S93WD662 Datasheet, PDF (2/14 Pages) Summit Microelectronics, Inc. – Precision Supply-Voltage Monitor and Reset Controller With a Watchdog Timer and 4k-bit Microwire Memory

PIN CONFIGURATION
8-Pin SOIC
CS 1
SK 2
DI 3
DO 4
8 VCC
7 RESET
6 RESET#
5 GND
2014 T PCon 2.0
PIN FUNCTIONS
Pin Name
CS
SK
DI
DO
V_CC
GND
RESET/RESET#
Function
Chip Select
Clock Input
Serial Data Input
Serial Data Output
+2.7 to 6.0V Power Supply
Ground
RESET I/O
DEVICE OPERATION
APPLICATIONS
The S93WD662/WD663 is ideal for applications requir-
ing low voltage and low power consumption. This device
provides microcontroller RESET control and can be
manually resettable.
RESET CONTROLLER DESCRIPTION
The S93WD662/WD663 provides a precision reset con-
troller that ensures correct system operation during
brownout and power-up/-down conditions. It is config-
ured with two open drain reset outputs: pin 7 is an active
high output and pin 6 is an active low output.
During power-up, the reset outputs remain active until
VCC reaches the VTRIP threshold. The outputs will con-
tinue to be driven for approximately 200ms after reach-
ing VTRIP. The reset outputs will be valid so long as VCC
is ≥ 1.0V. During power-down, the reset outputs will
begin driving active when VCC falls below VTRIP.
S93WD662/S93WD663
The reset pins are I/Os; therefore, the S93WD662/
WD663 can act as a stabilization circuit for an externally
applied reset. The inputs are edge triggered; that is, the
RESET input will initiate a reset time-out after detecting
a low to high transition and the RESET# input will initiate
a reset time-out after detecting a high to low transition.
Refer to the applications Information section for more
details on device operation as a debounce/reset ex-
tender circuit.
It should be noted the reset outputs are open drain.
When used as outputs driving a circuit they need to be
either tied high (RESET#) or tied to ground (RESET)
through the use of pull-up or pull-down resistors. Refer
to the applications aid section for help in determining the
value of resistor to be used. Internally these pins are
weakly pulled up (RESET#) and pulled down (RESET).
If the signals are not being used the pins may be left
unconnected.
WATCHDOG TIMER DESCRIPTION
The S93WD662/WD663 has a watchdog timer with a
nominal time-out period of 1.6 seconds. Whenever the
watchdog times out, it will generate a reset output to both
pins 6 and 7. The watchdog timer is reset by any
transition on CS.
The watchdog timer will be held in a reset state during
power-on while V_CC is less than V_TRIP. Once V_CC ex-
ceeds V_TRIP the watchdog will continue to be held in a
reset state for the t_PURST period. After t_PURST it will be
released and the timer will begin operation. If either
reset input is asserted the watchdog timer will be reset
and remain in the reset condition until either t_PURST has
expired or the reset input is released, whichever is
longer.
GENERAL OPERATION
The S93WD662/WD663 is a 4096-bit nonvolatile memory
intended for use with industry standard microproces-
sors. The S93WD663 is organized as X16, seven 11-bit
instructions control the reading, writing and erase op-
erations of the device. The S93WD662 is organized as
X8, seven 12-bit instructions control the reading, writing
and erase operations of the device. The device operates
on a single 3V or 5V supply and will generate on chip, the
high voltage required during any write operation.
Instructions, addresses, and write data are clocked into
the DI pin on the rising edge of the clock (SK). The DO
pin is normally in a high impedance state except when
reading data from the device, or when checking the
ready/busy status after a write operation.
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