S-816 Series
www.sii-ic.com
EXTERNAL TRANSISTOR TYPE
CMOS VOLTAGE REGULATOR
© Seiko Instruments Inc., 1996-2010 Rev.6.0_00
Seiko Instruments Inc. 1
The S-816 Series consists of external transistor type positive voltage regulators, which have b een developed
using the CMOS process. These voltage regulators incorporate an overcurrent protection, and shutdown
circuit. A low drop-out type regulator with an output current ranging from several hundreds of mA to 1 A can be
configured with the PNP transistor driven by this IC.
Despite the features of the S-816, which is low curren t consumption, the improvement in its transient response
characteristics of the IC with a newly deviced p hase compensation circuit made it possible to employ the
products of the S-816 Series even in app lications where heavy input variation or load variation is experienced.
The S-816 Series regulators serve as ideal power supply units for portable devices when coupled with the SOT-
23-5 minipackage, providi ng numerous outstanding f eatures, including low current consumption. Since this
series can accommodate an input voltage of up to 16 V, it is also suitable when operating via an AC adapter.
Features
(1) Low current consumption
• Operation mode: 30 μA typ., 40 μA max.
• Shutdown mode: 1 μA max.
(2) Input voltage range: 16 V max.
(3) Output voltage accuracy: ± 2.0%
(4) Output voltage range: Selectable between 2.5 V and 6.0 V in steps of 0.1 V.
(5) With shutdown curcuit.
(6) A built-in current source (10 μA) eliminates the n eed of a base-emitter resistance.
(7) With overcurrent (base current) protection function.
(8) Lead-free, Sn 100%, halogen-free*1
*1. Refer to “ Product Name Structure” for details.
Applications
• Power supplies for on-board such as battery devices for portable telephones, electronic notebooks, PDA s.
• Constant voltage power supplies for cameras, video equipment and portabl e communications equipment.
• Power Supplies for CPUs.
• Post-Regulators for Switching Regulators.
• Main Regulators in Multiple-Power Su pply Systems.
Package
• SOT-23-5
EXTERNAL TRANSISTOR TYPE CMOS VOLTAGE REGULATOR
S-816 Series Rev.6.0_00
2 Seiko Instruments Inc.
Block Diagram
+
−
EXT VOUT
VSS
OFFON/
VIN
VREF
Current Source
Overcurrent
Protection
Circuit
Pull-Up
Error
A
mplifie
r
Sink
Drive
r
+
−
+
−
Remark 1. To ensure you power cutoff of the external transistor when the device is powered down, the
EXT output is pulled up to VIN by a pull-up resistance (approx. 0.5 MΩ) inside the IC.
2. The diode inside the IC is a parasitic diode.
Figure 1
EXTERNAL TRANSISTOR TYPE CMOS VOLTAGE REGULATOR
Rev.6.0_00 S-816 Series
Seiko Instruments Inc. 3
Product Name Structure
1. Product Name
S-816 xx A MC - xxx T2 x
Environmental code
U : Lead-free (Sn 100%), halogen-free
G : Lead-free (for details, please contact
our sales office)
IC direction in tape specifications*1
Product name (abbreviation)
Package name (abbreviation)
MC : SOT-23-5
Output voltag e × 10
25 to 60 (2.5 V to 6.0 V)
*1. Refer to the tape specifications.
