Renesas RTKA211651DE0000BU User manual

Evaluation Board Manual
R16UH0013EU0100 Rev.1.0 Page 1
May 6, 2021 © 2021 Renesas Electronics
The RAA211651 is an integrated 60V, 5A
synchronous buck regulator with constant on time
modulating scheme. It supports a wide input voltage
range from 4.5V to 60V and adjustable output voltage.
The RAA211651 is offered in a 28Ld QFN package.
The RTKA211651DE0000BU evaluation board
provides a quick and comprehensive platform for
evaluating the high-performance features of
RAA2116510 buck regulator.
The RTKA211651DE0000BU evaluation board
operates from a supply voltage of 4.5V to 60VDC with
the capability of delivering continuous load of 5A.
Features
▪Switch selectable EN or option to drive it by
external signal
▪Internal and external compensation options
▪Internal and external soft-start options
▪Adjustable delay time options
▪Options to connect EBIAS to VOUT or drive by
external source
▪Output voltage programmable with external
feedback resistors
▪Options to use internal feedback resistors for 3.3V
VOUT
▪Connectors and test points for easy probing and
data acquisition
Specifications
This board is configured and optimized for the
following operating conditions:
▪Input voltage range:4.5V to 60V
▪Output voltage: 3.3V
▪Up to 5A output current capability
▪Internal compensation
▪Internal soft-start of 2ms
▪Start-up/shutdown delay of 2ms
▪EBIAS is connected to VOUT
▪Operating temperature range: -40°C to +125°C
Figure 1. RTKA211651DE0000BU Block Diagram
C
OUT
C
BOOT
C
IN
PGND
PHASE
BOOT
PVIN
COMP
AVCC
FB
VIN
V
OUT
(3.3V)
EN
EBIAS
C
EBI AS
PG
AGND
PVCC
SS
C
AVCC
C
PVCC
L
SET
C
DLY
RAA211651
R
SET
R
AVCC
R
PG
V3_DLY
EN
R
FB1
R
FB2
RTKA211651DE0000BU

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RTKA211651DE0000BU Evaluation Board Manual
Contents
1. Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1 Operating Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.2 Recommended Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.3 Quick Start Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.4 Connectors, Test Points, Selection Switches, and Jumper Descriptions . . . . . . . . . . . . . . . . . . . . . . . 4
1.4.1 Enable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.4.2 Soft-Start . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.4.3 Delay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.4.4 Set Resistor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.4.5 Compensation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.4.6 3.3V VOUT with Internal Feedback . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.4.7 Other Output Voltages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.4.8 EBIAS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2. Board Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.1 Layout Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.2 Schematic Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.3 Bill of Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.4 Board Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
3. Typical Performance Graphs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
4. Ordering Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
5. Revision History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

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RTKA211651DE0000BU Evaluation Board Manual
1. Functional Description
The RTKA211651DE0000BU provides a comprehensive and versatile platform for you to evaluate functionality
and prototype an application of the integrated 60V, 5A synchronous buck regulator RAA211651. This evaluation
board includes the options to evaluate most of the features of RAA211651. Either a toggle switch, jumper or 0Ω
jumper resistors have been used to evaluate the features.
1.1 Operating Range
The RTKA211651DE0000BU evaluation board evaluates the RAA211651 with PVIN from 4.5V to 60V and
continuous load of 5A. For proper functioning of the evaluation board, Renesas recommends operating the board
within the specifications.
The inductance, capacitance and RSET values for the regulator are chosen for 3.3V VOUT and 500kHz switching
frequency at full load(5A). You can replace these components with different values if a different operating
condition is required.
Also, you can change the EBIAS to an external source(<12V), soft-start time, start-up delay, compensation, and
on-time/switching frequency. See the RAA211651 datasheet and design spreadsheet to calculate the components
for a required setting.
Updates on the output inductor, capacitors, and R8 may be required with changes on the operating VOUT, load,
and switching frequency.
1.2 Recommended Equipment
▪Power supply that can deliver 5V or higher with at least 5A source current capability
▪Electronic load capable of sinking at least 5A current
▪4-channel oscilloscope with voltage and current probes
1.3 Quick Start Guide
Use the following Quick Setup Guide to configure and power-up the board for proper operation.
1. Set the power supply voltage to 12V and turn off the power supply. Connect the positive output of the power
supply to J1 (PVIN) and the negative output to J2 (GND).
2. Connect an electronic load to J5 (VOUT) for the positive connection and J4 (GND) for the negative connection.
3. Place scope probes to VOUT (J3), PHASE (J6), and/or other test points of interest.
4. Toggle the selection switch SW1 to ON position.
5. Set the load current to 0.1A and turn on the power supply. The output voltage should be in regulation with
nominal 3.3V output.
6. Slowly increase the load up to 5A. The output voltage should remain in regulation with nominal 3.3V output.
7. Slowly sweep PVIN from 4.5V to 60V. The output voltage should remain in regulation with nominal 3.3V output.
8. Decrease the input voltage to 0V to shut down the regulator.

