Step-down DC/DC Converter Controller
with Voltage Detector
51 6(5,(6
NO. EA-066-120404
OUTLINE
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FEATURES
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APPLICATIONS
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1
R1221N
BLOCK DIAGRAM
OSC
V
IN
V
OUT
EXT
Vref
PWM/VFM
CONTROL
Protection
Soft Start
Chip Enable
CE
Vref
VD
OUT
GND
SELECTION GUIDE
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Code
D
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6HWWLQJ 2XWSXW 9ROWDJH 9
287
6WHSZLVH VHWWLQJ ZLWK D VWHS RI 9 LQ WKH UDQJH RI 9 WR 9 LV SRVVLEOH
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Contents
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2
R1221N
PIN CONFIGURATION
SOT-23-6W
6
5
4
V
OUT
GND CE
(mark side)
EXT VD
OUT
V
IN
1
2
3
PIN DESCRIPTION
Pin No.
Symbol
(;7
9'
287
9
,1
&(
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9
287
([WHUQDO 7UDQVLVWRU 'ULYH 3LQ 2XWSXW 7\SH &026
9ROWDJH 'HWHFWRU 2XWSXW 3LQ 2XWSXW 7\SH 1FK 2SHQ 'UDLQ
3RZHU 6XSSO\ 3LQ
ABSOLUTE MAXIMUM RATING
Symbol
9
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D
9
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9'
287
9
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Item
3LQ IRU 0RQLWRULQJ 2XWSXW 9ROWDJH
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Description
d
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Unit
9
9
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Rating
∼9
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R1221N
ELECTRICAL CHARACTERISTICS
•
R1221NxxxA (C,E,G) Output Voltage : Vo, Detector Threshold : V
D
Symbol
Item
Conditions
9
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9
287
∆9
287
∆7
IRVF
∆IRVF
∆7
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Min.
9R×
9R
Typ.
7RSW &
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9R×
$
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R1221N
•
R1221NxxxB (D,F,H) Output Voltage : Vo, Detector Threshold : V
D
Symbol
Item
Conditions
9
,1
2SHUDWLQJ ,QSXW 9ROWDJH
9
287
∆9
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∆7
IRVF
6WHSGRZQ 2XWSXW 9ROWDJH
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Min.
9R×
Typ.
9R
Max.
9R×
7RSW &
Note* Unit
9
$
9
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