2. Package
Drawing Cod e
Package Name Package Tape Reel
SOT-23-5 MP005-A-P-SD MP005-A-C-SD MP005-A-R-SD
3. Product Name List
Table 1
Output Voltage
(V) Product Name Output Voltage
(V) Product Name
2.5 V±2.0% S-816A25AMC-BAAT2x 4.3 V±2.0% S-816A43AMC-BAST2x
2.6 V±2.0% S-816A26AMC-BABT2x 4.4 V±2.0% S-816A44AMC-BATT2x
2.7 V±2.0% S-816A27AMC-BACT2x 4.5 V±2.0% S-816A45AMC-BAUT2x
2.8 V±2.0% S-816A28AMC-BADT2x 4.6 V±2.0% S-816A46AMC-BAVT2x
2.9 V±2.0% S-816A29AMC-BAET2x 4.7 V±2.0% S-816A47AMC-BAWT2x
3.0 V±2.0% S-816A30AMC-BAFT2x 4.8 V±2.0% S-816A48AMC-BAXT2x
3.1 V±2.0% S-816A31AMC-BAGT2x 4.9 V±2.0% S-816A49AMC-BAYT2x
3.2 V±2.0% S-816A32AMC-BAHT2x 5.0 V±2.0% S-816A50AMC-BAZT2x
3.3 V±2.0% S-816A33AMC-BAIT2x 5.1 V±2.0% S-816A51AMC-BBAT2x
3.4 V±2.0% S-816A34AMC-BAJT2x 5.2 V±2.0% S-816A52AMC-BBBT2x
3.5 V±2.0% S-816A35AMC-BAKT2x 5.3 V±2.0% S-816A53AMC-BBCT2x
3.6 V±2.0% S-816A36AMC-BALT2x 5.4 V±2.0% S-816A54AMC-BBDT2x
3.7 V±2.0% S-816A37AMC-BAMT2x 5.5 V±2.0% S-816A55AMC-BBET2x
3.8 V±2.0% S-816A38AMC-BANT2x 5.6 V±2.0% S-816A56AMC-BBFT2x
3.9 V±2.0% S-816A39AMC-BAOT2x 5.7 V±2.0% S-816A57AMC-BBGT2x
4.0 V±2.0% S-816A40AMC-BAPT2x 5.8 V±2.0% S-816A58AMC-BBHT2x
4.1 V±2.0% S-816A41AMC-BAQT2x 5.9 V±2.0% S-816A59AMC-BBIT2x
4.2 V±2.0% S-816A42AMC-BART2x 6.0 V±2.0% S-816A60AMC-BBJT2x
Remark 1. x: G or U
2. Please select products of environmental cod e = U for Sn 100%, halogen-free pro ducts.
EXTERNAL TRANSISTOR TYPE CMOS VOLTAGE REGULATOR
S-816 Series Rev.6.0_00
4 Seiko Instruments Inc.
Pin Configuration
Table 2
Pin No. Symbol Description
1 EXT Output Pin for Base-Current Control
2 VSS GND Pin
3
OFFON/ Shutdown Pin ("H" active)
4 VIN IC Power Supply Pin
5 VOUT Output Voltage Monitoring Pin
SOT-23-5
Top view
1 2 3
5 4
Figure 2
EXTERNAL TRANSISTOR TYPE CMOS VOLTAGE REGULATOR
Rev.6.0_00 S-816 Series
Seiko Instruments Inc. 5
Absolute Maximum Ratings
Table 3 (Ta=25°C unless otherwise specified)
Item Symbol Absolute Maximum Ratings Unit
VIN Pin Voltage VIN VSS−0.3 to VSS+18 V
VOUT Pin Voltage VOUT VSS−0.3 to VSS+18 V
OFFON/ Pin Voltage VON/OFF VSS−0.3 to VSS+18 V
EXT Pin Voltage VEXT VSS−0.3 to VIN+0.3 V
EXT Pin Current IEXT 50 mA
250 (When not mounted on board) mW
Power Dissipation PD 600*1 mW
Operating Ambient Temperature Topr −40 to +85 °C
Storage Temperature Tstg −40 to +125 °C
*1. When mounted on board
[Mounted on board]
(1) Board size : 114.3 mm × 76.2 mm × t1.6 mm
(2) Board name : JEDEC STANDARD51-7
Caution The absolute maximum ratings are rated values exceeding which the product
could suffer physical damage. These values must therefore no t be exceeded
under any conditions.
(1) When mounted on board (2) When not mounted on board
0 50 100 150
600
400
0
Pow er Dissi
p
ation
(
PD
)
[
mW
]
Ambi en t Tem
p
erature
(
Ta
)
[
°C
]
200
100
300
500
700
050 100 150
300
200
0
Pow er Dissi
p
ation
(
PD
)
[
mW
]
Ambient Temperature (Ta)
[
°C]
100
250
150
50
Figure 3 Power Dissipation of Package
EXTERNAL TRANSISTOR TYPE CMOS VOLTAGE REGULATOR
S-816 Series Rev.6.0_00
6 Seiko Instruments Inc.
Electrical Characteristics
Table 4
(Ta
=
25
°
C unless otherwise specifie d)
Item Symbol Conditions Min. Typ. Max. Unit
Test
circuit
Input Voltage V
IN
⎯
⎯
⎯
16 V 1
Output Voltage V
OUT
V
IN
=
V
OUT
+
1 V, I
OUT
=
50 mA,
V
ON/OFF
=
"H" V
OUT
×
0.98 V
OUT
V
OUT
×
1.02 V 1
Maximum Output Current (PNP
Output)
*1
⎯
⎯
⎯
1
⎯
A 1
Drop-Out Voltage
*1
Δ
V
drop
I
OUT
=
100 mA
⎯
100
⎯
mV 1
Load Regulation (PNP Output )
*1
Δ
V
OUT
V
IN
=
V
OUT
+
1 V, 1 mA
<
I
OUT
<
1 A
⎯
⎯
60 mV 1
Line Regulation (PNP Output )
*1
INOUT
OUT
VV V
Δ•
Δ
I
OUT
=
50 mA, V
OUT
+
1 V
<
V
IN
<
16
V
−
0.15 0.01 0.15 %/V 1
Output Voltage Temperature
Coefficient
Ta
VOUT
Δ
Δ
V
IN
=
V
OUT
+
1 V, I
OUT
=
50 mA,
V
ON/OFF
=
"H", Ta
=−
40
to
85
°
C
⎯
±
0.15
⎯
mV/
°
C1
Current Consumption during
Operation I
SS
V
IN
=
V
OUT
+
1 V, V
ON/OFF
=
"H"
⎯
30 40
μ
A 1
Current Consumption during
