not
exactly right, or if higher precision is needed in the
threshold value, the X40620 trip points may be
adjusted. The procedure is described below, and uses
the application of a high voltage control signal.
Setting the V_TRIP Voltage
This procedure is used to set the V_TRIP,V2_TRIP to a
higher voltage value. For example, if the current V_TRIP
is 4.4V and the new V_TRIP is 4.6V, this procedure will
directly make the change. If the new setting is to be
lower than the current setting, then it is necessary to
reset the trip point before setting the new value.
To set the new voltages, apply the desired V_TRIP thresh-
old voltage to the V_CC pin, the V2_TRIP voltage to the
V2MON pin, then tie the RESET pin to the programming
voltage V_P. Then, write data 01h or 0Dh at address
00h to program V_TRIP, V2_TRIP respectively. The stop
bit following a valid write operation initiates the pro-
gramming sequence. Bring RESET LOW to complete
the operation. Note: this operation also writes 01h or
0Dh to address 00h.
Resetting the V_TRIP Voltage
This procedure is used to set the V_TRIP, the V2_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 the threshold is reset,
the new level is something less than 1.7V. This proce-
dure must be used to set the voltage to a lower value.
To reset the new V_TRIP, V2_TRIP voltage, apply the
desired V_TRIP or V2_TRIP threshold voltage to the
V_CCor V2MON pin, respectively, and tie the RESET
pin to the programming voltage V_P. Then write 03h or
0Fh to address 00h. The stop bit of a valid write opera-
tion initiates the programming sequence. Bring
RESET LOW to complete the operation. Note: this
operation also writes 03h or 0Fh to address 00h of the
EEPROM array.
Figure 6. Sample V_TRIP Reset Circuit
V_TRIP
Adj.
V2FAIL
RESET
V2_TRIP
Adj.
4.7K
5
8
4
2
7 ^X40620 6
1
3
V_P
Adjust
Run
µC
SCL
SDA
Characteristics subject to change without notice. 5 of 17