MIC2776_05 Datasheet, PDF (1/8 Pages) Micrel Semiconductor – Micro-Power Low Voltage Supervisor

MIC2776
MIC2776
Micrel, Inc.
Micro-Power Low Voltage Supervisor
General Description
The MIC2776 is a power supply supervisor which provides
under-voltage monitoring and power-on reset generation in a
compact 5-pin SOT package. Features include an adjustable
under-voltage detector, a delay-generator, a manual reset
input, and a choice of active-high, active-low, or open-drain
active-low reset output. The user-adjustable monitoring input
is compared against a 300mV reference. This low reference
voltage allows monitoring voltages lower than those supported
by previous supervisor ICs.
The reset output is asserted for no less than 140ms at power-
on and any time the input voltage drops below the reference
voltage. It remains asserted for the timeout period after the
input voltage subsequently rises back above the threshold
boundary. A reset can be generated at any time by asserting
the manual reset input, /MR. The reset output will remain ac-
tive at least 140ms after the release of /MR. The /MR input
can also be used to daisy-chain the MIC2776 onto existing
power monitoring circuitry or other supervisors. Hysteresis
is included to prevent chattering due to noise. Typical supply
current is a low 3.0µA.
Features
• User-adjustable input can monitor supplies as low as
0.3V
• ±1.5% threshold accuracy
• Separate V_DD input
• Generates power-on reset pulse (140ms min.)
• Manual reset input
• Choice of active-high, active-low or open-drain active-
low reset output
• Inputs can be pulled above V_DD (7V abs. max.)
• Open-drain output can be pulled above V_DD (7V abs.
max.)
• Ultra-low supply current, 3.0µA typical
• Rejects brief input transients
• IttyBitty™ SOT-23-5 package
Applications
• Monitoring processor, ASIC, or FPGA core voltage
• Computer systems
• PDAs/Hand-held PCs
• Embedded controllers
• Telecommunications systems
• Power supplies
• Wireless / cellular systems
• Networking hardware
Typical Application
V_CORE 1.0V
V_I/O 2.5V
R1
R2
Power_Good
Manual
Reset
MIC2776L
VDD /RST
IN
/MR GND
MICROPROCESSOR
VCORE
VI/O
/RESET GND
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
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MIC2776