Contents
Features .............................................................. 1
Applications ......................................................... 1
Block Diagram ..................................................... 1
Selection Guide ................................................... 2
Pin Assignment ................................................... 3
Absolute Maximum Ratings ................................. 3
Electrical Characteristics ..................................... 4
Test Circuits ........................................................ 9
Operation............................................................. 9
External Parts Selection for DC-DC Converter .... 12
Standard Circuits ................................................. 16
Precautions ......................................................... 18
Application Circuits .............................................. 19
Dimensions.......................................................... 24
Markings.............................................................. 24
Taping ................................................................ 25
Temperature Characteristics ............................... 28
Characteristics for the Power Voltage.................. 30
Ripple characteristics .......................................... 31
Transient Responses........................................... 32
Operation Start Voltage and Operation Holding
Voltage Characteristics for Output Current ......... 34
Input Voltage Characteristics for Input Current .... 34
Reference Data ................................................... 35
Frequently Asked Questions ............................. 48
SMALL PACKAGE PWM/PFM CONTROL
STEP-UP SWITCHING REGULATOR
S-8324/8328 Series
The S-8324/8328 is a series of CMOS PWM/PFM-control step-up
switching regulators which mainly consist of a reference voltage source,
an oscillation circuit, a power MOS FET (S-8324 Series) and an error
amplifier. The new method PWM/PFM control circuit automatically
switches the control method according to the current load, offering
products of a wide range, high efficiency. A step-up switching regulator
is constructed by externally connecting only a coil, a capacitor and a
diode to the S-8324 Series. This feature, along with its small package
and low current consumption, makes the S-8324 Series ideal for the
power supply of portable equipment. For applications requiring a high
output current, products used with an external transistor (S-8328 Series)
are also available.
Features
Low voltage operation : 0.9 V (I
OUT
= 1mA)
Low current consumption :
Applications
Power supplies for portable equipment such as
During operation : 17.2µA (typ.)
(V
OUT
= 3 V, 50 kHz)
During shutdown : 0.5µA (max.)
Low Input current : 10.4µA ( typ.)
(V
OUT
= 3 V, 50 kHz, no load)
Duty ratio :
During PWM control : 15 to 83 % typ.
During PFM control : 15 % typ.
External parts: coil, diode, and capacitor only
(a transistor is needed for the S-8328 Series.)
Output voltage: accuracy of ±2.4%
Software start function : 6 msec (typ.)
Shutdown function
External transistor type is available (S-8328 Series)
SOT-23-5 small plastic package
SOT-23-3 small plastic package
SOT-89-3 miniature power molded plastic package
Step-down and invert type are also available.
pagers, handy calculators, and remote controllers
Constant voltage power supplies for cameras,
video equipment, and communications equipment
Power supply for microcomputers
Block Diagram
(1)
S-8324 Series
CONT
V
OUT
(2) S-8328 Series
V
OUT
VREF
PWM/PFM
control
circuit
+
-
PWM/PFM
control
circuit
VREF
+
-
EXT
V
SS
Soft start circuit
Soft start circuit
V
SS
(ON / OFF)
(ON / OFF)
Figure 1 Block Diagram
Seiko Instruments Inc.
1
SMALL PACKAGE PWM/PFM CONTROL STEP-UP SWITCHING REGULATOR
S-8324/8328 Series
Selection Guide
1. Product Name
S - 832 X X XX XX - XXX - T2
Tape Specification
Product name (abbreviation)
Package name (abbreviation)
MA ; SOT-23-3
(without
shutdown function)
MC ; SOT-23-5
(with
shutdown function, V
DD
/V
OUT
separate product)
UA ; SOT-89-3
(without
shutdown function)
Output voltage (symbol)
×10
Product category
A ; Normal product, fosc=50 kHz (S-8324 only)
B ; Normal product, fosc=100 kHz (S-8328 only)
C ; For pagers, fosc=30 kHz (S-8324 only)
D ; V
DD
/V
OUT
separate product, fosc=50 kHz (S-8324 only)
E ; V
DD
/V
OUT
separate product, fosc=100 kHz (S-8328 only)
Power transistor
4 ; Built-in PWM/PFM control switch.
8 ; PWM/PFM control switch with an external transistor.
