S-8521B15MC-ATAT2x [SII]
STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER;
| 型号： | S-8521B15MC-ATAT2x |
| 厂家： | 
SEIKO INSTRUMENTS INC |
| 描述： | STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER 开关 |
| 文件： | 总44页 (文件大小：2578K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
S-8520/8521 Series
STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE
SWITCHING REGULATOR CONTROLLER
www.sii-ic.com
© SII Semiconductor Corporation, 1997-2010
Rev.9.0_01
The S-8520/8521 Series is a CMOS step-down switching regulator-controller with PWM control (S-8520 Series) and PWM
/ PFM switching control (S-8521 Series). The S-8520/8521 Series has a reference voltage source, an oscillation circuit, an
error amplifier, and other components.
The S-8520 Series provides low-ripple power, high efficiency, and excellent transient characteristics due to a PWM control
circuit capable of varying the duty ratio linearly from 0% up to 100%. The S-8520/8521 Series also has a soft-start circuit
that prevents overshoot at startup.
The S-8521 Series works with either PWM control or PFM control. It normally operates using PWM control with a duty ratio
of 25% to 100%, but under a light load, it automatically switches to PFM control with a duty ratio of 25%. The S-8520/8521
Series ensures high efficiency over a wide range of conditions for devices, from the standby mode to the operation.
By adding external Pch power MOS FET or PNP transistor, coil, capacitor, and externally connected diode, the
S-8520/8521 Series can function as a step-down switching regulator, and is ideal for power supply units of portable
devices due to small SOT-23-5 and the feature of low current consumption. It is also ideal for AC adapters due to the input
voltage up to 16 V.
Features
• Low current consumption During operation: 60 μA max. (A, B types)
21 μA max. (C, D types)
100 μA max. (E, F types)
During shutdown: 0.5 μA max.
• Input voltage:
2.5 V to 16 V (B, D, F types)
2.5 V to 10 V (A, C, E types)
• Output voltage:
• Duty ratio:
Selectable between 1.5 V and 6.0 V in 0.1 V step
0% to 100% PWM control (S-8520 Series)
25% to100% PWM / PFM switching control (S-8521 Series)
• External parts are Pch power MOS FET or PNP transistor, coil, diode, and capacitor only
(When using PNP transistor, add base resistor and capacitor).
• Oscillation frequency:
180 kHz typ. (A, B types)
60 kHz typ. (C, D types)
300 kHz typ. (E, F types)
• Soft-start function:
8 ms. typ.
(A, B types)
12 ms. typ. (C, D types)
4.5 ms. typ. (E, F types)
• With a shutdown function
• With a built-in overload protection circuit Overload detection time:
4 ms. typ.
(A type)
14 ms. typ. (C type)
2.6 ms. typ. (E type)
• Lead-free, Sn 100%, halogen-free*1
*1. Refer to “ Product Name Structure” for details.
1
STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER
S-8520/8521 Series
Rev.9.0_01
Applications
• On-board power supplies of battery devices for mobile phone, electronic notebooks, PDAs.
• Power supplies for audio equipment, including portable CD players and headphone stereo equipment.
• Fixed voltage power supply for cameras, video and communication devices.
• Power supplies for microcomputers
• Conversion from NiH or four NiCd cells or two lithium-ion cells to 3.3 V / 3 V.
• Conversion of AC adapter input to 5 V / 3 V.
Package
• SOT-23-5
2
STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER
Rev.9.0_01
S-8520/8521 Series
Block Diagrams
1. S-8520 Series
L
Tr
VIN
Reference voltage
source with soft-start
Oscillation
circuit
VOUT
EXT
+
−
+
PWM control
circuit
COUT
+
CIN
SD
VIN
______
VON/
VSS
OFF
______
ON/OFF
Remark All the diodes in the figure are parasitic diodes.
Figure 1
2. S-8521 Series
L
Tr
VIN
Reference voltage
source with soft-start
Oscillation
circuit
VOUT
EXT
+
+
PWM / PFM switching
control circuit
COUT
−
+
CIN
SD
VIN
______
VON/
VSS
OFF
______
ON/OFF
Remark All the diodes in the figure are parasitic diodes.
Figure 2
3
STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER
S-8520/8521 Series
Rev.9.0_01
Product Name Structure
The control types, product types, and output voltage for the S-8520/8521 Series can be selected at the user’s request.
Please refer to the “1. Product name” for the definition of the product name, “2. Package” regarding the package
drawings and “3. Product name list” for the full product names.
1. Product name
S-852
x
x
xx MC
−
xxx T2
x
Environmental code
U:
G:
Lead-free (Sn 100%), halogen-free
Lead-free (for details, please contact our sales office)
IC direction in tape specifications*1
Product name (abbreviation)*2
Package name (abbreviation)
MC : SOT-23-5
Output voltage
15 to 60
(When the output voltage is 1.5 V, it is expressed as 15.)
Product type
A: Oscillation frequency of 180 kHz,
With overload protection circuit
B: Oscillation frequency of 180 kHz,
Without overload protection circuit
C: Oscillation frequency of 60 kHz,
With overload protection circuit
D: Oscillation frequency of 60 kHz,
Without overload protection circuit
E: Oscillation frequency of 300 kHz,
With overload protection circuit
F: Oscillation frequency of 300 kHz,
Without overload protection circuit
Control system
0: PWM control
1: PWM / PFM switching control
*1. Refer to the tape specifications.
*2. Refer to “3. Product name list”.
2. Package
Drawing code
Package Name
SOT-23-5
Package
Tape
Reel
MP005-A-P-SD
MP005-A-C-SD
MP005-A-R-SD
4
STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER
Rev.9.0_01
S-8520/8521 Series
3. Product name list
3. 1 S-8520 Series
Table 1 (1 / 2)
Output voltage [V]
S-8520AxxMC Series
S-8520BxxMC Series
S-8520CxxMC Series
1.5
1.8
2.0
2.1
2.4
2.5
2.6
2.7
2.8
2.9
3.0
3.1
3.2
3.3
3.4
3.5
3.6
4.0
4.3
5.0
5.3
S-8520B15MC-ARAT2x
S-8520B18MC-ARDT2x
−
−
−
−
−
−
−
S-8520A20MC-AVFT2x
S-8520A21MC-AVGT2x
−
−
S-8520B24MC-ARJT2x
S-8520B25MC-ARKT2x
−
−
S-8520A25MC-AVKT2x
S-8520A26MC-AVLT2x
S-8520A27MC-AVMT2x
S-8520A28MC-AVNT2x
S-8520A29MC-AVOT2x
S-8520A30MC-AVPT2x
S-8520A31MC-AVQT2x
S-8520A32MC-AVRT2x
S-8520A33MC-AVST2x
S-8520A34MC-AVTT2x
S-8520A35MC-AVUT2x
S-8520A36MC-AVVT2x
−
S-8520C25MC-BRKT2x
−
S-8520B27MC-ARMT2x
S-8520B28MC-ARNT2x
S-8520B29MC-AROT2x
S-8520B30MC-ARPT2x
S-8520B31MC-ARQT2x
S-8520B32MC-ARRT2x
S-8520B33MC-ARST2x
S-8520B34MC-ARTT2x
S-8520B35MC-ARUT2x
S-8520B36MC-ARVT2x
S-8520B40MC-ARZT2x
S-8520B43MC-ASCT2x
S-8520B50MC-ASJT2x
S-8520B53MC-ASMT2x
S-8520C27MC-BRMT2x
S-8520C28MC-BRNT2x
S-8520C29MC-BROT2x
S-8520C30MC-BRPT2x
S-8520C31MC-BRQT2x
S-8520C32MC-BRRT2x
S-8520C33MC-BRST2x
S-8520C34MC-BRTT2x
S-8520C35MC-BRUT2x
S-8520C36MC-BRVT2x
−
−
−
S-8520A50MC-AWJT2x
S-8520C50MC-BSJT2x
−
−
Table 1 (2 / 2)
Output voltage [V]
S-8520DxxMC Series
S-8520ExxMC Series
S-8520E15MC-BJAT2x
S-8520E16MC-BJBT2x
S-8520E18MC-BJDT2x
S-8520FxxMC Series
S-8520F15MC-BNAT2x
−
S-8520F18MC-BNDT2x
S-8520F20MC-BNFT2x
S-8520F25MC-BNKT2x
S-8520F26MC-BNLT2x
S-8520F27MC-BNMT2x
S-8520F28MC-BNNT2x
−
1.5
1.6
1.8
2.0
2.5
2.6
2.7
2.8
2.9
3.0
3.1
3.2
3.3
3.4
3.5
3.6
4.0
4.5
5.0
5.2
5.5
6.0
−
−
−
−
−
S-8520D25MC-BVKT2x
S-8520E25MC-BJKT2x
−
−
−
S-8520D27MC-BVMT2x
S-8520D28MC-BVNT2x
S-8520D29MC-BVOT2x
S-8520D30MC-BVPT2x
S-8520D31MC-BVQT2x
S-8520D32MC-BVRT2x
S-8520D33MC-BVST2x
S-8520D34MC-BVTT2x
S-8520D35MC-BVUT2x
S-8520D36MC-BVVT2x
−
S-8520E28MC-BJNT2x
−
S-8520E30MC-BJPT2x
S-8520F30MC-BNPT2x
S-8520F31MC-BNQT2x
−
−
−
S-8520E33MC-BJST2x
S-8520F33MC-BNST2x
S-8520F34MC-BNTT2x
S-8520F35MC-BNUT2x
S-8520F36MC-BNVT2x
S-8520F40MC-BNZT2x
S-8520F45MC-BOET2x
S-8520F50MC-BOJT2x
−
−
−
−
−
−
−
S-8520D50MC-BWJT2x
S-8520E50MC-BKJT2x
S-8520E52MC-BKLT2x
−
−
−
S-8520F55MC-BOOT2x
S-8520F60MC-BOTT2x
−
−
Remark 1. Please contact our sales office for products with output voltage other than those specified above.
