Truth Table
IN0
IN1
Output Current
H
L
H
H
L
No Current
Low Current
Medium Current
High Current
H
L
L
Package Pin Description
PACKAGE PIN #
PIN SYMBOL
FUNCTION
16L
(Internally Fused Leads)
1
OUT B
Pulse
Output connection with OUTA. The output stage is a ÒHÓ bridge
formed by four transistors and four diodes suitable for switching
applications.
2
A parallel RC network connected to this pin sets the OFF time of
the lower power transistors. The pulse generator is a monostable
triggered by the rising edge of the output of the comparators
(tOFF = 0.69 RTCT).
3
VDDB
Gnd
Supply voltage input for half output stage.
4, 5, 12, 13
Ground connection. Also conducts heat from die to printed
circuit copper.
6
7
VCC
IN1
Supply voltage input for logic circuitry.
This pin and IN0 are logic inputs which select the outputs of the
three comparators to set the current level. Current also depends on
the sensing resistor and reference voltage. See truth table.
8
DIRECTION
This TTL-compatible logic input sets the direction of current
flow through the load. A high level causes current to flow from
OUTA (source) to OUTB (sink). A Schmitt trigger on this input
provides good noise immunity and a delay circuit prevents out-
put stage short circuits during switching.
9
IN0
See IN1.
10
Comp In
Input connected to the three comparators. The voltage across the
sense resistor is fed back to this input through the low pass filter
RCCC. The lower power transistors are disabled when the sense
voltage exceeds the reference voltage of the selected comparator.
When this occurs the current decays for a time set by RTCT,
tOFF = 0.69 RTCT.
11
VREF
A voltage applied to this pin sets the reference voltage of the
three comparators, thus determining the output current (also
dependent on RSense and the two inputs IN 0 and IN 1).
14
15
16
VDDA
OUT A
Sense
Supply voltage input for half output stage.
See OUTB.
Connection to lower emitters of output stage for insertion of
current sense resistor.
3
CHERRY [ CHERRY SEMICONDUCTOR CORPORATION ]