Shutdown I
STB
V
IN
=
16 V, V
ON/OFF
=
"L"
⎯
⎯
1
μ
A 1
EXT Output Source Constant
Current I
SRC
V
IN
=
V
OUT
+
1 V, V
ON/OFF
=
"H",
V
EXT
=
V
OUT
, V
OUT
=
V
OUT
×
0.95
⎯
−
10
⎯
μ
A 2
EXT Output Pull-Up Resistance R
UP
V
IN
=
16 V, V
ON/OFF
=
"L" 0.25 0.50 1.00 M
Ω
2
EXT Output Sink Current I
SINK
V
IN
=
V
OUT
+
1 V, V
ON/OFF
=
"H",
V
OUT
=
V
OUT
×
0.95
⎯
10
⎯
mA 2
Leakage Current during EXT
Output Off I
OFF
V
IN
=
V
EXT
=
V
OUT
+
1 V, V
OUT
=
0 V,
V
ON/OFF
=
"L"
⎯
⎯
0.1
μ
A 2
EXT Output Sink Overcurrent
Set Value I
MAX
V
IN
=
V
EXT
=
7 V, V
ON/OFF
=
"H",
V
OUT
=
V
OUT
×
0.95 12 16 20 mA 2
Shutdown Pin Input Voltage V
SH
V
IN
=
V
OUT
+
1 V, V
OUT
=
0 V,
Check V
EXT
=
"L" 2.4
⎯
⎯
V 3
V
SL
V
IN
=
V
OUT
+
1 V, V
OUT
=
0 V,
Check V
EXT
=
"H"
⎯
⎯
0.3
Shutdown Pin Input Current I
SH
V
ON/OFF
=
V
OUT
+
1 V
⎯
⎯
0.1
μ
A 2
I
SL
V
ON/OFF
=
0 V
⎯
⎯
−
0.1
*1.
The characteristics vary with the associated external comp onents.
The characteristics given above are those o btaine d when the IC is combined with a Toshiba Corporation 2SA1213-Y
for the PNP transistor and a 10
μ
F tantalum capacitor for the output capacitor (C
L
).
EXTERNAL TRANSISTOR TYPE CMOS VOLTAGE REGULATOR
Rev.6.0_00 S-816 Series
Seiko Instruments Inc. 7
Test Circuits
1. 2.
VIN EXT VOUT
VSS
OFFON/
A A
V
+
− +
−
VIN EXT VOUT
VSS
OFFON/
A A
A
A
Figure 4 Figure 5
3.
VIN EXT VOUT
VSS
OFFON/
A A
V
A
Figure 6
EXTERNAL TRANSISTOR TYPE CMOS VOLTAGE REGULATOR
S-816 Series Rev.6.0_00
8 Seiko Instruments Inc.
Operation
1. Basic Operation
Figure 7 shows a block diagram of the S-816 Series.
The device compares the voltage which is obtained from dividing output voltage VOUT by feedback
resistances RA and RB with reference voltage VREF through the error amplifier, output of which controls the
sink driver. By regulating the base current of the external PNP transistor, the IC maintains a constant
output voltage that is not susceptible to an input voltage variation or temperature variation.
OUT
IN
CL
EXT VOUT
VSS
OFFON/
VIN
VREF
Current Source
Overcurrent
Protection
Circuit
RB
R
A
RC
Error
Amplifier
Sink
Drive
r
+
−
+
−
Figure 7
2. Internal Circuits
2.1. Shutdown Pin ( OFFON/ Pin)
This pin activates and deactivates the regulating ope ration.
When the shutdown pin is set to "L", the VIN voltage appears through the EXT pin, prodding the external
PNP transistor to off. All the internal circuits stop working, and substantial savings in current consumption
are achieved accordingly. In this condition, the EXT pin is pulled up to VIN by a pull-up resistance
(approx. 0.5 MΩ) inside the IC in orde r to ensure you power cut off of the external PNP transistor.
The shutdown pin is configured as show n in Figure 8. Since neither pull-up or pull-down is performed
internally, please avoid using the pin in a floating state. Also, be sure to refrain from applying a voltage of
0.3 V to 2.4 V to this pin lest the current consumption increase. When this shutdown pi n is not used,
leave it coupled to the VIN pin.
Table 5
Shutdown Pin Internal Circuit EXT Pin Voltage VOUT Pin Voltage
"H" Activated
VIN−VBE Set value
"L" Deactivated VIN Hi-Z
VIN
VSS
OFFON/
Figure 8
EXTERNAL TRANSISTOR TYPE CMOS VOLTAGE REGULATOR
Rev.6.0_00 S-816 Series
Seiko Instruments Inc. 9
2.2. Overcurrent Protection Circuit
The overcurrent protection function of the S-816 Series monitors the EXT pin sink current (base current of
the external PNP transistor) with an ove rcu rrent protection circuit incorporated in the IC, and limits that
current (EXT pin sink current).
As the load current increases, the EXT pin sink current (base current of the external PNP transistor) also
grows larger to maintain the output voltage. The overcurrent protection circuit clamps and limits the EXT
pin sink current to the EXT output sink overcurrent set value (IMAX) in order to prevent it from incre asing
beyond that value.
