User’s Guide
ROHM Solution Simulator
3.5V to 40V Input, 1A Single 2.2MHz Buck DC/DC Converter for Automotive

BD9P155MUF-C / Frequency Response
This circuit simulates the frequency response of BD9P155MUF-C. You can customize the simulation conditions by changing
the parameters of components highlighted in blue.

General Cautions
Caution 1: The values from the simulation results are not guaranteed. Please use these results as a guide for your design.
Caution 2: These model characteristics are specifically at Ta=25°C. Thus, the simulation result with temperature variancesmay significantly differ from the result with the one done at actual application board (actual measurement).
Caution 3: Please refer to the datasheet for details of the technical information.
Caution 4: The characteristics may change depending on the actual board design and ROHM strongly recommend to
double check those characteristics with actual board where the chips will be mounted on.

1

Simulation Schematic

VOUT
VIN

IOUT

Figure 1. Simulation Circuit

2

How to simulate
The simulation settings, such as frequency range or convergence options, areconfigurable from the ‘Simulation Settings’ shown in Figure 2, and Table 1 shows
the default setup of the simulation.
In case of simulation convergence issue, you can change
advanced options to solve.
The parameters V_VIN, V_VOUT and I_IOUT are defined in the‘Manual Options’.

Simulation
Settings
Simulate
Figure 2. Simulation Settings and execution

Table 1. Simulation settings default setup
Parameters
Default

Note

Simulation TypeFrequency-Domain

Start Frequency

100 HzEnd Frequency

1.0e6 Hz

Advanced options

Balanced

Manual Options“.param V_VIN=12 V_VOUT=5.0 I_IOUT=0.5”(Do not change Simulation Type)Simulate the frequency response for thefrequency range from 100Hz to 1MHz.

See “Simulation Condition” for details
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3

Simulation Conditions
3.1 How to define VIN, VOUT and IOUT
These parameters are used to setup the simulation conditions and BD9P155MUF-C_Average model parameters,
therefore these are defined in the Manual Options as the common variables.
Table 2 shows the default value of VIN, VOUT and IOUT. Those values are defined and can be set in the ‘Manual
Options’ text box from Simulation Settings as shown in Figure 3.
The output voltage of VBAT and the load resistance RL are automatically set according to those parameters.
Table 2. Simulation Conditions
Parameters
Variable Name
VIN
V_VIN
VOUT
V_VOUT
IOUT
I_IOUT

Default Value
125.0
0.5

Units
VV
A

Descriptions

Set V_VIN, V_VOUT and I_IOUT
Figure 3. Definition of VIN, VOUT and IOUT

3.2 Resistive Load RL
RL is the resistive load and its resistance is determined from V OUT and IOUT. The resistance value is defined as theequation below.
Table 3. Resistive load
Instance Name
RL

Default Value{V_VOUT/I_IOUT}

Unitohm

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BD9P155MUF-C Frequency Response

4

BD9P155MUF-C_Average model
The simulation model in this circuit is designed for frequency response, and the functions not related to frequency
response are not implemented.
Table 4. BD9P155_Average model terminals used for frequency response
Terminals
Description
Power supply input
PVIN, VIN
Enable input
EN
Power ground
PGND
Over current selector input
OCP_SEL
Switching nodeSWGround
GND
Table 5. BD9P155_Average model terminals NOT used for frequency response
Terminals
Description
Input is ignore (no switching operation in this model)
BST
Input is ignore (no switching operation in this model)
MODE
Input is ignore (no switching operation in this model)
SSCG
The function is not implemented
RESET
Input is ignore (no switching operation in this model)
VOUT_DIS
Function not implemented
VOUT_SNS
Function not implemented
VCC_EX
Function not implemented
VREG(Note 1) This model is not compatible with the influence of ambient temperature.
(Note 2) This model is not compatible with the external synchronization function.
(Note 3) Use the simulation results only as a design guide and the data reported herein is not a guaranteed value.

4.1

BD9P155MUF-C_Average Model Parameters

BD9P155MUF-C_Average model has its parameters shown in Table 6. All the parameters are pre-defined andfixed in the simulation. V_VIN is substituted to VIN_VOLTAGE as shown in Table 6.
Table 6. Parameter ListParameters
VIN_VOLTAGE

Values{V_VIN}

Description
VIN voltage

Figure 4. Property Editor of BD9P155MUF-C_Average model

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BD9P155MUF-C Frequency Response
5Peripheral Components
To set parameters of components, open ‘property’ by double click or right click on a component. You can input a value toa property text box if available. Please refer to the hands-on manual for more details.

