S-1155 Series
www.sii-ic.com
HIGH RIPPLE-REJECTION LOW DROPOUT
HIGH OUTPUT CURRENT CMOS VOLTAGE REGULATOR
© Seiko Instruments Inc., 2007-2010 Rev.2.0_00
Seiko Instruments Inc. 1
The S-1155 Series, developed based on CMOS technology, is a positive voltage regulator with a super low dropout
voltage, high output voltag e accuracy, and l o w current consumpti on.
The S-1155 Series provides the very small dropout voltage and the large output current due to the built-in transistor with
low on-resistance. T he o verc urrent protector prevents t he load curr ent fr om e xceeding t he c apacita nce of outp ut transistor.
The thermal shutdown circuit prevents damage caused by heat, the rush current control circuit limits the excessive rush
current during start-up.
The ON/OFF circuit ensures l onger battery life. Various capacitors, also small ceramic capacitors, can be used for this IC
more than for the convention al regul ator ICs which hav e CMOS techn olog y.
The small package SOT-89-5 enab les h igh -den sit y mounting.
Features
• Output voltage : 1.0 to 5.0 V, selectable i n 0. 05 V step.
• Low equivalent series resist ance cap acitor : Ceramic capacitor of 4.7 μF or more can be used as the
I/O capacitor.
• Input voltage : 1.5 to 5.5 V
• High-accuracy output voltage : ±1.0% (1.0 to 1.45 V output product : ±15 mV)
• Low dropout voltage :
70 mV typ. (3.0 V output product, at I
OUT
= 200 mA)
• Low current consumption : During operation : 70 μA typ., 90 μA max. (3.0 V output
product)
During shutdown : 0.1 μA typ., 1.0 μA m ax.
• Output current : 500 mA (3.0 V output product, at VIN ≥ VOUT(S) + 1.0 V)*1
• High ripple rejection : 70 dB typ. (at 1.0 kHz, VOUT = 1.0 V)
• Built-in overcurrent protection circ uit : limits overcurrent of output tr ansist or
• Built-in thermal shutdown circuit : prevents damage caused b y heat
• Built-in rush current control circuit : limits excessive rush current during start-up
• Built-in power on/off circuit : Longer battery life
• Lead-free, Sn 100%, halogen-free*2
*1. Attention should be pai d to the power dissipation of the pack age when the output current is l arge.
*2. Refer to “ Product Name Structure” for details.
Applications
• Power supply for battery-powered device s
• Power supply for TV, notebook PCs an d home electric a pplia nces
• Constant-voltage power suppl y for portable equipm ent
Package
• SOT-89-5
HIGH RIPPLE-REJECTION LOW DROPOUT HIGH OUTPUT CURRENT CMOS VOLTAGE REGULATOR
S-1155 Series Rev.2.0_00
Seiko Instruments Inc.
2
■ Block Diagram
Reference
voltage circuit
ON/OFF
*1
ON/OFF circuit +
−
VIN
VSS
VOUT
Overcurrent
protection circuit
Therm al shutdown circuit
*1. Parasitic diode
Figure 1
HIGH RIPPLE-REJECTION LOW DROPOUT HIGH OUTPUT CURRENT CMOS VOLTAGE REGULATOR
Rev.2.0_00 S-1155 Series
Seiko Instruments Inc. 3
Product Name Structure
Users can select the product type, output vol tage, and pack age t ype for th e S-1155 S erie s. Refer to the “1. Product
Name” for the meanings of the char acters i n the pro duct na me, “2. Package” regarding the pack ag e drawings and “3.
Product Name List” for the full product names.
1. Product Name
S-1155 x xx - U5T1 x
Envir onmental code
U : Lead-free (Sn 100%), hal ogen- f ree
G : L ead- f ree (for det ai ls, please contact our sales o f fi ce)
Package name (a bbreviation ) and packing specificat i ons
*1
U5T1 : SOT- 89- 5, Tap e
Val u e of out p ut v olta g e
*2
10 to 50
(e.g., wh en the out put voltage is 1.0 V, i t is expressed as 10. )
Produ c t type
*3
A : ON/ O FF pin nega ti ve l ogic
B : ON/O FF pi n posi t ive logic
*1. Refer to the tape specifications.
*2. If you request the product which has 0.05 step, contact our sal es off ice.
*3. Refer to “3. Shutdown pin (ON/OFF pin)” in “ Operation”.
2. Package
Drawing Code
Package Name Package Tape Reel
SOT-89-5 UP005-A-P-SD UP005-A-C-SD UP005-A-R-SD
HIGH RIPPLE-REJECTION LOW DROPOUT HIGH OUTPUT CURRENT CMOS VOLTAGE REGULATOR
S-1155 Series Rev.2.0_00
Seiko Instruments Inc.
4
3. Product Name List
Table 1
Output Voltage SOT-89-5
1.0 V ±15 mV S-1155B10-U5T1x
1.1 V ±15 mV S-1155B11-U5T1x
1.2 V ±15 mV S-1155B12-U5T1x
1.3 V ±15 mV S-1155B13-U5T1x
1.4 V ±15 mV S-1155B14-U5T1x
1.5 V ±1.0% S-1155B15-U5T1x
1.6 V ±1.0% S-1155B16-U5T1x
1.7 V ±1.0% S-1155B17-U5T1x
1.8 V ±1.0% S-1155B18-U5T1x
1.85 V ±1.0% S-1155B1J-U5T1x
1.9 V ±1.0% S-1155B19-U5T1x
2.0 V ±1.0% S-1155B20-U5T1x
2.1 V ±1.0% S-1155B21-U5T1x
2.2 V ±1.0% S-1155B22-U5T1x
2.3 V ±1.0% S-1155B23-U5T1x
2.4 V ±1.0% S-1155B24-U5T1x
2.5 V ±1.0% S-1155B25-U5T1x
2.6 V ±1.0% S-1155B26-U5T1x
2.7 V ±1.0% S-1155B27-U5T1x
2.8 V ±1.0% S-1155B28-U5T1x
2.85 V ±1.0% S-1155B2J-U5T1x
2.9 V ±1.0% S-1155B29-U5T1x
3.0 V ±1.0% S-1155B30-U5T1x
3.1 V ±1.0% S-1155B31-U5T1x
3.2 V ±1.0% S-1155B32-U5T1x
3.3 V ±1.0% S-1155B33-U5T1x
3.4 V ±1.0% S-1155B34-U5T1x
3.5 V ±1.0% S-1155B35-U5T1x
3.6 V ±1.0% S-1155B36-U5T1x
3.7 V ±1.0% S-1155B37-U5T1x
3.8 V ±1.0% S-1155B38-U5T1x
3.9 V ±1.0% S-1155B39-U5T1x
4.0 V ±1.0% S-1155B40-U5T1x
4.1 V ±1.0% S-1155B41-U5T1x
4.2 V ±1.0% S-1155B42-U5T1x
4.3 V ±1.0% S-1155B43-U5T1x
4.4 V ±1.0% S-1155B44-U5T1x
4.5 V ±1.0% S-1155B45-U5T1x
4.6 V ±1.0% S-1155B46-U5T1x
4.7 V ±1.0% S-1155B47-U5T1x
4.8 V ±1.0% S-1155B48-U5T1x
4.9 V ±1.0% S-1155B49-U5T1x
5.0 V ±1.0% S-1155B50-U5T1x
Remark 1. Please contact our sales office for products with an
output voltage other than those specified above or
type A products.
