MC34921 Datasheet, PDF (19/36 Pages) List of Unclassifed Manufacturers – Configurable Motor Driver IC with Power Supplies

FUNCTIONAL DESCRIPTION
FUNCTIONAL TERMINAL DESCRIPTION
DC MOTOR A OUTPUT A (ADCMA)
A high-side and low-side driver output terminal, which
when combined with ADCMB forms the A H-bridge DC motor
driver. The driver is PWM controlled via the APWM input, and
direction controlled via the Serial I/O. It features current limit
and thermal shutdown protection.
DC MOTOR A OUTPUT B (ADCMB)
A high-side and low-side driver output terminal, which
when combined with ADCMA forms the A H-bridge DC motor
driver. The driver is PWM controlled via the APWM input and
direction controlled via the Serial I/O. It features current limit
and thermal shutdown protection.
BOOST VOLTAGE (VBOOST)
This is the boost voltage storage node for the charge pump
circuit. It provides the gate drive voltage for the high-side
FETS in the DC motor drivers, switch mode controllers, and
Gateout pin.
SWTICHING CAPACITOR (CP1 AND CP2)
These are the connections for the charge pump flying
capacitor.
HIGH-SIDE MOSFET GATE DRIVER (GATEOUT)
The output terminal for an external N-channel high-side
driver. Enabled via the Serial I/O, it provides gate drive
control for an external N-channel MOSFET high-side switch.
DC MOTOR B OUTPUT B (BDCMB)
A high-side and low-side driver output terminal, which
when combined with BDCMB, forms the B H-bridge DC motor
driver. The drivers are PWM controlled via the BPWM input,
and direction controlled via the Serial I/O. It features current
limit and thermal shutdown protection.
DC MOTOR B OUTPUT A (BDCMA)
A high-side and low-side driver output terminal, which
when combined with BDCMA, forms the B H-bridge DC motor
driver. The drivers are PWM controlled via the BPWM input,
and direction controlled via the Serial I/O. It features current
limit and thermal shutdown protection.
5.0 V REGULATOR MODE SELECT (5 V SELECT)
This terminal is used to set the 5v regulator to operate in
either linear or switching mode. Ground this terminal to
operate in switching mode, or float to operate in linear mode.
5.0 V REGULATOR SWITCH OUTPUT (5 V SWITCH)
This terminal is the high-side driver output used for the 5v
switching regulator. It uses the internal 200KHZ clock.
Analog Integrated Circuit Device Data
Freescale Semiconductor
5.0 V REGULATOR INPUT SUPPLY (5 V SUPPLY)
The input voltage terminal for the 5v regulator. Limit it to
20v in linear mode. An additional series resistor is
recommended to dissipate power off-chip.
5.0 V REGULATOR FEEDBACK (5 V)
This is the 5v feedback input terminal and output voltage
point for the 5v regulator when in the switch configuration,
and the output pin when tied to 5v SWITCH in linear
configuration. It is also the power supply terminal for the
MC34921AE on board logic.
AN0/ANALOGOUT_A (AN0/ANALOGOUT_A)
Mux input 0 for the A/D converter, which is also available
in Freescale test mode as an output for the AN2 I/V
converter.
AN1/ANALOGOUT_B (AN1/ANALOGOUT_B)
Mux input 1 for the A/D converter, which is also available
in Freescale test mode as an output for the AN3 I/V
converter.
AN2/ANALOGIN_A (AN2/ANALOGIN_A)
Mux input 2 for the A/D converter incorporating an I/V
converter with offset and gain calibration via the Serial I/O.
AN3/ANALOGIN_B (AN3/ANALOGIN_B)
Mux input 3 for the A/D converter incorporating an I/V
converter with offset and gain calibration via the Serial I/O.
ANALOG ENCODER CHANNEL B FILTER (ENC_FILTB)
Input to the AN3 I/V converter stage for feedback
components used with the I/V converter op amp.
ANALOG ENCODER CHANNEL A FILTER (ENC_FILTA)
Input to the AN2 I/V converter stage for feedback
components used with the I/V converter op amp.
RESET (RST)
Supervisory function I/O, incorporating a comparator input
and an open drain output, and typically connected to the RST
of a microprocessor. As an input, RST resets internal
registers to default states, turns step motor outputs off, forces
DC motor drive low-side drives on, and sets MISO to a high
Z state. As an output, RST is set during B+ UVLO, all
regulators UVLO, current limit, and thermal shutdown events.
MASTER IN SLAVE OUT (MISO)
This is the master-in-slave-out terminal; the serial output
port of the Serial I/O, which typically connects to the MISO of
a microprocessor. MISO reports two data frames: NORMAL
- A/D conversion and analog encoder signals, and INFO -
Fault data and analog encoder signals.
The output data is loaded into the output shift register on
each rising edge of SCLK, while CE is held in a logic high
34921
19