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RTKA211651DE0000BU Evaluation Board Manual
1.4 Connectors, Test Points, Selection Switches, and Jumper Descriptions
The RTKA211651DE0000BU evaluation board includes I/O connectors, test points, selection switch, and jumpers
to provide a comprehensive and versatile platform for evaluation of RAA211651.Tab le 1 shows the description of
them.
1.4.1 Enable
Switch SW1 enables and disables RAA211651. SW1 in position ON ties EN to PVIN through the R1, R2 divider on
PVIN. The EN threshold can be changed by changing the values of R1 and R2. With SW1 in OFF position, EN
can be driven by external source as well.
1.4.2 Soft-Start
The RTKA211651DE0000BU is set for an internal soft-start of 2ms. To change the soft-start time, remove R10 and
update C6 to get the required soft-start time using Equation 9.
where tss is the soft-start time in milliseconds.
1.4.3 Delay
The RTKA211651DE0000BU is set for start-up delay of 2ms. To change the delay time, change C8 using
Equation 10.
where tDELAY is the delay time in milliseconds.
Note: If no delay is required, mount a 0Ωresistor for R14.
Table 1. Connectors, Test Points, Selection Switches, and Jumper Descriptions
Reference Designator Description
J1 Input voltage positive connection
J2 Input voltage return connection
J3 VOUT/GND test points
J4 Output voltage return connection
J5 Output voltage positive connection
J6 PHASE/GND test points
PVIN_1 PVIN test point
GND_2, GND_3, GND_5 GND test points
EN ENABLE test point
V3_DLY DELAY test point
EBIAS EBIAS positive connection
PG Power-good output test point
SW1 Toggle switch to ENABLE regulator with PVIN
(EQ. 9)
(EQ. 10)
C6nF 6.25tSS ms=
C8nF 4.17tDELAY ms=

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RTKA211651DE0000BU Evaluation Board Manual
1.4.4 Set Resistor
The RTKA211651DE0000BU is set with R8 = 82.5kΩ, which sets for switching frequency close to 500kHz for
VOUT of 3.3V. Note: The switching frequency varies with the load. R8 can be changed for different operating
condition using Equation 11.
1.4.5 Compensation
The RTKA211651DE0000BU is set for internal compensation, operates with Diode Emulation Mode (DEM). To
change to an external compensation, remove R12 and update R15, C9, and C7. This puts the regulator to work in
Continuous Conduction Mode (CCM). Verify the compensation using the design spreadsheet.
1.4.6 3.3V VOUT with Internal Feedback
The RAA211651 has an internal feedback for a 3.3V VOUT setting. To use this feature, remove R22, C20, R23,
and R21, and use a 0Ωresistor for R24.
1.4.7 Other Output Voltages
RTKA211651DE0000BU is set for 3.3V VOUT using R21 and R23. Other output voltages are programmable by
updating the values for these resistors. Renesas recommends keeping R21 as 20kΩand change the value for
R23 using Equation 12.
With the change on VOUT, update the output inductor, capacitors, and R9 using the design spreadsheet.
1.4.8 EBIAS
EBIAS improves efficiency for the internal bias supply. The default setting on the board uses VOUT as source of
EBIAS. Limit the EBIAS source to 12V. If VOUT is more than 12V, remove R19 and an external EBIAS source
(within EBIAS specification) can be used by connecting the source to EBIAS and GND_3 test points. If EBIAS is
not used, remove R19 and install a 0Ωresistor for R20.
(EQ. 11)
(EQ. 12)
R8 k12.5 106
VOUT 
fSW
--------------------------------------------------=
R23 R21
VOUT
0.8
----------------1–


=

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RTKA211651DE0000BU Evaluation Board Manual
2. Board Design
Figure 2. RTKA211651DE0000BU Evaluation Board (Top)
Figure 3. RTKA211651DE0000BU Evaluation Board (Bottom)

