Renesas RTKA212831DR0000BU User manual

Demonstration Board Manual
R16UZ0022EU0101 Rev.1.01 Page 1
Jun 15, 2022 © 2021 Renesas Electronics
The RTKA212831DR0000BU provides a simple
platform to demonstrate the performances of the
RAA212831. The RAA212831 is an integrated 72V
input voltage, 0.5A output load one synchronous buck
regulator with fixed switching frequency from 350kHz
and two 100mA, and 50mA output load linear
regulators LDOs. The buck can support a wide input
voltage range of 14V to 72V and adjusted output
voltage from 1.25V to 24V. The LDO_3V3 can support
a wide input voltage range of 6V to 12V, and the
output voltage is fixed at 3.3V. The LDO_5 can
support a wide input voltage range of 6V to 12V, and
the output voltage is fixed at 5V. It is designed for
small size and high integration electric-bike control
board power management. Integrated buck and
LDOs minimize the system components.
The Buck converter adopts peak current mode
control, providing 500mA current for load and
downstream LDO regulators, while the following
LDOs provide 5V and 3.3V regulated power sources
to the system. The current-mode buck converter
provides a fast transient response and cycle-by-cycle
switching current limit. All output voltages are fixed
internally with few external components.
The RAA212831 has a fixed frequency operation,
even the output terminal is light load condition,
therefore, the switching frequency is fixed during the
load variation. The RAA212831 can also use external
components to achieve standby function to control
buck output voltage as 6V or 12V. When the chip
wants to save more energy with LDOs operations
only, the external component can control buck output
voltage from 12V to 6V.
Features
▪Buck Converter:
• 4.5V to 72V input voltage
• Adjustable output voltage from 1.25V to 24V
• 500mA output load capability
•0.6Ωhigh-side MOSEFT rDS(ON)
• Fixed switching frequency 350kHz operation
• High side OCP, UVP, UVLO, OTP fault protection
▪5V LDO Regulator:
• 6V to 12V input voltage
• Fixed output voltage 5V
• 100mA output load capability
• Current limit foldback function
▪3.3V LDO Regulator:
• 6V to 12V input voltage
• Fixed output voltage 3.3V
• 50mA output load capability
• Current limit foldback function
Specifications
This board is configured and optimized for the
following operating conditions:
▪VIN = 14V to 72V (For VOUT is operated at 6V~12V)
▪VOUT = 6V~12V (For LDOs normal operations)
▪IOUT_MAX = 0.5A
▪VLDO_5V = 5V
▪LDO_5V_MAX = 0.1A
▪VLDO_3V3 = 3.3V
▪ILDO_3V3_MAX = 0.05A
(a) Without External Standby Function (b) with external standby function
Figure 1. Typical Application Diagrams
RTKA212831DR0000BU

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RTKA212831DR0000BU Demonstration Board Manual
Contents
1. Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1 Operation Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.2 Setup and Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Board Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1 Layout Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.2 Schematic Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.3 Bill of Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.4 Board Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3. Typical Performance Graphs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
4. Ordering Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
5. Revision History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

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RTKA212831DR0000BU Demonstration Board Manual
1. Functional Description
The RTKA212831DR0000BU demonstration board provides a simple platform to demonstrate the features of the
RAA212831. The RTKA212831DR0000BU has a functionally optimized RAA212831 circuit layout that allows
efficient operation up to the maximum output current.
The RTKA212831DR0000BU demonstration board is shown in Figure 3 and Figure 4. Figure 5 shows the
schematic. The bill of materials and PCB layout information are also provided for your reference. Figure 8 through
Figure 31 show performance data taken using this hardware.
1.1 Operation Range
The RTKA212831DR0000BU demonstration board input voltage range is 14V to 72V. The output voltage is fixed
at 12V when the EXTFB test point is high and 6V when the EXTFB test point is low. It is a simple setting for use.
For the LDO_5V rail, the output voltage is 5V (default) with a 100mA maximum output current. For the LDO_3V3
rail, the output voltage is 3.3V (default) with a 50mA maximum output current.
1.2 Setup and Configuration
See Figure 2 and complete the following steps:
1. Connect the power supply to the input terminals VIN (J1) and GND (J6). Connect the load to the output
terminals, VOUT (J3) and GND (T2). Connect the load to the LDO_5V output terminals, LDO_5V (J2) and
GND(J8). Connect the load to the LDO_3V3 output terminals, LDO_3V3 (J2) and GND (J8).
2. Ensure the setup is correctly connected before applying any power or load to the board.
3. Turn on the power supply and the part should start operating.
4. Verify that the buck output voltage is 12V with the EXTFB test point high, and phase node waveforms can be
monitored at TP1. Verify that the LDO_5V output voltage is 5V and the LDO_3V3 output voltage is 3.3V.
Figure 2. RTKA212831DR0000BU Board Setup
+
-
++
Buck_Iout
--
LDO5V_Iout LDO3.3V_Iout
+
-
+
-
++
Buck_Iout
--
LDO5V_Iout LDO3.3V_Iout
+
-

