SP690A Datasheet, PDF (4/16 Pages) Sipex Corporation – Low Power Microprocessor Supervisory with Battery Switch-Over

VOUT ¹
VCC ²
GND 3
PFI 4
8 VBATT
7 RESET (RESET)*
6 WDI
5 PFO
*( ) SP805 only
Figure 10. Pinout
PIN ASSIGNMENTS
Pin 1 —V_OUT — Output Supply Voltage. V_OUT
connects to V_CC when V_CC is greater than
V_BATT and V_CC is above the reset thresh-
old. When V_CC falls below V_BATT and
V_CC is below the reset threshold, V_OUT
connects to V_BATT. Connect a 0.1µF
capacitor from V_OUT to GND.
Pin 2 — V_CC — +5V Supply Input
Pin3 — GND — Ground reference for all signals
Pin 4 — PFI — Power-Fail Input. This is the
noninverting input to the power-fail com-
parator. When PFI is less than 1.25V,
PFO goes low. Connect PFI to GND or
V_OUT when not used.
Pin 5 — PFO — Power-Fail Output.
Pin 6 — WDI — Watchdog Input. WDI is a
three level input. If WDI remains high or
low for 1.6sec, the internal watchdog timer
triggers a reset. If WDI is left floating or
connected to a high-impedance tri-state
buffer, the watchdog feature is disabled.
The internal watchdog timer clears when-
ever reset is asserted.
Pin 7 for SP690A/692A/802 only — RESET
(Active Low)– Reset Output. RESET Out-
put goes low whenever V_CC falls below
the reset threshold or whenever WDI
remains high or low longer than 1.6
seconds. RESET remains low for 200ms
after V_CC crosses the reset threshold
voltage on power-up or after being trig-
gered by WDI.
VBATT ^{BATTERY-SWITCHOVER}
CIRCUITRY
VOUT
VCC
RESET
RESET
GENERATOR (RESET)*
1.25V
3.5V
WDI
WATCHDOG
TIMER
0.8V
PFI
PFO
1.25V
*( ) SP805 only
Figure 11. Internal Block Diagram
Pin 7 for SP805 only — RESET (Active High)–
Reset Output is the inverse of RESET;
when RESET is asserted, the RESET
output voltage = V_CC or V_BATT ,
whichever is higher.
Pin 8 — V_BATT — Backup-Battery Input. When
V_CC falls below the reset threshold, V_BATT
will be switched to V_OUT if V_BATT is
20mV greater than V_CC. When V_CC rises
20mV above V_BATT, V_OUT will be
reconnected to V_CC. The 40mV
hysteresis prevents repeated switching if
V_CC falls slowly.
SP690A/692ADS/08
SP690A/692A Low Power Microprocessor Supervisory with Battery Switch-Over
4
© Copyright 2000 Sipex Corporation