S1170 Datasheet, PDF (16/30 Pages) Seiko Instruments Inc – HIGH RIPPLE-REJECTION AND LOW DROPOUT

HIGH RIPPLE-REJECTION LOW DROPOUT HIGH OUTPUT CURRENT CMOS VOLTAGE REGULATOR
S-1170 Series
Rev.4.1_00
4. Thermal shutdown circuit
The S-1170 Series implements a thermal shutdown circuit to protect the device from damage due to
overheating. When the junction temperature rises to 150°C (typ.), the thermal shutdown circuit operates
and the regulator operation stops. When the junction temperature drops to 120°C (typ.), the thermal
shutdown circuit is released and the regulator operation resumes.
If the thermal shutdown circuit starts operating due to self-heating, the regulator operation stops and the
output voltage falls. When the regulator operation has stopped, no self-heat is generated and the
temperature of the IC is lowered. When the temperature has dropped, the thermal shutdown circuit is
released, the regulator operation resumes, and self-heat is generated again. By repeating this procedure,
the output voltage waveform forms pulses. Stop or restart of regulation continues unless decreasing
either or both of the input voltage and the output current in order to reduce the internal power
consumption, or decreasing the ambient temperature.
Table 7
Thermal Shutdown Circuit
Operating: 150°C (typ.)
Released: 120°C (typ.)
VOUT Pin Voltage
V_SS level
Set value
16
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