Rohm BD9F800MUX-EVK-001 User manual

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User’s Guide
© 2020 ROHM Co., Ltd.
No. 63UG048E Rev.001
2020.10
Switching Regulator Series
1ch Buck Converter with Integrated FET
BD9F800MUX EVK
BD9F800MUX-EVK-001 (12V to 1V, 8A)
Introduction
This user's guide describes the steps required to operate the EVK of BD9F800MUX. The document includes a
description of the peripheral components, operating instructions, and reference data.
Description
BD9F800MUX-EVK-001 uses BD9F800MUX to output 1V from a 12V input voltage. The input voltage of the
BD9F800MUX is from 4.5V to 28V and the output voltage is configurable from 0.765V to 13.5V with external
resistors. The switching frequency can be selected as 300 kHz or 600 kHz. BD9F800MUX is a constant on-time
controlled DC/DC converter with fast transient response and does not require external phase compensation circuit.
It includes built-in soft start function for start-up rush current protection, Under Voltage Lock Out (UVLO),
Thermal Shutdown Detection (TSD), Over Current Protection (OCP), and Short Circuit Protection (SCP).
Application
Step-down power supplies for DSPs, microprocessors, etc.
Set-top box
Liquid crystal TV
DVD/Blu-ray player/recorder
Amusement equipment

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© 2020 ROHM Co., Ltd.
No. 63UG048E Rev.001
2020.10
User’s Guide
BD9F800MUX-EVK-001
EVK Operating Limits
Parameter Min Typ Max Units Conditions
Input Voltage 4.5 12.0 28.0 V
Output Voltage 1.0 V
Maximum Output Current 8.0 A
Switching Frequency 300 kHz
Maximum Efficiency 89 % Io = 2A
UVLO Threshold Voltage 4.2 V VIN sweep up
UVLO Hysteresis Voltage 400 mV
EVK Overview
Figure 1. BD9F800MUX-EVK-001(Top View) Figure 2.BD9F800MUX-EVK-001(Bottom View)

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© 2020 ROHM Co., Ltd.
No. 63UG048E Rev.001
2020.10
User’s Guide
BD9F800MUX-EVK-001
EVK Schematic
Figure 3. BD9F800MUX-EVK-001 Schematic
Operating Procedure
1. Turn off the DC power supply and connect the GND terminal of the power supply to the PGND pin of TB1.
2. Connect the VCC terminal of the DC power supply to the VIN pin of EVK TB1.
3. Connect the load to the VOUT and GND pins of the EVK TB2. In the case of an electronic load, connect it with
the load turned off.
4. Connect the VOUT terminal of the voltmeter to EVK's VOUT_S and the GND terminal to EVK's PGND_S.
5. Connect the J1 jumper to the VIN side.
6. Turn on the DC power. Make sure the voltmeter shows 1 V.
7. Turn on the electronic load.
(Caution) This EVK does not support hot plug. Do not perform hot plug test.

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© 2020 ROHM Co., Ltd.
No. 63UG048E Rev.001
2020.10
User’s Guide
BD9F800MUX-EVK-001
Operating State Settings
Select the status of BD9F800MUX as shown in Table 1 according to the EN pin voltage.
Table 1. EN Pin Setting
EN Pin Voltage
State
HIGH (≥ 2.3 V)
Enable
LOW (≤ 0.7 V)
Shutdown
Switching Frequency Setting
The switching frequency of BD9F800MUX is selected as shown in Table 2 by the FREQ pin. This EVK is equipped with
optimum parts at 300 kHz. When changing the operating frequency, it is necessary to change the parts.
Table 2．Switching Frequency Setting
FREQ Pin Voltage
Switching Frequency
HIGH (≥ 2.2 V)
600kHz
LOW (≤ 0.8 V)
300kHz

