®
SP791
Low Power Microprocessor Supervisory
with Battery Switch-Over
s
Precision 4.65V Voltage Monitoring
s
200ms Power-OK/Reset Time Delay
s
Independent Watchdog Time-Preset or Adjustable
s
75µA Maximum Operating Supply Current
s
1.0µA Maximum Battery Backup Current
s
0.1µA Maximum Battery Standby Current
s
Power Switching
250mA Output in Vcc Mode (0.6Ω)
25mA Output in Battery Mode (5Ω)
s
On-Board Gating of Chip-Enable Signals
Memory Write-Cycle Completion
6ns CE Gate Propagation Delay
s
Voltage Monitor for Power-Fail or Low Battery
s
Backup-Battery Monitor
s
RESET Valid to Vcc=1V
s
Pin Compatible Upgrade to MAX791
DESCRIPTION
The
SP791
is a microprocessor (µP) supervisory circuit that integrates a myriad of compo-
nents involved in discrete solutions to monitor power-supply and battery-control functions in
µP
and digital systems. The
SP791
offers complete
µP
monitoring and watchdog functions.
The
SP791
is ideal for a low-cost battery management solution and is well suited for portable,
battery-powered applications with its supply current of 40µA. The 6ns chip-enable propaga-
tion delay, the 25mA current output in battery-backup mode, and the 250mA current output
in standard operation also makes the
SP791
suitable for larger scale, high-performance
equipment.
SP791
V
OUT
15
RESET
1
V
BATT
3
Vcc
_
4.65V
_
+
+
+
150mV
10
5
MR
9
+
_
RESET
GENERATION
_
LOWLINE
BATT ON
+
2
_
SWT
V
OUT
8
11
TIMEBASE FOR
RESET AND
WATCHDOG
WATCHDOG
TRANSITION
DETECTOR
WATCHDOG
TIMER
WDI
+
_
CHIP-ENABLE
OUTPUT
CONTROL
PFI
7
+
_
1.25V
2V
12
CE OUT
6
PFO
14
16
4
GND
13
CE
IN
WDO WDPO
Figure 1. Block Diagram
SP791DS/08
SP791 Low Power Microprocessor Supervisory with Battery Switch-Over
© Copyright 2000 Sipex Corporation
1
SIPEX [ SIPEX CORPORATION ]