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RTKA211651DE0000BU Evaluation Board Manual
2.1 Layout Guidelines
The printed circuit board (PCB) layout is critical for proper operation of the RAA211651. The following guidelines
are recommended to achieve good performance.
1. Use multilayer PCB structure to achieve optimized performance. Renesas recommends using a four layer PCB
with 2oz copper on outer and 1oz copper in inner layers.
2. Use the combination of a bulk capacitor and smaller ceramic capacitors with low ESL for input capacitors and
place them as close as possible to the IC. Place the ceramic input capacitor on the same PCB surface layer.
3. Place the ceramic AVCC capacitor on the same PCB surface layer as the regulator and as close as possible
to the AVCC and AGND pins. Use a 1µF ceramic capacitor for AVCC and use a 1Ωresistor to connect AVCC
to PVCC.
4. Place the ceramic PVCC capacitor on the same PCB surface layer as the regulator and as close as possible
to the PVCC and PGND pins.
5. Add plenty of thermal vias under the exposed pad of the regulator for better heat dissipation. Connect the vias
to GND planes underneath.
6. Route the output voltage feedback signal away from BOOST and PHASE. Place feedback resistors close to
FB pin of the regulator.
7. Place bootstrap capacitor close to the IC between BOOT and PHASE pins on same PCB layer as the regulator.
Renesas recommends using a 0.1µF ceramic capacitor.
8. The copper area of the PHASE NODE should not be more than needed. Place the inductor close to regulator.
9. Place an output capacitor close to the inductor.
10. Keep SET resistor close to the SET pin. Avoid running other analog signals close to the SET pin or SET resistor.

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2.2 Schematic Diagram
Figure 4. RTKA211651DE0000BU Schematic
RED
GND
BLACK
GND
BLACK
RED
GND PHASE
OUT
IN
0.1UF
C11
DNP
C28
GND_3
Default
100K
R2
8200PF
C8
20
R22
EN
Default
C13
2.2UF
J2
12
J3
EBIAS
Default
100K
R1
C22
10UF
C15
10UF
J1
PG
J4
C6
8200PF
C19
10UF
C5
10UF
OPEN
C9
C23
10UF
Default
GND_2
100K
R18
J5
0
R10
C20
22PF
DNP
R15
R24
DNP
C17
10UF
68UF C1
1
R17
12
J6
10UF C21
0.1UF
C14
10UF C24
DNP
R20
10UF
C2
NC
SS
NC
BOOT
PHASE PHASE PHASE PHASE
PHASE
PGND
PVIN
EP
V3_DLY PG
AGND
EBIAS
PVCC
PVIN
PGND
PGND
EN
PGND
COMP
FB
PGND
AVCC
PVIN
PVIN
SET
U1
RAA2116514GNP#HA0
1
2
3
4
5
6
7
8
9
10 11 12 13 14
15
16
17
18
19
20
21
22
23 24 25 26 27 28
29
DNP
R14
DNP
C25
Default
GND_5
0
R19
10UF
C3
L1
3.3UH
744325330
1 2
OPEN
C7
20K R21
10K
R3
1UF
C10
DNP
C26
82.5K
R8
10UF C18
10UF
C4
2.2UF
C12
0
R12
SW1
1
2
3
V3_DLY
Default
DNP
C27
Default
PVIN_1
R23 62K
0.1UF
C29
AVCC
AVCC
AVCC
AVCC
AVCC
AVCC
AVCC
BOOT
COMP
EBIAS
EN
FB
PG
PHASE
PVCC
PVIN
PVIN
PVIN
SET
SS/ST
UNNAMED_3_GTSERI ES_I834_NC
UNNAMED_3_GTSERIES_I834_NO
UNNAMED_3_SMCAP_I730_A
UNNAMED_3_SMCAP_I733_A
V3_DLY
VOUT