The load current at which the overcurrent protection function works is represented by the following
equation:
IOUT_MAX = IMAX × hFE
In this case, hFE is the DC amplification factor of the external PNP transistor.
IOUT_MAX represents the maximum output current of this reg ulator. If it is attempted to obtain a higher load
current, the output voltage will fall.
Note that within the overcurrent protection function of this IC, the external PNP transistor may not be able
to be protected from collector overcu rrents produced by an EXT-GND short-circuiting or other
phenomenon occurring outside the IC. To protect the external PNP transistor from such collector
overcurrents, it will be necessary to choose a transistor with a larger powe r dissip ation than IOUT_MAX × VIN,
or to add an external overcurrent protection ci rcuit. With regard to this externa l overcurrent protection
circuit, refer to "Overcurrent Protection Circuit" in " Application Circuits".
2.3. Phase Compensation Circuit
The S-816 Series performs phase compensation with a phase compensation circuit, incorporated in the
IC, and the ESR (Equivalent Series Resistance) of an output capacitor, to secure stable operation even in
the presence of output load variation. A uniquely devised phase compensation circuit has resulted in
improved transient response characteristics of the IC, while p reserving the same feature of low current
consumption. This feature allows the IC to be used in applications where the input variation or load
variation is heavy.
Because the S-816 Series is design ed to perform the phase compensation, utilizing the ESR of an output
capacitor, such output capacitor (CL) should always be placed between VOUT and VSS. Since each
capacitor to be employed has an optimum range of their own characteristics, be sure to choose
components for the IC with your all attention. For details, refer to " Selection of Associated External
Components".
EXTERNAL TRANSISTOR TYPE CMOS VOLTAGE REGULATOR
S-816 Series Rev.6.0_00
10 Seiko Instruments Inc.
Selection of Associated External Components
1. External PNP Transistor
Select an external transistor according to the conditions of input voltage, output voltage, and output
current. A low-saturation voltage PNP transistor with "hFE" ranging from 100 to 300 will be suitable for this
IC.
The parameters for sel ection of the external PNP transistor include the maximum collector-base voltage,
the maximum collector-emitter voltage, the DC amplification fa ctor (hFE), the maximum coll ector current
and the collector dissipation.
The maximum collector-base voltage a nd the maximum collector-emitter voltage are determined by the
input voltage range in each spe cific ap plication to be employed. You may select a transistor with an input
voltage at least several volts higher than the expected maximum input voltage.
The DC amplification factor (hFE) affects the maximum output current that can be supplied to the load.
With an internal overcurrent protection circuit of this IC, the base current is clamped, and will not exceed
the overcurrent set value (IMAX). Select a transistor which is capable of delivering the requi red maximum
output current to the intended application, with hfe and maximum collecto r cu rrent. (Refer to
" Overcurrent Protection Circuit")
Likewise, select a tran sistor, based on the maximum output current and the difference between the input
and output voltages, with due attention to the collector dissipation.
2. Output Capacitor (CL)
The S-816 Series performs pha se compensation by an internal phase compensation circuit o f IC, and the
ESR (Equivalent Series Resistance) of an output ca pacitor for to se cure stable operation even in the
presence of output load variation. Therefore, always place a capacit or (CL) of 4.7 μF or more b etween
VOUT and VSS.
For stable operation of the S-816 Serie s, it is essential to employ a capacitor with an ESR having
optimum range. Whether an ESR is larger or smaller than that optimum range (approximately 0.1 Ω to
5 Ω), this could produce an unstable output, and cause a possibility of oscillations. For this reason, a
tantalum electrolytic capacitor is recommended.
When a ceramic capacitor or an OS capacitor having a low ESR is selected, it will be necessary to
connect an additional resistance that serves for the ESR in series with the output capa citor, as illustrated
in Figure 9. The resistance value that needs to be added will be from 0.1 Ω to 5 Ω, but this value may
vary depends on the service conditions, and should be defined through careful evaluation in advance. In
general, our recommen dation is 0.3 Ω or so.
An aluminum electrolytic capacitor tends to produce oscillations as its ESR increases at a low
temperature. Beware of this case. When this type of capacitor is employed, make thorough evaluation of
it, including its temperature characteri stics.
OUT
IN
R
≅
0.3
Ω
CL
S-816 Series
EXT VOUT
VSS
OFFON/
VIN
Figure 9
Caution The above connection diagram and constant will not guarantee successful operation.
Perform through evaluation using the actual application to set the constant.
EXTERNAL TRANSISTOR TYPE CMOS VOLTAGE REGULATOR
Rev.6.0_00 S-816 Series
Seiko Instruments Inc. 11
Standard Circuit
+
−
EXT VOUT
VSS
OFFON/
VIN
VREF
Current Source
Overcurrent
Protection
Circuit
Pull-Up
Error
A
mplifier
Sink
Driver
+
−
+
−
Figure 10
Caution The above connection diagram does not guarantee correct operation. Perform
sufficient evaluation using the ac tual application to set the constant.
