Rohm BD9E304FP4-EVK-001 User manual

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© 2021 ROHM Co., Ltd. No. 63UG030E Rev.001
2021.7
User’s Guide
Switching Regulator Series
Buck Converter with Integrated FET
BD9E304FP4 EVK
BD9E304FP4-EVK-001 (12V→1.2V, 3.0A)
Introduction
This user’s guide provides the necessary steps to operate the EVK of ROHM’s BD9E304FP4 1-channel Buck DC/DC
converter. This includes the external parts, operating procedures, and application data.
Description
This EVK has been developed for ROHM’s synchronous buck DC/DC converter customers evaluating BD9E304FP4 and
outputs 1.2V from 12V input voltage. The BD9E304FP4 accepts a power supply input range of 4.5V to 36V and generates
an output voltage ranging from (0.1 x VIN or 0.7V) to 0.8 x VIN using external resistors. The operating frequency is fixed at
300 kHz. The Light Load Mode control provides good efficiency characteristics in light load conditions, which is ideal for
applications that needs to lessen the standby power. The current mode control DC/DC converter provides high-speed
transient response performance. Additional protection functions includes a built-in soft start function to prevent inrush
current at startup, UVLO (Under Voltage Lock Out), TSD (Thermal Shutdown Detection), SCP (Short Current Protection),
OCP (Over Current Protection), and OVP (Over Voltage Protection).
Application
Industrial Products as Factory Automation
Secondary power supply and adapter equipment
Telecommunication Devices
Operating Limits
Parameter Min Typ Max Units Conditions
Input Voltage 5.5 - 12.0 V
Output Voltage 1.2 V
Output Current Range 3.0 A
Operating Frequency 300 kHz
Maximum Efficiency 90.15 % Vin=5.5VIout=0.7A
UVLO Detect Voltage 3.9 V Vin sweep down
UVLO Hysteresis Width 350 mV

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© 2021 ROHM Co., Ltd. No. 63UG030E Rev.001
2021.7
User’s Guide
BD9E304FP4-EVK-001
EVK
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Figure 1. BD9E304FP4-EVK-001(Top View)
EVK Schematic
Figure 2. BD9E304FP4-EVK-001 Circuit Diagram
Operating Procedure
1. Turn off the DC power supply and connect the GND terminal of the power supply to the GND_F terminal (left side in
EVK) of the EVK.
2. Connect the VCC pin of the DC power supply to the VIN_F pin of the EVK.
3. Connect the load to the VOUT_F and GND_F (right side in EVK) terminal of EVK. When using an electronic load,
connect with the load turned off.
4. Connect a voltmeter to the VOUT_S terminal and the GND_S terminal (right side in EVK) of EVK.
5. Connect the jumper of SW_EN to VIN (ON) side.
6. Turn on the DC power supply. Make sure the voltmeter shows 1.2V.
7. Turn on the electronic load.
(Caution) This EVK does not support hot plug. Do not perform hot plug test.

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© 2021 ROHM Co., Ltd. No. 63UG030E Rev.001
2021.7
User’s Guide
BD9E304FP4-EVK-001
Operation State Settings
Below is a table of BD9E304FP4 condition selectable using SW_EN.
Table 1. SW_EN Settings
SW_EN state BD9E304FP4 Condition
ON
(short to VIN)
Enable
OFF
(short to GND)
Shutdown
Parts list
Table 2. Parts list
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Parts
number
Type
Value
Size/
Size Code
[unit:mm(inch)］
Power
Rating
Voltage
Rating
/Saturation
current
Temp.
Coefficient
/DCR
Tolera
nce Parts Name Manufacturer Quantity
C1,C6 Capacitor 0.1μF 1005(0402) - 50V X5R ±10% GRM155R61H104KE14 Murata 2
C2 Capacitor 10μF 3225(1210) - 100V X7S ±10% GRM32EC72A106KE05 Murata 1
C7,C8 Capacitor 47μF 3216(1206) - 16V X5R ±20% GRM31CR61C476ME44 Murata 2
C5 Capacitor 120pF 1005(0402) - 50V C0G ±5% GRM1555C1H121JA01 Murata 1
C3 Capacitor 390pF 1005(0402) - 50V C0G ±5% GRM1555C1H391JA01 Murata 1
R3 Resistor 43k
Ω
1005(0402) 1/16W - - ±1% MCR01MZPF433 ROHM 1
R4 Resistor Short - - - - - Shorted by solder - 0
R2,R1 Resistor 100k
Ω
1005(0402) 1/16W - - ±1% MCR01MZPF1003 ROHM 2
L1 Inductor 3.3μH 8080(3232) - Isat=6.8A DCR=14.4mΩ
max ±30% DEM8045Z-3R3N=P3 Murata 1
U1 IC - 2.80x2.92 - - - - BD9E304FP4-LB ROHM 1
R5 - Short - - - - - Shorted by solder - 0
R6 - Open - - - - - - - 0
R0 - Short - - - - - Shorted by solder - 0
EN,
VIN_S,VIN_F,
GND_Fx2,
GND_Sx2,
SS,
VOUT_S,
VOUT_F
Test Pin - 1mm hole 10A - - - ST-2-2 Mac8 10
SW_EN Header - - - - - - 68000-103HLF Amphenol FCi 1
SW_EN Jumper - - - - - - QPC02SXGN-RC SULLINS 1

