Renesas RAA211805 User manual

Evaluation Board Manual
R16UZ0087EU0100 Rev.1.00 Page 1
Sep 22, 2023 © 2023 Renesas Electronics
The RAA211805 is an integrated 5V, 300mA buck
regulator with an ultra-low quiescent current (IQ) of
5.5µA. It supports a wide input voltage range from 7V
to 80V. The RAA211805 is offered in a TSOT23-5
package. The RTKA211805DE0000BU evaluation
board provides a quick and comprehensive platform
for evaluating the performance features of the
RAA211805 buck regulator.
The RTKA211805DE0000BU evaluation board
operates from a supply voltage of 7V to 80VDC,
delivering a continuous load up to 300mA at 5V
output voltage.
Specifications
This board is configured and optimized for the
following operating conditions:
▪Input voltage range: 7V to 80V
▪Output voltage: 5V
▪Up to 300mA output current capability
▪Inductor current limit of 750mA (typical) peak
▪Operating temperature range: -40°C to +125°C
Features
▪7V to 80V input supply range
▪Up to 300mA output current
▪IQ= 5.5µA at 80V, at no load conditions, switching
▪IQ= 4.5µA at 80V at no load and no switching
conditions
▪Minimum on-time of 75ns
▪Fixed 5V VOUT
▪Variable frequency operation, frequency
programmed by external inductor (15µH to 33µH)
▪Pre-bias start-up/Monotonic/ smooth start-up
▪Total of four external components
▪Protections: Overcurrent (OC) Limit, input
Undervoltage Lockout (UVLO), Over-Temperature
Protection (OTP), output Overvoltage Protection
(OVP)
▪Accurate EN threshold
Figure 1. RTKA211805DE0000BU Block Diagram
VIN
VOUT
SW
GND
EN
4
5
2
1
3
GND GND
VOUT = 5V
VSW
GND
VIN
R2
1Meg
U1
EN
CIN
4.7µF
D1
2
22µH
12
COUT2
22µF
J1
J2
J3
J4
TP3
TP1 TP2
L
RAA211805
COUT1
22µF
RTKA211805DE0000BU

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RTKA211805DE0000BU Evaluation Board Manual
Contents
1. Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1 Operational Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.2 Connectors, Test Points, Selection Switches, and Jumper Descriptions . . . . . . . . . . . . . . . . . . . . . . . 3
1.3 Recommended Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.4 Quick Start Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.5 Enable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.6 Soft-Start . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.7 Switching Frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Board Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.1 Layout Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.2 Schematic Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.3 Bill of Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.4 Board Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3. Typical Performance Graphs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
4. Ordering Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
5. Revision History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

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RTKA211805DE0000BU Evaluation Board Manual
1. Functional Description
The RTKA211805DE0000BU evaluation board provides a comprehensive and versatile platform to asses
functionality and prototype an application with the integrated 5V, 300mA buck regulator RAA211805. The board
has options for evaluating most features of the RAA211805 and includes test points that facilitate probing.
1.1 Operational Characteristics
The RTKA211805DE0000BU evaluation board evaluates the RAA211805 with VIN from 7V to 80V and a
continuous load of 300mA. Renesas recommends operating the board within the specifications for the proper
functioning of the evaluation board.
Connect EN to VIN through a resistor, or connect EN to external logic voltage for enable and disable.
1.2 Connectors, Test Points, Selection Switches, and Jumper Descriptions
The RTKA211805DE0000BU evaluation board includes I/O connectors, test points, selection switches, and
jumpers to provide a comprehensive and versatile platform for evaluating the RAA211805 (see Tabl e 1).
1.3 Recommended Equipment
▪Power supply that can deliver 80V or higher with at least 350mA source current capability
▪Electronic load capable of sinking at least 350mA current
▪4-channel oscilloscope with voltage and current probes
1.4 Quick Start Guide
Use the Quick Setup Guide to configure and power up the board properly.
1. Set the power supply voltage to 24V and turn off the power supply. Connect the positive output of the power
supply to J1 (VIN) and the negative output to J2 (GND).
2. Connect an electronic load to J3 (VOUT) for the positive connection and J4 (GND) for the negative connection.
3. Place scope probes to VOUT (J3), VSW (TP2), and/or other test points of interest.
4. Set the load current to 0.1A and turn on the power supply. The output voltage should be in regulation with a
nominal 5V output.
5. Slowly increase the load up to 300mA. The output voltage should remain in regulation with a nominal 5V output.
6. Slowly sweep VIN from 7V to 80V. The output voltage should remain in regulation with a nominal 5V output.
7. Decrease the input voltage to 0V to shut down the regulator.
Table 1. Connectors, Test Points, Selection Switches, and Jumper Descriptions
Reference
Designator Description
J1 Input voltage positive connection
J2 Input voltage return connection
J3 Output voltage positive connection
J4 Output voltage return connection
TP1 GND test point
TP2 VSW
TP3 ENABLE test point