EXTERNAL TRANSISTOR TYPE CMOS VOLTAGE REGULATOR
S-816 Series Rev.6.0_00
12 Seiko Instruments Inc.
Precautions
• The overcurrent protection function of this IC detects and limits the sink current at the EXT pin inside the
IC. Therefore, it does not work on collector overcurrents which are caused by an EXT-GND short -
circuiting or other phenomenon o utside the IC. To protect the external PNP transistor from collector
overcurrents perfectly, it is necessary to provide anoth er extern al overcurrent protection circuit.
• This IC performs phase compensation b y using an internal phase compensator circuit and the ESR of an
output capacitor. Therefor e, always place a capacitor of 4.7 μF or more between VOUT and VSS.
A tantalum type capacitor is recommended for this purpose. Moreover, to secure stable op eration of the
S-816 Series, it will be necessary to employ a capacitor having an ESR (Equivalent Series Resistance)
covered in a certain optimum ran ge (0.1 Ω to 5 Ω). Whether an ESR is larger or smaller than that
optimum range, this could result in an un stable o utput, and cause a possibility of oscillation s. Select a
capacitor through careful ev aluation made according to the actual service condit i ons.
• Do not apply an electrostatic discharge to this IC that exceeds the performance ratings of the built-in
electrostatic protection circuit.
• Make sure that the power dissipation inside the IC due to the EXT output sink current (especially at a high
temperature) will not surpass the power dissipation of the package.
• SII claims no responsibility for any disputes arising out of or in connection with any infringement by
products including this IC of patents o wned by a third party.
EXTERNAL TRANSISTOR TYPE CMOS VOLTAGE REGULATOR
Rev.6.0_00 S-816 Series
Seiko Instruments Inc. 13
Application Circuits
1. Overcurrent Protection Circuit
Figure 11 shows a sample of overcurre nt protection implemented with an external circuit connected.
The internal overcurrent protection function of the S-8 16 Series is designed to detect the sink current
(base current of the PNP transistor) at the EXT pin, therefore it may not be able to protect the external
PNP transistor from collector overcurren ts caused by an EXT-GND short-circuiting or other p henomenon
occurring outside the IC.
This sample circuit activates the regulat or intermittently against collector overcurrents, thereby
suppressing the heat generation of the external PNP transistor.
The duty of the on-time and off-time of the intermittent operation can be regulated through an ex ternal
component.
VIN CIN
10 μF
+
− R2
2 kΩ R1
100 kΩ
RS
0.5 Ω
R4
2 kΩ
Tr1
R3
2 kΩ C2
0.22 μF
Tr2 C1
0.22 μF
CL
10 μF
+
−
VIN
EXT VOUT
S-816 Series
VSS
OUT
OFFON/
2SA1213
Y
Figure 11
Caution The above connection diagram and constant will not guarantee success ful operation.
Perform through evaluation using the actual application to set the constant.
S-816A30A MC (V IN =4 V)
1 A
Load Current
(0.5 A/div)
0 A
2 V
VON/OFF
(1 V/div)
0 V
t (2 ms/div)
S-816A30AMC (V IN =4 V )
1 A
Load Current
(0.5 A/div)
0 A
2 V
VON/OFF
(1 V/div)
0 V
t (100 μs/div)
Figure 12
Output Current Waveforms duri ng Intermittent Operation Prompted by Load Short-Ci rc uiti ng
EXTERNAL TRANSISTOR TYPE CMOS VOLTAGE REGULATOR
S-816 Series Rev.6.0_00
14 Seiko Instruments Inc.
The detection of the overcurrent is done by the sense resistance (RS) and the PNP transi stor (Tr1 ).
When Tr1 comes on, trigg ered by a voltage drop of RS, the NPN transistor (Tr2) also comes on, according
to the time constants of the capacitor (C2) and resistance (R2). This causes the shutdown pin to turn to
the "L" level, and the regulating operation to stop, and interrupting the current to the load.
When the load current is cut off, the voltage drop of RS stops. This makes Tr1 off again, and also makes
the NPN transistor (Tr2) off.
In this condition, the shutdown pin returns to the "H" level, according to the time constants of the
capacitor ( C1) and re sistance (R1). This delay time in which shutdown pin returns to the "H" level from the
"L" level is the time in which the load current remains cut off.
If an overcurrent flows again after the shutdown pin has assumed the "H" level following the delay time
and the regulating operation has b een restarted, the circuit will again su spend the regulating operatio n
and resume the intermittent operation. This intermittent operation will be continued till the overcurrentt is
eliminated, and once theovercurrent disappears, the norm al operation will be restored.
The overcurrent detection value (IOUT_MAX) is represented by the following equation:
IOUT_MAX = |VBE1| / RS
In this case, RS denotes the resistance value of the sense resistance, and VBE1 denote s the b ase-emitter
saturation voltage of Tr1.
For the PNP transistor (Tr1) and the NPN transistor (Tr2), try to select those of small-signal type that offer
a sufficient withstand voltage against the input voltage (VIN).
