S-8424A Series
www.sii-ic.com
© Seiko Instruments Inc., 2001-2010
BATTERY BACKUP SWITCHING IC
Rev.3.0
_00
The S-8424A Series is a CMOS IC designed for use in the switching circuits of primary and backup power supplies on
a single chip. It consists of two voltage regulators, three voltage detectors, a power supply switch and its controller, as
well as other functions.
In addition to the switching function between the primary and backup power supply, the S-8424A Series can provide
the micro controllers with three types of voltage detection output signals corresponding to the power supply voltage.
Moreover adopting a special sequence for switch control enables the effective use of the backup power supply,
making this IC ideal for configuring a backup system.
Features
•
Low power consumption
Normal operation: 15
μA
Max. (V
IN
=
6 V)
Backup:
2.1
μA
Max.
•
Voltage regulator
Output voltage tolerance :
±2
%
Output voltage:
Independently selectable in 0.1 V steps in the range of 2.3 V to 5.4 V
•
Three built-in voltage detectors (CS,
PREEND
,
RESET
)
Detection voltage precision:
±2
%
Detection voltage:
Selectable in 0.1 V steps in the range of 2.4 V to 5.3 V (CS voltage detector)
Selectable in 0.1 V steps in the range of 1.7 V to 3.4 V (
PREEND
,
RESET
voltage detector)
•
Switching circuit for primary power supply and backup power supply configurable on one chip
•
Efficient use of backup power supply possible
•
Special sequence
Backup voltage is not output when the primary power supply voltage does not reach the initial voltage at which
the switch unit operates.
•
Lead-free, Sn 100%, halogen-free
*1
*1.
Refer to “
Product Name Structure”
for details.
Packages
•
8-Pin TSSOP
•
8-Pin SON(B)
Applications
•
Video camera recorders
•
Still video cameras
•
Memory cards
•
SRAM backup equipment
Seiko Instruments Inc.
1
BATTERY BACKUP SWITCHING IC
S-8424A Series
Product Name Structure
1. Product name
(1) 8-Pin TSSOP
S-8424A xx
FT - TB - x
Environmental code
U: Lead-free (Sn 100%), halogen-free
G: Lead-free (for details, please contact our sales office)
IC direction in tape specification
Package code
FT: 8-Pin TSSOP
Serial code
Rev.3.0
_00
(2) 8-Pin SON(B)
S-8424A xx
PA - TF - G
Environmental code
G: Lead-free (for details, please contact our sales office)
IC direction in tape specification
Package code
PA: 8-Pin SON(B)
Serial code
2. Package
Package Name
8-Pin TSSOP
8-Pin SON(B)
Environmental code = G
Environmental code = U
Drawing Code
Tape
FT008-E-C-SD
FT008-E-C-SD
PA008-B-C-SD
Package
FT008-A-P-SD
FT008-A-P-SD
PA008-B-P-SD
Reel
FT008-E-R-SD
FT008-E-R-S1
PA008-B-R-SD
2
Seiko Instruments Inc.
Rev.3.0
_00
3. Product name list
Part No.