2. x: G or U
3. Please select products of en vironm ent al co de = U for
Sn 100%, halogen-free pr od ucts.
HIGH RIPPLE-REJECTION LOW DROPOUT HIGH OUTPUT CURRENT CMOS VOLTAGE REGULATOR
Rev.2.0_00 S-1155 Series
Seiko Instruments Inc. 5
Pin Configuration
Table 2
Pin No. Symbol Description
1 ON/OFF Shutdown pin
2 VSS GND pin
3
NC*1 No connection
4 VIN Input voltage pin
5 VOUT Output voltage pin
5 4
1 3 2
SOT-89-5
Top vie
w
*1. The NC pin is electrically open.
The NC pin can be connected to VIN or VSS.
Figure 2
HIGH RIPPLE-REJECTION LOW DROPOUT HIGH OUTPUT CURRENT CMOS VOLTAGE REGULATOR
S-1155 Series Rev.2.0_00
Seiko Instruments Inc.
6
Absolute Maximum Ratings
Table 3 (Ta = 25°C unless otherwise specified
)
Item Symbol Absolute Maximum Rating Unit
VIN V
SS − 0.3 to VSS + 6 V Input voltage VON/OFF V
SS − 0.3 to VIN + 0.3 V
Output voltage VOUT V
SS − 0.3 to VIN + 0.3 V
Power dissipation PD 1000*1 mW
Operating ambient temperature Topr −40 to +85 °C
Storage temperature Tstg −40 to +125 °C
*1. When mounted on board
[Mounted board]
(1) Board size : 114.3 mm × 76.2 mm × t1.6 mm
(2) Name : JEDEC STANDARD51-7
Caution The absolute maximum ratings are rated values exceeding which the product could suffer physical
damage. These values must therefore not be exceeded under any conditions.
050 100 150
1200
800
0
Power dissipation (PD) [mW]
Ambient temperature (Ta) [°C]
400
1000
600
200
Figure 3 Power Dissipation of Package (When Moun ted o n Bo ard)
Table 4
Condition Power Dissipation Thermal Resistance Val ue ( θj−a)
SOT-89-5 (When mounted o n boar d) 1000 mW 100°C/W
HIGH RIPPLE-REJECTION LOW DROPOUT HIGH OUTPUT CURRENT CMOS VOLTAGE REGULATOR
Rev.2.0_00 S-1155 Series
Seiko Instruments Inc. 7
Electrical Characteristics
Table 5 (1 / 2) (Ta = 25°C unless otherwise specifie d)
Item Symbol Conditions Min. Typ. Max. Unit
Test
Circuit
1.0 V
≤
V
OUT(S)
< 1.5 V V
OUT(S)
−
0.015 V
OUT(S)
V
OUT(S)
+ 0.015 V 1
V
IN
= V
OUT(S)
+ 1.0 V,
I
OUT
= 100 mA 1.5 V
≤
V
OUT(S)
≤
4.5 V V
OUT(S)
×
0.99 V
OUT(S)
V
OUT(S)
×
1.01 V 1
Output voltage
*1
V
OUT(E)
V
IN
= 5.5 V,
I
OUT
= 100 mA 4.5 V < V
OUT(S)
≤
5.0 V V
OUT(S)
×
0.99 V
OUT(S)
V
OUT(S)
×
1.01 V 1
V
IN
≥
V
OUT(S)
+ 1.0 V 1.0 V
≤
V
OUT(S)
≤
4.5 V 500
*5
−
−
mA 3
Output current
*2
I
OUT
V
IN
= 5.5 V 4.5 V < V
OUT(S)
≤
5.0 V 500
*5
−
−
mA 3
1.0 V
≤
V
OUT(S)
< 1.1 V 0.5 0.54 0.58 V 1
1.1 V
≤
V
OUT(S)
< 1.2 V
−
0.44 0.48 V 1
1.2 V
≤
V
OUT(S)
< 1.3 V
−
0.34 0.38 V 1
1.3 V
≤
V
OUT(S)
< 1.4 V
−
0.24 0.28 V 1
1.4 V
≤
V
OUT(S)
< 1.5 V
−
0.14 0.18 V 1
1.5 V
≤
V
OUT(S)
< 2.6 V
−
0.10 0.15 V 1
Dropout voltage
*3
V
drop
I
OUT
= 200 mA
2.6 V
≤
V
OUT(S)
≤
5.0 V
−
0.07 0.10 V 1
1.0 V
≤
V
OUT(S)
< 3.6 V
−
0.05 0.2 %/V 1
V
OUT(S)
+ 0.5 V
≤
V
IN
≤
5.5 V,
I
OUT
= 100 mA 3.6 V
≤
V
OUT(S)
≤
4.8 V
−
2.5 10 mV 1
Line regulation
OUTIN
1OUT
VV V
•Δ
Δ
5.3 V
≤
V
IN
≤
5.5 V,
I
OUT
= 100 mA 4.8 V < V
OUT(S)
≤
5.0 V
−
2.5 10 mV 1
V
IN
= V
OUT(S)
+ 1.0 V,
1 mA
≤
I
OUT
≤
200 mA 1.0 V
≤
V
OUT(S)
≤
4.5 V
−
15 30 mV 1
Load regulation
Δ
V
OUT2
V
IN
= 5.5 V,