The on-time (tON) and the off-time (tOFF) of the intermittent operation are broa dly expressed by the
following equations:
tON = −1 × C2 × R2 × LN ( 1 − ( VBE2 × ( 1 + R2 / R3 ) ) / ( VIN − VBE1 ) )
tOFF = −1 × C1 × R1 × LN ( 1 − VSH / VIN )
In this case, VBE2 denotes the base-emitter saturation voltage of Tr2, VIN denotes the input voltage, and
VSH denotes the inversion voltage ("L"→"H") of the shutdown pin.
Set the on-time value that does not cause the overcurrent protection to be activated by a rush curre nt to
the load capacitor. Then, compute the ratio between the on-time and the off-time from the m aximum
input voltage of the appropriate applicati on and the power dissipation of the external PNP transistor, and
decide the off-time with reference to the on-time established earlier.
Take the equation above as a rough guide, because the actual on-time (tON) and off-time (tOFF) should be
defined and checked using the utilizing components.
2. External Adjustment of Output Voltage
The S-816 Series allows you to adju st the output voltage or to set its value over the output voltage range
(6 V) of the products of this series, when external resistances RA, RB and capacitor CC are added, as
illustrated in Figure 13. Moreover, a temperature gradient can be obtained by inserting a thermisto r or
other element in series with external resistances RA and RB.
VIN C
IN
+
− CL
OFFON/
VIN EXT
+
−
VOUT
VSS
OUT
+
−
CCRA
RB
R1
R2
Error
amplifier
VREF
Figure 13
EXTERNAL TRANSISTOR TYPE CMOS VOLTAGE REGULATOR
Rev.6.0_00 S-816 Series
Seiko Instruments Inc. 15
The S-816 Series has an internal impedance resulting from R1 and R2 between the VOUT and the VSS
pin, as shown in Figure 13. Therefore, the influence of the internal resistances (R1, R2) of the IC has to
be taken into consideration in defining th e output voltage (OUT).
The output voltage (OUT) is expressed by the following equation:
OUT = VOUT + VOUT × RA ÷ ( RB // *1 RI )
*1. "//" denotes a combined resistance in parallel.
In this case, VOUT is the output voltage value of the S-816 Series, RA and RB is the resistance values of
the external resistances, and RI is the resista nce value (R1+R2) of the internal resistances in the IC.
The accuracy of the output voltage (OUT) is determined by the absolute accuracy of external connecting
resistances RA and RB, the output voltage accuracy (VOUT ±2.0%) of the S-816 Series, and deviations in
the absolute value of the internal resist ance (RI) in the IC.
The maximum value (OUTmax) and the minimum value (OUTmi n) of the output voltage (OUT), including
deviations, are expressed by the following equation s:
OUTmax = VOUT × 1.02 + VOUT × 1.02 × RAmax ÷ ( RBmin // RImin )
OUTmin = VOUT × 0.98 + VOUT × 0.98 × RAmin ÷ ( RBmax // RImax )
Where RAmax, RAmin, RBmax and RBmin denote the maximum and minimum of the absolute accu racy of
external resistances RA and RB, and RImax and RImin denote the maximum and minimum deviations of the
absolute value of the internal resistan ce (RI) in the IC, respectively.
The deviations in the absolute value of internal resistance (RI) in the IC vary with the output voltage set
value of the S-816 Series, and are broadly classified as follows:
• Output voltage (VOUT) 2.5 V to 2.7 V ⇒ 3.29 MΩ to 21.78 MΩ
• Output voltage (VOUT) 2.8 V to 3.1 V ⇒ 3.29 MΩ to 20.06 MΩ
• Output voltage (VOUT) 3.2 V to 3.7 V ⇒ 2.23 MΩ to 18.33 MΩ
• Output voltage (VOUT) 3.8 V to 5.1 V ⇒ 2.23 MΩ to 16.61 MΩ
• Output voltage (VOUT) 5.2 V to 6.0 V ⇒ 2.25 MΩ to 14.18 MΩ
If a value of RI given by the equation shown below is taken in calculating the output voltage (OUT), a
median voltage deviation of the output voltage (OUT) will be obtained.
R
I
=
2
÷
( 1
÷
(Maximum value of internal resistance of IC)
+
1
÷
(Minimum value of internal resistance of IC) )
The closer the output voltage (OUT) and the output voltage set value (VOUT) of the IC are brought to each
other, the more the accuracy of the output voltage (OUT) remains immune to deviations in the absolute
accuracy of external resistances (RA, RB) and the absolute value of the internal resistance (RI) of the IC.
In particular, to suppress the influence of deviations in the internal resistance (RI), the resistance values
of external resistances (RA, RB) need to be limited to a much small er value than that of the internal
resistance (RI). However, since reactive current flows through the external resistances (RA, RB), there is a
tradeoff between the accuracy of the output voltage (OUT) and the reactive current. This should be taken
into consideration, according to the requirements of the intended a pplication.
Note that when larger value (more than 1 MΩ) is take n for the external resistances (RA, RB), IC is
vulnerable to external noise. Check the influen ce of this value well with the actual application.
Furthermore, add a capacitor CC in parallel to the external resistance RA in order to avoid output
oscillations and other types of instability. (Refer to Figure 13)
Make sure that the capacitance value of CC is larger than the value given by the following equation:
CC[F] ≥ 1 ÷ ( 2 × π × RA[Ω] × 6000 )
Caution The above connec tion diagram and c onstant will not guarantee successful operation.