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RTKA211651DE0000BU Evaluation Board Manual
2.3 Bill of Materials
Qty Reference Designator Description Manufacturer
Manufacturer
Part Number
1SW1 SWITCH-TOGGLE, TH, 5PIN, SPDT, 2POS,
On-None-On, ROHS
C&K GT11MCBE
3EN, EBIAS, PVIN_1 CONN-Miniature Red Test Point, Vertical,
ROHS
Keystone 5000
3GND_2, GND_3,
GND_5
CONN-Miniature Black Test Point, Vertical,
ROHS
Keystone 5001
2PG, V3_DLY CONN-Miniature White Test Point, Vertical,
ROHS
Keystone 5002
4J1, J2, J4, J5 CONN-SOLDER MOUNT BANANA PLUG Keystone 575-4
3J3, J6 CONN-HEADER, 2 Pin, BLK, 2.54mm Pitch,
ROHS
Samtec TSW-102-07-G-S
1L1 COIL-INDUCTOR, SMD,10.2mmx10.5mm,
3.3µH, 12A, 20%, ROHS
Wurth
Elektronik
744325330
1R23 RES, SMD, 0603, 62k, 1/10W, 1%, TF, ROHS Panasonic ERJ-2RKF6202X
0R14, R15, R20, R24 RES, SMD, 0603, DNP-Place Holder, ROHS
1R22 RES, SMD, 0603, 20Ω, 1/16W, 1%, TF, ROHS Generic H2511-00200-1/16W1
3R10, R12, R19 RES, SMD, 0603, 0Ω, 1/10W, 1%, TF, ROHS Generic H2511-00R00-1/10W1
2R3 RES, SMD, 0603, 010k, 1/10W, 1%, TF, ROHS Generic H2511-01002-1/10W1
3R1, R2, R18 RES, SMD, 0603, 100k, 1/10W, 1%, TF, ROHS Generic H2511-01003-1/10W1
1R21 RES, SMD, 0603, 20k, 1/10W, 1%, TF, ROHS Generic H2511-02002-1/10W1
1R8 RES, SMD, 0603, 82.5k, 1/16W, 1%, TF, ROHS Generic H2511-03012-1/16W1
1R17 RES, SMD, 0603, 1Ω, 1/10W, 1%, TF, ROHS Vishay RCA06031R00FKEA
0C25-C28 CAP, SMD, 3x4, DNP-Place Holder, ROHS
1C10 CAP, SMD, 0603, 1µF, 10V, 10%, X7R, ROHS Murata GRM188R71A105KA61D
3C11, C14, C29 CAP, SMD, 0603, 0.1µF, 100V, 10%, X7R,
ROHS
Murata GRM188R72A104KA35J
12 C2-C5, C15, C17-C19,
C21-C24
CAP, SMD, 1210, 10µF, 100V, 10%, X7S,
ROHS
Murata GRM32EC72A106KE05L
1C20 CAP, SMD, 0603, 22pF, 50V, 5%, C0G, ROHS Generic H1045-00220-50V5
2C6, C8 CAP, SMD, 0603, 8.2nF, 25V, 5%, X7R, ROHS Generic H1045-00822-25V10
0C7, C9 CAP, SMD, 0603, DNP-Place Holder, ROHS Generic H1045-OPEN
2C12, C13 CAP, SMD, 0603, 2.2µF, 10V, 10%, X7R, ROHS Taiyo Yuden LMK107B7225KA-T
1C1 CAP, SMD,10mm(dia)x12mm(H), ALUM, 68µF,
20%, 80V, ROHS
Vishay MAL214699705E3
1U1 IC-BUCK Regulator, 28P, QFN, 4x5, ROHS Renesas RAA211651
1PCB PWB-PCB, RAA211651, REVA, ROHS Imagineering
Inc
RTKA211651DE0000BU_REVA

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RTKA211651DE0000BU Evaluation Board Manual
2.4 Board Layout
Figure 5. Silkscreen Top Layer Figure 6. Top Layer
Figure 7. Layer 2 Figure 8. Layer 3
Figure 9. Bottom Layer Figure 10. Silkscreen Bottom Layer

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RTKA211651DE0000BU Evaluation Board Manual
3. Typical Performance Graphs
4. Ordering Information
5. Revision History
PVIN = 24V, VOUT = 3.3V, L = 3.3µH, COUT = 80µF, RSET = 82.5kΩ, TA= +25°C, internal compensation, internal soft-start unless
otherwise stated.
Figure 11. Efficiency vs Load Current (VOUT = 3.3V) Figure 12. Steady-State Operation IOUT = 5A
Figure 13. Shutdown through EN, IOUT = 0A Figure 14. Shutdown through EN, IOUT = 0A
Part Number Description
RTKA211651DE0000BU RAA211651 28Ld QFN evaluation board
Revision Date Description
1.0 May 6, 2021 Initial release
60
65
70
75
80
85
90
95
100
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
Efficiency (%)
Load Current (A)
Vin = 5V Vin = 24V
Vin = 36V Vin = 60V
VOUT 2V/Div
1µs/Div
IL5A/Div
PHASE 10V/Div
5s/Div
Phase 20V/Div
IL 5A/Div
VOUT 2V/Div
ENABLE 10V/Div
VOUT 2V/Div
500µs/Div
IL2A/Div
ENABLE 10V/Div
PHASE 20V/Div

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(Rev.1.0 Mar 2020)