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© 2020 ROHM Co., Ltd.
No. 63UG048E Rev.001
2020.10
User’s Guide
BD9F800MUX-EVK-001
Parts List
Table 1. Parts List
Count Parts
No. Type Value Description Manufacturer Part Number Manufacturer Configuration (mm)
1 U1 IC - Single Synchronous
BUCK Converter
BD9F800MUX ROHM 3.5 x 3.5
1 L1 Inductor 2.2µH 11A max, ±20% CMLB104T2R2MS Cyntec L
: W
0
C0
-
-
Open
-
-
-
1 C1 Ceramic
Capacitor
10μF 50V, X5R, ±20% GRM32ER61H106MA12 Murata 3225
1 C2 Ceramic
Capacitor
10μF 50V, X5R, ±20% GRM32ER61H106MA12 Murata 3225
1 C3 Ceramic
Capacitor
0.1μF 50V, X5R, ±10% GRM155R61H104KE14 Murata 1005
1 C4 Ceramic
Capacitor
2.2μF 10V, X5R, ±10% GRM188R61A225KE34 Murata 1608
1 C5 Ceramic
Capacitor
0.1μF 10V, X5R, ±10% GRM152R61A104KE19 Murata 1005
0
C6
-
-
Open
-
-
-
1 C7 Ceramic
Capacitor
47μF 6.3V, X5R, ±20% GRM31CR60J476ME19 Murata 3216
1 C8 Ceramic
Capacitor
22μF 6.3V, X5R, ±20% GRM21BR60J226ME39 Murata 2012
0
C9
-
-
Open
-
-
-
0
C10
-
-
Open
-
-
-
0
C11
-
-
Open
-
-
-
0
C12
-
-
Open
-
-
-
1
R1A
Resistor
0Ω
Jumper
MCR01MZPJ000
ROHM
1005
1
R1B
Resistor
6.8kΩ
50V, ±1%, 1/16W
MCR01MZPF6801
ROHM
1005
1
R2
Resistor
22kΩ
50V, ±1%, 1/16W
MCR01MZPF2202
ROHM
1005
1
R3
Resistor
100kΩ
50V, ±1%, 1/16W
MCR01MZPF1003
ROHM
1005
0
R4
-
-
Open
-
-
-
1
R5
Resistor
10kΩ
50V, ±1%, 1/16W
MCR01MZPF1002
ROHM
1005
1
R6
Resistor
0Ω
Jumper
MCR01MZPJ000
ROHM
1005
1
R7
Resistor
0Ω
Jumper
MCR01MZPJ000
ROHM
1005
1
R8
Resistor
0Ω
Jumper
MCR01MZPJ000
ROHM
1005
0
R9
-
-
Open
-
-
-

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© 2020 ROHM Co., Ltd.
No. 63UG048E Rev.001
2020.10
User’s Guide
BD9F800MUX-EVK-001
EVK PCB Layout
EVK PCB Information
Number of Layers
Material
Board Size
Copper Thickness
4 FR-4 85mm x 85mm x 1.6mmt 2oz (70μm) *Top, Bottom Layer
1oz (35μm) *Middle Layers
Figure 4. Top Layer Layout
(To p View)
Figure 5. Middle1 Layer Layout
(To p View)
Figure 6. Middle2 Layer Layout
(To p View)
Figure 7. Bottom Layer Layout
(To p View)

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© 2020 ROHM Co., Ltd.
No. 63UG048E Rev.001
2020.10
User’s Guide
BD9F800MUX-EVK-001
Reference Application Curves
Ta = 2 5 ℃, VCC = 12V, EN = VCC, unless otherwise specified
Figure 8. Current Consumption vs VIN
(IO = 0mA)
Figure 10. Line Regulation
(IO = 0mA)
Figure 9. Shutdown Current vs VIN
(EN=GND)
Figure 11. Load Regulation
0
5
10
15
20
0 5 10 15 20 25 30
IIN [mA]
VIN [V]
0.0
0.5
1.0
1.5
0 5 10 15 20 25 30
VOUT [V]
VIN [V]
0
5
10
15
20
0 5 10 15 20 25 30
IIN [μA]
VIN [V]
0.96
0.98
1
1.02
1.04
02468
VOUT [V]
IOUT [A]

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© 2020 ROHM Co., Ltd.
No. 63UG048E Rev.001
2020.10
User’s Guide
BD9F800MUX-EVK-001
Reference Application Curves –Cont’d
Figure 12. Switching Frequency vs VIN
(IO = 1A)
Figure 14. Load Response
Figure 13. Efficiency vs Load Current
Figure 15. Frequency Response
(IO = 8A)
200
250
300
350
400
0 5 10 15 20 25 30
Frequency [kHz]
VIN [V]
VOUT: 0.05V/div
(Offset = 1V)
IOUT: 2A/div
0
20
40
60
80
100
0246810
Efficiency [%]
IOUT [A]

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© 2020 ROHM Co., Ltd.
No. 63UG048E Rev.001
2020.10
User’s Guide
BD9F800MUX-EVK-001
Reference Application Curves –Cont’d
Figure 16. Start Up Waveform
(IO = 1A)
Figure 17. Shutdown Waveform
(IO = 1A)
VIN: 10V/div
SW: 10V/div
VOUT: 0.5V/div
PGD: 5V/div
VIN: 10V/div
SW: 10V/div
VOUT: 0.5V/div
PGD: 5V/div

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© 2020 ROHM Co., Ltd.
No. 63UG048E Rev.001
2020.10
User’s Guide
BD9F800MUX-EVK-001
Revision History
Date Revision
Number
Description
2020.10. 2
001
Initial release