Datasheet
2.7 V to 5.5 V Input, 2 A
Single Synchronous Buck DC/DC Converter
for Automotive
BD9S201NUX-C
General Description
BD9S201NUX-C is a synchronous buck DC/DC
Converter with built-in low On Resistance power
MOSFETs. It is capable of providing current up to 2 A.
Small inductor is applicable due to high switching
frequency of 2.2 MHz. It is a current mode control
DC/DC Converter and features high-speed transient
response. It has a built-in phase compensation circuit.
Applications can be created with a few external
components.
Key Specifications
Input Voltage:
2.7 V to 5.5 V
Output Voltage Setting:
0.8 V to V
IN
Output Current:
2 A (Max)
Switching Frequency:
2.2 MHz (Typ)
High Side FET ON Resistance:
150 mΩ (Typ)
Low Side FET ON Resistance:
95 mΩ (Typ)
Shutdown Circuit Current:
0 μA (Typ)
Operating Temperature:
-40 °C to +125 °C
W (Typ) x D (Typ) x H (Max)
2.0 mm x 2.0 mm x 0.6 mm
Features
AEC-Q100 Qualified
(Note 1)
Single Synchronous Buck DC/DC Converter
Adjustable Soft Start Function
Output Discharge Function
Power Good Output
Input Under Voltage Lockout Protection (UVLO)
Short Circuit Protection (SCP)
Output Over Voltage Protection (OVP)
Over Current Protection (OCP)
Thermal Shutdown Protection (TSD)
Package
VSON008X2020
(Note 1)
Grade 1
Applications
Automotive Equipment
Other Electronic Equipment
Typical Application Circuit
V
IN
VIN
PGD
C
IN1
V
EN
EN
SW
L
1
V
OUT
SS
C
OUT1
R
1
GND
FB
R
2
Figure 1. Application Circuit
〇Product
structure : Silicon integrated circuit
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〇This
product has no designed protection against radioactive rays
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BD9S201NUX-C
Pin Configuration
SW
1
8
GND
SW
2
EXP-PAD
7
VIN
SS
3
6
EN
FB
4
5
PGD
(TOP VIEW)
Pin Descriptions
Pin No.
1, 2
3
4
5
6
7
8
-
Pin Name
SW
SS
FB
PGD
EN
VIN
GND
EXP-PAD
Function
Switch pin. These pins are connected to the drain of the High Side FET and the Low Side FET.
Pin for setting the soft start time. The rise time of the output voltage can be specified by
connecting a capacitor to this pin. See
page 17
for how to calculate the capacitance.
V
OUT
feedback pin. Connect output voltage divider to this pin to set the output voltage. See
page
15
on how to compute for the resistor values.
Power Good pin, an open drain output. It is need to be pulled up to the power supply with a
resistor. See
page 11
for setting the resistance.
Pin for controlling the device. Turning this pin Low forces the device to enter the shutdown mode.
Turning this pin High makes the device to start up.
Power supply pin. Connecting a 10 µF (Typ) ceramic capacitor is recommended. The detail of a
selection is described in
page 16.
Ground pin.
A backside heat dissipation pad. Connecting to the internal PCB ground plane by using via
provides excellent heat dissipation characteristics.
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Block Diagram
EN
6
SS
3
VREF
Slope
VIN
7
Soft
Start
Error
Amplifier
PWM
Comparator
FB
4
OCP
VIN
R
S
OSC
Q
Driver
Logic
SW
1
2
V
OUT
UVLO
SCP
OVP
R
Discharge
GND
Power
Good
5
PGD
TSD
8
Figure 2. Block Diagram
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Description of Blocks
1. VREF
The VREF block generates the internal reference voltage.
2. UVLO (Under Voltage Lockout)
The UVLO block is for under voltage lockout protection. It shuts down the device when the V
IN
falls to 2.45 V (Typ) or lower.
The threshold voltage has a hysteresis of 100 mV (Typ).
3. SCP (Short Circuit Protection)
This is the short circuit protection circuit. After soft start is judged to be completed, if the FB pin voltage falls to 0.56 V (Typ)
or less and remain in that state for 1 ms (Typ), output MOSFETs turn OFF for 14 ms (Typ) and then restart the operation.
4. OVP (Over Voltage Protection)
This is the output over voltage protection circuit. When the FB pin voltage becomes 0.88 V (Typ) or more, it turns the output
MOSFETs OFF. After output voltage falls 0.856 V (Typ) or less, the output MOSFETs return to normal operation.