1 mA
≤
I
OUT
≤
200 mA 4.5 V < V
OUT(S)
≤
5.0 V
−
15 30 mV 1
V
IN
= V
OUT(S)
+ 1.0 V,
I
OUT
= 100 mA,
−
40
≤
Ta
≤
85°C 1.0 V
≤
V
OUT(S)
≤
4.5 V
−
±
130
−
ppm/
°
C1
Output voltage
temperature
coefficient
*4
OUT
OUT
VTaV
•Δ
Δ
V
IN
= 5.5 V,
I
OUT
= 100 mA,
−
40
≤
Ta
≤
85°C 4.5 V < V
OUT(S)
≤
5.0 V
−
±
130
−
ppm/
°
C1
V
IN
=
V
OUT(S)
+
1.0 V, ON/ OF F pi n
=
ON,
no load, 1.0 V
≤
V
OUT(S)
< 1.8 V
−
90 110
μ
A 2
V
IN
=
V
OUT(S)
+
1.0 V, ON/ OF F pi n
=
ON,
no load, 1.8 V
≤
V
OUT(S)
≤
4.5 V
−
70 90
μ
A 2
Current consumption
during operation I
SS1
V
IN
=
5.5 V, ON/OFF pin
=
ON,
no load, 4.5 V < V
OUT(S)
≤
5.0 V
−
70 90
μ
A 2
V
IN
=
V
OUT(S)
+
1.0 V,
ON/OFF pin
=
OFF,
no load 1.0 V
≤
V
OUT(S)
≤
4.5 V
−
0.1 1.0
μ
A 2
Current consumption
during shutdown I
SS2
V
IN
=
5.5 V,
ON/OFF pin
=
OFF,
no load 4.5 V < V
OUT(S)
≤
5.0 V
−
0.1 1.0
μ
A 2
Input voltage V
IN
−
1.5
−
5.5 V
−
HIGH RIPPLE-REJECTION LOW DROPOUT HIGH OUTPUT CURRENT CMOS VOLTAGE REGULATOR
S-1155 Series Rev.2.0_00
Seiko Instruments Inc.
8
Table 5 (2 / 2) (Ta = 25°C unless otherwise specifie d)
Item Symbol Conditions Min. Typ. Max. Unit
Test
Circuit
V
IN
= V
OUT(S)
+ 1.0 V,
R
L
= 1.0 k
Ω
,
determined by V
OUT
output level
1.0 V
≤
V
OUT(S)
≤
4.5 V 1.0
−
−
V 4
Shutd own pi n
input
voltage “H” V
SH
V
IN
= 5.5 V,
R
L
= 1.0 k
Ω
,
determined by V
OUT
output level
4.5 V < V
OUT(S)
≤
5.0 V 1.0
−
−
V 4
V
IN
= V
OUT(S)
+ 1.0 V,
R
L
= 1.0 k
Ω
,
determined by V
OUT
output level
1.0 V
≤
V
OUT(S)
≤
4.5 V
−
−
0.3 V 4
Shutd own pi n
input
voltage “L” V
SL
V
IN
= 5.5 V,
R
L
= 1.0 k
Ω
,
determined by V
OUT
output level
4.5 V < V
OUT(S)
≤
5.0 V
−
−
0.3 V 4
Shutd own pi n
input
current “H” I
SH
V
IN
= 5.5 V, V
ON/OFF
= 5.5 V
−
0.1
−
0.1
μ
A 4
Shutd own pi n
input
current “L” I
SL
V
IN
= 5.5 V, V
ON/OFF
= 0 V
−
0.1
−
0.1
μ
A 4
1.0 V
≤
V
OUT(S)
< 1.2 V
−
70
−
dB 5
1.2 V
≤
V
OUT(S)
≤
3.0 V
−
65
−
dB 5
V
IN
= V
OUT(S)
+ 1.0 V,
f = 1 kHz,
Δ
V
rip
= 0.5 Vrms,
I
OUT
= 100 mA 3.0 V < V
OUT(S)
≤
4.5 V
−
60
−
dB 5
Ripple rejection
RR
V
IN
= 5.5 V,
f = 1 kHz,
Δ
V
rip
= 0.5 Vrms,
I
OUT
= 100 mA
4.5 V < V
OUT(S)
≤
5.0 V
−
60
−
dB 5
V
IN
=
V
OUT(S)
+
1.0 V,
ON/OFF pin
=
ON,
V
OUT
=
0 V 1.0 V
≤
V
OUT(S)
≤
4.5 V
−
200
−
mA 3
Short-cir c uit curr ent I
SHORT
V
IN
=
5.5 V,
ON/OFF pin
=
ON,
V
OUT
=
0 V 4.5 V < V
OUT(S)
≤
5.0 V
−
200
−
mA 3
Thermal shutdown
detecti o n te mp erat ur e T
SD
Junction temperature
−
150
−
°
C
−
Thermal shutdown
releas e t em per a tur e T
SR
Junction temperature
−
120
−
°
C
−
*1. V
OUT(S) : Specified output voltage
VOUT(E) : Actual output voltage
The output voltage when fixin g IOUT (= 100 m A) and i nputtin g VOUT(S) + 1.0 V or 5.5 V
*2. The output current at which the o utput voltage b ecomes 9 5% of VOUT(E) after gradua lly i ncreasin g the outp ut current.
*3. V
drop = VIN1 − (VOUT3 × 0.98)
V
OUT3 is the output voltage when VIN = VOUT(S) + 1.0 V or 5.5 V, and IOUT = 200 mA.
V
IN1
is the input voltage at which the output voltage becomes 98% of
V
OUT3
after gradually decreasing the input voltage.
