MIC2777_05 Datasheet, PDF (1/8 Pages) Micrel Semiconductor – Dual Micro-Power Low Voltage Supervisor

MIC2777
MIC2777
Micrel, Inc.
Dual Micro-Power Low Voltage Supervisor
General Description
The MIC2777 is a dual power supply supervisor that provides
under-voltage monitoring, manual reset capability, and power-
on reset generation in a compact 5-pin SOT package. Fea-
tures include two under-voltage detectors, one fixed and one
adjustable, and both active-high and active-low reset outputs.
One under-voltage detector compares V_DD against a fixed
threshold. Ten factory-programmed thresholds are available.
The other under-voltage detector is user-adjustable.
The reset outputs are asserted for no less than 140ms at
power-on and any time V_DD or the input voltage drops below
the corresponding reference voltage. They remain asserted
for the timeout period after the input voltage and V_DD sub-
sequently rise back above the threshold boundaries. A reset
can be generated at any time by pulling down on the adjust-
able input. Hysteresis is included to prevent chattering due
to noise. Typical supply current is a low 3.5µA.
Features
• Monitors two independent power supplies for under-volt-
age conditions
• One fixed and one user adjustable input
• 1.5% theshold accuracy
• Choice of factory-programmed thresholds
• User-adjustable input can monitor supplies as low as
0.3V
• Generates 140ms (minimum) power-on RESET pulse
• Manual reset capability
• Both active-high and active-low RESET outputs
• Input may be pulled above V_DD (abs. max.)
• /RST output valid down to 1.2V
• Ultra-low supply current, 3.5µA typical
• Rejects brief input transients
• IttyBitty™ 5-pin SOT-23 package
Applications
• Monitoring processor, ASIC, or FPGA core and I/O volt-
ages
• Computer systems
• PDAs, hand-held PCs
• Embedded controllers
• Telecommunications systems
• Power supplies
• Wireless / Cellular systems
• Networking hardware
Ordering Information
Standard
MIC2777-XXBM5
Part Number
Marking Pb-Free
UNXX MIC2777-XXYM5
Marking
UNXX
Junction Tem. Range
–40ºC to +85ºC
Package
SOT-23-5
Typical Application
V_CORE 1.0V
V_I/O 1.8V
Manual
Reset
MIC2777
VDD /RST
R1
IN
RST
R2
GND
MICROPROCESSOR
V_CORE
V_I/O
/RESET
GND
Typical Application
OTHER
LOGIC
IttyBitty™ is a trademark of Micrel, Inc.
Micrel, Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 [phone] • fax + 1 [phone] • http://www.micrel.com
November 2005
1
MIC2777