`
2. Product List
Output
voltage(v)
2.0
2.5
2.7
2.8
3.0
3.3
5.0
Output
voltage(v)
2.0
2.5
2.7
3.0
3.3
3.6
3.8
5.0
5.2
S-8324AXXMC
Series
—
S-8324A25MC-EOF-T2
S-8324A27MC-EOH-T2
S-8324A28MC-EOI-T2
S-8324A30MC-EOK-T2
S-8324A33MC-EON-T2
S-8324A50MC-EPE-T2
S-8328BXXMC
Series
—
S-8328B25MC-EWF-T2
S-8328B28MC-EWH-T2
S-8328B30MC-EWK-T2
S-8328B33MC-EWN-T2
S-8328B36MC-EWQ-T2
S-8328B38MC-EWS-T2
S-8328B50MC-EXE-T2
S-8328B52MC-EXG-T2
S-8324AXXMA
Series
—
S-8324A25MA-EOF-T2
S-8324A27MA-EOH-T2
—
S-8324A30MA-EOK-T2
S-8324A33MA-EON-T2
S-8324A50MA-EPE-T2
S-8324AXXUA
S-8324CXXMA
S-8324DXXMC
Series
Series
Series
—
—
S-8324D20MC-E2A-T2
S-8324A25UA-EOF-T2 S-8324C25MA-EQF-T2
—
S-8324A27UA-EOH-T2 S-8324C27MA-EQH-T2
—
—
—
—
S-8324A30UA-EOK-T2 S-8324C30MA-EQK-T2 S-8424D30MC-E2K-T2
S-8324A33UA-EON-T2
—
—
S-8324A50UA-EPE-T2
—
S-8324D50MC-E4E-T2
S-8328BXXUA
S-8328EXXMC
Series
Series
—
S-8328E20MC-EYA-T2
S-8328B25UA-EWF-T2
—
S-8328B28UA-EWH-T2
—
S-8328B30UA-EWK-T2
—
S-8328B33UA-EWN-T2
—
—
—
—
—
S-8328B50UA-EXE-T2 S-8328E50MC-E9E-T2
—
—
S-8328BXXMA
Series
—
S-8328B25MA-EWF-T2
S-8328B28MA-EWH-T2
S-8328B30MA-EWK-T2
S-8328B33MA-EWN-T2
—
—
S-8328B50MA-EXE-T2
—
Consult our sales person for products with an output voltage other than specified above.
3. Function List
Built In power with external Switching Shutdown V
DD
/V
OUT
Product Name
transistor
power
frequency function separate Package
Application
Reference
transistor
(KHz)
type
page
S-8324AXXMC
Yes
—
50
Yes
—
SOT-23-5 With a shutdown function
—
S-8324AXXMA
Yes
—
50
—
—
SOT-23-3 without shutdown function
—
S-8324AXXUA
Yes
—
50
—
—
SOT-89-3 without shutdown function
—
For variable output voltage by
S-8324DXXMC
Yes
—
50
—
Yes
SOT-23-5
step-up DC/DC converter and
Page.15
step-down inverted output DC/DC
converter with an external resistor
S-8324CXXMA
Yes
—
30
—
—
SOT-23-3 For pagers
—
For large load current with
Page.14 to 15
S-8328BXXMC
—
Yes
100
Yes
—
SOT-23-5 shutdown function
For large load current without
Page.14 to 15
S-8328BXXMA
—
Yes
100
—
—
SOT-23-3 shutdown function
For large load current without
Page.14 to 15
S-8328BXXUA
—
Yes
100
—
—
SOT-89-3 shutdown function
For variable output voltage by
S-8328EXXMC
—
Yes
100
—
Yes
SOT-23-5 step-up DC/DC converter with an
Page.15
external resistor
2
Seiko Instruments Inc.
SMALL PACKAGE PWM/PFM CONTROL STEP-UP SWITCHING REGULATOR
S-8324/8328 Series
Pin Assignment
5
SOT-23-5
Top view
4
SOT-23-3
Top view
1
2
3
2
SOT-89-3
Top view
1
3
Figure 2
1
2
3
S-8324AXXMC, S-8328BXXMC
SOT-23-5
Pin No.
1
Functions
Shutdown pin
ON / OFF “H”:
normal operation
(stepping up operation)
“L”:
stop stepping up
(whole circuit stop)
V
OUT
Output voltage pin and power
supply pin
N.C. (Non Connection)
—
V
SS
GND pin
CONT External inductor connection
pin (for S-8324 Series)
EXT
External transistor connection
pin (for S-8328 Series)
Pin name
S-8324DXXMC, S-8328EXXMC
SOT-23-5
Pin No.
1
2
3
4
5
Pin name
Functions
V
OUT
Output voltage pin
V
DD
Power supply pin
N.C. (Non Connection)
—
V
SS
GND pin
CONT External inductor connection
pin (for S-8324 Series)
External transistor connection
EXT
pin (for S-8328 Series)
2
3
4
5
S-8324AXXMA, S-8324AXXUA, S-8324CXXMA
S-8328BXXMA, S-8328BXXUA
SOT-23-3, SOT-89-3
Pin No.
1
2
Pin name
Functions
V
SS
GND pin
V
OUT
Output voltage pin and power
supply pin
CONT External inductor connection
pin (for S-8324 Series)
EXT
External transistor connection
pin (for S-8328 Series)
3
Absolute Maximum Ratings
Note:
A protect circuit for static electricity is built into this IC chip.
However, prevent a charge of static electricity which exceeds the capacity of the protect circuit.
( Unless otherwise specified: Ta=25
C)
Parameter
VOUT pin voltage
ON/OFF pin voltage
CONT pin voltage
CONT pin current
EXT pin voltage
EXT pin current
Power dissipation
Operating temperature
Storage temperature
Symbol
V
OUT
ON/OFF
V
CONT
I
CONT
V
EXT
I
EXT
PD SOT-89-3
SOT-23-5, SOT-23-3
T
OPR
T
STG
Ratings
11
V
ss
- 0.3 to 11
11
300
V
ss
- 0.3 to V
OUT
+0.3
±50
500
150
-40 to +85
-40 to +125
C
C
Unit
V
V
V
mA
V
mA
mW
Seiko Instruments Inc.
