HIGH RIPPLE-REJECTION LOW DROPOUT HIGH OUTPUT CURRENT CMOS VOLTAGE REGULATOR
S-1170 Series
Rev.4.0_00
Seiko Instruments Inc.
16
4. T
hermal 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. This phenomenon, stopping and resuming the regulator
operation, continues until the internal power consumption is reduced by reducing either the input voltage
or output current or both, or the ambient temperature is lowered.
Table 7
Thermal Shutdown Circuit VOUT Pin Voltage
Operating: 150°C (typ.)
V
SS
level
Released: 120°C (typ.)
Set value
HIGH RIPPLE-REJECTION LOW DROPOUT HIGH OUTPUT CURRENT CMOS VOLTAGE REGULATOR
Rev.4.0_00
S-1170 Series
Seiko Instruments Inc.
17
Precautions
Wiring patterns for the VIN, VOUT and GND pins should be designed so that the impedance is low.
When mounting an output capacitor between the VOUT and VSS pins (C
L
) and a capacitor for stabilizing
the input between VIN and VSS pins (C
IN
), the distance from the capacitors to these pins should be as
short as possible.
Note that the output voltage may increase when a series regulator is used at low load current (1.0 mA or
less).
Generally a series regulator may cause oscillation, depending on the selection of external parts. The
following conditions are recommended for this IC. However, be sure to perform sufficient evaluation
under the actual usage conditions for selection, including evaluation of temperature characteristics.
Input capacitor (C
IN
): 4.7 μF or more
Output capacitor (C
L
): 4.7 μF or more
Equivalent series resistance (ESR): 0.5 Ω or less
The voltage regulator may oscillate when the impedance of the power supply is high and the input
capacitor is small or an input capacitor is not connected.
The application conditions for the input voltage, output voltage, and load current should not exceed the
package power dissipation.
Do not apply an electrostatic discharge to this IC that exceeds the performance ratings of the built-in
electrostatic protection circuit.
In determining the output current, attention should be paid to the output current value specified in Table
5 in the “ Electrical Characteristics” and footnote *5 of the table.
SII claims no responsibility for any disputes arising out of or in connection with any infringement by
products including this IC of patents owned by a third party.
HIGH RIPPLE-REJECTION LOW DROPOUT HIGH OUTPUT CURRENT CMOS VOLTAGE REGULATOR
S-1170 Series
Rev.4.0_00
Seiko Instruments Inc.
18
Typical Characteristics
(1) Output Voltage vs. Output current (when load current increases)
S-1170B15 (Ta = 25°C) S-1170B30 (Ta = 25°C)
VOUT [V]
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
0 200 400 600
800 1000
1200
V
IN
= 2.0 V
2.5 V
6.5 V
VOUT [V]
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
400 600
800 1000
2000 1200
V
IN
= 3.5 V
4.0 V
6.5 V
IOUT [mA]
IOUT [mA]
S-1170B50 (Ta = 25°C)
VOUT [V]
6
5
4
3
2
1
0
400 600 8002000
1000
1200
V
IN
= 5.5 V
6.0 V
6.5 V
IOUT [mA]
Remark In determining the output current, attention
should be paid to the following.
1) The minimum output current value
and footnote *5 in the “ Electrical
Characteristics
2) The package power dissipation
(2) Output voltage vs. Input voltage
S-1170B15 (Ta = 25°C) S-1170B30 (Ta = 25°C)
VOUT [V]
1.6
1.5
1.4
1.3
1.2
1.1
1.0
3.53.0
2.5
2.0
1.5
1.0
I
OUT
= 1 mA
10 mA
100 mA
300 mA
VOUT [V]
3.1
3.0
2.9
2.8
2.7
2.6
2.5
5.04.5
4.0 3.53.02.5
I
OUT
= 1 mA
10 mA
100 mA
300 mA
VIN [V]
VIN [V]
S-1170B50 (Ta = 25°C)
VOUT [V]
5.1
5.0
4.9
4.8
4.7
4.6
4.5
7.06.5
6.0 5.5 5.0 4.5
I
OUT
=
1 mA
10 mA
100 mA
300 mA
VIN [V]

S-1170B26UC-OTLTFU

Mfr. #:
Manufacturer:
ABLIC
Description:
LDO Voltage Regulators Linear LDO Reg Hi 80uA Iq 800mA Iout
Lifecycle:
New from this manufacturer.
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