*4. The change in temper ature [ mV/°C] is calc ulat ed us in g the foll o wing eq uatio n.
[] [] []
1000Cppm/
VΔTa
ΔV
VVCmV/
ΔTa
ΔV
OUT
OUT
OUT(S)
OUT ÷°
•
×=° *3*2*1
*1. Change in temperatur e of the out put v olta ge
*2. Specified output voltage
*3. Output voltage temperat ure co efficient
*5. The output current ca n be at least this valu e.
Due to limitation of the package power dissipation, this value may not be satisfied. Attention should be paid to the
power dissipation of the pack age when the outp ut current is large.
This specification is g uar ant eed b y desi gn.
*1 *2 *3
HIGH RIPPLE-REJECTION LOW DROPOUT HIGH OUTPUT CURRENT CMOS VOLTAGE REGULATOR
Rev.2.0_00 S-1155 Series
Seiko Instruments Inc. 9
Test Circuits
1. +
VOUT
VIN
VSS
+
V
A
ON/OFF
Set to power
ON
Figure 4
2.
VOUT
VIN
VSS
ON/OFF
Set to V
IN
or GND
+
A
Figure 5
3.
Set to power
ON
VOUT
VIN
VSS
+
V
+
A
ON/OFF
Figure 6
4.
VOUT
VIN
VSS
+
V
ON/OFF
+
A R
L
Figure 7
5.
VOUT
VIN
VSS
+
V
ON/OFF RL
Set to power
ON
Figure 8
HIGH RIPPLE-REJECTION LOW DROPOUT HIGH OUTPUT CURRENT CMOS VOLTAGE REGULATOR
S-1155 Series Rev.2.0_00
Seiko Instruments Inc.
10
Standard Circuit
C
IN*1
C
L*2
Input Output
GND
Single GND
VOUT
VIN
VSS
ON/OFF
*1. C
IN is a capacitor for stabilizi ng the inp ut.
*2. Ceramic capacitor of 4. 7 μF or more ca n be u sed as CL.
Figure 9
Caution The above con nectio n di agram and con stant w ill not gu arante e suc c essful o per ation . Perfo rm
thorough evaluation using the actual application to set the constant.
Application Conditions
Input capacitor (CIN) : 4.7 μF or more
Output capacitor (CL) : 4.7 μF or more (ceram ic capacitor)
Caution 1. Set input capacitor (CIN) and output capacitor (CL) as CIN = CL.
2. Generally, series regulator may oscillate depending on the external components. Confirm that
no oscillation occurs in the application for which the above capacitors are used.
Selection of Input and Output Capacitors (CIN, CL)
The S-1155 Series requires an output capacitor bet ween the VOUT and VSS pin for phase compensation. Operation
is stabilized by a ceramic capacitor with an output capacitance of 4.7 μF or more over the entire temperature range.
When using an OS capacit or, a tantalum capacitor, or an alumin um electrolytic cap acitor, the capacitance must be 4.7
μF or more.
The values of output overshoot and undershoot, which are transient response characteristics, vary depending on the
value of output capacitor.
The required valu e of capac itance f or the i n put capacit or d iffers depe ndin g on the ap pl ic ation.
Set the value for input capaci tor (CIN) and o utput capac itor (CL) as follo ws.
CIN ≥ 4.7 μF
CL ≥ 4.7 μF
CIN = CL
Caution The S-1155 Series may oscillate if setting the value as CIN ≥ 4.7 μF, CL ≥ 4.7 μF, CIN < CL.
Define the values by sufficient evaluation including the temperature characteristics under the usage
condition.
HIGH RIPPLE-REJECTION LOW DROPOUT HIGH OUTPUT CURRENT CMOS VOLTAGE REGULATOR
Rev.2.0_00 S-1155 Series
Seiko Instruments Inc. 11
Explanation of Terms
1. Low dropout voltage regulator
This IC’s voltage regulator has the l o w dropout v oltage due to its b uilt- in transi stor with lo w on-resist ance.
2. Output voltage (VOUT)
The accuracy of the output voltage is ensured at ±1.0% or ±15 mV*2 under the specified conditions of fixed input
voltage*1, fixed output current, and fi xed tem perat ure.
*1. Differs depending o n the prod uct.
*2. When V
OUT < 1.5 V : ±15 mV, When 1.5 V ≤ VOUT : ±1.0%
Caution If the above conditions change, the output voltage value may vary and exceed the accuracy
range of the output voltage. See “ Electrical Characteristics” and “ Characteristics (Typical
Data)” for details.
3. Line regulation ⎟
⎠
⎞
⎜
⎝
⎛
•Δ
Δ
OUTIN
OUT1
V V
V
Indicates the dependency of the output voltage against the input voltage. That is, the value shows how much the
output voltage changes du e to a chang e i n the inp ut voltage after fixing output current constant.
4. Load regulation (ΔVOUT2)
Indicates the dependency of the output voltage against the output current. That is, the value shows how much the
output voltage changes du e to a chang e i n the output cu rr ent after fixi ng output current consta nt.
5. Dropout voltage (Vdrop)
Indicates the difference b et ween the out put volta ge a nd the in put voltag e VIN1, which is the inp ut voltage (VIN) when;
decreasing input voltage VIN gradually until the output voltage has dropped to the value of 98% of output voltage
VOUT3, which is at VIN = VOUT(S) + 1.0 V or 5.5 V.
Vdrop = VIN1 − (VOUT3 × 0.98)
HIGH RIPPLE-REJECTION LOW DROPOUT HIGH OUTPUT CURRENT CMOS VOLTAGE REGULATOR
S-1155 Series Rev.2.0_00
Seiko Instruments Inc.
12
6. Temperature coefficient of output voltage ⎟
⎠
⎞
⎜
⎝
⎛
•Δ
Δ
OUT
OUT
V Ta
V
The shadowed area in Figure 10 is the range where VOUT varies in the operating temperature range when the
temperature coefficient of the outp ut volt age is ±1 30 ppm/ °C.
Ex. S-1155B30 Typ.
