Microprocessor Supervisory Circuits

6

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____________________________Typical Operating Characteristics (continued)

20

0

0

BATTERY CURRENT

vs. INPUT SUPPLY VOLTAGE

16

3

8

4

1

2

5

12

4

VBATT = 2.8V

100

0.1

WATCHDOG AND RESET TIMEOUT PERIOD

vs. OSC IN TIMING CAPACITOR (COSC)

10

COSC (pF)

100

1

10

1000

VBATT = 2.8V

LONG WATCHDOG

TIMEOUT PERIOD

SHORT WATCHDOG

TIMEOUT PERIOD

RESET ACTIVE

TIMEOUT PERIOD

0

300

CHIP-ENABLE PROPAGATION DELAY

vs. CE OUT LOAD CAPACITANCE

150

8

0

50

100

250

16

20

4

12

200

CE IN = 0V TO 5V

DRIVER SOURCE

IMPEDANCE = 50

Ω

1000

1

1

(NORMAL OPERATING MODE)

100

100

10

10

1000

VBATT = 0V

SLOPE = 0.8

Ω

1000

1

(BATTERY-BACKUP MODE)

100

10

10

1

100

VBATT = 4.5V

SLOPE = 8

Ω

LO

AND CE OUT DELAY

LOW LINE

5V

THRESHOLD

LO

HI

HI

HI

LO

CE OUT

RESET

12

µs

800ns

80

µs