33874 datasheet(16/37 Pages) FREESCALE

16 / 37 page

Analog Integrated Circuit Device Data

Freescale Semiconductor

33874

FUNCTIONAL DESCRIPTION

FUNCTIONAL PIN DESCRIPTION

described in Table 9, page 21. The SI input has an active

internal pulldown, IDWN.

DIGITAL DRAIN VOLTAGE (VDD)

This pin is an external voltage input pin used to supply

power to the SPI circuit. In the event VDD is lost, an internal

supply provides power to a portion of the logic, ensuring

limited functionality of the device.

GROUND (GND)

This pin is the ground for the device.

POSITIVE POWER SUPPLY (VPWR)

This pin connects to the positive power supply and is the

source of operational power for the device. The VPWR contact

is the backside surface mount tab of the package.

SERIAL OUTPUT (SO)

The SO data pin is a tri-stateable output from the shift

the CS pin is put into a logic [0] state. The SO data is capable

of reporting the status of the output, the device configuration,

and the state of the key inputs. The SO pin changes state on

the rising edge of SCLK and reads out on the falling edge of

SCLK. Fault and input status descriptions are provided in

Table 16, page 25.

HIGH-SIDE OUTPUTS (HS3, HS1, HS0, HS2)

Protected 35 m

Ω high-side power output pins to the load.

FAIL-SAFE INPUT (FSI)

The value of the resistance connected between this pin

and ground determines the state of the outputs after a

Watchdog timeout occurs. Depending on the resistance

value, either all outputs are OFF or the output HSO only is

ON. If the FSI pin is left to float up to a logic [1] level, then the

outputs HS0 and HS2 will turn ON when in the Fail-Safe

state. When the FSI pin is connected to GND, the Watchdog

circuit and Fail-Safe operation are disabled. This pin

incorporates an active internal pullup current source.

33874 Datasheet(PDF) 16 Page - Freescale Semiconductor, Inc