33811 datasheet(11/18 Pages) FREESCALE

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Analog Integrated Circuit Device Data

Freescale Semiconductor

33811

FUNCTIONAL DESCRIPTION

FUNCTIONAL PIN DESCRIPTION

FUNCTIONAL DESCRIPTION

FUNCTIONAL PIN DESCRIPTION

ANALOG VOLTAGE SUPPLY (VPWR)

The VPWR pin is battery input to the 33811 IC. The VPWR

pin requires external reverse battery and transient protection.

Maximum input voltage on VPWR is 15.5V for full operation.

All IC analog current is provided from the VPWR pin through

an internal voltage regulator. The VPWR pin requires

adequate decoupling capacitance to the A_GND pin.

DIGITAL VOLTAGE SUPPLY (VDD)

The VDD pin is Logic Supply input to the 33811 IC. Maximum

input voltage on VDD is 5.25V for full operation. All IC digital

logic current except the SPI SO output pin is provided from

the VDD pin. The VDD pin requires adequate decoupling

capacitance to the D_GND pin.

SPI INTERFACE VOLTAGE (VSPI)

The VSPI input pin is used to determine communication logic

voltage levels between the microprocessor and the 33811

device. Current from VSPI is used to drive SO output and

pull-up current for CS and SI. VSPI must be connected to +5

Volts or +3.3 Volts for normal operation.

ANALOG GROUND (A_GND)

The Analog Ground (A_GND) pin provides a low current

analog ground for the IC. The VPWR supply is referenced to

the A_GND pin. The A_GND pin should be used for

decoupling the VPWR pin.

DIGITAL GROUND (D_GND)

The Digital Ground (D_GND) pin provides a dedicated

ground for the VDD and VSPI supplies and should be

connected to the A_GND pin.

SERIAL CLOCK INPUT (SCLK)

The system clock (SCLK) pin clocks the internal shift

shift register on the rising edge of SCLK signal. The SO pin

shifts status bits out on the falling edge of SCLK. The SO data

is available for the MCU to read on the rising edge of SCLK.

With CS in a logic high state, signals on the SCLK and SI pins

will be ignored and the SO pin is tri-state.

CHIP SELECT (CS)

The system MCU selects the 33811 to receive

communication using the chip select (CS) pin. With the CS in

a logic low state, command words may be sent to the 33811

via the serial input (SI) pin, and status information is received

by the MCU via the serial output (SO) pin. The falling edge of

CS enables the SO output and transfers status information

into the SO buffer.

Rising edge of the CS initiates the following operation:

1. Disables the SO driver (high-impedance)

2. Activates the received command word, allowing the

33811 to activate/deactivate output drivers.

To avoid any spurious data, it is essential the high-to-low

and low-to-high transitions of the CS signal occur only when

SCLK is in a logic low state. Internal to the 33811 device is an

active pull-up to VSPI on CS. In cases where voltage exists on

CS without the application of VSPI, no current will flow from

CS to the VSPI pin.

SERIAL INPUT DATA (SI)

The SI pin is used for serial instruction data input. SI

information is latched into the input register on the rising edge

of SCLK. A logic high state present on SI will program a one

in the command word on the rising edge of the CS signal. To

program a complete word, 16 bits of information must be

entered into the device.

SERIAL OUTPUT DATA (SO)

The SO pin is the output from the shift register. The SO pin

remains tri-stated until the CS pin transitions to a logic low

state. All normal operating drivers are reported as zero, all

faulted drivers are reported as one. The negative transition of

CS enables the SO driver.

The SI/SO shifting of the data follows a first-in-first-out

protocol, with both input and output words transferring the

most significant bit (MSB) first.

RESET INPUT (RESET)

The RESET pin is an active high digital input pin used to

clear the fault outputs and registers in the device. During

normal operation the RESET pin should be held low.

SOLENOID MONITOR INPUT (SOLM1, SOLM2,

SOLM3, SOLM4, SOLM5)

These are the five solenoid monitor inputs that are

connected to the Solenoid solenoid driver output pins.

33811 Datasheet(PDF) 11 Page - Freescale Semiconductor, Inc

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