2. x: G or U
3. Please select products of environmental code = U for Sn 100%, halogen-free products.
5
STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER
S-8520/8521 Series
Rev.9.0_01
3. 2 S-8521 Series
Table 2 (1 / 2)
S-8521AxxMC Series
Output voltage [V]
S-8521BxxMC Series
S-8521B15MC-ATAT2x
−
S-8521CxxMC Series
1.5
1.6
1.8
1.9
2.0
2.1
2.3
2.5
2.6
2.7
2.8
2.9
3.0
3.1
3.2
3.3
3.4
3.5
3.6
4.0
4.4
5.0
5.1
5.3
6.0
−
−
−
−
−
−
−
−
S-8521C16MC-BTBT2x
S-8521B18MC-ATDT2x
S-8521B19MC-ATET2x
S-8521B20MC-ATFT2x
S-8521B21MC-ATGT2x
S-8521B23MC-ATIT2x
S-8521B25MC-ATKT2x
S-8521B26MC-ATLT2x
S-8521B27MC-ATMT2x
S-8521B28MC-ATNT2x
S-8521B29MC-ATOT2x
S-8521B30MC-ATPT2x
S-8521B31MC-ATQT2x
S-8521B32MC-ATRT2x
S-8521B33MC-ATST2x
S-8521B34MC-ATTT2x
S-8521B35MC-ATUT2x
S-8521B36MC-ATVT2x
S-8521B40MC-ATZT2x
S-8521B44MC-AUDT2x
S-8521B50MC-AUJT2x
S-8521B51MC-AUKT2x
S-8521B53MC-AUMT2x
S-8521B60MC-AUTT2x
−
−
−
−
−
S-8521A25MC-AXKT2x
S-8521C25MC-BTKT2x
−
−
S-8521A27MC-AXMT2x
S-8521A28MC-AXNT2x
S-8521A29MC-AXOT2x
S-8521A30MC-AXPT2x
S-8521A31MC-AXQT2x
S-8521A32MC-AXRT2x
S-8521A33MC-AXST2x
S-8521A34MC-AXTT2x
S-8521A35MC-AXUT2x
S-8521A36MC-AXVT2x
−
S-8521C27MC-BTMT2x
S-8521C28MC-BTNT2x
S-8521C29MC-BTOT2x
S-8521C30MC-BTPT2x
S-8521C31MC-BTQT2x
S-8521C32MC-BTRT2x
S-8521C33MC-BTST2x
S-8521C34MC-BTTT2x
S-8521C35MC-BTUT2x
S-8521C36MC-BTVT2x
−
−
−
S-8521A50MC-AYJT2x
S-8521C50MC-BUJT2x
−
−
−
−
−
−
Table 2 (2 / 2)
Output voltage [V]
S-8521DxxMC Series
S-8521ExxMC Series
S-8521FxxMC Series
1.5
1.6
1.7
1.8
1.9
2.0
2.1
2.2
2.5
2.7
2.8
2.9
3.0
3.1
3.2
3.3
3.4
3.5
3.6
4.0
4.2
4.5
5.0
5.2
5.3
5.5
−
S-8521E15MC-BLAT2x
S-8521E16MC-BLBT2x
S-8521E17MC-BLCT2x
S-8521E18MC-BLDT2x
S-8521E19MC-BLET2x
S-8521E20MC-BLFT2x
S-8521F15MC-BPAT2x
S-8521D16MC-BXBT2x
−
S-8521D18MC-BXDT2x
−
−
S-8521F18MC-BPDT2x
S-8521F19MC-BPET2x
−
S-8521D20MC-BXFT2x
S-8521D21MC-BXGT2x
S-8521D22MC-BXHT2x
S-8521D25MC-BXKT2x
S-8521D27MC-BXMT2x
S-8521D28MC-BXNT2x
S-8521D29MC-BXOT2x
S-8521D30MC-BXPT2x
S-8521D31MC-BXQT2x
S-8521D32MC-BXRT2x
S-8521D33MC-BXST2x
S-8521D34MC-BXTT2x
S-8521D35MC-BXUT2x
S-8521D36MC-BXVT2x
S-8521D40MC-BXZT2x
−
−
−
−
−
S-8521E22MC-BLHT2x
S-8521E25MC-BLKT2x
S-8521F25MC-BPKT2x
−
−
−
−
−
−
S-8521E30MC-BLPT2x
S-8521F30MC-BPPT2x
−
−
−
S-8521F32MC-BPRT2x
S-8521F33MC-BPST2x
S-8521F34MC-BPTT2x
S-8521E33MC-BLST2x
－
S-8521E35MC-BLUT2x
−
−
−
S-8521F36MC-BPVT2x
S-8521F40MC-BPZT2x
S-8521E42MC-BMBT2x
−
−
S-8521D45MC-BYET2x
S-8521D50MC-BYJT2x
S-8521D52MC-BYLT2x
−
−
S-8521E50MC-BMJT2x
S-8521F50MC-BQJT2x
−
−
−
S-8521E53MC-BMMT2x
S-8521D55MC-BYOT2x
−
S-8521F55MC-BQOT2x
Remark 1. Please contact our sales office for products with output voltage other than those specified above.
2. x: G or U
3. Please select products of environmental code = U for Sn 100%, halogen-free products.
6
STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER
Rev.9.0_01
S-8520/8521 Series
Pin Configuration
Table 3
SOT-23-5
Top view
Pin No.
1
Symbol
Description
Shutdown pin
“H”: Normal operation
5
4
______
(Step-down operation)
“L”: Stop step-down operation
(All circuits stop)
ON/OFF
2
3
4
5
VSS
VOUT
EXT
GND pin
Output voltage monitoring pin
Connection pin for external transistor
IC power supply pin
VIN
1
2
3
Figure 3
7
STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER
S-8520/8521 Series
Rev.9.0_01
Absolute Maximum Ratings
Table 4
(Ta = +25°C unless otherwise specified)
Item
Symbol
VIN
VOUT
Absolute maximum rating
VSS − 0.3 to VSS + 12.0
VSS − 0.3 to VSS + 18.0
VSS − 0.3 to VSS + 12.0
VSS − 0.3 to VSS + 18.0
VSS − 0.3 to VSS + 12.0
VSS − 0.3 to VSS + 18.0
VSS − 0.3 to VIN + 0.3
50
Unit
V
A, C, E types
VIN pin voltage
B, D, F types
V
A, C, E types
VOUT pin voltage
V
B, D, F types
V
______
______
A, C, E types
V
OFF
VON/
ON/OFF pin voltage
B, D, F types
V
EXT pin voltage
EXT pin current
VEXT
IEXT
V
mA
mW
mW
°C
°C
250 (When not mounted on board)
600*1
Power dissipation
PD
Operating ambient temperature
Storage temperature
Topr
Tstg
−40 to +85
−40 to +125
*1. When mounted on board
[Mounted 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 not be exceeded under any conditions.
(1) When mounted on board
(2) When not mounted on board
700
300
600
500
400
300
200
250
200
150
100
50
100
0
0
0
50
Ambient Temperature (Ta) [°C]
Figure 4 Power Dissipation of Package
100
150
0
50
100
150
Ambient Temperature (Ta) [°C]
8
STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER
Rev.9.0_01
S-8520/8521 Series
Electrical Characteristics
1. A type, B type
Table 5
(Ta = +25°C unless otherwise specified)
Test
Circuit
Item
Output voltage*1
Input voltage
Symbol
VOUT(E)
Conditions
Min.
Typ.
Max. Unit
VOUT(S)
× 0.976
2.5
VOUT(S)
× 1.024
−
VOUT(S)
V
3
A type
B type
−
−
35
10.0
16.0
60
V
V
2
2
2
VIN
−
2.5
Current consumption 1
Current consumption
during shutdown
ISS1
ISSS
VOUT = VOUT(S) × 1.2
−
μA
______
OFF
−
−
0.5
μA
2
VON/
= 0 V
S-8520/8521x15 to 24 −2.3
S-8520/8521x25 to 34 −3.7
VEXT = VIN − 0.4 V S-8520/8521x35 to 44 −5.3
S-8520/8521x45 to 54 −6.7
−4.5
−7.0
−9.3
−
−
−
−
−
−
−
−
−
mA
mA
mA
mA
mA
mA
mA
mA
mA
mA
mV
mV
mV
−
−
−
−
−
−
−
−
−
−
3
3
3
IEXTH
−11.3
−13.3
+8.4
+13.2
+17.5
+21.4
+25.1
30
S-8520/8521x55 to 60 −8.0
S-8520/8521x15 to 24 +4.3
S-8520/8521x25 to 34 +7.0
S-8520/8521x35 to 44 +9.9
S-8520/8521x45 to 54 12.6
S-8520/8521x55 to 60 +15.0
EXT pin output current
IEXTL
VEXT = 0.4 V
−
VOUT(S) ≤ 2.0 V VIN = 2.5 V to 2.94 V
VOUT(S) > 2.0 V VIN = VOUT(S) × 1.2 to 1.4
Load current = 10 μA to IOUT × 1.25
−
−
−
60
60
60
Line regulation
ΔVOUT1
30
Load regulation
ΔVOUT2
ΔVOUT
ΔTa
30
Output voltage
temperature coefficient
VOUT(S)
× 5E − 5
180
Ta = −40°C to +85°C
−
−
V/°C
3
VOUT(S) ≤ 2.4 V
VOUT(S) ≥ 2.5 V
144
153
216
207
kHz
kHz
3
3
Measure waveform at
EXT pin.
Oscillation frequency
fosc
180
PWM / PFM control
switching duty ratio
PFMDuty No load, measure waveform at EXT pin.
