Document
IMP706P/R/S/T/J, IMP708R/S/T/J
POWER MANAGEMENT
3/3.3/4.0V µP Supervisor Circuits
– – – Lo w suppl y cur r ent Watc hdog timer Br o wnout det ection
Key Features
N Lower power, pin compatible replacements for Maxim MAX706P/R/S/T, MAX708R/S/T – 30% lower supply current:140µA vs. 200µA N Precision power supply monitor – 2.63V threshold (IMP706P/R, IMP708R) – 2.93V threshold (IMP706S, IMP708S) – 3.08V threshold (IMP706T, IMP708T) – New 4.00V threshold (IMP706J, IMP708J) N Debounced manual reset input N Auxiliary voltage monitor comparator – 1.25V threshold – Battery monitor/auxiliary supply monitor N Watchdog timer (IMP706P/R/S/T/J) – Watchdog can be disabled by floating WDI N 200ms reset time delay N Three reset signal options – Active HIGH: IMP706P – Active LOW: IMP706R/S/T/J – Active HIGH & LOW outputs: IMP708R/S/T/J N DIP, SO and MicroSO packages N Guaranteed RESET assertion to VCC = 1.1V
The IMP706P/R/S/T/J and IMP708R/S/T/J CMOS supervisor circuits monitor power-supply and battery voltage level, and µP/µC operation. A reset is generated when the supply drops below 2.63V (IMP706P/R, IMP708R), 2.93V (IMP706S, IMP708S), 3.08V (IMP706T, IMP708T) or 4.00 (IMP706J, IMP708J). The family offers several functional options. Each device generates a reset signal during power-up, power-down and during brownout conditions. In addition, the IMP706P/R/S/T/J feature a 1.6 second watchdog timer. The watchdog timer output will trigger a reset if connected to MR. Unlike competitive devices, floating the WDI input pin disables the watchdog timer. The IMP708R/S/T/J have both active-HIGH and active-LOW reset outputs but no watchdog function. The IMP706P has the same pin-out and functions as the IMP706R but has an active-HIGH reset output. A versatile power-fail circuit, useful in checking battery levels and non-5V supplies, has a 1.25V threshold. All devices have a manual reset input. All devices are available in 8-pin DIP, SO and the compact MicroSO packages. The MicroSO package requires 50% less PC board area than the conventional SO package.
Applications
N N N N N N N Computers and controllers CTI applications Embedded controllers Battery operated systems Intelligent instruments Wireless communication systems PDAs and handheld equipment
Block Diagrams
WDI
VCC Timebase 20kΩ Transition Detector Watchdog Timer
WDO
VCC 20kΩ
RESET
MR VCC + + –
RESET Generator
RESET (RESET) IMP706P
MR VCC + + –
2.63V (IMP708R) 2.93V (IMP708S) 3.08V (IMP708T) 4.00V (IMP708J)
RESET Generator
RESET
PFI
2.63V (IMP706P/R) 2.93V (IMP706S) 3.08V (IMP706T) 4.00V (IMP706J) 1.25V
+ – PFO
PFI
1.25V
+ PFO –
IMP706P/R/S/T/J
GND
706P_01.eps
IMP708R/S/T/J
706P_02.eps
GND
© 1999 IMP, Inc.
408-432-9100/www.impweb.com
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IMP706P/R/S/T/J, IMP708R/S/T/J
Pin Configuration
DIP/SO
MR VCC GND PFI 1 2
IMP708R/S/T/J
MicroSO
8 7 WDO RESET WDI PFO MR VCC GND PFI 1 2
IMP706R/S/T/J
8 7 6 5
RESET RESET NC PFO
MR VCC GND PFI
1 2
IMP706P
8 7 6 5
WDO RESET WDI PFO
(RESET) RESET (IMP706P).