Perform through evaluation using the actual application to set the constant.
EXTERNAL TRANSISTOR TYPE CMOS VOLTAGE REGULATOR
S-816 Series Rev.6.0_00
16 Seiko Instruments Inc.
Typical Characteristics
1. Input Voltage (VIN) - Output Voltage (V OUT) Characteristics
VIN-VOUT
S-816A30AMC (IOUT=50 mA) VIN-VOUT
S-816A50AMC (IOUT=50 mA)
Ta=−40°C
Ta=85°C
Ta=25°C
3.10
3.08
3.06
3.04
3.02
3.00
2.98
2.96
2.94
2.92
2.90 2 4 6 8 10 12 14 16
VIN (V)
VOUT
(V)
Ta=85°C
Ta=−40°C
Ta=25°C
5.10
5.08
5.06
5.04
5.02
5.00
4.98
4.96
4.94
4.92
4.90 2 4 6 8 10 12 14 16
VIN (V)
VOUT
(V)
VIN-VOUT
S-816A30AMC (Ta=25°C) VIN-VOUT
S-816A50AMC (Ta=25°C)
IOUT=1 mA
IOUT=100 mA
IOUT=500 mA
IOUT=1 A
3.10
3.05
3.00
2.95
2.90
2.85
2.80 2.8 2.9 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8
VIN (V)
VOUT
(V)
IOUT
=
1A
IOUT=1 mA
IOUT=100 mA
IOUT=500 mA
5.10
5.05
5.00
4.95
4.90
4.85
4.80 4.8 4.9 5.0 5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8
VIN (V)
VOUT
(V)
2. Output Current (IOUT) - Output Voltage (VOUT) Characteristics
IOUT-VOUT
S-816A30AMC (VIN=4 V) IOUT-VOUT
S-816A50AMC (VIN=6 V)
Ta=85°C
Ta=25°C
Ta=−40°C
3.10
3.08
3.06
3.04
3.02
3.00
2.98
2.96
2.94
2.92
2.90 1 10 100 1000
IOUT (mA)
VOUT
(V)
Ta=25°C
Ta=85°C
Ta=−40°C
5.10
5.08
5.06
5.04
5.02
5.00
4.98
4.96
4.94
4.92
4.90 1 10 100 1000
IOUT (mA)
VOUT
(V)
EXTERNAL TRANSISTOR TYPE CMOS VOLTAGE REGULATOR
Rev.6.0_00 S-816 Series
Seiko Instruments Inc. 17
3. Temperature (Ta) - Output Voltage (VOUT) Characteristics
Ta-VOUT
S-816A30AMC (VIN=4 V, IOUT=50 mA) Ta-VOUT
S-816A50AMC (VIN=6 V, IOUT=50 mA)
3.10
3.08
3.06
3.04
3.02
3.00
2.98
2.96
2.94
2.92
2.90
−50 −25 0 25 50 75 100
Ta (°C)
VOUT
(V)
5.10
5.08
5.06
5.04
5.02
5.00
4.98
4.96
4.94
4.92
4.90 −50 −25 0 25 50 75 100
Ta (°C)
VOUT
(V)
4. Input Voltage (VIN) - Consumption Current (ISS) Char acteristi cs
VIN-ISS
S-816A30AMC (VON/OFF="H")
Ta=−40°C
Ta=85°C
Ta=25°C
50
45
40
35
30
25
20
15
10
5
0 0 2 4 6 8 10 12 14 16
VIN (V)
ISS
(μA)
5. Input Voltage (VIN) - EXT Output Sink Overcurrent Set Value (IMAX) Characteristics
VIN-IMAX
S-816A30AMC
Ta=−40°C
Ta=85°C
Ta=25°C
22
20
18
16
14
12
10 4 6 8 10 12 14 16
VIN (V)
IMAX
(mA)
