R1232D Series
PWM Step-down DC/DC Converter with Synchronous Rectifier
The R1232D Series are low supply current CMOS-based PWM step-down DC/DC converters with synchronous rectifier. R1232D
includes a soft start circuit, under-voltage lockout circuit (UVLO) and latch type protection circuit. By simply using an inductor, a
capacitor, and (resistors) as external components, a high-efficiency step-down DC/DC converter can be easily configured. R1232D
comes in two types: R1232Dxx1A/B with internally fixed output voltage and R1232D001C/D with adjustable output voltage with
external resistors.
FEATURES
•
Supply Current (I
DD
) ························ Typ. 140μA (1MHz), 240μA (2.25MHz) (No switching)
•
Standby Current (
I
standby
)·················· Max. 5μA (CE="L")
•
Input Voltage Range (V
IN
) ··············· 2.6V to 5.5V
•
Output Voltage Range (V
OUT
)·········· 0.9V to 3.3V (Internally fixed, R1232Dxx1A/B)
•
Output Voltage Accuracy ················± 2% (Feedback Voltage Accuracy :
±
16mV)
•
Oscillator Frequency (f
osc
)··············· 1MHz, 2.25MHz
•
Oscillator Maximum Duty Cycle (Maxduty) ····· Min. 100%
Externally adjustable (Feedback voltage : 0.8V, R1232D001C/D)
•
UVLO Detect Voltage (V
UVLO
) ·········Typ. 2.25V
•
Soft Start Time (t
start
) ·······················Typ. 1ms (1MHz)
•
•
•
•
Typ. 0.4ms (2.25MHz)
Coil-current Limit Circuit ················Current limit Typ. 1.4A
Latch Type Protection Circuit··········Delay time for protection
Typ. 2ms
Package··········································SON-8
Ceramic capacitors can be used. ···C
IN
=C
OUT
=10μF or more
BLOCK DIAGRAMS
R1232Dxx1A/B
(Internally fixed output voltage type)
V
DD
3
V
IN
2
Current Limit
Slope
Compensation
Phase
Compensation
Q
R
S
PWM
Comparator
Vref
Error
Amplifer
Soft Start
R1232D001C/D
(Externally adjustable output voltage type)
V
DD
3
V
IN
5
V
OUT
AGND
7
AGND
7
2
Current Limit
Slope
Compensation
Phase
Compensation
Q
R
S
PWM
Comparator
Error
Amplifer
Soft Start
Vref
5
V
FB
L
X
8
Output
Contorol
L
X
4
CE
“H” Active
8
Output
Contorol
Oscillator
Oscillator
4
CE
“H” Active
TEST Circuit
UVLO
Chip Enable
TEST Circuit
UVLO
Chip Enable
1
PGND
6
TEST
“L” or GND Fixed
1
PGND
6
TEST
“L” or GND Fixed
SELECTION GUIDE
Halogen Free
-
Package
SON-8
Part No.
R1232D.xx.1.
∗
-TR-F
3,000 pcs
R1232D.00.1.$.-TR-F
Q'ty per Reel
TYPICAL APPLICATIONS
R1232Dxx1A/B
L
1
PGND
R1232D001C/D
V
OUT
1
PGND
L
X
8
L
L
X
8
V
OUT
C
IN
2
V
IN
AGND
7
C
IN
LOAD
.xx.
: Specify the output voltage within the range of
0.9V (.09.) to 3.3V (.33.) in 0.1V steps.
For the externally adjustable output voltage type (.00.)
.
∗
.
: Select the oscillator frequency and output voltage type from
(.A.) 1MHz, internally fixed type or (.B.) 2.25MHz, internally fixed type.
.$.
: Select the oscillator frequency and output voltage type from
(.C.) 1MHz, externally adjustable type or
(.D.) 2.25MHz, externally adjustable type.
2
V
IN
AGND
7
3
V
DD
TEST
6
V
OUT
5
C
OUT
3
V
DD
TEST
6
C
OUT
Cb
R1
R2
4
CE
4
CE
V
FB
5
L=4.7μH, 2.2μH
C
IN
=10μF, C
OUT
=10μF
For V
OUT
=2.0V,
R1=33kΩ, R2=22kΩ, Cb=100pF
PACKAGE
SON-8
Top View
8
7
6
5
TYPICAL CHARACTERISTIC
R1232D331A Efficiency vs. Output Current
6
7
8
Bottom View
5
∗
1
2
3
4
4
3
2
1
1
2
3
4
PGND
V
IN
V
DD
CE
5
6
7
8
V
OUT
or V
FB
TEST
AGND
Lx
100
90
80
70
60
50
40
30
20
10
0
V
IN
=5.0V
Efficiency
η
(%)
∗)
The tab suspension leads are substrate level (GND).
1
10
100
Output Current I
OUT
(mA)
1000
APPLICATIONS
•
Power source for hand-held communication equipment, cameras, and VCRs
•
Power source for home appliances
EK-129-121001
•
Power source for battery-powered equipment
Step-down DC/DC Converter
LOAD
1. The products and the product specifications described in this document are subject to change or
discontinuation of production without notice for reasons such as improvement. Therefore, before
deciding to use the products, please refer to Ricoh sales representatives for the latest
information thereon.
2. The materials in this document may not be copied or otherwise reproduced in whole or in part
without prior written consent of Ricoh.
3. Please be sure to take any necessary formalities under relevant laws or regulations before
exporting or otherwise taking out of your country the products or the technical information
described herein.
4. The technical information described in this document shows typical characteristics of and
example application circuits for the products. The release of such information is not to be
construed as a warranty of or a grant of license under Ricoh's or any third party's intellectual
property rights or any other rights.
5. The products listed in this document are intended and designed for use as general electronic
components in standard applications (office equipment, telecommunication equipment,
measuring instruments, consumer electronic products, amusement equipment etc.). Those
customers intending to use a product in an application requiring extreme quality and reliability,
for example, in a highly specific application where the failure or misoperation of the product
could result in human injury or death (aircraft, spacevehicle, nuclear reactor control system,
traffic control system, automotive and transportation equipment, combustion equipment, safety
devices, life support system etc.) should first contact us.
6. We are making our continuous effort to improve the quality and reliability of our products, but
semiconductor products are likely to fail with certain probability. In order to prevent any injury to
persons or damages to property resulting from such failure, customers should be careful enough
to incorporate safety measures in their design, such as redundancy feature, firecontainment
feature and fail-safe feature. We do not assume any liability or responsibility for any loss or
damage arising from misuse or inappropriate use of the products.
7. Anti-radiation design is not implemented in the products described in this document.
8. Please contact Ricoh sales representatives should you have any questions or comments
concerning the products or the technical information.
Halogen Free
For the conservation of the global environment, Ricoh is advancing the decrease of the negative environmental impact material.
After Apr. 1, 2006, we will ship out the lead free products only. Thus, all products that will be shipped from now on comply with RoHS Directive.
Basically after Apr. 1, 2012, we will ship out the Power Management ICs of the Halogen Free products only. (Ricoh Halogen Free products are
also Antimony Free.)
RICOH COMPANY, LTD.
Electronic Devices Company
http://www.ricoh.com/LSI/
RICOH COMPANY, LTD.
Electronic Devices Company
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