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RTKA211805DE0000BU Evaluation Board Manual
1.5 Enable
EN is connected to VIN through R2. EN can be driven by an external source or by removing R2. Do not leave this
pin floating.
1.6 Soft-Start
RAA211805 is naturally current limited and automatically provides a smoothly rising VOUT voltage at power up.
Because the total output of the device is limited, a startup with a heavy load generates a longer VOUT ramp; a
startup with no load generates a faster ramp.
The approximate soft-start time[1] based on the RTKA211805DE0000BU with 24V input at no load is 360µs and
590µs at full load.
1.7 Switching Frequency
The regulator is a variable frequency converter, and the switching frequency varies proportionally to the load. The
maximum switching frequency is dependent on inductance and input voltage.
Figure 2 and Figure 3 show the bench data for the evaluation board. Use Equation 1 to approximate the switching
frequency.
1. Test conditions: VIN = 24V, COUT = 2x22µF (PN:GRM187R61A226ME15D), CIN = 4.7µF (PN:GRM31CC72A475KE11L),
L = 22µH (PN:74404054330), Power supply: Chroma-632012P-100-50, Load: Resistive Load equivalent to full load at nominal Vout.
Measured from 0 to 100% of nominal VOUT.
(EQ. 1)
Figure 2. Switching Frequency (Full Load, 300mA)
vs. Input Voltage
Figure 3. Switching Frequency vs. Load Current
SwitchingFrequency 2xIload
LxIpeakxIpeakx 1
VIN VOUT–
-----------------------------------1
VOUT
------------------
+


xefficiency
--------------------------------------------------------------------------------------------------------------------------------------------------
=
0
20
40
60
80
100
120
140
160
180
0204060
80
Switching Frequency (kHz)
Input Voltage (V)
L = 22µH
0
20
40
60
80
100
120
140
160
0 50 100 150 200 250
300
Switching Frequency (kHz)
Load Current (mA)
L = 22µH

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RTKA211805DE0000BU Evaluation Board Manual
2. Board Design
2.1 Layout Guidelines
The printed circuit board (PCB) layout is critical for properly operating the RAA211805. The following guidelines
are recommended to achieve optimal performance.
▪Use a multilayer PCB structure to achieve optimized performance. The evaluation board
RTKA211805DE0000BU uses a 2-layer PCB with 1oz copper and a bottom layer as ground.
▪Place the input capacitor as close as possible to the IC. The input capacitor is the most important component
for any step-down converter and should be placed first in the layout.
▪The copper area of the PHASE NODE should not be more than needed. Place the inductor close to the
regulator.
▪Place an output capacitor close to the inductor.
▪Place and route the power component to keep the power loop area as minimum and short as possible.
▪Keep all the power components on the same side of the PCB.
▪Include thermal vias as necessary to improve heat dissipation.
Figure 4. RTKA211805DE0000BU Evaluation Board (Top)

