Datasheet

1. General description
The PCA9670 provides general-purpose remote I/O expansion via the two-wire
bidirectional I
2
C-bus (serial clock (SCL), serial data (SDA)).
The devices consist of eight quasi-bidirectional ports, 1 MHz 30 mA drive I
2
C-bus
interface, three hardware address inputs and a reset input operating between 2.3 V and
5.5V. 1MHz I
2
C-bus Fast-mode Plus (Fm+) can support PWM dimming of LEDs, and
higher I
2
C-bus drive 30 mA allows more devices to be on the bus without the need for bus
buffers. The quasi-bidirectional port can be independently assigned as an input to monitor
interrupt status or keypads, or as an output to activate indicator devices such as LEDs.
The system master can read from the input port or write to the output port through a single
register.
The low current consumption of 2.5 A (typical, static) is great for mobile applications and
the latched output ports have 25 mA high current sink drive capability for directly driving
LEDs.
The PCA9670 has three hardware address pins and allows up to 64 of these PCA9670
I/O expanders on the same I
2
C-bus without the need for bus buffers, supporting up to
512 I/Os (for example, 512 LEDs).
The internal Power-On Reset (POR) and active LOW hardware reset pin (RESET
)
initialize the I/Os as inputs with a weak internal pull-up 100 A current source.
2. Features and benefits
 I
2
C-bus to parallel port expander
 1MHz I
2
C-bus interface (Fast-mode Plus I
2
C-bus)
 SDA with 30 mA sink capability for 4000 pF buses
 Operating supply voltage 2.3 V to 5.5 V with 5.5 V tolerant I/Os held to V
DD
with
100 A current source
 8-bit remote I/O pins that default to inputs at power-up
 Latched outputs with 25 mA sink capability for directly driving LEDs
 Total package sink capability of 200 mA
 Active LOW reset input
 Sixty-four programmable slave addresses using three address pins
 Readable device ID (manufacturer, device type, and revision)
 Software reset
 Low standby current (2.5 A typical)
 40 C to +85 C operation
PCA9670
Remote 8-bit I/O expander for Fm+ I
2
C-bus with reset
Rev. 3 — 30 May 2013 Product data sheet