UPD17145CT datasheet(65/102 Pages) NEC

Part #	UPD17145CT

Description	SMALL, GENERAL-PURPOSE 4-BIT SINGLE-CHIP MICROCONTROLLERS

PDF	102 Pages

Scroll/Zoom	100%

Manufacturer	NEC [NEC]

Direct Link	http://www.nec.com/

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65 / 102 page

µPD17145(A1), 17147(A1), 17149(A1)

19. POC CIRCUIT (MASK OPTION)

The POC circuit monitors the supply voltage. When the supply voltage is turned ON/OFF, it automatically

resets the internal circuitry of the microcontroller. This circuit can be used in an application circuit with a clock

frequency of 400 kHz to 4 MHz.

The

µPD17149 (A1) can be provided with the POC circuit by mask option.

Caution

The POC circuit is not provided to the PROM model (

µPD17P149).

19.1 Function of POC Circuit

The POC circuit has the following functions:

• Generates internal reset signal when VDD

≤ VPOC

• Clears internal reset signal when VDD > VPOC

(where, VDD: supply voltage, VPOC: POC detection voltage)

Figure 19-1. Operation of POC Circuit

5.5 V

4.5 V

VPOC

2.7 V

0 V

Note 3

VDD

Note 1

→ t

Reset

Operation modeNote 4

Reset

Operation guaranteed range

Internal reset signal

↑

Note 2

Note 3

UPD17145CT Datasheet(PDF) 65 Page - NEC