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RTKA211805DE0000BU Evaluation Board Manual
2.2 Schematic Diagram
2.3 Bill of Materials
Figure 5. RTKA211805DE0000BU Schematic
Qty Reference
Designator Description Manufacturer Manufacturer Part Number
1L
COIL-PWR Inductor, SMD, 5mm, 22µH, 20%,
1.35A, 225mΩDCR, WW, ROHS Wurth 74404052220
1 CIN Multilayer Cap, SMD, 1206, 4.7µF, 10%, 100V Murata GRM31CC72A475KE11L
1R2
Thick Film Chip Resistor, SMD, 0603, 1M, 1%,
1/10W Generic Various
1D1
0.5A 100V Low Vf Schottky Barrier Rectifier,
SOD323 Panjit BAS100CS_R1_00001
1U1
5V, 300mA DC-DC Buck Regulator with low
quiescent current, SOT23-5 Renesas RAA211805
1 COUT1 Multilayer Cap, SMD, 0805, 22µF, 20%, 16V Generic Various
4 COUT2 Multilayer Cap, SMD, 0805, 22µF, 20%, 16V Generic Various
1 J1, J2, J3, J4 Brass Test Point Turret, 0.150 Pad, 0.100 Thole,
PCB Depth <0.078 in Keystone 1502-1
2 GND Miniature Black Test Point, 0.100 Pad, 0.040 Thole Keystone 5001
2 VSW, EN Miniature White Test Point, 0.100 Pad, 0.040 Thole Keystone 5002
VIN
VOUT
VSW
GND
GND
GND
EN
D1
12
J2
22UH
L
1 2
J1
COUT1
22UF
CIN1
4.7UF
22UF
COUT2
U1
RAA2118054GP3#JA0
1
VOUT
2
GND
3
EN
4
VIN
5
SW
J3
R2
1M
J4
TP3
TP1
TP2
GND
UNNAMED _2_POWERIND_I71_AS1UNNAMED _2_POWERIND_I71_BS2
UNNAMED _2_RAA211805_I76_3UNNAMED _2_RAA211805_I76_4

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RTKA211805DE0000BU Evaluation Board Manual
2.4 Board Layout
Figure 6. Silkscreen Top
Figure 7. Top Layer
SW
GND
GND
GND EN
VIN
VOUT
GND
EN
VOUT
VIN
SW

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RTKA211805DE0000BU Evaluation Board Manual
Figure 8. Bottom Layer
Figure 9. Silkscreen Bottom

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RTKA211805DE0000BU Evaluation Board Manual
3. Typical Performance Graphs
VIN = 24V, VOUT = 5V, L = 22µH, IOUT = 300mA, COUT = 2x22µF, Ren = 1MΩ, TA= +25°C, internal compensation, internal soft-start
unless otherwise stated.
Figure 10. Startup through VIN Figure 11. Shutdown through VIN
Figure 12. Startup through EN Figure 13. Shutdown through EN
Figure 14. Short-Circuit Figure 15. Recovery from Short-Circuit and startup to
Full Load
VIN 3V/Div
VOUT 0.6V/Div
VSW 3V/Div
IL100mA/Div
520µs/Div
VIN 3V/Div
VOUT 0.6V/Div
VSW 3V/Div
IL100mA/Div
6ms/Div
VEN 0.4V/Div
VOUT 0.6V/Div
VSW 3V/Div
IL100mA/Div
300µs/Div
VEN 0.4V/Div
VOUT 0.6V/Div
VSW 3V/Div
IL100mA/Div
200µs/Div
VIN 3V/Div
VOUT 0.6V/Div
VSW 3V/Div
IL100mA/Div
100µs/Div
VIN 3V/Div
VOUT 0.6V/Div
VSW 3V/Div
IL100mA/Div
200µs/Div

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RTKA211805DE0000BU Evaluation Board Manual
Figure 16. Typical Operation (Full Load) Figure 17. Typical Operation (No Load)
Figure 18. Load Transient(10mA to 300mA) Figure 19. IQvs VIN (In Regulation: No Load)
Figure 20. Efficiency Figure 21. Load Regulation
VIN = 24V, VOUT = 5V, L = 22µH, IOUT = 300mA, COUT = 2x22µF, Ren = 1MΩ, TA= +25°C, internal compensation, internal soft-start
unless otherwise stated. (Cont.)
VIN 3V/Div
VOUT 50mV/Div (5V offset)
VSW 3V/Div
IL100mA/Div
20µs/Div
VIN 3V/Div
VOUT 50mV/Div (5V offset)
VSW 3V/Div
IL100mA/Div
100ms/Div
VIN 3V/Div
VOUT 50mV/Div (5V offset)
VSW 3V/Div
IL100mA/Div
560µs/Div
0
5
10
15
20
25
0204060
80
IQ(μA)
VIN (V)
n40C 0C
25C 55C
85C
40
45
50
55
60
65
70
75
80
0.0001 0.001 0.01 0.1
1
Efficiency (%)
Load Current (A)
12V 24V 40V
60V 80V
4.80
4.85
4.90
4.95
5.00
5.05
5.10
0.001 0.101 0.201 0.301
Output Voltage(V)
Load Current (A)
12V 24V 40V
60V 80V