15
25
40
%
3
(S-8521 Series)
OFF
ON/
pin
VSH
VSL
ISH
ISL
Determine oscillation at EXT pin
1.8
−
−
−
−
V
2
2
1
1
3
input voltage
OFF
Determine oscillation stop at EXT pin
0.3
0.1
0.1
16.0
V
ON/
pin
−
−
−
−0.1
−0.1
4.0
−
μA
μA
ms
input leakage current
−
8.0
Soft start time
Overload detection time
(A type)
tss
Time until the EXT pin reaches VIN after
dropping VOUT to 0 V.
tpro
2.0
4.0
93
8.0
ms
%
2
3
Efficiency
EFFI
−
−
−
External parts
Coil:
Sumida Corporation CD54 (47 μH)
Diode:
Matsushita Electric Industrial Co., Ltd. MA720 (Shottky type)
Capacitor:
Transistor:
Matsushita Electric Industrial Co., Ltd. TE (16 V, 22 μF tantalum type)
Toshiba Corporation 2SA1213
Base resistance (Rb): 0.68 kΩ
Base capacitor (Cb): 2200 pF (Ceramic type)
Unless otherwise indicated, connect the recommended components to the IC. When VIN = VOUT(S) × 1.2 V (VIN = 2.5 V
______
when VOUT(S) ≤ 2.0 V), IOUT = 120 mA, connect the ON/OFF pin to the VIN pin.
*1.
VOUT(S): Specified output voltage value, VOUT(E): Actual output voltage value
9
STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER
S-8520/8521 Series
Rev.9.0_01
2. C type, D type
Table 6
(Ta = +25°C unless otherwise specified)
Test
Circuit
Item
Symbol
Conditions
Min.
Typ.
Max. Unit
VOUT(S)
× 0.976
2.5
VOUT(S)
× 1.024
10.0
16.0
21
Output voltage*1
Input voltage
VOUT(E)
−
VOUT(S)
V
3
C type
D type
−
−
10
V
V
2
2
2
VIN
−
2.5
Current consumption 1
Current consumption
during shutdown
ISS1
ISSS
VOUT = VOUT(S) × 1.2
−
μA
______
OFF
−
−
0.5
μA
2
VON/
= 0 V
S-8520/8521x15 to 24 −2.3
S-8520/8521x25 to 34 −3.7
VEXT = VIN − 0.4 V S-8520/8521x35 to 44 −5.3
S-8520/8521x45 to 54 −6.7
−4.5
−7.0
−9.3
−11.3
−13.3
+8.4
+13.2
+17.5
+21.4
+25.1
30
−
−
−
−
−
−
−
−
−
mA
mA
mA
mA
mA
mA
mA
mA
mA
mA
mV
mV
mV
−
−
−
−
−
−
−
−
−
−
3
3
3
IEXTH
S-8520/8521x55 to 60 −8.0
S-8520/8521x15 to 24 +4.3
S-8520/8521x25 to 34 +7.0
S-8520/8521x35 to 44 +9.9
S-8520/8521x45 to 54 +12.6
S-8520/8521x55 to 60 +15.0
EXT pin output current
IEXTL
VEXT = 0.4 V
−
VOUT(S) ≤ 2.0 V VIN = 2.5 V to 2.94 V
VOUT(S) > 2.0 V VIN = VOUT(S) × 1.2 to 1.4
Load current = 10 μA to IOUT × 1.25
−
−
−
60
60
60
Line regulation
ΔVOUT1
30
Load regulation
ΔVOUT2
ΔVOUT
ΔTa
30
Output voltage
temperature coefficient
VOUT(S)
× 5E − 5
60
Ta = −40°C to +85°C
−
−
V/°C
3
VOUT(S) ≤ 2.4 V
VOUT(S) ≥ 2.5 V
45
48
75
72
kHz
kHz
3
3
Measure waveform at
EXT pin.
Oscillation frequency
fosc
60
PWM / PFM control
switching duty ratio
PFMDuty No load, measured waveform at EXT pin.
15
25
40
%
3
(S-8521 Series)
OFF
ON/
pin
VSH
VSL
ISH
ISL
Determine oscillation at EXT pin
1.8
−
−
−
−
V
2
2
1
1
3
input voltage
OFF
Determine oscillation stop at EXT pin
0.3
0.1
0.1
24.0
V
ON/
pin
−
−
−
−0.1
−0.1
6.0
−
μA
μA
ms
input leakage current
−
12.0
Soft start time
Overload detection time
(C type)
tss
Time until the EXT pin reaches VIN after
dropping VOUT to 0 V.
tpro
7.0
14.0
93
28.0
ms
%
2
3
Efficiency
EFFI
−
−
−
External parts
Coil:
Sumida Corporation CD54 (47 μH)
Diode:
Matsushita Electric Industrial Co., Ltd. MA720 (Shottky type)
Capacitor:
Transistor:
Matsushita Electric Industrial Co., Ltd. TE (16 V, 22 μF tantalum type)
Toshiba Corporation 2SA1213
Base resistance (Rb): 0.68 kΩ
Base capacitor (Cb): 2200 pF (Ceramic type)
Unless otherwise indicated, connect the recommended components to the IC. When VIN = VOUT(S) × 1.2 V (VIN = 2.5 V
______
when VOUT(S) ≤ 2.0 V), IOUT = 120 mA, connect the ON/OFF pin to the VIN pin.
*1.
VOUT(S): Specified output voltage value, VOUT(E): Actual output voltage value
10
STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER
Rev.9.0_01
S-8520/8521 Series
3. E type, F type
Table 7
(Ta = +25°C unless otherwise specified)
Test
Circuit
Item
Output voltage*1
Input voltage
Symbol
VOUT(E)
Conditions
Min.
Typ.
Max. Unit
VOUT(S)
× 0.976
2.5
VOUT(S)
× 1.024
−
VOUT(S)
V
3
E type
F type
−
−
60
10.0
16.0
100
V
V
2
2
2
VIN
−
2.5
Current consumption 1
Current consumption
during shutdown
ISS1
ISSS
VOUT = VOUT(S) × 1.2
−
μA
______
OFF
−
−
0.5
μA
2
VON/
= 0 V
S-8520/8521x15 to 24 −2.3
S-8520/8521x25 to 34 −3.7
VEXT = VIN − 0.4 V S-8520/8521x35 to 44 −5.3
S-8520/8521x45 to 54 −6.7
−4.5
−7.0
−9.3
−
−
−
−
−
−
−
−
−
mA
mA
mA
mA
mA
mA
mA
mA
mA
mA
mV
mV
mV
−
−
−
−
−
−
−
−
−
−
3
3
3
IEXTH
−11.3
−13.3
+8.4
+13.2
+17.5
+21.4
+25.1
30
S-8520/8521x55 to 60 −8.0
S-8520/8521x15 to 24 +4.3
S-8520/8521x25 to 34 +7.0
S-8520/8521x35 to 44 +9.9
S-8520/8521x45 to 54 +12.6
S-8520/8521x55 to 60 +15.0
EXT pin output current
IEXTL
VEXT = 0.4 V
−
VOUT(S) ≤ 2.0 V VIN = 2.5 V to 2.94 V
VOUT(S) > 2.0 V VIN = VOUT(S) × 1.2 to 1.4
Load current = 10 μA to IOUT × 1.25
−
−
−
60
60
60
Line regulation
ΔVOUT1
30
Load regulation
ΔVOUT2
ΔVOUT
ΔTa
30
Output voltage
temperature coefficient
VOUT(S)
× 5E − 5
300
Ta = −40°C to +85°C
−
−
V/°C
3
VOUT(S) ≤ 2.4 V
VOUT(S) ≥ 2.5 V
225
240
375
360
kHz
kHz
3
3
Measure waveform at
EXT pin.
Oscillation frequency
fosc
300
PWM / PFM control
switching duty ratio
PFMDuty No load, measure waveform at EXT pin.
15
25
40
%
3
(S-8521 Series)
OFF
ON/
pin
VSH
VSL
ISH
ISL
Determine oscillation at EXT pin
1.8
−
−
−
−
V
2
2
1
1
3
input voltage
OFF
Determine oscillation stop at EXT pin
0.3
0.1
0.1
9.2
V
ON/
pin
−
−
−
−0.1
−0.1
2.0
−
μA
μA
ms
input leakage current
−
4.5
Soft start time
Overload detection time
(E type)
tss
Time until the EXT pin reaches VIN after
dropping VOUT to 0 V.
tpro
1.3
2.6
90
4.5
ms
%
2
3
Efficiency
EFFI
−
−
−
External parts
Coil:
Sumida Corporation CD54 (47 μH)
Diode:
Matsushita Electric Industrial Co., Ltd. MA720 (Shottky type)
Capacitor:
Transistor:
Matsushita Electric Industrial Co., Ltd. TE (16 V, 22 μF tantalum type)
Toshiba Corporation 2SA1213
Base resistance (Rb): 0.68 kΩ
Base capacitor (Cb): 2200 pF (Ceramic type)
Unless otherwise indicated, connect the recommended components to the IC. When VIN = VOUT(S) × 1.2 V (VIN = 2.5 V
______
when VOUT(S) ≤ 2.0 V), IOUT = 120 mA, connect the ON/OFF pin to the VIN pin.
*1.
VOUT(S): Specified output voltage value, VOUT(E): Actual output voltage value
11
STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER
S-8520/8521 Series
Rev.9.0_01
Test Circuit
open
EXT
1.
open
VOUT
VIN
_____
A
ON/OFF
VSS
Figure 5
2.
A
VIN
EXT
VSS
VOUT
+
−
_____
ON/OFF
Figure 6
3.
