1. General description
The PCA9621 is a monolithic CMOS integrated circuit for general purpose output drive
configurable from a 2-wire bus interface (including I
2
C-bus, SMBus, PMBus, and other
systems based on similar principles). Output ports have a 65 mA sink capability, making
them ideal for driving LEDs.
The state of the outputs is determined by a programmable 8-bit register which can be read
and written via signals from the 2-wire bus (e.g., I
2
C-bus or similar).
The 2-wire bus interface also has 30 mA Fast-mode Plus (Fm+) capability, and
consequently can be run in excess of 1 MHz or up to 4000 pF capacitance. As such, the
PCA9621 can be connected to other 2-wire devices across long cable connections.
It can be mixed with other Fast-mode Plus slaves in systems driven by Fm+ buffers or by
the PCA9646 (fully buffered 4-channel bus switch) to build large scale systems with
high-speed or high-capacitance drive capability, for example large scale LED displays or
controlled lighting.
2. Features and benefits
8 individually selectable open-drain output ports
65 mA static sink capability on all output ports
Ports may be paralleled for up to 500 mA drive
Ideal for simple LED or general purpose output drive
Fast-mode Plus (30 mA, 4000 pF) 2-wire bus capability
Works with I
2
C-bus (Standard-mode, Fast-mode, and Fast-mode Plus), SMBus
(standard and high power mode), and PMBus
Fast switching times allow operation in excess of 1 MHz
Operating voltages from 2.7 V to 5.5 V
3. Applications
LED and 7-segment displays
Simple high-power (500 mA) LED dimming
General purpose output
Instrumentation indicators
PCA9621
65 mA 8-bit 2-wire bus output port
Rev. 1 — 9 March 2011 Product data sheet
