1. General description
The NCA9595 provides 16 bits of General Purpose Input/Output (GPIO) expansion for I²Cbus/
SMBus applications. It is designed for a wide voltage range of 1.65 V to 5.5 V with interrupt
and default pull-up resistors on GPIOs. Nexperia GPIO expanders provide an elegant solution
when additional IOs are needed while keeping the interconnections to a minimum, for example,
in ACPI power switches, sensors, push buttons, LEDs and fan control. The NCA9595 contains
a set of 8 bit input, output, configuration, polarity inversion and configuration pull-up registers. At
power up all IOs default to inputs. Each IO can be configured as either input or output by changing
the corresponding bit in the configuration register. The data for each input or output is stored in
the corresponding input or output register. The polarity inversion register can be programmed to
invert the polarity of the input register. The pull-up resistors can be disconnected by programming
configuration pull up registers. The NCA9595 has an open-drain interrupt output which is activated
when any one of the GPIO changes from its corresponding input port register state. The power on
reset sets the registers to default values and initializes the device state machine. The NCA9595
has three address pins A0, A1 and A2 which can be used to configure the I²C bus slave address of
the device. It allows up-to eight devices to share the same I²C-bus/SMBus.
2. Features and benefits
• I²C-bus to parallel port expander
• Operating power supply voltage range of 1.65 V to 5.5 V
• Low standby current consumption:
• 2.5 μA (maximum)
• Schmitt-trigger action allows slow input transition and better switching noise immunity at the
SCL and SDA inputs
• Vhys = 0.10 × VCC (typical)
• Noise filter on SCL and SDA inputs
• 5 V tolerant I/Os
• 16 I/O pins which power up configured in input state with weak configurable pull-up resistors
• Open-drain active LOW interrupt output (INT)
• 400 kHz Fast-mode I²C-bus
• Internal power-on reset
• Configuration pull-up registers to disable pull up resistors on GPIOs
• No glitch on power-up
• Latched outputs with 25 mA drive maximum capability for directly driving LEDs
• Latch-up performance exceeds 100 mA per JESD78, Class II
• ESD protection:
• HBM ANSI/ESDA/JEDEC JS-001 Class 2 exceeds 2000 V
• CDM ANSI/ESDA/JEDEC JS-002 Class C3 exceeds 1000 V
• Specified from -40 °C to +85 °C