0.68 kΩ
2200 pF
VOUT
EXT
VIN
+
−
+
−
_____
V
ON/OFF
VSS
Figure 7
12
STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER
Rev.9.0_01
S-8520/8521 Series
Operation
1. Switching control method
1. 1 PWM control (S-8520 Series)
The S-8520 Series is a DC-DC converter using a pulse width modulation method (PWM) and features a low
current consumption.
In conventional PFM DC-DC converters, pulses are skipped when the output load current is low, causing a
fluctuation in the ripple frequency of the output voltage, resulting in an increase in the ripple voltage.
The switching frequency does not change, although the pulse width changes from 0 to 100% corresponding to
each load current. The ripple voltage generated from switching can thus be removed easily through a filter
because the switching frequency is constant. And the ripple voltage will be skipped to be low current
consumption when the pulse width is 0% or it is no load, input current voltage is high.
1. 2 PWM / PFM switching control (S-8521 Series)
S-8521 Series is a DC-DC converter that automatically switches between a pulse width modulation method
(PWM) and a pulse frequency modulation method (PFM), depending on the load current, and features low
current consumption.
The S-8521 Series operates under PWM control with the pulse width duty changing from 25 to 100% in a high
output load current area.
The S-8521 Series operates under PFM control with the pulse width duty fixed at 25%, and pulses are skipped
according to the load current. The oscillation circuit thus oscillates intermittently so that the resultant lower self
current consumption prevents a reduction in the efficiency at a low load current. The switching point from PWM
control to PFM control depends on the external devices (coil, diode, etc.), input voltage and output voltage.
The S-8521 Series is an especially highly efficient DC-DC converter at an output current around 100 μA.
13
STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER
S-8520/8521 Series
Rev.9.0_01
2. Soft start function
The S-8520/8521 Series has a built-in soft start-circuit. This circuit enables the output voltage (VOUT) to rise
______
gradually over the specified soft start time (t), when power-on or when the ON/OFF pin is at the “H” level. This
prevents the output voltage from overshooting.
However, the soft-start function of this IC is not able to perfectly prevent a rush current from flowing to the load
(Refer to Figure 8). Since this rush current depends on the input voltage and load conditions, Perform sufficient
evaluation with actual device for design.
S-8520A33MC (VIN: 0 V→4.0 V)
3 V
VOUT
[1 V/div]
0 V
1.5 A
Rush current
[0.5 A/div]
0 A
t [1 ms/div]
Figure 8 Waveforms of output voltage and rush current at soft start
_______
3. ON/OFF pin (Shutdown pin)
______
The ON/OFF pin stops or starts step-up operation.
______
Setting the ON/OFF pin to the “L” level stops operation of all the internal circuits and reduces current consumption
significantly. The EXT pin’s voltage is set to the VIN voltage level so that the switching transistor is turned off.
______
Do not use the ON/OFF pin in a floating state because it has the structure shown in Figure 9 and is not pulled up
______
or pulled down internally. Do not apply a voltage of between 0.3 V and 1.8 V to the ON/OFF pin because applying
______
such a voltage increases the current consumption. When not using the ON/OFF pin, connect it to the VIN pin.
Table 8
_____
ON/OFF pin
CR Oscillation Circuit
Operation
Output voltage
Set value
VSS
“H”
“L”
Stop
VIN
_____
ON/OFF
VSS
Figure 9
14
STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER
Rev.9.0_01
S-8520/8521 Series
4. Overload protection circuit (A, C, E types)
The A, C and E types of the S-8520/8521 Series have a built-in overload protection circuit.
If the output voltage drops under the overload status, the maximum duty status (100%) continues. If this 100% duty
status lasts longer than the overload detection time (tpro), the circuit keeps the EXT pin at “H” to protect the
switching transistor and inductor. When the overload protection circuit is functioning, the soft start works in the IC
for the reference voltage, and the reference voltage rises slowly from 0 V. The reference voltage and the feedback
voltage obtained by dividing the output voltage are compared to each other. While the reference voltage is low, the
EXT pin keeps “H” and oscillation stops. If the reference voltage rises and exceeds the feedback voltage, oscillation
restarts.
After oscillation is restarted, if a load is heavy and the EXT pin keeps the “L” level longer than the overload
detection time (tpro), the circuit operates again, and the IC enters the intermittent operation mode by repeating the
action described above. Once the overload state is off, the IC restarts the normal operation.
Waveforms
at EXT pin
Protection circuit ON
Overload detection time (tpro
)
[tss × 0.3]
Figure 10 Waveforms at EXT pin when the overload protection circuit operates
5. 100% duty cycle
The S-8520/8521 Series operates with a maximum duty cycle of 100%. When using the B, D and F types products,
which do not have the overload protection circuit, the switching transistor keeps ON continually to supply current to
the load, even in cases where the input voltage drops to the set value of output voltage or less. The output voltage
in this case is; the voltage subtracting both of the inductance’s DC resistance and the voltage drop by the switching
resistor’s ON-resistance, from the input voltage.
The A, C and E types that have the overload protection circuit cannot be used for continually supplying current to
the load, as described above, because these types enter the intermittent operation mode by the overload protection
circuit’s operation, when 100% duty lasts longer than the overload detection time (tpro).
15
STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER
S-8520/8521 Series
Rev.9.0_01
Selection of Products and External Parts
1. Method for selecting series products
The S-8520/8521 Series is classified into 12 types, according to the control systems (PWM control and PWM / PFM
switching control), the different oscillation frequencies, and set-up of an overload protection circuit. Please select
the type for your application according to the following features.
1. 1 Control systems
Two different control systems are available: PWM control system (S-8520 Series) and PWM / PFM switching
control system (S-8521 Series).
For applications for which the load current greatly differs between standby and operation, if the efficiency during
standby is important, applying the PWM/PFM switching system (S-8321 Series) realizes high efficiency during
standby.
For applications for which switching noise is critical, applying the PWM control system (S-8320 Series) whereby
switching frequency does not change due to load current allows the ripple voltage to be easily suppressed by
using a filter.
1. 2 Oscillation frequencies
Either oscillation frequency, 180 kHz (A and B types), 60 kHz (C and D types), or 300 kHz (E and F types), can
be selected.
The A, B, E and F types have high oscillation frequency, how ripple voltage and excellent transient response
characteristics. A small inductance can be used for these types because the peak current is low when inducing
the same load current. Use of small output capacitors is effective for downsizing devices.
The C and D types, whereby lower oscillation frequency realizes smaller self-consumption current, are highly
efficient under light loads. In particular, the D type, when combined with a PWM/PFM switching control system,
drastically improves the operation efficiency when the output load current is approximately 100 mA.
16
STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER
Rev.9.0_01
S-8520/8521 Series
1. 3 Overload protection circuit
Types are selectable the S-8520/8521 Series with the overload protection circuit (A, C and E types) or without
the overload protection circuit (B, D and F types).
By the S-8520/8521 Series with the overload protection circuit (A, C and E types), the switching components
and inductor can be protected because the overload protection circuit works and is set to the intermittent mode,
in case of overload or load short-circuit.
But in case of supplying current to load by using 100% duty cycle, select the S-8520/8521 Series without the
overload protection circuit (B, D and F types), according to the conditions of application.
The operation voltage differs in 10 V (A, B and E types) or 16 V (B, D and F types) whether the overload
protection circuit is available or not.
Table 9 shows items for selecting the type according to the requirements of application. Select it matching the
marks () for your requirement.
Table 9
S-8520 Series
S-8521 Series
Item
A
B
C
D
E
F
A
B
C
D
E
F
The need of overload protection circuit
Input voltage exceeds 10 V
Focusing on efficiency of light load status
(1 mA or less)
Using with middle load current (about 200
mA)
Using with large load current (about 1 A)
Focusing on the low ripple voltage
Focusing on downsizing external parts
Remark : Indispensable condition
: Superiority of requirement
: Particularly superiority of requirement
17
STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER
S-8520/8521 Series
Rev.9.0_01
2. Inductor
The inductance value (L value) has a strong influence on the maximum output current (IOUT) and efficiency (η).
The peak current (IPK) increases by decreasing L value and the stability of the circuit improves and IOUT increases. If
L value is decreased, the efficiency falls causing a decline in the current drive capacity for the switching transistor,
and IOUT decreases.
The loss of IPK by the switching transistor decreases by increasing L and the efficiency becomes the maximum at a
certain L value. Further increasing L value decreases the efficiency due to the loss of the direct current resistance
of the coil. IOUT also decreases.
For the S-8520/8521 Series, increasing the inductance value, the output voltage may be unstable in some cases,
depending on the conditions of the input voltage, output voltage, and the load current. Perform sufficient evaluation
under the actual condition and decide an optimum inductance value.
The recommended inductances are 47 μH for A, B, C, D types and 22 μH for E, F types.
Be careful of the allowable inductor current when choosing an inductor. Exceeding the allowable current of the
inductor causes magnetic saturation, much lower efficiency and destruction of the IC chip due to a large current.
Choose an inductor so that IPK does not exceed the allowable current. IPK in continuous mode is calculated by the
following equation:
(VOUT + VF*2 ) × (VIN − VOUT
)
I
PK = IOUT +
*2
2 × fosc*1 × L × (VIN + VF
)
*1. fosc: Oscillation frequency
*2. VF: Forward voltage of the diode
3. Diode
Use an external diode that meets the following requirements :
• Its forward voltage is low (Schottky barrier diode is recommended).
• Its switching speed is high (50 ns max.).
• Its reverse direction voltage is higher than VIN.
• Its current rating is higher than IPK
.
4. Capacitors (CIN, COUT
)
A capacitor for the input (CIN) improves efficiency by reducing power impedance and stabilizing the input current.
Select the CIN value according to impedance of the power supply to be used. Approximately 47 to 100 μF is
recommended for the capacitor depending on impedance of the power source and load current value.
