PCAL9714 datasheet(26/56 Pages) NXP

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NXP Semiconductors

PCAL9714

Ultra low-voltage translating 14-bit SPI I/O expander with Agile I/O features, interrupt output, and

reset

7 Application information

PCAL9714

P0_0

P0_1

SCLK

SDIN

VDD

SCLK

SDOUT

P0_2

P0_3

VSS

MASTER

CONTROLLER

VSS

VDD(SPI) = 1.8 V

controlled

switch

enable

INT

VDD(P)

INT

10 k

SUBSYSTEM 1

(e.g., alarm system)

ALARM(1)

P0_4

P0_5

P0_6

P0_7

RESET

VDD(P)

aaa-031781

P1_0

P1_1

P1_2

P1_3

P1_4

P1_5

VDD(SPI)

ADDR

KEYPAD

10 k

10 k (×7)

SDOUT

SDIN

Device address configured as 0100 000x for this example.

P0_0 and P0_2 through P1_0 are configured as inputs.

P0_1 and P1_1 through P1_5 are configured as outputs.

1. External resistors are required for inputs (on P port) that may float. Also, internal pullup or pulldown may be used to

eliminate the need for external components. If a driver to an input will never let the input float, a resistor is not needed.

If an output in the P port is configured as a push-pull output there is no need for external pullup resistors. If an output

in the P port is configured as an open-drain output, external pullup resistors are required.

Figure 15. Typical application

7.1 Minimizing IDD when the I/Os are used to control LEDs

When the I/Os are used to control LEDs, they are normally connected to VDD through a resistor as shown in

Figure 15. Since the LED acts as a diode, when the LED is off the I/ O VI is about 1.2 V less than VDD(P). The

supply current, IDD(P), increases as VI becomes lower than VDD(P).

Designs needing to minimize current consumption, such as battery power applications, should consider

maintaining the I/O pins greater than or equal to VDD when the LED is off. Figure 16 shows a high value resistor

in parallel with the LED. Figure 17 shows VDD(P) less than the LED supply voltage by at least 1.2 V. Both of

these methods maintain the I/O VI at or above VDD(P) and prevents additional supply current consumption when

the LED is off.

PCAL9714

All information provided in this document is subject to legal disclaimers.

Product data sheet

Rev. 1.0 — 1 May 2023

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