−40 25
+0.39 mV / °C
V
OUT
[V]
85 Ta [°C]
V
OUT(E)*1
−0.39 mV / °C
*1. VOUT(E) is the value of the output voltage meas ured at 2 5°C.
Figure 10
A change in the temperatur e of the out put v oltage [m V/°C] is calculat ed u sing th e following equation.
[] [] []
1000C/ppm
VTaV
VVC/mV
Ta
V
OUT
OUT
OUT(S)
OUT ÷°
•
Δ
Δ
×=°
Δ
Δ3*2*1*
*1. Change in temperatur e of outp ut voltage
*2. Specified output voltage
*3. Output voltage temperat ure co efficient
HIGH RIPPLE-REJECTION LOW DROPOUT HIGH OUTPUT CURRENT CMOS VOLTAGE REGULATOR
Rev.2.0_00 S-1155 Series
Seiko Instruments Inc. 13
Operation
1. Basic operation
Figure 11 shows the block diagram of the S-115 5 Ser ies.
The error amplifier c ompares the reference voltage (V ref) with Vfb, which is the output vo ltage resistance-divided by
feedback resistors Rs and Rf. It supplies the gate voltage necessary to maintain the constant output voltage which
is not influenced by the input volta ge and temperat ure c ha nge, to the out put trans istor.
VOUT
*1
VSS
VIN
Rs
Rf
Error amplifier
Current
supply
Vref
Vfb
−
+
Reference voltage
circuit
*1. Parasitic diode
Figure 11
2. Output transistor
In the S-1155 Series, a low on-resistanc e P -channe l MOS FET is used as the outp ut transistor.
Be sure that VOUT does not exceed V IN + 0.3 V to prevent the voltage regulator from being dam aged due to inverse
current which flows, because of a parasitic diode between the VIN and VOUT pin, when the potential of VOUT
became higher than VIN.
HIGH RIPPLE-REJECTION LOW DROPOUT HIGH OUTPUT CURRENT CMOS VOLTAGE REGULATOR
S-1155 Series Rev.2.0_00
Seiko Instruments Inc.
14
3. Shutdown pin (ON/OFF pin)
This pin starts and stops the regu lat or.
When the ON/OFF pin is set to the shutdown level, the entire internal circuit stops operating, and the built-in
P-channel MOS FET output transistor between the VIN and VOUT pin is turned off, in order to reduce the current
consumption significantly. The VOUT pin is set to the VSS level by the internal dividing resistor of several hundred
kΩ between the VOUT and V SS pin.
Note that the current consum ptio n incr eas es when a volta ge of 0.3 V to 1.0 V is a pplie d to the ON/OFF pin.
The ON/OFF pin is configured as shown in Figure 12. Since the ON/OFF pin is neither pulled down nor pulled up
internally, do not use it in the floati ng stat e.
When not using the ON/OFF pin, connect it to the VSS pin in the product A type, and connect it to the VIN pin in B
type.
Table 6
Logic Type ON/OFF Pin Internal Circuits VOUT Pin Voltage Current Co nsum ption
A “L”: Power on Operate Set value ISS1
A “H”: Power off Stop VSS level ISS2
B “L”: Power off Stop VSS level ISS2
B “H”: Power on Operate Set value I SS1
VSS
ON/OFF
VIN
Figure 12
4. Overcurrent protection circuit
The S-1155 Series ha s an overcurrent pr otection circ uit having the char acteristics sho wn in (1) Outp ut Voltage vs.
Output Current (W hen load current is increased ) (Ta = 25°C) in “ Characteristics (Typical Dat a)”, in order to
protect the output transistor against an excessive output current and short circuiting between the VOUT and VSS
pin. The current (ISHORT) when the output pin is short-circuited is internally set at approx. 200 mA (Typ.), and the
initial value is restored for the output v oltage , if releas ing a short circ uit once.
Caution This overcurrent protection circuit does not work as for thermal protection. If this IC long keeps
short circuiting inside, pay attention to the conditions of input voltage and the load current so
that, under the usage conditions including short circuit, the loss of the IC will not exceed power
dissipation of the packag e.
HIGH RIPPLE-REJECTION LOW DROPOUT HIGH OUTPUT CURRENT CMOS VOLTAGE REGULATOR
Rev.2.0_00 S-1155 Series
Seiko Instruments Inc. 15
5. Thermal shutdown circuit
The S-1155 Series has a thermal shutdown circuit to protect the device from damage due to overheat. When the
junction temperature rises to 150°C (Typ.), the thermal shutdown circuit operates to stop regulating. When the
junction temperature d rop s to 120°C (T yp.), the therm al sh utdo wn circuit is released to restart regulating.
Due to self-heating of the S-115 5 Series, if the thermal shutdown circuit starts operatin g, it stops regulating so that
the output voltage drops. When regulation stops, the S-1155 does not itself generate heat so that the IC’s
temperature drops. Wh en the temperatur e drops, the th ermal s hutdown circuit is released to r estart regul ating, thus
this IC generates heat again. Repeating this procedure makes waveform of the output voltage pulse-like form.
Stop/Restart of regulation continues unless decreasing either/both of the input voltage and the output voltage in
order to reduce the internal c urrent c onsum ption, or decr e asin g the ambi ent temperatur e.
Table 7
Thermal Shutdown Circu it VOUT Pin Voltage
Operation : 150°C (Typ.)*1 V
SS level
Release : 120°C (Typ.)*1 Set value
*1. Junction temperature
6. Rush current control circuit
The S-1155 Series has a rush current c ontrol circuit to co ntrol the rush current ge nerated during power-on or when
the ON/OFF pin is ON. This circuit limits the rush current (400 mA, Typ.) immediately after power-on or from the
ON/OFF pin is ON until the specified time ( 100 μs min.) which is set internally.
Caution The junction temperature drops to 120°C (Typ.) by the operation of thermal shutdown circuit,
after stopping regulation, the circuit is released to restart regulation; in this case, note that the
period to limit rush current may become shorter (10 μs min.).
HIGH RIPPLE-REJECTION LOW DROPOUT HIGH OUTPUT CURRENT CMOS VOLTAGE REGULATOR
S-1155 Series Rev.2.0_00
Seiko Instruments Inc.
