CS1107
Circuit Description
The CS1107 relay driver IC provides up to 350mA of drive
current in a low-side configuration. The Output driver pin
is controlled through the TTL compatible Control input
pin. A high condition on the Control pin turns the output
pin on.
The Fault pin reports short circuit, open circuit, and
overtemperature conditions on the IC. If a fault is present,
the open collector output Fault pin will be low. Typical
numbers for faults are: exceeding 500mA of drive current
will report a short circuit. Less than 40mA (typical) will
report an open circuit. A temperature fault will be reported
when the die temperature exceeds 180¡C (typical). Faults
are only reported when the Control pin is high, due to the
low quiescent current when the Control pin is low and the
output device is turned off.
Overcurrent protection is provided by duty cycle control.
When the Output current exceeds the current limit thresh-
old, the output enters duty cycle mode to reduce power
dissipation of the IC to a safe level. The higher the thresh-
old is exceeded the lower the duty cycle becomes.
A 33V on-chip zener diode on the Output pin protects the
device from flyback pulses when a relay is turned off. The
saturation voltage of this pin will not exceed 1.5V at
350mA.
Applications Diagram
Output
C
MODULE(ESD)
10nF
CS1107
V
CC
Fault
20k
Control
V
BAT
V
CC
Gnd
Gnd
Gnd
Gnd
microprocessor
3
CHERRY [ CHERRY SEMICONDUCTOR CORPORATION ]