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RTKA212831DR0000BU Demonstration Board Manual
2. Board Design
2.1 Layout Guidelines
A good PCB layout is important to achieve expected performance. Consideration should be taken when placing
the components and routing the trace to minimize the ground impedance and keep the parasitic inductance low.
The input and output capacitors should have a good ground connection and be placed as close to the IC as
possible. Place the LDO_VIN pin trace away from noisy planes and traces. The via pattern under the RAA212831
is connected to a large ground copper plane on the bottom layer for effective thermal dissipation.
Figure 3. RTKA212831DR0000BU Demonstration Board (Top)
Figure 4. RTKA212831DR0000BU Demonstration Board (Bottom)

R16UZ0022EU0101 Rev.1.01 Page 5 Jun 15, 2022 RTKA212831DR0000BU Demonstration Board Manual
2.2 Schematic Diagram
Figure 5. RTKA212831DR0000BU Board Circuit Schematic
GND
GND
GND
E
E E
E
E
E
E
E
E
TP10
4.7UF
C7
10UF
C1
R1
0
J8
1
0.1UF
C23
R4
20K
4.7UF
C8
R2 1.5
J7
1
TP3
76.8K
R3
10UF
C10
C5
1UF
J6
1
L1
120UH
C25
0.1UF
C14
0.068UF
TP4
J5
1
J3
1
0.1UF
C24
10
R12
TP1
J2
1
R6
15.8K
0.1UF
C12
TP5
J1
1
Q1
SI2342DS
C2
10UF
D1
B180-13-F
20
R8
LDO_VIN
BST
SW
LDO_3V3
LDO_5V
GND
VIN
FB
PAD
RAA212831
U1
1
2
34
5
6
7
8
9
TP2
C3
0.1UF
10UF
C9
OPEN
C4
EXTFB
LDO_3V3
LDO_5V
LDO_VIN
SW
UNNAMED_3_NCHA NNEL_I133_D
UNNAMED _3_NCHANNEL_I133_G
UNNAMED _3_RAA212831_I160_3
UNNAMED _3_RAA212831_I160_7
UNNAMED _3_SMCAP_I130_B
VIN
VOUT
VOUTN

