N

°

NAME

FUNCTION

1

SYNC

Output of the on-chip chopper oscillator.

The SYNC connections The SYNC connections of all L297s to be

synchronized are connected together and the oscillator

components are omitted on all but one. If an external clock source

is used it is injected at this terminal.

2

GND

Ground connection.

3

HOME

Open collector output that indicates when the L297 is in its initial

state (ABCD = 0101).

The transistor is open when this signal is active.

4

A

Motor phase A drive signal for power stage.

5

INH1

Active low inhibit control for driver stage of A and B phases.

When a bipolar bridge is used this signal can be used to ensure

fast decay of load current when a winding is de-energized. Also

used by chopper to regulate load current if CONTROL input is low.

6

B

Motor phase B drive signal for power stage.

7

C

Motor phase C drive signal for power stage.

8

INH2

Active low inhibit control for drive stages of C and D phases.

Same functions as INH1.

9

D

Motor phase D drive signal for power stage.

10

ENABLE

Chip enable input. When low (inactive) INH1, INH2, A, B, C and D

are brought low.

11

CONTROL

Control input that defines action of chopper.

When low chopper acts on INH1 and INH2; when high chopper

acts on phase lines ABCD.

12

5V supply input.

13

Input for load current sense voltage from power stages of phases

C and D.

14

Input for load current sense voltage from power stages of phases

A and B.

15

Reference voltage for chopper circuit. A voltage applied to this pin

determines the peak load current.

16

OSC

determines the chopper rate. This terminal is connected to ground

on all but one device in synchronized multi - L297 configurations. f

≅ 1/0.69 RC

17

CW/CCW

Clockwise/counterclockwise direction control input.

Physical direction of motor rotation also depends on connection

of windings.

Synchronized internally therefore direction can be changed at any

time.

18

CLOCK

Step clock. An active low pulse on this input advances the motor

one increment. The step occurs on the rising edge of this signal.

PIN FUNCTIONS - L297/L297D

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L297-L297D