Type
V
RO
S-8424AAAFT-TB-x
S-8424AAAPA-TF-G
S-8424AABFT-TB-x
S-8424AACFT-TB-x
S-8424AADFT-TB-x
S-8424AAEFT-TB-x
S-8424AAFFT-TB-x
S-8424AAGFT-TB-x
S-8424AAHFT-TB-x
S-8424AAJFT-TB-x
S-8424AAKFT-TB-x
8-Pin TSSOP
8-Pin SON(B)
8-Pin TSSOP
8-Pin TSSOP
8-Pin TSSOP
8-Pin TSSOP
8-Pin TSSOP
8-Pin TSSOP
8-Pin TSSOP
8-Pin TSSOP
8-Pin TSSOP
3.300
3.200
5.000
3.150
3.200
2.800
5.000
3.100
3.200
3.300
3.200
5.000
3.150
3.200
2.800
5.000
3.100
3.200
4.000
3.300
4.600
4.200
4.400
4.400
4.600
4.400
4.600
4.129
3.401
4.753
4.337
4.545
4.545
4.753
4.545
4.753
2.300
2.400
2.300
2.300
2.400
2.400
2.550
2.200
2.400
3.000
Package
Output
Voltage
(V)
CS Voltage
(V)
−
V
DET1
+
V
DET1
BATTERY BACKUP SWITCHING IC
S-8424A Series
RESET Voltage
(V)
−
V
DET2
+
V
DET2
PREEND
Voltage
(V)
−
V
DET3
+
V
DET3
Switch Voltage
(V)
V
SW1
+
V
DET1
×
0.85
+
V
DET1
×
0.77
+
V
DET1
×
0.85
+
V
DET1
×
0.77
+
V
DET1
×
0.77
+
V
DET1
×
0.77
+
V
DET1
×
0.77
+
V
DET1
×
0.77
+
V
DET1
×
0.77
+
V
DET1
×
0.77
V
OUT
3.000
3.300
3.401
2.200
2.312
2.420
2.528
2.420
2.420
2.528
2.528
2.690
2.312
2.528
2.600
2.500
2.600
2.500
2.500
2.600
2.600
2.700
2.600
2.600
2.748
2.640
2.748
2.640
2.640
2.748
2.748
2.856
2.748
2.748
Caution Set the CS voltage so that the switch voltage (V
SW1
) is equal to or greater than the
RESET
detection voltage (−V
DET2
).
Remark 1.
The selection range is as follows.
V
RO
, V
OUT
: 2.3 to 5.4 V (0.1 V steps)
2.4 to 5.3 V (0.1 V steps)
−V
DET1
:
1.7 to 3.4 V (0.1 V steps )
−V
DET2
:
1.7 to 3.4 V (0.1 V steps)
−V
DET3
:
+V
DET1
×
0.85 or
+V
DET1
×
0.77
V
SW1
:
2.
If a product with a voltage other than above is required, contact our sales representative.
3.
x: G or U
4.
Please select products of environmental code = U for Sn 100%, halogen-free products.
Seiko Instruments Inc.
3
BATTERY BACKUP SWITCHING IC
S-8424A Series
Block Diagram
VOUT
Rev.3.0
_00
VIN
M1
REG2
VBAT
PREEND
V
SW1
Detector
PREEND
Voltage
detector
CS
CS
Voltage
detector
RESET
V
SW2
Detector
RESET
Voltage
detector
Switch
controller
REG1
VRO
VSS
Figure 1 Block Diagram
4
Seiko Instruments Inc.
Rev.3.0
_00
Pin Configurations
8-Pin TSSOP
Top View
VSS
PREEND
BATTERY BACKUP SWITCHING IC
S-8424A Series
Table 1
Pin No.
1
2
3
4
5
6
7
8
Symbol
VSS
PREEND
VBAT
*1
CS
RESET
VOUT
*2
VIN
*3
VRO
*4
Description
Ground
Output pin of
PREEND
voltage detector
Backup power supply input pin
Output pin of CS voltage detector
Output pin of
RESET
voltage detector
Output pin of voltage regulator 2
Primary power supply input pin
Output pin of voltage regulator 1
1
2
3
4
8
7
6
5
VRO
VIN
VOUT
RESET
VBAT
CS
Figure 2
*1 to *4.
Mount capacitors between VSS (GND pin) and the VIN, VBAT,
VOUT, and VRO pins. (Refer to the
“Standard Circuit”)
8-Pin SON(B)
Top View
1
PREEND
2
VBAT
3
CS
4
VSS
Table 2
Pin No.
1
2
3
4
5
6
7
8
Symbol
VSS
PREEND
VBAT
*1
CS
RESET
VOUT
*2
VIN
*3
VRO
*4
Description
Ground
Output pin of
PREEND
voltage detector
Backup power supply input pin
Output pin of CS voltage detector
Output pin of
RESET
voltage detector
Output pin of voltage regulator 2
Primary power supply input pin
Output pin of voltage regulator 1
8
VRO
7
VIN
6
VOU T
5
RESET
Figure 3
*1 to *4.
Mount capacitors between VSS (GND pin) and the VIN, VBAT,
VOUT, and VRO pins. (Refer to the
“Standard Circuit”)
Seiko Instruments Inc.
5
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