16
Precautions
• Wiring patterns for the VIN, VOUT and GND pins sho uld be designed so that the impeda nce is low. When mounting
an output capacitor between the VOUT and VSS pin (CL) and a capacitor for stabilizing the input between the VIN
and VSS pin (CIN), the distance from the capacit ors to these pi ns sh ould be as s hort as possibl e.
• Note th at the output vo ltage ma y increas e when a series regu lat or is used at l o w load current (1.0 mA or less).
• Note that the output voltage may gener ally increase due to the leakage current from a driver when a series regulat or
is used at high temperature.
• Generally series regulator may oscillate, 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 the temperature characteristics. Regarding the equivalent series resistance (RESR) for the output
capacitor, refer to (5) Example of Equivalent Series Resistance vs. Output Current Characteristics (Ta = 25°C)
in “ Reference Data”.
Input capacitor (CIN) : 4.7 μF or more
Output capacitor (CL) : 4.7 μF or more
• The voltage regulator may oscillate when the impedance of the power supply is high and the input capacitance is
small, or an input capacitor is not connected. Note that the voltage regulator may oscillate when the value of the
input capacitor is great er tha n that of the output capacit or.
• Ringing may occur when these three conditions below are satisfied. Before selecting an input capacitor, be sure to
evaluate sufficientl y under the actual usa ge cond it io ns, in cludi ng th e temperatur e ch aracteristics.
The power supply indu ctanc e is high.
The load current is 100 mA o r more.
The difference between the input volt ag e an d the output voltage is clo se t o the va lue of drop out volta ge.
• If the output capacitance is small, power suppl y’s fluctuation and the c haracteristics of load fluctuati on become worse.
Sufficiently evaluate the output voltage’s fluctuation with the actual device.
• A momentary overshoot may be output when the power supply suddenly increases, and the output capacitance is
small. It is therefore importan t to sufficient l y evaluat e the output vo ltage a t po wer applic ation in a ctua l devic e.
• The applic ation conditions for the input voltage, output vol tage, and load current should not e xceed power dissipation
of the package.
• 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 “
Electrical Characteri stics ” and foot note *5 of the table.
• SII claims no responsi bilit y for any disputes arising out of or in connection with any infrin gement by products including
this IC of patents owned by a third party.
HIGH RIPPLE-REJECTION LOW DROPOUT HIGH OUTPUT CURRENT CMOS VOLTAGE REGULATOR
Rev.2.0_00 S-1155 Series
Seiko Instruments Inc. 17
Characteristics (Typical Data)
(1) Output Voltage vs. Output Current (when load current is increased) (Ta = 25°C)
S-1155B10 S-1155B30
200 400 600
V
OUT
[V]
I
OUT
[mA]
0
0.6
0.4
0.8
1.0
800
0
0.2
1000
1.2
V
IN
= 1.5 V 3.0 V
5.5 V
2.0 V
200 400 600
V
OUT
[V]
I
OUT
[mA]
0
1.0
2.0
1.5
2.5
3.0
800
0
0.5
1000
3.5
4.0 V 5.5 V
V
IN
= 3.5 V 5.0 V
S-1155B50
200 400 600
VOUT [V]
IOUT [mA]
0
3
2
4
5
800
0
1
1000
5.5 V
VIN = 5.3 V
6
Remark In determining the out put curr ent, attenti on
should be paid to the foll o wing.
1. The minimum value of output current
in Table 5 and footnote *5 in “ Electrical
Characteristics”
2. Power dissipation of the package
(2) Output Voltage vs. Input Voltage (Ta = 25°C)
S-1155B10 S-1155B30
1.0 1.5 2.0
V
OUT
[V]
V
IN
[V]
0.5
1.1
0.5
0.8
0.7
0.9
1.0
2.5 3.0
0.6
I
OUT
= 1 mA
50 mA
100 mA
3.0 3.5 4.0
V
OUT
[V]
V
IN
[V]
2.5
3.1
2.6
2.8
2.7
2.9
3.0
4.5 5.0
2.5
I
OUT
= 1 mA
50 mA
100 mA
S-1155B50
4.7 4.9 5.1
VOUT [V]
VIN [V]
4.5
5.1
4.6
4.8
4.7
4.9
5.0
5.3
4.5 5.5
IOUT = 1 mA
100 mA
50 mA
HIGH RIPPLE-REJECTION LOW DROPOUT HIGH OUTPUT CURRENT CMOS VOLTAGE REGULATOR
S-1155 Series Rev.2.0_00
Seiko Instruments Inc.
18
(3) Dropout Voltage vs. Output Current
S-1155B10 S-1155B30
-
°
°
°
-
°
°
°
S-1155B50
-
°
°
°
(4) Dropout Voltage vs. Set Output Voltage
123
Vdrop [V]
VOTA [V]
0
0.40
5
0
0.35
0.30
0.25
0.20
0.15
46
0.10
0.05
IOUT = 500 mA
300 mA
10 mA
HIGH RIPPLE-REJECTION LOW DROPOUT HIGH OUTPUT CURRENT CMOS VOLTAGE REGULATOR
Rev.2.0_00 S-1155 Series
Seiko Instruments Inc. 19
(5) Output Voltage vs. Ambient T emperat u re
S-1155B10 S-1155B30
−25 025
V
OUT
[V]
Ta [°C]
−40
1.050
1.075
75
1.025
1.000
0.975
0.950
0.925
0.900 50 85
1.100
−25 0 25
VOUT [V]
Ta [°C]
−40
3.10
3.15
75
3.05
3.00
2.95
2.90
2.85
2.80 50 85
3.20
S-1155B50
−25 0 25
V
OUT
[V]
Ta [°C]
−40
5.10
5.20
75
5.00
4.90
4.80
4.70 50 85
5.30
(6) Current Consumption vs. Input Voltage
S-1155B10 S-1155B30
0.5 2.5 4.5
I
SS1
[μA]
V
IN
[V]
0
100
120
80
60
40
1.5 3.5 5.5
20
01.0 3.0 5.0
2.0 4.0
−40 °C
Ta = 85 °C
25 °C
m
-
°
°
°
S-1155B50
m
-
°
°
°
HIGH RIPPLE-REJECTION LOW DROPOUT HIGH OUTPUT CURRENT CMOS VOLTAGE REGULATOR
S-1155 Series Rev.2.0_00
Seiko Instruments Inc.