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RTKA212831DR0000BU Demonstration Board Manual
2.3 Bill of Materials
Qty Ref Des Description Manufacturer Part Number
1 U1 IC SWITCHING REGULATOR, 8P, PSOP-8E, ROHS Renesas RAA212831GSP#AA0
1 L1 COIL PWR INDUCTOR, SM, 8mm, 120µH, 20%, 1.15A,
ROHS
Wurth 74404084121
1 D1 1A 80V SCHOTTKY BARRIER RECTIFIER Diodes B180-13-F
1 Q1 6A, 8V, N-Channel (D-S) MOSFET Vishay SI2342DS
2 C1, C2 CAP, SMD, 1206, 10µF, 35V, 10%, X7R, ROHS TDK CGA5L1X7R1V106K160AC
4C3,C23-
C25
CAP, SMD, 0603, 0.1µF, 16V, 10%, X7R, ROHS Murata GCM188R71C104KA37D
2 C7, C8 CAP, SMD, 0805, 4.7µF, 10V, 10%, X7R, ROHS Murata GRM21BR71A475KA73
1 C5 CAP, SMD, 0603, 1µF, 25V, 10%, X7R, ROHS Murata GCM188R71E105KA64D
2 C9, C10 CAP, SMD, 1210, 10µF, 100V, 10%, X7S, ROHS Murata GRM32EC72A106KE05L
1 C12 CAP, SMD, 0603, 0.1µF, 100V, 10%, X7R, ROHS Murata GRM188R72A104KA35J
1 C14 CAP, SMD, 0603, 0.068µF, 25V, 10%, X7R, ROHS Kemet C0603C683K3RACTU
1 R2 RES, SMD, 0603, 1.5Ω, 1/10W, 1%, ROHS Various Generic
1 R1 RES, SMD, 0603, 0Ω, 1/10W, 1%, ROHS Various Generic
1 R12 RES, SMD, 0603, 10Ω, 1/10W, 1%, ROHS Various Generic
1 R6 RES, SMD, 0603, 15.8kΩ, 1/10W, 1%, ROHS Various Generic
1 R4 RES, SMD, 0603, 20kΩ, 1/10W, 1%, ROHS Various Generic
1 R3 RES, SMD, 0603, 76.8kΩ, 1/10W, 1%, ROHS Various Generic
1 R8 RES, SMD, 0603, 20Ω, 1/10W, 1%, ROHS Various Generic
6 TP1-TP6 CONN MINI TEST POINT, VERTICAL, WHITE, ROHS Keystone 5002
7 J1-J3, J5-J8 CONN DBL TURRET, TH, 0.218x0.078 PCB MNT,
TIN/BRASS, ROHS
Keystone 1502-2

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RTKA212831DR0000BU Demonstration Board Manual
2.4 Board Layout
Figure 6. Top Layer
Figure 7. Bottom Layer

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RTKA212831DR0000BU Demonstration Board Manual
3. Typical Performance Graphs
VIN = 56V, VOUT = 6V, TA= +25°C, unless otherwise noted.
Figure 8. Load Regulation Figure 9. Efficiency
Figure 10. Buck Output Ripple at Full Load Figure 11. Buck Output Ripple at No Load
Figure 12. Power-On at Full Load Figure 13. Power-On at Full Load with LDO Channels
5.97
5.98
5.99
6.00
6.01
6.02
6.03
0 0.1 0.2 0.3 0.4 0.5
V
OUT
(V)
Output Load (A)
VIN = 16V VIN = 24V
VIN = 36V VIN = 48V
VIN = 56V VIN = 64V
VIN = 72V
30
40
50
60
70
80
90
100
0 0.1 0.2 0.3 0.4
0.5
Efficiency (%)
Output Load (A)
VIN = 16V VIN = 24V
VIN = 36V VIN = 48V
VIN = 56V VIN = 64V
VIN = 72V
VSW 10V/Div
VOUT 5mV/Div
IL 100mA/Div
IOUT 100mA/Div
2µs/Div
VSW 10V/Div
VOUT 10mV/Div
IL 100mA/Div
IOUT 100mA/Div
1ms/Div
VSW 10V/Div
VOUT 1V/Div
IL 100mA/Div
IOUT 100mA/Div
10ms/Div
VIN 10V/Div
VOUT 1V/Div
VLDO5V 1V/Div
VLDO3V3 500mV/Div
2ms/Div