5.1

Bill of Material
Table 7 shows the list of components used in the simulation schematic. Each of the capacitor and inductor has theparameters of equivalent circuit shown below. The default value of equivalent components are set to zero except forthe parallel resistance of L1. You can modify the values of each component.
Table 7. List of components used in the simulation circuit
TypeInstance Name
Default Value
CIN1
0.1
CIN2
4.7
Capacitor
CREG
1.0
COUT1
22Inductor
L1
4.7

Units
µF
µF
µF
µF
µH

5.2 Capacitor Equivalent Circuits(a) Property editor(b) Equivalent circuit
Figure 5. Capacitor property editor and equivalent circuit

5.3 Inductor Equivalent Circuits(a) Property editor(b) Equivalent circuitFigure 6. Inductor property editor and equivalent circuit
The default value of PAR_RES is 6.6kohm.
(Note 5) These parameters can take any positive value or zero in simulation but it does not guarantee the operationof the IC in any condition. Refer to the datasheet to determine adequate value of parameters.

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BD9P155MUF-C Frequency Response

6Open Loop Transfer Function (OLTF) Monitor
OLTF1 is the insert model to measure AC open loop transfer function and is inserted to acquire the gain and phase
output. To monitor the gain and phase from OLTF1, select probe items ‘dbMag’ for gain and ‘phase’ for phase plot,
respectively from ‘property’ of OLTF1.

Figure 7. Probe Items of OLTF1

7

Link to the product information and tools
7.1

Product webpage link:
https://www.rohm.com/products/power-management/switching-regulators/integrated-fet/buck-converters-synchron
ous/bd9p155muf-c-product

7.2

Related documents
The application notes are available from ‘Documentation’ tab of the product page.

7.3

Design assist tools are available from ‘Tools’ tab of the product page.
The Circuit constant calculation sheet is useful for Febiding the application circuit constants.

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NoticeNotes
1) The information contained herein is subject to change without notice.
2) Before you use our Products, please contact our sales representative and verify the latest specifications :3) Although ROHM is continuously working to improve product reliability and quality, semiconductors can break down and malfunction due to various factors.
Therefore, in order to prevent personal injury or fire arising from failure, please take safetymeasures such as complying with the derating characteristics, implementing redundant andfire prevention designs, and utilizing backups and fail-safe procedures. ROHM shall have noresponsibility for any damages arising out of the use of our Poducts beyond the rating specified byROHM.
4) Examples of application circuits, circuit constants and any other information contained herein areprovided only to illustrate the standard usage and operations of the Products. The peripheral
conditions must be taken into account when designing circuits for mass production.
5) The technical information specified herein is intended only to show the typical functions of andexamples of application circuits for the Products. ROHM does not grant you, explicitly or implicitly,
any license to use or exercise intellectual property or other rights held by ROHM or any otherparties. ROHM shall have no responsibility whatsoever for any dispute arising out of the use ofsuch technical information.
6) The Products specified in this document are not designed to be radiation tolerant.
7) For use of our Products in applications requiring a high degree of reliability (as exemplifiedbelow), please contact and consult with a ROHM representative : transportation equipment (i.e.
cars, ships, trains), primary communication equipment, traffic lights, fire/crime prevention, safety
equipment, medical systems, servers, solar cells, and power transmission systems.
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9) ROHM shall have no responsibility for any damages or injury arising from non-compliance withthe recommended usage conditions and specifications contained herein.
10) ROHM has used reasonable care to ensure the accuracy of the information contained in thisdocument. However, ROHM does not warrants that such information is error-free, and ROHM
shall have no responsibility for any damages arising from any inaccuracy or misprint of suchinformation.
11) Please use the Products in accordance with any applicable environmental laws and regulations,such as the RoHS Directive. For more details, including RoHS compatibility, please contact aROHM sales office. ROHM shall have no responsibility for any damages or losses resulting
non-compliance with any applicable laws or regulations.
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you must abide by the procedures and provisions stipulated in all applicable export laws andregulations, including without limitation the US Export Administration Regulations and the Foreign
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