5. TSD (Thermal Shutdown)
This is the thermal shutdown circuit. It shuts down the device when the junction temperature (Tj) reaches to 175 °C (Typ)
or more. When the Tj falls below the TSD threshold, the circuits are automatically restored to normal operation with
hysteresis of 25 °C (Typ).
6. OCP (Over Current Protection)
The Over Current Protection function operates by limiting the current that flows through High Side FET at each cycle of
the switching frequency.
7. Soft Start
The Soft Start circuit slows down the rise of output voltage during startup, which allows the prevention of output voltage
overshoot. The soft start time of the output voltage can be specified by connecting a capacitor to the SS pin. See
page 17
for how to calculate the capacitance. A built-in soft start function is provided and a soft start is initiated in 1 ms (Typ) when
the SS pin is open.
8. Error Amplifier
The Error Amplifier block is an error amplifier and its inputs are the reference voltage and the FB pin voltage.
9. PWM Comparator
The PWM Comparator block compares the output voltage of the Error Amplifier and the Slope signal to determine the
output switching pulse duty.
10. OSC (Oscillator)
This block generates the oscillating frequency.
11. Driver Logic
This block controls switching operation and various protection functions.
12. Power Good
When the FB pin voltage reaches 0.8 V (Typ) within ±7 %, the built-in Nch MOSFET turns OFF and the PGD output turns
high. There is a 3 % hysteresis on the threshold voltage, so the PGD output turns low when the FB pin voltage reaches
outside ±10 % of 0.8 V (Typ).
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BD9S201NUX-C
Absolute Maximum Ratings
Parameter
Input Voltage
EN Voltage
PGD Voltage
FB, SS Voltage
Maximum Junction Temperature
Storage Temperature Range
Symbol
V
IN
V
EN
V
PGD
V
FB,
V
SS
Tjmax
Tstg
Rating
-0.3 to +7
-0.3 to V
IN
-0.3 to +7
-0.3 to V
IN
150
-55 to +150
Unit
V
V
V
V
°C
°C
Caution 1:
Operating the IC over the absolute maximum ratings may damage the IC. The damage can either be a short circuit between pins or an open circuit
between pins and the internal circuitry. Therefore, it is important to consider circuit protection measures, such as adding a fuse, in case the IC is
operated over the absolute maximum ratings.
Caution 2:
Should by any chance the maximum junction temperature rating be exceeded the rise in temperature of the chip may result in deterioration of the
properties of the chip. In case of exceeding this absolute maximum rating, design a PCB with thermal resistance taken into consideration by
increasing board size and copper area so as not to exceed the maximum junction temperature rating.
Thermal Resistance
(Note 1)
Parameter
VSON008X2020
Junction to Ambient
Junction to Top Characterization Parameter
(Note 2)
θ
JA
Ψ
JT
181.90
20.00
47.90
7.00
°C/W
°C/W
Symbol
Thermal Resistance (Typ)
1s
(Note 3)
2s2p
(Note
4)
Unit
(Note 1)
Based on JESD51-2A(Still-Air), using a BD9S201NUX-C Chip.
(Note 2)
The thermal characterization parameter to report the difference between junction temperature and the temperature at the top center of the outside surface
of the component package.
(Note 3)
Using a PCB board based on JESD51-3.
(Note 4)
Using a PCB board based on JESD51-5, 7.
Layer Number of
Measurement Board
Single
Top
Copper Pattern
Footprints and Traces
Layer Number of
Measurement Board
4 Layers
Top
Copper Pattern
Footprints and Traces
Material
FR-4
Thickness
70 μm
Material
FR-4
Thickness
70 μm
Board Size
114.3 mm x 76.2 mm x 1.57 mmt
Board Size
114.3 mm x 76.2 mm x 1.6 mmt
2 Internal Layers
Copper Pattern
74.2 mm x 74.2 mm
Thickness
35 μm
Thermal Via
(Note 5)
Pitch
Diameter
1.20 mm
Φ0.30 mm
Bottom
Copper Pattern
74.2 mm x 74.2 mm
Thickness
70 μm
(Note 5)
This thermal via connects with the copper pattern of all layers.
Recommended Operating Conditions
Parameter
Input Voltage
Operating Temperature
Output Current
Symbol
V
IN
Ta
I
OUT
Min
2.7
-40
-
Max
5.5
+125
2.0
Unit
V
°C
A
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