PRELIMINARY
ML4435
PIN CONFIGURATION
ML4435
20-P n PDIP P20
20-P n SOIC S20
20
CVCO
SOFT START
SPEED FB
ND
ISENSE
TACH
2
3
4
5
6
9
SPEED COMP
RVCO
SPEED SET
RT
6
5
4
3
2
FB C
FB B
FB A
HA
LC
HB
9
LB
HC
0
LA
VCC
TOP VIEW
PIN DESCRIPTIONS
PIN
NAME
FUNCTION
1
ISENSE
Motor current sense input which triggers pulse by pulse current limit when
ISENSE exceeds 0.55V
2
TACH
A clock output of 6 pulses per commutation cycle when SPEED FB is greater
than 0.97V otherwise the TACH output is at 5V
3
4
SPEED COMP
RVCO
SPEED SET
RT
Connection node for speed loop compensation components
Connection node for external resistor to set VCO frequency
DC input for setting motor speed
5
6
External resistor from this pin to ground controls the IC's PWM timing (frequency)
High-side output driver for motor phase A
7
HA
8
HB
High-side output driver for motor phase B
9
HC
High-side output driver for motor phase C
10
11
12
13
14
15
16
17
18
19
20
VCC
Power Supply input
LA
Low-side output driver signal for motor phase A
Low-side output driver signal for motor phase B
Low-side output driver signal for motor phase C
Back EMF signal input for motor phase A
LB
LB
FB A
FB B
Back EMF signal input for motor phase B
FB C
Back EMF signal input for motor phase C
GND
SPEED FB
SOFT START
CVCO
Signal and power ground
Connection node for back-EMF sensing compensation components
Connection node for external soft start capacitor which reduces start up current
Connection node for external capacitor to set VCO frequency. Forcing this input
below 1.5V causes the commutation to stop and the motor to coast
4
PRELIMINARY DATASHEET
May, 2000
MICRO-LINEAR [ MICRO LINEAR CORPORATION ]
