MCP8026 datasheet(23/64 Pages) MICROCHIP

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 2016 Microchip Technology Inc.

DS20005339B-page 23

MCP8025/6

3.9

LIN Transceiver Transmit Data

Input (TX)

The TX input pin is used to send data to the LIN Bus.

The LIN_BUS pin is low (dominant) when TXD is low

and high (recessive) when TXD is high. Data to be

transmitted from a host MCU is sent to the LIN bus via

the TX pin.

3.10

LIN Transceiver Fault/

Transmit Enable (FAULTn/TXE)

Fault Detect output and Transmitter Enable input

bidirectional pin. The FAULTn/TXE pin will be driven

low whenever a LIN fault occurs. There is a

47 k

 resistor between the internal fault signal and the

FAULTn/TXE pin to allow the pin to be externally driven

high after a fault has occurred. The FAULTn/TXE pin

must be pulsed high to start a transmit. If there is no

fault present when the pin is pulsed, the FAULTn/TXE

pin will latch and be driven high by an internal 47 k



impedance. The FAULTn/TXE pin may then be

monitored for faults.

No external pull up is needed. The microcontroller pin

controlling the FAULTn/TXE pin must be able to switch

between output and input modes.

3.11

Zero-Crossing Multiplexer Inputs

(MUX1, MUX2)

The MUX1 and MUX2 multiplexer inputs select the

desired phase winding to be used as the zero-crossing

Back EMF phase reference. The output of the

multiplexer connects to one input of the zero-crossing

comparator. The other zero-crossing comparator input

connects to the neutral voltage. The MUX1 and MUX2

inputs must be driven by the host processor

synchronously with the motor commutation.

3.12

Zero-Crossing Detector Output

(ZC_OUT)

The ZC_OUT output pin is the output of the

zero-crossing comparator. When the phase voltage

selected by the multiplexer inputs crosses the neutral

voltage, the zero-crossing detector will change the

output state.

The ZC_OUT output is an open-drain output.

3.13

Neutral Voltage Reference Input

(COMP_REF)

The COMP_REF input pin is used to connect to the

neutral point of a motor if the neutral point is available.

The COMP_REF input may be selected via a

configuration register as the neutral voltage reference

used by the zero-crossing comparator.

3.14

Current Limit and Driver Fault

Output (ILIMIT_OUT)

Dual-purpose output pin. The open-drain output goes

low when the current sensed by current sense

amplifier 1 exceeds the value set by the internal current

reference DAC. The DAC has an offset of 0.991V

(typical) which represents the zero current flow.

The open-drain output will also go low while a fault is

active. Table 4-1 shows the faults that cause the

ILIMIT_OUT pin to go low.

The ILIMIT_OUT pin is able to sink 1 mA of current

while maintaining less than a 50 mV drop across the

output.

3.15

Operational Amplifier Outputs

(I_OUT1, I_OUT2, I_OUT3)

Current sense amplifier outputs. May be used with

feedback resistors to set the current sense gain. The

amplifiers are disabled when CE = 0.

3.16

Operational Amplifier Inputs

(ISENSE1 +/-, ISENSE2 +/-,

ISENSE3 +/-)

Current sense amplifier inverting and non-inverting

inputs. Used in conjunction with the I_OUTn pin to set

the current sense gain. The amplifiers are disabled

when CE = 0.

3.17

Low-Side N-Channel MOSFET

Driver Outputs (LSA, LSB, LSC)

Low-side N-channel MOSFET drive signal. Connect to

the gate of the external MOSFETs. A low-impedance

resistor may be used between these pins and the

MOSFET gates to limit current and slew rate.

3.18

High-Side N-Channel MOSFET

Driver Outputs (HSA, HSB, HSC)

High-side N-channel MOSFET drive signal. Connect to

the gate of the external MOSFETs. A low-impedance

resistor may be used between these pins and the

MOSFET gates to limit current and slew rate.

3.19

Driver Phase Inputs

(PHA, PHB, PHC)

Phase signals from motor. These signals provide

high-side N-channel MOSFET driver reference and

Back EMF sense input. The phase signals are also

used with the bootstrap capacitors to provide high-side

gate drive via the VBx inputs.

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