SENSITRON

SEMICONDUCTOR

TECHNICAL DATA

©2007 Sensitron Semiconductor

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Deer Park, NY 11729-4681

Phone (631) 586 7600 Fax (631) 242 9798

• www.sensitron.com • sales@sensitron.com • Page 6

SPDPXXD375 SERIES

The watchdog timer operates from its own internal clock so a failure of the main clock will not stop the watchdog

timer. The code programmed in the microcontroller will periodically reset the watchdog timer preventing it from

timing out. If the code malfunctions for any reason, the watchdog timer is not reset and it times out. When the

watchdog timer times out, it resets the microcontroller. Since the code is designed to detect levels and not

command on its input.

The “Control & Protection Circuitry” block also has the ability for the user to adjust the current rating by varying

the trip point with a resistor between the “I

Trip current level with a resistor between the “INSTANT TRIP ADJ” pin and the “TRIM COMMON” pin. See

Figures 4 and 5 to select the appropriate resistor for adjusting the current rating for the SPDP03D375 and

SPDP10D375 models, respectively. See Figures 6 and 7 to select the appropriate resistor for adjusting the

Instant Trip current level for the SPDP03D375 and SPDP10D375 models, respectively.

When setting the current rating, select a resistor according to Figures 4 and 5 for 10% above the desired rating.

Example: to set the SPDP03D375 to a rating of 2 Amps, look on Figure 4 for 2.2 Amps and select a resistor of

2.7K.

Figure 4 – SPDP03D375 Current Rating Trim Resistor Selection