For a capacitor for output (CL), select a large capacitance with low ESR (Equivalent Series Resistance) for
smoothing the ripple voltage. However, capacitor with extremely small ESR such as ceramic capacitor (about 0.3
Ω or less) may destabilize the output voltage, according to the conditions of input and output voltages. A
tantalum electrolyte capacitor is recommended. 47 μF to 100 μF is recommended for the capacitor.
18
STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER
Rev.9.0_01
S-8520/8521 Series
5. External transistor
Enhancement (Pch) MOS FET or bipolar (PNP) MOS FET can be used for external transistor.
5. 1 Enhancement (Pch) MOS FET type
The EXT pin of the S-8520/8521 Series is capable of directly driving a Pch MOS FET with a gate capacity
around 1000 pF.
When using a Pch MOS FET, 2 to 3% higher efficiency is provided because its switching speed is faster and it
does not cause power dissipation, compared to PNP bipolar transistors.
The important parameters in selecting MOS FETs are the threshold voltage, the breakdown voltage between
gate and source, the breakdown voltage between drain and source, the total gate capacity, the on-resistance,
and the current ratings.
The EXT pin swings from voltages between VIN to VSS. If the input voltage is low, use a MOS FET with the low
threshold voltage. If the input voltage is high, use a MOS FET having the breakdown voltage between gate and
source higher several volts than the input voltage.
Immediately after the power-on or power-off (stopping the step-down operation), the input voltage will be applied
between drain and source of the MOS FET. Use the breakdown voltage between drain and source also higher
several volts than the input voltage.
The total gate capacity and the on-resistance affect efficiency.
Power dissipation when charging and discharging the gate capacity by switching operation affects efficiency, in
the area of low load current, as the total gate capacity is larger and the input voltage is higher. Select a MOS
FET with a small total gate capacity for efficiency at light load.
In the area of large load current, efficiency is affected by power dissipation caused by MOS FET’s on-resistance.
For efficiency at large load, select a MOS FET having as low on-resistance as possible.
As for the current rating, select a MOS FET having the maximum continuous drain current rating higher than IPK
.
For reference, this document has the data of efficiency. TM6201 by Toyota Industries Corporation for
applications with an input voltage of 10 V or less, IRF7606 by International Rectifier Corporation Japan for
applications with an input voltage over 10 V (Refer to “ Reference Data”).
19
STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER
S-8520/8521 Series
Rev.9.0_01
5. 2 Bipolar PNP type
Figure 11 shows the sample of circuit diagram using Toshiba Corporation 2SA1213 as the bipolar transistor
(PNP). The hFE value and the Rb value of that bipolar transistor determine the driving capacity, which is used for
increasing the output current.
Toshiba Corporation
2SA1213
VIN
Rb
Cb
EXT
VIN
Figure 11
The Rb value is given by the following equation:
VIN − 0.7
0.4
Rb =
−
Ib
IEXTL
IPK
hFE
Calculate the necessary base current (Ib) using the (hFE) value of bipolar transistor by the equation, Ib =
and select a smaller Rb value.
,
A small Rb value increases the output current, but it also decreases efficiency. Determine the optimum value
through experiment, since the base current may flow on the pulse, or voltage may drop due to wiring resistance.
In addition, if speed-up capacitor Cb is connected in parallel with resistor Rb, as shown in Figure 11, the loss in
switching will be reduced, leading to higher efficiency.
Determine the Cb value using the following equation:
1
Cb ≤
2 × π × Rb × fosc × 0.7
Select the Cb value after performing sufficient evaluation since the optimum Cb value differs depending upon the
characteristics of the bipolar transistor.
20
STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER
Rev.9.0_01
S-8520/8521 Series
Standard Circuits
1. Using a bipolar transistor
L
Tr
VIN
Oscillation
circuit
Reference voltage
source with soft start
VOUT
Rb
Cb
EXT
+
PWM control or
PWM / PFM switching
control circuit
+
COUT
+
−
SD
VIN
CIN
______
VON/
______
OFF
ON/OFF
VSS
Figure 12
2. Using a Pch MOS FET transistor
L
Tr
VIN
Oscillation
circuit
Reference voltage
source with soft start
VOUT
EXT
+
PWM control or
PWM / PFM switching
control circuit
+
COUT
+
CIN
SD
−
VIN
______
VON/
______
OFF
ON/OFF
VSS
Figure 13
Caution The above connection diagram and constant will not guarantee successful operation. Perform
through evaluation using the actual application to set the constant.
21
STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER
S-8520/8521 Series
Rev.9.0_01
Precautions
• Mount the external capacitors, the diode and the coil as close as possible to the IC, and secure grounding at a
single location.
• Characteristics ripple voltage and spike noise occur in IC containing switching regulators. Moreover, rush current
flows at the time of a power supply injection. Because these largely depend on the coil, the capacitor and
impedance of power supply used, fully check them using an actually mounted model.
• The overload protection circuit of this IC performs the protective function by detecting the maximum duty time
(100 %). In choosing the components, make sure that over currents generated by short-circuits in the load, etc.,
will not surpass the allowable dissipation of the switching transistor and inductor.
• Make sure that dissipation of the switching transistor (especially at a high temperature) does not exceed the
allowable 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.
• SII Semiconductor Corporation claims no responsibility for any and all disputes arising out of or in connection with
any infringement by products including this IC of patents owned by a third party.
22
STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER
Rev.9.0_01
S-8520/8521 Series
Application Circuits
1. External adjustment of output voltage
In the S-8550/8521 Series, by adding external resistors (RA, RB) and a capacitor (CFB), the output voltage can be
adjusted or be set freely in the range of 1.5 to 6.0 V, as shown in Figure 14. Temperature gradient can be given by
inserting a thermistor in series to RA and RB.
OUT
EXT
CC
RA
S-8520/8521 Series
VIN
VOUT
R1
R2
PWM control or PWM /
+
−
+
−
RB
+
−
D1
PFM switching control unit
Reference voltage
source with soft start
Oscillation
Circuit
______
ON/OFF
VSS
Figure 14
Caution The above connection diagram and constant will not guarantee successful operation. Perform
through evaluation using the actual application to set the constant.
The S-8520/8521 Series have an internal impedance of R1 and R2 between the VOUT pin and the VSS pin, as
shown in Figure 14.
Therefore, OUT (the output voltage) is determined by the output voltage value (VOUT) of the S-8520/8521 Series,
and the ratio of the parallel resistance value of external resistance (RB) and internal resistances (R1 + R2) of the IC,
to external resistance (RA). The output voltage is expressed by the following equation:
OUT = VOUT + VOUT × RA ÷ (RB //*1(R1 + R2))
*1. // shows the combined resistance in parallel.
The voltage accuracy of the OUT set by resistances (RA and RB) is not only affected by the IC’s output voltage
accuracy (VOUT 2.4 %), but also by the absolute precision of external resistances (RA and RB) in use and the
absolute value deviations of internal resistances (R1 and R2) in the IC.
Let us designate the maximum deviations of the absolute value of RA and RB by RA max. and RB max., respectively,
the minimum deviations by RA min. and RB min., respectively, and the maximum and minimum deviations of the
absolute value of R1 and R2 in the IC by (R1 + R2) max. and (R1 + R2) min., respectively. Then, the minimum
deviation value OUT min. and the maximum deviation value OUT max. of the OUT are expressed by the following
equations:
OUT min. = VOUT × 0.976 + VOUT × 0.976 × RA min. ÷ (RB max. // (R1 + R2) max.)
OUT max. = VOUT × 1.024 + VOUT × 1.024 × RA max. ÷ (RB min. // (R1 + R2) min.)
23
STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER
S-8520/8521 Series
Rev.9.0_01
The voltage accuracy of the OUT cannot be made higher than the output voltage accuracy (VOUT 2.4%) of the IC
itself, without adjusting the RA and RB involved. The closer the voltage value of the output OUT and the output
voltage value (VOUT) of the IC are brought to one other, the more the output voltage remains immune to deviations
in the absolute accuracy of RA and RB and the absolute value of R1 and R2 in the IC. In particular, to suppress the
influence of deviations in R1 and R2 in the IC, a major contributor to deviations in the OUT, the RA and RB must be
limited to a much smaller value than that of R1 and R2 in the IC.
On the other hand, a reactive current flows through RA and RB. This reactive current must be reduced to a
negligible value with respect to the load current in the actual use of the IC so that the efficiency characteristics will
not be degraded. This requires that the value of RA and RB be made sufficiently large.
However, too large a value (more than 1 MΩ) for the RA and RB would make the IC vulnerable to external noise.
Check the influence of this value on actual equipment.
There is a tradeoff between the voltage accuracy of the OUT and the reactive current. This should be taken into
consideration based on the requirements of the intended application.
Deviations in the absolute value of the internal resistances (R1 and R2) in the IC vary with the output voltage of the
S-8520/8521 Series, and are broadly classified as follows:
Table 10
Output voltage
1.5 V to 2.0 V
2.1 V to 2.5 V
2.6 V to 3.3 V
3.4 V to 4.9 V
5.0 V to 6.0 V
Deviations in the absolute value of R1 and R2 in the IC
5.16 MΩ to 28.9 MΩ
4.44 MΩ to 27.0 MΩ
3.60 MΩ to 23.3 MΩ
2.44 MΩ to 19.5 MΩ
2.45 MΩ to 15.6 MΩ
When a value of R1 + R2 given by the equation indicated below is taken in calculating the voltage value of the
output OUT, a median voltage deviation will be obtained for the OUT.
R1 + R2 = 2 ÷ (1 ÷ maximum deviation in absolute value of R1 and R2 + 1 ÷ minimum deviation in absolute value
of R1 and R2)
Moreover, 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 14).
