Typical Performance Characteristics

for R and C

Selection Graph

vs Temperature

Supply Currents

vs Temperature

Supply Currents

(

TLH8679 – 2

Description of Inputs and Outputs

Pin 2 DIRECTION

This input determines the direction of

rotation of the motor ie

clockwise vs counterclockwise

See truth table

Pin 3 DEAD-TIME ENABLE

This input enables or disables

dead-time and grounding pin 3 disables it Pin 3 should not

be allowed to float

Pin 4 CLOCK TIMING

An RC network connected between

this pin and ground sets the period of the clock oscillator

which determines the amount of dead-time See

Figure 2

and text

Pins 5 thru 7 HS1 HS2 and HS3 (Hall-sensor inputs)

These inputs receive the rotor-position sensor inputs from

the motor Three-phase motors provide all three signals

four phase motors provide only two one of which is con-

nected to both HS2 and HS3

Pin 8 3060 SELECT

This input is used to select the re-

quired decoding for three-phase motors ie either ‘‘30-de-

a

5V when using a four-phase motor

Pin 9 LOGIC GROUND

Ground for the logic power supply

Pin 10 POWER GROUND

Ground for the output buffer

supply

Pins 11 thru 13 SOURCE OUTPUTS

The three current-

sourcing outputs which drive the external power devices

that drive the motor

Pins 14 thru 16 SINK OUTPUTS

The three current-sinking

outputs which drive the external power devices that drive

the motor

Pin 17 OUTPUT INHIBIT

This input disables the LM621

outputs It is typically driven by the magnitude signal from an

outputs off

collectors of the three current-sourcing outputs (pins 11 thru

13) When driving MOSFET power devices pin 18 may be

sufficient output swing for the gate When driving bipolar

mize on-chip power dissipation Undervoltage lockout auto-

tage lockout voltage

4