20
(7) Ripple Rejection (Ta = 25°C)
S-1155B10 VIN = 2.0 V, COUT = 4.7 μF
S-1155B30 VIN = 4.0 V, COUT = 4.7 μF
100 1K 10K
Ripple Rejection [dB]
Frequency [Hz]
10 1M
0
100
80
60
40
20
100K
I
OUT
= 1 mA
30 mA
100 mA
100 1K 10K
Ripple Rejection [dB]
Frequency [Hz]
10 1M
0
100
80
60
40
20
100K
I
OUT
= 1 mA
30 mA
100 mA
S-1155B50 VIN = 5.5 V, COUT = 4.7 μF
100 1K 10K
Ripple Rejection [dB]
Frequency [Hz]
10 1M
0
100
80
60
40
20
100K
I
OUT
= 1 mA
30 mA
100 mA
HIGH RIPPLE-REJECTION LOW DROPOUT HIGH OUTPUT CURRENT CMOS VOLTAGE REGULATOR
Rev.2.0_00 S-1155 Series
Seiko Instruments Inc. 21
Reference Data
(1) Characteristics of Input Transient Response (Ta = 25°C)
S-1155B10
IOUT = 100 mA, tr = tf = 5.0 μs, COUT = 4.7 μF, CIN = 4.7 μF S-1155B30
IOUT = 100 mA, tr = tf = 5.0 μs, COUT = 4.7 μF, CIN = 4.7 μF
0 200
V
OUT
[V]
t [μs]
−200 600 0
4
3
2
1
400 800 1000 1200
0.95
V
IN
[V]
1.00
1.05
1.10
1.15 V
IN
V
OUT
0
6
5
4
3
2
1
V
IN
[V]
0 200 t [μs]
−200 600
400 800 1000 1200
V
OUT
[V]
3.00
3.05
3.10
3.15
3.20
2.90
2.95
V
IN
V
OUT
S-1155B50
IOUT = 100 mA, tr = tf = 5.0 μs, COUT = 4.7 μF, CIN = 4.7 μF
0
7
6
5
4
3
2
4.90
4.95
V
IN
[V]
5.00
5.05
5.10
5.15
5.20
5.25
0 200 t [μs]
−200 600
400 800 1000 1200
V
OUT
[V]
1
V
IN
V
OUT
(2) Characteri stics of L oad T ransien t Res po nse (T a = 25°C)
S-1155B10
V
IN
= 2.0 V, C
OUT
= 4.7
μ
F, C
IN
= 4.7
μ
F, I
OUT
= 50
↔
100 mA
S-1155B30
V
IN
= 4.0 V, C
OUT
= 4.7
μ
F, C
IN
= 4.7
μ
F, I
OUT
= 50
↔
100 mA
0
150
100
50
I
OUT
[mA]
−50
−100
0.90
0.95
1.00
1.05
1.10
1.15
1.20
V
OUT
[V]
0 200 t [μs]
−200 600
400 800 1000 1200
−150
I
OUT
V
OUT
0
150
100
50
I
OUT
[mA]
−50
−100
2.90
2.95
3.00
3.05
3.10
3.15
3.20
V
OUT
[V]
0 200 t [μs]
−200 600
400 800 1000 1200
−150
I
OUT
V
OUT
S-1155B50
V
IN
= 5.5 V, C
OUT
= 4.7
μ
F, C
IN
= 4.7
μ
F, I
OUT
= 50
↔
100 mA
0
50
I
OUT
[mA]
−50
−100
4.90
4.95
5.00
5.05
5.10
5.15
5.20
V
OUT
[V]
0 200 t [μs]
−200 600
400 800 1000 1200
−150
I
OUT
V
OUT
100
150
HIGH RIPPLE-REJECTION LOW DROPOUT HIGH OUTPUT CURRENT CMOS VOLTAGE REGULATOR
S-1155 Series Rev.2.0_00
Seiko Instruments Inc.
22
(3) Transient Respon se Chara cteristics o f ON/OFF Pin (Ta = 25°C)
S-1155B10
VIN = 2.0 V, COUT = 4.7 μF, CIN = 4.7 μF, IOUT = 100 mA S-11 55B30
VIN = 4.0 V, COUT = 4.7 μF, CIN = 4.7 μF, IOUT = 100 mA
V
OUT
[V]
2
0
3
V
OUT
1
4
5
−1
1
0
−1
−2
2
3
V
ON/OFF
[V]
−3
t [μs]
0 500−500 1000 1500 2000
V
ON/OFF
V
OUT
[V]
4
0
6
2
8
10
−2
2
0
−2
−4
4
6
V
ON/OFF
[V]
−6
t [μs]
0 500−500 1000 1500 2000
V
OUT
V
ON/OFF
S-1155B50
VIN = 5.5 V, COUT = 4.7 μF, CIN = 4.7 μF, IOUT = 100 mA
V
OUT
[V]
8
0
12
4
16
20
−4
3
0
−3
−6
6
9
V
ON/OFF
[V]
−9
t [μs]
0 500−500 1000 1500 2000
V
OUT
V
ON/OFF
(4) Characteri stics of Ru sh Curren t (T a = 25°C)
S-1155B10
VIN = 2.0 V, COUT = 4.7 μF, CIN = 4.7 μF, IOUT = 100 mA
VIN = 2.0 V, COUT = 4.7 μF, CIN = 4.7 μF, IOUT = 500 mA
−4
−2
−6
0
2
1.2
1.0
0.8
I
OUT
[A]
0.6
t [μs]
050−50 100 150 200
0.2
0.4
0
V
ON/OFF
[V] / V
OUT
[V]
4
6
V
OUT
V
ON/OFF
I
OUT
−4
−2
−6
0
2
1.2
1.0
0.8
I
OUT
[A]
0.6
t [μs]
0 100−100 200 300 400
0.2
0.4
0
V
ON/OFF
[V] / V
OUT
[V]
4
6
500
V
OUT
V
ON/OFF
I
OUT
S-1155B30
VIN = 4.0 V, COUT = 4.7 μF, CIN = 4.7 μF, IOUT = 100 mA
VIN = 4.0 V, COUT = 4.7 μF, CIN = 4.7 μF, IOUT = 500 mA
−4
−2
−6
0
2
1.2
1.0
0.8
I
OUT
[A]
0.6
t [μs]
050−50 100 150 200