EXTERNAL TRANSISTOR TYPE CMOS VOLTAGE REGULATOR
S-816 Series Rev.6.0_00
18 Seiko Instruments Inc.
6. Input Voltage (VIN) - Shutdown Pin Input Voltage (VSH, VSL) Characteristics
VIN-VSH
S-816A30AMC VIN-VSL
S-816A30AMC
Ta
=
−
40°C
Ta=85°C
Ta=25°C
2.5
2.0
1.5
1.0
0.5
0.0 4 6 8 10 12 14 16
VIN (V)
VSH
(V)
Ta=−40°C
Ta=85°C
Ta=25°C
2.5
2.0
1.5
1.0
0.5
0.0 4 6 8 10 12 14 16
VIN (V)
VSL
(V)
EXTERNAL TRANSISTOR TYPE CMOS VOLTAGE REGULATOR
Rev.6.0_00 S-816 Series
Seiko Instruments Inc. 19
Transient Response Characteristics (Typical Data)
1. Input Transient Response Characteristics
(Power-on V
IN
=
0 V
→
V
OUT
+
1 V, I
OUT
=
0 A, C
L
=
10
μ
F)
S-816A30AMC (V IN =0 V → 4 V )
4 V
VIN
(2 V/div)
0 V
VOUT
(2 V/div)
0 V
t (100 μs/div)
S-816A50A MC (V IN =0 V → 6 V)
6 V
VIN
(2 V/div)
0 V
VOUT
(2 V/div)
0 V
t (100 μs/div)
2. Input Transient Response Characteristics
(Supply voltage variation V
IN
=
V
OUT
+
1 V
↔
V
OUT
+
2 V, C
L
=
10
μ
F)
S-816A30AMC (I OUT =10 mA)
5 V
VIN
(0.5 V/div)
4 V
VOUT
(20 mV/div)
3 V
t (100 μs/div)
S-816A30A MC (I OUT =300 mA)
5 V
VIN
(0.5 V/div)
4 V
VOUT
(20 mV/div)
3 V
t (100 μs/div)
S-816A50AMC (I OUT =10 mA)
7 V
VIN
(0.5 V/div)
6 V
VOUT
(20 mV/div)
5 V
t (100 μs/div)
S-816A50A MC (I OUT =300 mA)
7 V
VIN
(0.5 V/div)
6 V
VOUT
(20 mV/div)
5 V
t (100 μs/div)
EXTERNAL TRANSISTOR TYPE CMOS VOLTAGE REGULATOR
S-816 Series Rev.6.0_00
20 Seiko Instruments Inc.
3. Load Transient Response Characteristics
(Power-on I
OUT
=
1 mA
↔
100 mA, C
L
=
10
μ
F)
S-816A30AMC (V IN =4 V)
100 mA
IOUT
(50 mA/div)
1 mA
VOUT
(20 mV/div)
3 V
t (50 μs/div)
S-816A30A MC (V IN =4 V )
100 mA
IOUT
(50 mA/div)
1 mA
VOUT
(20 mV/div)
3 V
t (50 μs/div)
S-816A50AMC (V IN =6 V)
100 mA
IOUT
(50 mA/div)
1 mA
VOUT
(20 mV/div)
5 V
t (50 μs/div)
S-816A50A MC (V IN =6 V)
100 mA
IOUT
(50 mA/div)
1 mA
VOUT
(20 mV/div)
5 V
t (50 μs/div)
4. Shutdown Pin Transient Response Chara cteristics
(V
ON/OFF
=
0 V
→
V
IN
, I
OUT
=
0 A, C
L
=
10
μ
F)
S-816A30AMC (V IN =4 V)
4 V
VON/OFF
(2 V/div)
0 V
VOUT
(2 V/div)
0 V
t (100 μs/div)
S-816A50A MC (V IN =6V)
6 V
VON/OFF
(2 V/div)
0 V
VOUT
(2 V/div)
0 V
t (100 μs/div)
No.
TITLE
SCALE
UNIT mm
Seiko Instruments Inc.
2.9±0.2
1.9±0.2
0.95±0.1
0.4±0.1
0.16 +0.1
-0.06
123
4
5
No. MP005-A-P-SD-1.2
MP005-A-P-SD-1.2
SOT235-A-PKG Dimensions
No.
TITLE
SCALE
UNIT mm
Seiko Instruments Inc.
ø1.5 +0.1
-0 2.0±0.05
ø1.0 +0.2
-0 4.0±0.1
1.4±0.2
0.25±0.1
3.2±0.2
123
45
No. MP005-A-C-SD-2.1
MP005-A-C-SD-2.1
SOT235-A-Carrier Tape
Feed direction
4.0±0.1(10 pitches:40.0±0.2)
No.
TITLE
SCALE
UNIT mm
Seiko Instruments Inc.
12.5max.
9.0±0.3
ø13±0.2
(60°) (60°)
QTY. 3,000
No. MP005-A-R-SD-1.1
MP005-A-R-SD-1.1
SOT235-A-Reel
Enlarged drawing in the central part
www.sii-ic.com
• The information described herein is subject to change without notice.
• Seiko Instruments Inc. is not responsible for any problems caused by circuits or diagrams described herein
whose related industrial properties, patents, or other rights belong to third parties. The application circuit
examples explain typical applications of the products, and do not guarantee the success of any specific
mass-production design.
• When the products described herein are regulated products subject to the Wassenaar Arrangement or other
agreements, they may not be exported without authorization from the approp riate governmental authority.
• Use of the information described herein for other purposes and/or reproduction or copying without the
express permissi on of Seiko Instruments Inc. is strictly prohibited.
• The products described herein cannot be used as part of any device or equipment affecting the human
body, such as exercise equipment, medical equipment, security systems, gas equipment, or any apparatus
installed in airplanes and other vehicle s, without prior written permission of Seiko Instrum ents Inc.
• The products described herein are not designed to be radiation -p roof.
• Although Seiko Instruments Inc. exerts the greatest possible effort to ensure high quality and reliability, the
failure or malfunction of semiconductor products may occur. The user of these products should therefore
give thorough consideration to safety design, including redundancy, fire-prevention measures, and
malfunction prevention, to prevent any accidents, fires, or comm unity damage that may ensue.