SMALL PACKAGE PWM/PFM CONTROL STEP-UP SWITCHING REGULATOR
S-8324/8328 Series
Electrical Characteristics
1-1.S-8324AXXMC
(Unless otherwise specified: Ta=25°C)
Min.
Typ.
Max.
Unit
Test circuit
S-8324A50MC
S-8324A33MC
S-8324A30MC
S-8324A28MC
S-8324A27MC
S-8324A25MC
I
OUT
=1mA
No external parts, voltage applied to V
OUT
CONTpulled up to 5 V by 10kΩ
I
OUT
=1mA, Measured by decreasing V
IN
voltage
gradually
S-8324A50MC
S-8324A33MC
No load
S-8324A30MC
S-8324A28MC
S-8324A27MC
S-8324A25MC
S-8324A50MC
S-8324A33MC
V
OUT
=output voltage×0.95
S-8324A30MC
S-8324A28MC
S-8324A27MC
S-8324A25MC
S-8324A50MC
S-8324A33MC
V
OUT
=output voltage+0.5
S-8324A30MC
S-8324A28MC
S-8324A27MC
S-8324A25MC
shutdown pin=0V
S-8324A50MC
S-8324A33MC
S-8324A30MC
S-8324A28MC
S-8324A27MC
S-8324A25MC
4.880
3.221
2.928
2.733
2.635
2.440
—
—
—
0.7
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
114
78
78
61
61
61
—
—
—
—
—
—
—
—
—
42.5
75
5
0.75
—
—
3.0
—
—
—
—
—
—
5.000
3.300
3.000
2.800
2.700
2.500
—
—
—
—
10.5
10.4
10.4
10.5
10.5
10.5
30.2
19.1
17.2
16.1
15.5
14.3
3.5
3.3
3.2
3.2
3.2
3.2
—
182
125
125
98
98
98
—
30
30
±0.25
±0.17
±0.15
±0.14
±0.14
±0.13
50
83
15
—
—
—
6.0
87
83
83
79
79
79
5.120
3.379
3.072
2.867
2.765
2.560
9
0.9
0.8
—
21.1
20.8
20.7
21.0
21.1
21.0
50.3
31.8
28.7
26.8
25.9
23.9
6.9
6.5
6.4
6.4
6.4
6.3
0.5
—
—
—
—
—
—
1.0
60
60
—
—
—
—
—
—
57.5
90
%
24
—
0.3
0.2
12.0
—
—
—
—
—
—
ms
—
V
2
1
Parameter
Symbol
Conditions
Output voltage
V
OUT
V
1
Input voltage
Operation start voltage
Oscillation start voltage
Operation holding voltage
V
IN
V
ST1
V
ST2
V
HLD
2
V
1
Input current at no load
I
IN
—
Current consumption 1
I
SS1
µA
2
Current consumption 2
I
SS2
Current consumption during
shutdown
I
SSS
Switching current
I
SW
VCONT=0.4V
mA
—
µA
mV
Switchin transistor leak
current
Line regulation
Load regulation
Output voltage
temperature
coefficient
I
SWQ
∆V
OUT1
∆V
OUT2
∆V
OUT
/∆Ta
V
OUT
= VCONT=10V
V
IN
=output voltage×0.4 to
×0.6
I
OUT
=10µA to I
OUT
(below)
×1.25
S-8324A50MC
S-8324A33MC
S-8324A30MC
S-8324A28MC
S-8324A27MC
S-8324A25MC
1
mV/°C
Ta=-40°C to +85°C
Oscillation frequency
Max duty ratio
PWM/PFM control switch
duty ratio
Shutdown pin
Input voltage
(ON/OFF type)
fosc
MaxDuty
PFMDuty
VSH
VSL1
VSL2
V
OUT
=output voltage×0.95
Measured waveform at CONT pin
V
OUT
=output voltage×0.95
Measured waveform at CONT pin
V
IN
= output voltage - 0.1V
No load
V
OUT
=output voltage×0.95
Measured the oscillation at CONT pin
V
OUT
=output voltage×0.95
When
V
OUT
≥1.5V
Judged the stop of oscillation When
at CONT pin
V
OUT
<1.5V
S-8324A50MC
S-8324A33MC
S-8324A30MC
S-8324A28MC
S-8324A27MC
S-8324A25MC
kHz
1
Soft start time
T
SS
Efficiency
EFFI
%
1
External parts used:
-Coil:
CD54 (100µH) of Sumida Electric Co., Ltd.
-Diode:
MA720 (schottky type) of Matsushita Electronic Components Co., Ltd.
-Capacitor: F93 (16V, 22µF, tantalum type) of Nichicon Corporation)
Applied V
IN
=output voltage×0.6, I
OUT
=output voltage/250Ω
The shutdown pin is connected to V
OUT
pin.
Note 1 :
The output voltage specified above is the typical value.
4
Seiko Instruments Inc.
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