Make sure that CC is larger than the value given by the following equation:
CC [F] ≥ 1 ÷ (2 × π × RA [Ω] × 7.5 kHz)
If a large CC value is selected, a longer soft start time than the one set up in the IC will be set.
Caution The above connection diagram and constant will not guarantee successful operation. Perform
through evaluation using the actual application to set the constant.
24
STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER
Rev.9.0_01
S-8520/8521 Series
Characteristics (Typical Data)
1. Examples of major parameters characteristics
(1) Current consumption (ISS1)-Input voltage (VIN)
(fosc = 60 kHz)
(fosc = 180 kHz)
40
30
20
10
0
20
Ta = +25°C
15
Ta = +25°C
Ta = +85°C
Ta = −40°C
10
Ta = +85°C
5
Ta = −40°C
0
2
4
6
8
V
10
IN [V]
12
14
16
2
4
6
8
V
10
IN [V]
12
14
16
(fosc = 300 kHz)
60
50
40
30
20
10
0
Ta = +85°C
Ta = −40°C
Ta = +25°C
2
4
6
8
10
12
14
16
VIN [V]
(2) Oscillation frequency (fosc)-Input voltage (VIN)
(fosc = 60 kHz)
(fosc = 180 kHz)
220
210
200
190
80
75
70
Ta = +25°C
65
Ta = +25°C
Ta = +85°C
180
170
160
150
140
60
55
Ta = −40°C
50
Ta = +85°C
Ta = −40°C
45
40
2
4
6
8
V
10
IN [V]
12
14
16
2
4
6
8
10
12
14
16
VIN [V]
(fosc = 300 kHz)
360
340
320
300
280
260
240
Ta = +25°C
Ta = −40°C
Ta = +85°C
2
4
6
8
V
10
IN [V]
12
14
16
25
STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER
S-8520/8521 Series
Rev.9.0_01
(3) EXT pin output current “H” (IEXTH)-
Input voltage (VIN)
(4) EXT pin output current “L” (IEXTL)-
Input voltage (VIN)
60
50
40
30
20
10
0
−60
−50
−40
−30
−20
−10
0
Ta = −40°C
Ta = +25°C
Ta = +85°C
Ta = −40°C
Ta = +25°C
Ta = +85°C
2
4
6
8
V
10
IN [V]
12
14
16
2
4
6
8
V
10
IN [V]
12
14
16
(5) Soft start time (tSS)-Input voltage (VIN)
(fosc = 60 kHz)
(fosc = 180 kHz)
25
20
15
10
5
25
20
15
10
5
Ta = −40°C
Ta = +25°C
Ta = −40°C
Ta = +25°C
Ta = +85°C
Ta = +85°C
0
0
2
4
6
8
V
10
IN [V]
12
14
16
2
4
6
8
10
12
14
16
VIN [V]
(fosc = 300 kHz)
10
8
Ta = −40°C
Ta = +85°C
6
4
Ta = +25°C
2
0
2
4
6
8
10
12
14
16
VIN [V]
26
STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER
Rev.9.0_01
S-8520/8521 Series
(6) Overload detection time (tpro)-Input voltage (VIN)
(fosc = 60 kHz)
(fosc = 180 kHz)
30
8
7
6
5
4
3
2
26
22
Ta = +85°C
Ta = −40°C
Ta = +85°C
18
Ta = +25°C
14
Ta = −40°C
10
Ta = +25°C
6
2
4
6
8
10
12
14
16
2
4
6
8
10
IN [V]
12
14
16
VIN [V]
V
(fosc = 300 kHz)
4
3
2
1
Ta = +85°C
Ta = +25°C
Ta = −40°C
2
4
6
8
V
10
IN [V]
12
14
16
______
______
(7) ON/OFF pin input voltage “H” (VSH)-
(8) ON/OFF pin input voltage “L” (VSL)-
Input voltage (VIN)
Input voltage (VIN)
1.8
1.7
1.5
1.3
1.1
1.6
Ta = −40°C
Ta = +25°C
1.4
1.2
1.0
Ta = −40°C
Ta = +25°C
0.9
0.7
0.5
0.3
0.8
Ta = +85°C
0.6
0.4
Ta = +85°C
2
4
6
8
10
12
14
16
2
4
6
8
10
12
14
16
VIN [V]
VIN [V]
27
STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER
S-8520/8521 Series
Rev.9.0_01
(9) Output voltage (VOUT)-Input voltage (VIN)
S-8521B30MC
S-8521B50MC
(Ta = +25°C)
(Ta = +25°C)
5.08
5.07
5.06
5.05
5.04
5.03
5.02
5.01
5.00
4.99
3.08
3.07
3.06
3.05
3.04
3.03
3.02
3.01
3.00
2.99
2.98
IOUT = 0.1 mA
IOUT = 500 mA
IOUT = 0.1 mA
IOUT = 500 mA
IOUT = 100 mA
IOUT = 100 mA
4.98
2
2
4
6
8
10
12
14
16
4
6
8
10
12
14
16
VIN [V]
VIN [V]
S-8521F33MC
S-8521F50MC
(Ta = +25°C)
(Ta = +25°C)
3.38
3.37
3.36
3.35
3.34
3.33
3.32
3.31
3.30
3.29
5.07
5.06
5.05
5.04
5.03
5.02
5.01
5.00
4.99
4.98
4.97
IOUT = 0.1 mA
IOUT = 100 mA
IOUT = 0.1 mA
IOUT = 100 mA
IOUT = 500 mA
12 14 16
IOUT = 500 mA
12 14 16
3.28
2
4
6
8
10
2
4
6
8
10
VIN [V]
VIN [V]
28
STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER
Rev.9.0_01
S-8520/8521 Series
2. Transient Response Characteristics
2. 1 Power-on (IOUT: no load)
(1) S-8520/8521C30MC
(VIN = 0 V→3.6 V)
(VIN = 0 V→9.0 V)
10 V
10 V
VIN
VIN
[2.5 V/div]
[2.5 V/div]
0 V
3 V
0 V
3 V
VOUT
[1 V/div]
VOUT
[1 V/div]
0 V
0 V
t [2 ms/div]
t [1 ms/div]
t [1 ms/div]
t [2 ms/div]
(2) S-8520/8521A30MC
(VIN = 0 V→3.6 V)
(VIN = 0 V→9.0 V)
10 V
10 V
VIN
[2.5 V/div]
VIN
[2.5 V/div]
0 V
3 V
0 V
3 V
VOUT
[1 V/div]
VOUT
[1 V/div]
0 V
0 V
t [1 ms/div]
(3) S-8520/8521E33MC
(VIN = 0 V→4.0 V)
(VIN = 0 V→9.0 V)
10 V
10 V
VIN
[2.5 V/div]
VIN
[2.5 V/div]
0 V
3 V
0 V
3 V
VOUT
[1 V/div]
VOUT
[1 V/div]
0 V
0 V
t [1 ms/div]
29
STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER
S-8520/8521 Series
Rev.9.0_01
______
OFF
2. 2 Shutdown pin response (VON/
(1) S-8520/8521C30MC
= 0 V→1.8 V, IOUT = No load)
(VIN = 3.6 V)
(VIN = 9.0 V)
(VIN = 9.0 V)
(VIN = 9.0 V)
3 V
3 V
VON / OFF
[1 V/div]
VON / OFF
[1 V/div]
0 V
0 V
3 V
3 V
VOUT
[1 V/div]
VOUT
[1 V/div]
0 V
0 V
t [2 ms/div]
t [1 ms/div]
t [1 ms/div]
t [2 ms/div]
t [1 ms/div]
t [1 ms/div]
(2) S-8520/8521A30MC
(VIN = 3.6 V)
3 V
3 V
VON / OFF
[1 V/div]
VON / OFF
[1 V/div]
0 V
0 V
3 V
3 V
VOUT
[1 V/div]
VOUT
[1 V/div]
0 V
0 V
(3) S-8520/8521E33MC
(VIN = 4.0 V)
3 V
3 V
VON / OFF
[1 V/div]
0 V
VON / OFF
[1 V/div]
0 V
3 V
3 V
VOUT
[1 V/div]
VOUT
[1 V/div]
0 V
0 V
30
STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER
Rev.9.0_01
S-8520/8521 Series
2. 3 Supply voltage variation (VIN = 4 V→9 V, 9 V→4 V)
(1) S-8520/8521C30MC
(2) S-8520/8521C30MC
(IOUT = 10 mA)
(IOUT = 500 mA)
10 V
10 V
VIN
VIN
[2.5 V/div]
[2.5 V/div]
0 V
0 V
VOUT
[0.2 V/div]
VOUT
[0.2 V/div]
t [0.5 ms/div]
t [0.5 ms/div]
(3) S-8520/8521A30MC
(4) S-8520/8521A30MC
(IOUT = 10mA)
(IOUT = 500 mA)
10 V
10 V
VIN
[2.5 V/div]
VIN
[2.5 V/div]
0 V
0 V
VOUT
[0.2 V/div]
VOUT
[0.2 V/div]
t [0.5 ms/div]
t [0.5 ms/div]
(5) S-8520/8521E33MC
(6) S-8520/8521E33MC
(IOUT = 10 mA)
(IOUT = 500 mA)
10 V
10 V
VIN
VIN
[2.5 V/div]
[2.5 V/div]
0 V
0 V
VOUT
[0.2 V/div]
VOUT
[0.2 V/div]
t [0.5 ms/div]
t [0.5 ms/div]
31
STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER
S-8520/8521 Series
Rev.9.0_01
2. 4 Load variation
(1) S-8520/8521C30MC
(VIN = 3.6 V, IOUT = 0.1 mA→500 mA)
(VIN = 3.6 V, IOUT = 500 mA→0.1 mA)
500 mA
500 mA
IOUT
IOUT
0.1 mA
0.1 mA
VOUT
VOUT
[0.1 V/div]
[0.1 V/div]
t [0.1 ms/div]
t [5 ms/div]
(2) S-8520/8521A30MC
(VIN = 3.6 V, IOUT = 0.1 mA→500 mA)
(VIN = 3.6 V, IOUT = 500 mA→0.1 mA)
500 mA
IOUT
500 mA
IOUT
0.1 mA
0.1 mA
VOUT
VOUT
[0.1 V/div]
[0.1 V/div]
t [0.1 ms/div]
t [10 ms/div]
(3) S-8520/8521E33MC
(VIN = 4.0 V, IOUT = 0.1 mA→500 mA)
(VIN = 4.0 V, IOUT = 500 mA→0.1 mA)
500 mA
500 mA
IOUT
IOUT
0.1 mA
0.1 mA
VOUT
[0.1 V/div]
VOUT
[0.1 V/div]
t [0.1 ms/div]
t [5 ms/div]
32
STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER
Rev.9.0_01
S-8520/8521 Series
Reference Data
This reference data is intended to help you select peripheral components to be externally connected to the IC.
