S814 Datasheet, PDF (13/32 Pages) Seiko Instruments Inc – LOW DROPOUT CMOS VOLTAGE REGULATOR

Rev.3.1_00
LOW DROPOUT CMOS VOLTAGE REGULATOR
S-814 Series
3. ON/OFF pin
This pin starts and stops the regulator.
When the ON/OFF pin is set to OFF level, the entire internal circuit stops operating, and the built-in P-
channel MOS FET output transistor between VIN pin and VOUT pin is turned off, reducing current
consumption significantly. The VOUT pin enters the Vss level due to internally divided resistance of
several MΩ between VOUT pin and VSS pin.
Furthermore, the structure of the ON/OFF pin is as shown in Figure 13. Since the ON/OFF pin is neither
pulled down nor pulled up internally, do not use it in the floating status. In addition, please note that
current consumption increases if a voltage of 0.3 V to V_IN−0.3 V is applied to the ON/OFF pin. When not
using the ON/OFF pin, connect it to the VIN pin in case of the product A type, connect it to the VSS pin in
B type.
V_IN
ON/OFF
V_SS
Figure 13
Product type
A
A
B
B
ON/OFF pin
“H”: ON
“L”: OFF
“H”: OFF
“L”: ON
Table 6
Internal circuit
Operate
Stop
Stop
Operate
VOUT pin voltage
Set value
V_SS level
V_SS level
Set value
Current consumption
I_SS1
I_SS2
I_SS2
I_SS1
4. Short-circuit protection circuit
The S-814 Series incorporates a short-circuit protection circuit to protect the output transistor against
short-circuiting between VOUT pin and VSS pin.
The short-circuit protection circuit controls output current as shown in “1. Output voltage (V_OUT) vs.
Output current (I_OUT) (When load current increases)” in “ Characteristics (Typical Data)”, and
prevents output current of approx. 70 mA or more from flowing even if VOUT pin and VSS pin are shorted.
However, the short-circuit protection circuit does not protect thermal shutdown. Be sure that input voltage
and load current do not exceed the specified power dissipation level.
When output current is large and a difference between input and output voltages is large even if not
shorted, the short-circuit protection circuit may start functioning and the output current may be controlled
to the specified amperage. For details, refer to “3. Maximum output current (I_OUTmax) vs. Input voltage
(V_IN)” in“ Characteristics (Typical Data)”.
Seiko Instruments Inc.
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