APPLICATION NOTES

IN

MSK 4251 PIN DESCRIPTIONS

AV+, BV+ - are the power connections from the hybrid to

the bus. All pins for the motor voltage supply should be con-

nected together to share the current through the pins in the

hybrid.

The external wiring to these pins should be sized

according to the RMS current required by the motor. A high

quality monolithic ceramic capacitor for high frequencies and

enough bulk capacitance for keeping the V+ supply from

drooping should bypass these pins. 1000µF is recommended.

Capacitors should be placed as close to these pins as practi-

cal.

AØ, BØ - are the connections to the motor phase windings

from the bridge output. The wiring to these pins should be

sized according to the required current by the motor. There

are no short circuit provisions for these outputs. Shorts to

V+ or gound from these pins must be avoided or the bridge

will be destroyed. All pins for each phase should be con-

nected together to share the current through the three pins in

the hybrid.

RTN - is the power return connection from the module to the

bus. All internal ground returns connect to this point inside

the hybrid. All three pins should be connected together to

share the current. All capacitors from the V+ bus should

connect to this point as close as possible. All external V+

return connections should be made as close to these pins as

possible. Wiring sizing to this pin should be made according

to the required current.

GND - is the return point for the low powered circuitry inside

the hybrid. All GND pins should be tied together. All capaci-

tors for bypassing the + and -15V supplies should be tied at

this point, as close to the pins as possible. Any ground plane

connections for low powered and analog citcuitry outside the

hybrid should be tied to this point.

+15VIN - is the input for applying +15 volts to run the low

power section of the hybrid. Both pins should be used to-

gether for optimum operation. These pins should be bypassed

with a 10µF capacitor and a 0.1µF capacitor as close to these

pins as possible.

-15VIN - is the input for applying -15 volts to run the low

power section of the hybrid. Both pins should be used to-

gether for optimum operation. These pins should be bypassed

with a 10µF capacitor and a 0.1µF capacitor as close to these

pins as possible.

SENSE RESISTOR + - is the top of the sense resistor for

sensing the bridge current and closing the loop. The bottom

of the sense resistor is RTN. All the AV- and BV- pins should

be connected to this point.

AV-,BV- - are the power pins for the bottom of the bridge.

These are to be connected to sense resistor +.

DISABLE - is a pin for externally disabling the output bridge.

A TTL logic low will enable the bridge and a TTL high will

disable it. It is internally pulled up by a 100µAmp pull-up.

CURRENT COMMAND (+,-)

- are differential inputs for con-

trolling the module in current mode. Scaled at 2 amps per

volt of input command, the bipolar input allows both forward

and reverse current control capability regardless of motor com-

mutation direction. The maximum operational command volt-

age should be ±5 volts for ±10 amps of motor current.

Going beyond 5 volts of command voltage will force the bridge

to conduct more than the desired maximum current. There is

internal current limiting that will ultimately limit the absolute

maximum current being output by the bridge.

CURRENT MONITOR- is a pin providing a current viewing

signal for external monitoring purposes. This is scaled at ±2

amps of motor current per volt output, up to a maximum of

±5 volts, or ±10 amps. Going beyond the 5 volt maximum

may result in clipping of the waveform peaks.

E/A OUT - is the current loop error amplifier output.

It is

brought out for allowing various loop compensation circuits

to be connected between this and E/A-.

E/A- - is the current loop error amplifier inverting input. It is

brought out for allowing various loop compensation circuits

to be connected between this and E/A OUT.

3

Rev. B 1/05