Therefore, this information provides recommendations on external components selected with a view to accommodating
a wide variety of IC applications. Characteristic data is duly indicated in the table below.
Table 11 External parts for efficiency data
Product name Output voltage
Inductor
Transistor Diode Output capacitor
Application
S-8520B30MC
S-8520F33MC
S-8520F33MC
3.0 V
CD105 / 47 μH
D62F / 22 μH
CDH113 / 22 μH IRF7606 MA737
MA737
MA720
47 μF
IOUT ≤ 1 A, VIN ≤ 10 V
IOUT ≤ 0.5 A, VIN ≤ 10 V
IOUT ≤ 1 A, VIN ≤ 16 V
TM6201
3.3 V
22 μF
IOUT ≤ 0.5 A, VIN ≤ 10 V,
With equipment standby mode
IOUT ≤ 0.5 A, VIN ≤ 16 V,
With equipment standby mode
IOUT ≤ 1 A, VIN ≤ 10 V,
S-8521D30MC
S-8521D30MC
S-8521B30MC
S-8521B30MC
S-8521F33MC
S-8521F33MC
TM6201
CD54 / 47 μH
MA720
MA737
47 μF × 2
47 μF
IRF7606
TM6201
IRF7606
3.0 V
3.3 V
With equipment standby mode
CD105 / 47 μH
D62F / 22 μH
IOUT ≤ 1 A, VIN ≤ 16 V,
With equipment standby mode
IOUT ≤ 0.5 A, VIN ≤ 10 V,
With equipment standby mode
IOUT ≤ 1 A, VIN ≤ 16 V,
TM6201 MA720
22 μF
CDH113 / 22 μH IRF7606 MA737
CD54 / 47 μH TM6201 MA720
CD105 / 47 μH IRF7606 MA737
D62F / 22 μH TM6201 MA720
CDH113 / 22 μH IRF7606 MA737
CD54 / 47 μH TM6201 MA720
With equipment standby mode
S-8520B50MC
S-8520B50MC
S-8520F50MC
S-8520F50MC
IOUT ≤ 0.5 A, VIN ≤ 10 V
IOUT ≤ 1 A, VIN ≤ 16 V
IOUT ≤ 0.5 A, VIN ≤ 10 V
IOUT ≤ 1 A, VIN ≤ 16 V
47 μF
22 μF
IOUT ≤ 0.5 A, VIN ≤ 10 V,
With equipment standby mode
IOUT ≤ 1 A, VIN ≤ 16 V,
With equipment standby mode
IOUT ≤ 0.5 A, VIN ≤ 10 V,
With equipment standby mode
IOUT ≤ 1 A, VIN ≤ 16 V,
With equipment standby mode
IOUT ≤ 0.5 A, VIN ≤ 10 V,
With equipment standby mode
IOUT ≤ 1 A, VIN ≤ 16 V,
S-8521D50MC
S-8521D50MC
S-8521B50MC
S-8521B50MC
S-8521F50MC
S-8521F50MC
47 μF × 2
47 μF
CD105 / 47 μH IRF7606 MA737
CD54 / 47 μH TM6201 MA720
CD105 / 47 μH IRF7606 MA737
D62F / 22 μH TM6201 MA720
CDH113 / 22 μH IRF7606 MA737
5.0 V
22 μF
With equipment standby mode
33
STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER
S-8520/8521 Series
Rev.9.0_01
Table 12 External parts for Ripple data
Product name Output voltage
S-8520D30MC
Inductor
Transistor
Rb
Cb
Diode
Output capacitor
47 μF × 2
S-8521D30MC
3.0 V
CD105 / 47 μH
2SA1213
680 Ω
2200 pF
MA720
S-8520B30MC
22 μF × 2
22 μF
S-8521B30MC
S-8520F33MC
3.3 V
−
−
−
−
CDH113 / 22 μH
CD105 / 47 μH
CDH113 / 22 μH
IRF7606
2SA1213
IRF7606
MA737
MA720
MA737
S-8521F33MC
S-8520D50MC
S-8521D50MC
47 μF × 2
22 μF × 2
22 μF
680 Ω
2200 pF
S-8520B50MC
5.0 V
S-8521B50MC
S-8520F50MC
S-8521F50MC
−
−
−
−
Table 13 Performance Data
Maximum
Component
Product name Manufacturer name “L” value DC resistance allowable Diameter
current
Height
CD54
CD105
CDH113
D62F
0.37 Ω
0.17 Ω
0.09 Ω
0.25 Ω
0.72 A
1.28 A
1.44 A
0.70 A
5.8 mm
4.5 mm
47 μH
22 μH
Sumida Corporation
10.0 mm 5.4 mm
11.0 mm 3.7 mm
Inductor
Toko Ink.
6.0 mm
2.7 mm
MA720
MA737
F93
Forward current 500 mA (at VF = 0.55 V)
Matsushita Electric
Industrial Co., Ltd.
Nichicon Corporation
Matsushita Electric
Industrial Co., Ltd.
Diode
Forward current 1.5 A (at VF = 0.5 V)
−
Output capacity
TE
−
External transistor
(Bipolar PNP)
VCEO: 50 V max., IC: −2 A max., hFE: 120 to 240,
SOT-89-3 package
2SA1213
Toshiba Corporation
VGS: 12 V max., ID: −2 A max., Vth: －0.7 V min.,
Ciss: 320 pF typ., Ron: 0.25 Ω max. (VGS = −4.5 V),
SOT-89-3 package
Toyota Industries
Corporation
TM6201
IRF7606
External transistor
(MOS FET)
VGS: 20 V max., ID: −2.4 A max., Vth: −1 V min.,
Ciss: 470 pF typ., Ron: 0.15 Ω max. (VGS = −4.5 V),
Micro 8 package
International Rectifier
Corporation
34
STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER
Rev.9.0_01
S-8520/8521 Series
1. Efficiency Characteristics: Output current (IOUT)-Efficiency (EFFI)
(1) S-8520B30MC
(CD105 / 47 μH, TM6201)
100
90
80
70
60
50
VIN = 3.6 V
IN = 9.0 V
V
0.01
0.1
1
I
10
OUT [mA]
100 1000
(2) S-8520F33MC
(D62F / 22 μH, TM6201)
(CDH113 / 22 μH, IRF7606)
100
100
90
80
70
60
50
VIN = 14 V
VIN = 9 V
VIN = 6 V
VIN = 4 V
VIN = 9 V
VIN = 6 V
VIN = 4 V
90
80
70
60
50
0.01
0.1
0.1
0.1
1 10
IOUT [mA]
100
1000
0.01
0.1
1
10
100
1000
I
OUT [mA]
(3) S-8521D30MC
(CD54 / 47 μH, TM6201)
(CD54 / 47 μH, IRF7606)
100
100
90
80
70
60
50
90
80
70
60
50
VIN = 3.6 V
VIN = 9.0 V
VIN = 3.6 V
VIN = 9.0 V
0.01
0.1
1
I
10
100
1000
0.01
1
10
100
1000
OUT [mA]
IOUT [mA]
(4) S-8521B30MC
(CD105 / 47 μH, IRF7606)
(CD105 / 47 μH, TM6201)
100
90
80
70
60
50
100
90
80
70
60
50
VIN = 3.6 V
VIN = 9.0 V
VIN = 3.6 V
VIN = 9.0 V
0.01
1
10
100
1000
0.01
0.1
1
10
100
1000
IOUT [mA]
IOUT [mA]
35
STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER
S-8520/8521 Series
Rev.9.0_01
(5) S-8521F33MC
(D62F / 22 μH, TM6201)
(CDH113 / 22 μH, IRF7606)
100
100
90
80
70
60
50
VIN = 14 V
VIN = 9 V
VIN = 6 V
VIN = 4 V
VIN = 9 V
VIN = 6 V
VIN = 4 V
90
80
70
60
50
0.01
0.1
1
10
OUT [mA]
100
1000
0.01
0.1
1
I
10
OUT [mA]
100
1000
I
(6) S-8520B50MC
(CD54 / 47 μH, TM6201)
(CD105 / 47 μH, IRF7606)
100
90
80
70
60
50
100
VIN = 14 V
VIN = 9 V
VIN = 6 V
90
80
70
60
50
VIN = 6.0 V
VIN = 9.0 V
0.01
0.1
1
I
10
OUT [mA]
100
1000
0.01
0.1
1
10
100
1000
IOUT [mA]
(7) S-8520F50MC
(D62F / 22 μH, TM6201)
(CDH113 / 22 μH, IRF7606)
100
100
90
80
70
60
50
VIN = 14 V
VIN = 9 V
VIN = 6 V
VIN = 9 V
VIN = 6 V
90
80
70
60
50
0.01
0.1
1
I
10
OUT [mA]
100
1000
0.01
0.1
1
10
IOUT [mA]
100
1000
(8) S-8521D50MC
(CD54 / 47 μH, TM6201)
(CD105 / 47 μH, IRF7606)
100
90
80
70
60
50
100
90
80
70
60
50
VIN = 14 V
VIN = 9 V
VIN = 6 V
VIN = 6.0 V
VIN = 9.0 V
0.01
0.1
1
I
10
OUT [mA]
100
1000
0.01
0.1
1
I
10
OUT [mA]
100
1000
36
STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER
Rev.9.0_01
S-8520/8521 Series
(9) S-8521B50MC
(CD54 / 47 μH, TM6201)
(CD105 / 47 μH, IRF7606)
100
90
80
70
60
50
100
VIN = 14 V
VIN = 9 V
VIN = 6 V
90
80
70
60
50
VIN = 6.0 V
VIN = 9.0 V
0.01
0.1
1
10
OUT [mA]
100
1000
0.01
0.1
1
10
100
1000
I
IOUT [mA]
(10) S-8521F50MC
(CDH113 / 22 μH, IRF7606)
(D62F / 22 μH, TM6201)
100
90
80
70
60
50
100
VIN = 14 V
VIN = 9 V
VIN = 6 V
VIN = 9 V
VIN = 6 V
90
80
70
60
50
0.01
0.1
1
10
OUT [mA]
100
1000
0.01
0.1
1
10
100
1000
I
IOUT [mA]
37
STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER
S-8520/8521 Series
Rev.9.0_01
2. Ripple Voltage Characteristics: Ripple voltage (Vrip)-Input voltage (VIN) (L: CD105 / 47
SBD: MA720)
μH, Tr: 2SA1213,
(1) S-8520D30MC
(2) S-8521D30MC
(COUT = 47 μF×2)
(COUT = 47 μF×2)
240
200
160
120
80
240
200
160
120
80
IOUT = 500 mA
IOUT = 100 mA
IOUT = 0.1 mA
IOUT = 500 mA
IOUT = 100 mA
IOUT = 0.1 mA
40
40
0
0
2
4
6
8
10
12
14
16
2
4
6
8
10
12
14
16
VIN [V]
VIN [V]
(3) S-8520B30MC
(4) S-8521B30MC
(COUT = 22 μF×2)
(COUT = 22 μF×2)
240
200
160
120
80
240
200
160
120
80
IOUT = 500 mA
IOUT = 100 mA
IOUT = 0.1 mA
IOUT = 500 mA
IOUT = 100 mA
IOUT = 0.1 mA
40
40
0
0
2
4
6
8 10
VIN [V]
12
14
16
2
4
6
8
10
12
14
16
VIN [V]
(5) S-8520F33MC
(6) S-8521F33MC
(COUT = 22 μF)
