33811 datasheet(12/18 Pages) FREESCALE

12 / 18 page

Analog Integrated Circuit Device Data

Freescale Semiconductor

33811

FUNCTIONAL DESCRIPTION

FUNCTIONAL INTERNAL BLOCK DESCRIPTION

Figure 7. Functional Internal Block Diagram

POWER SUPPLY AND OSCILLATOR

The 33811 is designed to operate from 10.5V to 15.5V on

the VPWR pin. The VPWR pin supplies power to the internal

regulator which, in turn, supplies the analog circuit blocks.

The VDD Supply is used internally to supply the logic

circuitry. The VSPI supply is used for setting the SPI

communication threshold levels by supplying power to the

SO driver and the SI and CS input buffers. The on-chip

oscillator is used to set the solenoid sample period window

and sample rate.

MCU INTERFACE:

The 33811 device directly interfaces to a 3.3V or 5.0V

micro controller unit (MCU) using 16 bit Serial Peripheral

Interface (SPI) protocol. SPI serial clock frequencies up to

3.2MHz may be used when programming and reading output

status information. The RESET pin is used to place the 33811

into the Reset Mode. Normally the RESET pin is held at logic

0 by the MCU. When the MCU raises the RESET pin to a

logic 1, the 33811 enters the reset Mode. The reset initializes

the 5 fault outputs.

SOLENOID MONITORS: SOLM1 - SOLM5

These are the five solenoid monitor inputs that are

connected to the external solenoid driver output pins. The IC

has the ability to determine the correct movement of solenoid

armatures by analyzing the variation in the voltage profile,

across the solenoid driver MOSFET, which represents the

actual solenoid current profile.

33811 Datasheet(PDF) 12 Page - Freescale Semiconductor, Inc