G696H250T1U GMT [Global Mixed-mode Technology Inc], G696H250T1U Datasheet - Page 9

• Manufacturer Part Number: G696H250T1U
• Description: Microprocessor Reset IC
• Manufacturer: GMT [Global Mixed-mode Technology Inc]

Interfacing to µ Ps with Bidirectional Reset Pins
Since the RESET output on the G697L is open drain,
this device interfaces easily with µ Ps that have bidirec-
tional reset pins, such as the Motorola 68HC11. Con-
necting the µ P supervisor ’ s RESET output directly to
the microcontroller’s ( µ C ’ s) RESET pin with a single
pull-up resistor allows either device to assert reset
(Figure 5).
G697L Open-Drain
Multiple Supplies
Generally, the pull-up connected to the G697L will
connect to the supply voltage that is being monitored
at the IC ’ s V
the open-drain output to level-shift from the monitored
supply to reset circuitry powered by some other supply
(Figure 6). Note that as the G697L ’ s V
below 1V, so does the IC ’ s ability to sink current at
Ver: 1.8
May 10, 2006
RESET . Also, with any pull-up, RESET will be pulled
CC
Global Mixed-mode Technology Inc.
pin. However, some systems may use
RESET
Output Allows Use with
CC
decreases
9
high as
occurs depends on the pull-up resistor value and the
voltage to which it is connected.
Benefits of Highly Accurate Reset Threshold
Most µ P supervisor ICs have reset threshold voltages
between 5% and 10% below the value of nominal
supply voltages. This ensures a reset will not occur
within 5% of the nominal supply, but will occur when
the supply is 10% below nominal.
When using ICs rated at only the nominal supply ± 5%,
this leaves a zone of uncertainty where the supply is
between 5% and 10% low, and where the reset may or
may not be asserted.
The G69_ _463/G69_ _308 use highly accurate circuitry
to ensure that reset is asserted close to the 5% limit,
and long before the supply has declined to 10% below
nominal.
VCC
decays toward 0. The voltage where this
G696/G697
http://www.gmt.com.tw
TEL: [phone]