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© 2021 ROHM Co., Ltd. No. 63UG030E Rev.001
2021.7
User’s Guide
BD9E304FP4-EVK-001
Board Layout
EVK PCB information
Number of Layers Material Board Size Copper Thickness
4 FR-4 67.5mm x 67.5mm x 1.6mmt 1oz (35μm)
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The layout of BD9E304FP4-EVK-001 is shown below.
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Figure 3. Top Layer Layout
(Top View)
Figure 4. Middle1 Layer Layout
(Top View)
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Figure 5. Middle2 Layer Layout
(Top View)
Figure 6. Bottom Layer Layout
(Top View)

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© 2021 ROHM Co., Ltd. No. 63UG030E Rev.001
2021.7
User’s Guide
BD9E304FP4-EVK-001
Reference application data
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Figure 7. Operating Quiescent Current vs Input Voltage
VOUT=1.2V, IOUT=0A
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Figure 8. Switching Frequency vs Input Voltage
(VOUT=1.2V, IOUT=3A)
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Figure 9. Efficiency vs Output Current (VOUT=1.2V)
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0
20
40
60
80
100
5 6 7 8 9 10 11 12
Operating Supply Current: IOPR [µA]
Input Voltage: VIN [V]
255
270
285
300
315
330
345
5 6 7 8 9 10 11 12
Switching Frequency: fosc [kHz]
Input Voltage: VIN [V]
0
10
20
30
40
50
60
70
80
90
100
1 10 100 1000 10000
Efficiency: ƞ[%]
Output Current: IOUT [mA]
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© 2021 ROHM Co., Ltd. No. 63UG030E Rev.001
2021.7
User’s Guide
BD9E304FP4-EVK-001
Reference application data - continued
Figure 10. VOUT Load Regulation
(VIN=12V, VOUT=1.2V)
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Figure 11. VOUT Line Regulation
(VOUT=1.2V, IOUT=3A)
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Figure 12. Rise-up Waveform
(VEN=0V→12V, IOUT=3A)
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Figure 13. Shut-down Waveform
(VEN=12V→0V, IOUT=3A)
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-2.0
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
0 500 1000 1500 2000 2500 3000
Output Voltage Change: VCHANGE [%]
Output Current: IOUT [mA]
-2.0
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
5 6 7 8 9 10 11 12
Output Voltage Change: VCHANGE [%]
Input Voltage: VIN [V]
VOUT (1V/div)
SW (10V/div)
EN (10V/div)
VIN (10V/div)
2ms/div
VIN (10V/div)
EN (10V/div)
VOUT (1V/div)
SW (10V/div)

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© 2021 ROHM Co., Ltd. No. 63UG030E Rev.001
2021.7
User’s Guide
BD9E304FP4-EVK-001
Reference application data - continued
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Figure 14. SW Waveform
VIN=12V, VOUT=1.2V, IOUT=30A
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Figure 15. SW Waveform
(VIN=12V, VOUT=1.2V, IOUT=3A)
Figure 16. Frequency Response
(VIN=12V, IOUT=3A)
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
µ
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
µ
VOUT AC (50mV/div)
SW (5V/div) 40µs/div SW (5V/div)
VOUT AC (50mV/div)
2µs/div
6.07kHz

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© 2021 ROHM Co., Ltd. No. 63UG030E Rev.001
2021.7
User’s Guide
BD9E304FP4-EVK-001
Products lists in the Parts list
The product names listed in the parts list are available during the time of creating this user’s guide. In case some parts are
no longer available in the future, select the equivalent products.
Selection of Ceramic Capacitors
In selecting the ceramic capacitors, consider the DC bias characteristics and select the parts with equivalent actual
capacitance of capacitors in the Parts List (Table 2). For reference, Figure 17 shows the DC bias characteristics of
GRM32EC72A106KE05 (Murata) listed as C2 in the Parts list (Table 2). Actual capacitance degrades to 8.1μF under the
condition of 12V output (DC bias voltage is 12V). When selecting an alternative component, select the product that has same
capacitance under 12V of DC bias voltage. (The data shown in Figure 18 is for reference only. Please check with the capacitor
manufacturer for the DC bias characteristics of ceramic capacitors.)
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Figure 17. GRM32EC72A106KE05 (Murata) DC bias characteristics
DC bias characteristics
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© 2021 ROHM Co., Ltd. No. 63UG030E Rev.001
2021.7
User’s Guide
BD9E304FP4-EVK-001
Revision History
Date
Revision
Number Description
28.Jul.2021 001 Initial release
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