Microprocessor and Non-Volatile

Memory Supervisory Circuits

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7

______________________________________________________________Pin Description

PIN

NAME

FUNCTION

1

RESET

2

RESET

Reset is the inverse of RESET.

Input Supply Voltage

4

RESET IN/INT

5

LLIN/REF OUT

6

OVO

7

OVI

8

SWT

9

MR

10

LOW LINE

11

WDI

12

GND

Ground

13

CE OUT

old programming mode, or RESET IN falls below 1.30V in external threshold programming mode.

RESET remains low for 200ms typ after the threshold is exceeded on power-up.

Reset-Input/Internal-Mode Select. Connect this input to GND to select internal threshold mode.

Select external programming mode by pulling this input 600mV or higher through an external volt-

age divider.

Low-Line Input/Reference Output connects directly to the low-line comparator in external program-

ming mode (RESET IN/INT

≥ 600mV). Connects directly to the internal 1.30V reference in internal

threshold mode (RESET IN/INT

≤60mV).

Overvoltage Comparator Output goes low when OVI is greater than 1.30V. This is an uncommitted

comparator and has no effect on any other internal circuitry.

Inverting Input to the Overvoltage Comparator. When OVI is greater than 1.30V, OVO goes low.

timeout period. Connect a capacitor between this input and GND to select another watchdog-

timeout period. Watchdog timeout period = k x (capacitor value in nF)mV, where k = 27 for

16

WDPO

15

WDO

14

CE IN

Manual-Reset Input. This input can be tied to an external momentary pushbutton switch, or to a

Low-Line Output. LOW LINE goes low 120mV above the reset threshold in internal threshold mode,

or when LLIN/REFOUT goes below 1.30V in external programming mode.

Watchdog Input. If WDI remains either high or low for longer than the watchdog timeout period,

WDPO pulses low and WDO goes low. WDO remains low until the next transition at WDI. Connect to

Chip-Enable Output. CE OUT goes low only when CE IN is low and reset is not asserted. If CE IN is

low when reset is asserted, CE OUT will stay low for 15µs or until CE IN goes high, whichever

occurs first.

used.

Watchdog Output. WDO goes low if WDI remains either high or low longer than the watchdog time-

out period. WDO returns high on the next transition at WDI.

Watchdog-Pulse Output. Upon the absence of a transition at WDI, WDPO will pulse low for a mini-

mum of 500µs. WDPO precedes WDO by typically 70ns.