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RTKA212831DR0000BU Demonstration Board Manual
Figure 14. Load Transient between 0.25A to 0.5A Figure 15. With External Standby Function at Full Load
VIN = 56V, VOUT = 12V, TA= +25°C, unless otherwise noted.
Figure 16. Load Regulation Figure 17. Efficiency
Figure 18. Buck Output Ripple at Full Load Figure 19. Buck Output Ripple at No Load
VIN = 56V, VOUT = 6V, TA= +25°C, unless otherwise noted.
VSW 10V/Div
VOUT 50mV/Div
IL 100mA/Div
IOUT 100mA/Div
200µs/Div
VSW 10V/Div
VOUT 2V/Div
IL 200mA/Div
VSTBY 500mV/Div
200µs/Div
11.96
11.97
11.98
11.99
12.00
12.01
12.02
12.03
12.04
0 0.1 0.2 0.3 0.4
0.5
VOUT (V)
Output Load (A)
VIN = 16V VIN = 24V
VIN = 36V VIN = 48V
VIN = 56V VIN = 64V
VIN = 72V
30
40
50
60
70
80
90
100
0 0.1 0.2 0.3 0.4
0.5
Efficiency (%)
Output Load (A)
VIN = 16V VIN = 24V
VIN = 36V VIN = 48V
VIN = 56V VIN = 64V
VIN = 72V
VSW 10V/Div
VOUT 500mV/Div
IL 100mA/Div
IOUT 100mA/Div
2µs/Div
VSW 10V/Div
VOUT 500mV/Div
IL 100mA/Div
IOUT 100mA/Div
400µs/Div

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RTKA212831DR0000BU Demonstration Board Manual
Figure 20. Power-On at Full Load Figure 21. Power-On at Full Load with LDO Channels
Figure 22. Load Transient between 0.25A to 0.5A Figure 23. UVP Fault with Hiccup Operation
VOUT = VINLDO = 6V, VLDO5V = 5V, VLDO3V3 = 3.3V, TA= +25°C, unless otherwise noted.
Figure 24. VLDO3V3 Load Regulation Figure 25. VLDO5V Load Regulation
VIN = 56V, VOUT = 12V, TA= +25°C, unless otherwise noted.
VSW 10V/Div
VOUT 2V/Div
IL 100mA/Div
IOUT 100mA/Div
10ms/Div
VIN 10V/Div
VOUT 2V/Div
VLDO5V 1V/Div
VLDO3V3 500mV/Div
2ms/Div
VSW 10V/Div
VOUT(AC) 50mV/Div
IL 100mA/Div
IOUT 100mA/Div
200µs/Div
VSW 10V/Div
VOUT 50mV/Div
IL 500mA/Div
10ms/Div
3.20
3.24
3.28
3.32
3.36
3.40
0 10203040
50
VLDO3.3V (V)
ILDO3.3V (mA)
4.90
4.94
4.98
5.02
5.06
5.10
0 20406080
100
VLDO5V (V)
ILDO5V (mA)

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RTKA212831DR0000BU Demonstration Board Manual
Figure 26. VLDO3V3 Load Transient between 0A to
0.05A
Figure 27. VLDO5V Load Transient between 0A to 0.1A
Figure 28. VLDO3V3 OCP Fault with Current Foldback Figure 29. VLDO5V OCP Fault with Current Foldback
Figure 30. VLDO3V3 PSRR at Full Load Figure 31. VLDO5V PSRR at Full Load
VOUT = VINLDO = 6V, VLDO5V = 5V, VLDO3V3 = 3.3V, TA= +25°C, unless otherwise noted. (Cont.)
VLDOIN 50mV/Div
VLDO3V3 10mV/Div
ILDO3V3 10mA/Div
200µs/Div
VLDOIN 50mV/Div
VLDO5V 20mV/Div
ILDO5V 20mA/Div
200µs/Div
VLDOIN 1V/Div
VLDO3V3 1V/Div
ILDO3V3 20mA/Div
2µs/Div
VLDOIN 1V/Div
VLDO5V 1V/Div
ILDO5V 20mA/Div
2µs/Div
10
15
20
25
30
35
40
45
50
55
60
65
100 1k 10k 100k 1M 10M
PSRR (dB)
Frequency (Hz)
10
15
20
25
30
35
40
45
50
55
60
65
70
75
100 1k 10k 100k 1M 10M
PSRR (dB)
Frequency (Hz)

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RTKA212831DR0000BU Demonstration Board Manual
4. Ordering Information
5. Revision History
Part Number Description
RTKA212831DR0000BU RAA212831 Demonstration Board
Revision Date Description
1.01 Jun 15, 2022 Updated Figures 3 and 4.
1.00 Sep 27, 2021 Initial release

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