MIC845_11 Datasheet, PDF (1/7 Pages) Micrel Semiconductor – Micro-Power Comparator Battery Monitor

MIC845
Micro-Power Comparator /
Battery Monitor
General Description
The MIC845 is a precision micro-power voltage
comparator with an on-chip 2.55V reference voltage
source.
Intended for voltage monitoring applications, the
MIC845 can be used with an external resistor divider
to detect a wide range of voltages, or without
external resistors to directly monitor voltages with its
high input impedance CMOS input.
The MIC845 incorporates a voltage reference and
comparator with fixed internal hysteresis. When the
2.55V internal threshold is crossed, the output
switches polarity.
MIC845 is available with a push-pull or open-drain
output stage. The push-pull output stage is
configured for both active high or active low output;
the open-drain output stage is only configured active
high.
Supply current is extremely low (typically 1µA),
making it ideal for portable applications.
MIC845 is supplied in Micrel’s Teeny™ 5-lead SC-
70 package.
Data sheets and support documentation can be
found on Micrel’s web site at www.micrel.com.
Teeny™
Features
• Extremely low 1µA supply current (typical)
• 2.55V on chip reference
• ±2% voltage threshold accuracy
• Optimized for PDAs, cellular telephones, pagers,
and other battery-powered devices
• Open-drain output can be pulled up to 6V
regardless of supply voltage
• 5-lead SC-70 package
Applications
• PDAs
• Pagers
• Cordless phones
• Portable electronics
• Motherboards
• Bladed servers
____________________________________________________________________________________________________
Typical Applications
V_IN VDD
MIC845
V_DD OUT
R1
INP GND
R2
3.3V
V_OUT
Memory
power
V_REF = 2.55V
2.75V < V_DD < 5.5V
Lithium
Coin Cell
MIC845
V_DD
INP _OUT
GND
to Host
Threshold Detector with
Internal Fixed Hysteresis
Nano-Power Battery Monitor
Teeny™ is a trademark of Micrel, Inc.
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel [phone] • fax + 1 [phone] • http://www.micrel.com
July 2005
M9999-070505
[phone]