0.2
0.4
0
V
ON/OFF
[V] / V
OUT
[V]
4
6
V
OUT
V
ON/OFF
I
OUT
−4
−2
−6
0
2
1.2
1.0
0.8
I
OUT
[A]
0.6
t [μs]
0 100−100 200 300 400
0.2
0.4
0
V
ON/OFF
[V] / V
OUT
[V]
4
6
500
V
OUT
V
ON/OFF
I
OUT
HIGH RIPPLE-REJECTION LOW DROPOUT HIGH OUTPUT CURRENT CMOS VOLTAGE REGULATOR
Rev.2.0_00 S-1155 Series
Seiko Instruments Inc. 23
S-1155B50
VIN = 5.5 V, COUT = 4.7 μF, CIN = 4.7 μF, IOUT = 100 mA
VIN = 5.5 V, COUT = 4.7 μF, CIN = 4.7 μF, IOUT = 500 mA
−4
−2
−6
0
2
1.2
1.0
0.8
I
OUT
[A]
0.6
t [μs]
0 100−100 200 300 400
0.2
0.4
0
V
ON/OFF
[V] / V
OUT
[V]
4
6
500
V
OUT
V
ON/OFF
I
OUT
−4
−2
−6
0
2
1.2
1.0
0.8
I
OUT
[A]
0.6
t [μs]
0 100−100 200 300 400
0.2
0.4
0
V
ON/OFF
[V] / V
OUT
[V]
4
6
500
V
OUT
V
ON/OFF
I
OUT
(5) Example of Equi valent Series Resista nce vs. Output Current Charact eri stics (T a = 25°C)
CL : Taiyo Yuden LMK316BJ 475ML (4.7 μF)
100
0.1 500
IOUT [mA]
RESR [Ω]
CIN = CL = 4.7
μ
F
0
Stable
CIN
VIN
VSS
CL
RESR
S-1155 Series VOUT
ON/OFF
HIGH RIPPLE-REJECTION LOW DROPOUT HIGH OUTPUT CURRENT CMOS VOLTAGE REGULATOR
S-1155 Series Rev.2.0_00
Seiko Instruments Inc.
24
Marking Specifications
SOT-89-5
(1) to (3) : Product abbreviation (refer to Product Name vs. Product Code)
(4) to (6) : Lot number
5 4
1 3 2
SOT-89-5
Top view
(2) (1) (3)
(5) (4) (6)
Product Name vs. Product Code
Product Code Product Code
Product Name (1) (2) (3) Product Name (1) (2) (3)
S-1155B10-U5T1x S K A S-1155B30-U5T1x S K W
S-1155B11-U5T1x S K B S-1155B31-U5T1x S K X
S-1155B12-U5T1x S K C S-1155B32-U5T1x S K Y
S-1155B13-U5T1x S K D S-1155B33-U5T1x S K Z
S-1155B14-U5T1x S K E S-1155B34-U5T1x S L A
S-1155B15-U5T1x S K F S-1155B35-U5T1x S L B
S-1155B16-U5T1x S K G S-1155B36-U5T1x S L C
S-1155B17-U5T1x S K H S-1155B37-U5T1x S L D
S-1155B18-U5T1x S K I S-1155B 38-U5T 1x S L E
S-1155B1J-U5T1x S K J S-1155B39- U5T1x S L F
S-1155B19-U5T1x S K K S-1155B40-U5T1x S L G
S-1155B20-U5T1x S K L S-1155B41-U5T1x S L H
S-1155B21-U5T1x S K M S-1155B42-U5T1x S L I
S-1155B22-U5T1x S K N S-1155B43-U5T1x S L J
S-1155B23-U5T1x S K O S-1155B44-U5T1x S L K
S-1155B24-U5T1x S K P S-1155B45-U5T1x S L L
S-1155B25-U5T1x S K Q S-1155B46-U5T1x S L M
S-1155B26-U5T1x S K R S-1155B47-U5T1x S L N
S-1155B27-U5T1x S K S S-1155B48-U5T1x S L O
S-1155B28-U5T1x S K T S-1155B49- U5T1x S L P
S-1155B2J-U5T1x S K U S-1155B50-U5T1x S L Q
S-1155B29-U5T1x S K V
Remark 1. Please contact our sales office for products with an output voltage oth er than those spec ified above or
type A products.
2. x: G or U
3. Please select products of environment al code = U for Sn 100 %, halo gen -free pr odu cts.
No.
TITLE
SCALE
UNIT mm
Seiko Instruments Inc.
1.5±0.1 1.5±0.1
1.6±0.2
4.5±0.1
132
1.5±0.1
0.4±0.05
0.4±0.1
0.45±0.1
0.4±0.1
45°
0.3
54
No. UP005-A-P-SD-1.1
UP005-A-P-SD-1.1
SOT895-A-PKG Dimensions
No.
TITLE
SCALE
UNIT mm
Seiko Instruments Inc.
2.0±0.1
0.3±0.05
8.0±0.1
ø1.5+0.1
-0
2.0±0.05
ø1.5+0.1
-0
4.75±0.1
5° max.
1
32
54
No. UP005-A-C-SD-1.1
UP005-A-C-SD-1.1
SOT895-A-Carrier Tape
Feed direction
4.0±0.1(10 pitches : 40.0±0.2)
No.
TITLE
SCALE
UNIT mm
Seiko Instruments Inc.
16.5max.
13.0±0.3
QTY. 1,000
(60°)
(60°)
No. UP005-A-R-SD-1.1
UP005-A-R-SD-1.1
SOT895-A-Reel
Enlarged drawing in the central part
www.sii-ic.com
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