(COUT = 22 μF)
240
200
160
120
80
240
200
160
120
80
IOUT = 500 mA
IOUT = 100 mA
IOUT = 0.1 mA
IOUT = 500 mA
IOUT = 100 mA
IOUT = 0.1 mA
40
40
0
0
2
4
6
8 10
VIN [V]
12
14
16
2
4
6
8
V
10
IN [V]
12
14
16
(7) S-8520D50MC
(8) S-8521D50MC
(COUT = 47 μF×2)
(COUT = 47 μF×2)
240
200
240
200
IOUT = 500 mA
IOUT = 100 mA
IOUT = 0.1 mA
IOUT = 500 mA
IOUT = 100 mA
IOUT = 0.1 mA
160
120
80
160
120
80
40
0
40
0
2
4
6
8
10
12
14
16
2
4
6
8
10
12
14
16
VIN [V]
VIN [V]
38
STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER
Rev.9.0_01
S-8520/8521 Series
(9) S-8520B50MC
(10) S-8521B50MC
(COUT = 22 μF×2)
(COUT = 22 μF×2)
240
200
160
240
200
IOUT = 500 mA
IOUT = 100 mA
IOUT = 0.1 mA
160
120
80
IOUT = 500 mA
120
80
40
0
IOUT = 100 mA
IOUT = 0.1 mA
40
0
2
4
6
8
V
10
IN [V]
12
14
16
2
4
6
8 10
VIN [V]
12
14
16
(11) S-8520F50MC
(12) S-8521F50MC
(COUT = 22 μF)
(COUT = 22 μF)
240
200
160
120
80
240
200
160
120
80
IOUT = 500 mA
IOUT = 500 mA
IOUT = 100 mA
IOUT = 100 mA
IOUT = 0.1 mA
IOUT = 0.1 mA
40
40
0
0
2
4
6
8
10
12
14
16
2
4
6
8
10
12
14
16
VIN [V]
VIN [V]
39
STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER
S-8520/8521 Series
Rev.9.0_01
3. PWM / PFM switching characteristics: Input voltage (VIN)-Output current (IOUT
)
(1) S-8521D30MC
(2) S-8521B30MC
14
14
10
6
10
6
2
1
2
1
10
100
1000
10
10
10
100
100
100
1000
1000
1000
IOUT [mA]
IOUT [mA]
(3) S-8521F33MC
(4) S-8521D50MC
14
14
10
6
10
6
2
1
2
1
10
100
1000
IOUT [mA]
IOUT [mA]
(5) S-8521B50MC
(6) S-8521F50MC
14
14
10
6
10
6
2
1
2
1
10
100
1000
IOUT [mA]
IOUT [mA]
40
2.9±0.2
1.9±0.2
4
5
+0.1
-0.06
1
2
3
0.16
0.95±0.1
0.4±0.1
No. MP005-A-P-SD-1.2
TITLE
SOT235-A-PKG Dimensions
MP005-A-P-SD-1.2
No.
SCALE
UNIT
mm
SII Semiconductor Corporation
4.0±0.1(10 pitches:40.0±0.2)
+0.1
-0
2.0±0.05
0.25±0.1
ø1.5
+0.2
-0
4.0±0.1
ø1.0
1.4±0.2
3.2±0.2
3
4
2 1
5
Feed direction
No. MP005-A-C-SD-2.1
TITLE
SOT235-A-Carrier Tape
MP005-A-C-SD-2.1
No.
SCALE
UNIT
mm
SII Semiconductor Corporation
12.5max.
9.0±0.3
Enlarged drawing in the central part
ø13±0.2
(60°)
(60°)
No. MP005-A-R-SD-1.1
TITLE
SOT235-A-Reel
MP005-A-R-SD-1.1
No.
SCALE
UNIT
QTY.
3,000
mm
SII Semiconductor Corporation
Disclaimers (Handling Precautions)
1. All the information described herein (product data, specifications, figures, tables, programs, algorithms and
application circuit examples, etc.) is current as of publishing date of this document and is subject to change without
notice.
2. The circuit examples and the usages described herein are for reference only, and do not guarantee the success of
any specific mass-production design.
SII Semiconductor Corporation is not responsible for damages caused by the reasons other than the products or
infringement of third-party intellectual property rights and any other rights due to the use of the information described
herein.
3. SII Semiconductor Corporation is not responsible for damages caused by the incorrect information described herein.
4. Take care to use the products described herein within their specified ranges. Pay special attention to the absolute
maximum ratings, operation voltage range and electrical characteristics, etc.
SII Semiconductor Corporation is not responsible for damages caused by failures and/or accidents, etc. that occur
due to the use of products outside their specified ranges.
5. When using the products described herein, confirm their applications, and the laws and regulations of the region or
country where they are used and verify suitability, safety and other factors for the intended use.
6. When exporting the products described herein, comply with the Foreign Exchange and Foreign Trade Act and all
other export-related laws, and follow the required procedures.
7. The products described herein must not be used or provided (exported) for the purposes of the development of
weapons of mass destruction or military use. SII Semiconductor Corporation is not responsible for any provision
(export) to those whose purpose is to develop, manufacture, use or store nuclear, biological or chemical weapons,
missiles, or other military use.
8. The products described herein are not designed to be used as part of any device or equipment that may affect the
human body, human life, or assets (such as medical equipment, disaster prevention systems, security systems,
combustion control systems, infrastructure control systems, vehicle equipment, traffic systems, in-vehicle equipment,
aviation equipment, aerospace equipment, and nuclear-related equipment), excluding when specified for in-vehicle
use or other uses. Do not use those products without the prior written permission of SII Semiconductor Corporation.
Especially, the products described herein cannot be used for life support devices, devices implanted in the human
body and devices that directly affect human life, etc.
Prior consultation with our sales office is required when considering the above uses.
SII Semiconductor Corporation is not responsible for damages caused by unauthorized or unspecified use of our
products.
9. Semiconductor products may fail or malfunction with some probability.
The user of these products should therefore take responsibility to give thorough consideration to safety design
including redundancy, fire spread prevention measures, and malfunction prevention to prevent accidents causing
injury or death, fires and social damage, etc. that may ensue from the products' failure or malfunction.
The entire system must be sufficiently evaluated and applied on customer's own responsibility.
10. The products described herein are not designed to be radiation-proof. The necessary radiation measures should be
taken in the product design by the customer depending on the intended use.
11. The products described herein do not affect human health under normal use. However, they contain chemical
substances and heavy metals and should therefore not be put in the mouth. The fracture surfaces of wafers and chips
may be sharp. Take care when handling these with the bare hands to prevent injuries, etc.
12. When disposing of the products described herein, comply with the laws and ordinances of the country or region where
they are used.
13. The information described herein contains copyright information and know-how of SII Semiconductor Corporation.
The information described herein does not convey any license under any intellectual property rights or any other
rights belonging to SII Semiconductor Corporation or a third party. Reproduction or copying of the information
described herein for the purpose of disclosing it to a third-party without the express permission of SII Semiconductor
Corporation is strictly prohibited.
14. For more details on the information described herein, contact our sales office.
1.0-2016.01
www.sii-ic.com
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