Renesas ISL81806EVAL1Z User manual

User Manual
X0119392 Rev.1.1 Page 1
May 13, 2021 © 2021 Renesas Electronics
The ISL81806EVAL1Z dual-phase evaluation board (shown in Figure 4) features the ISL81806, an 80V high
voltage dual synchronous buck controller, optimized for E-mode GaN FET, with external soft-start, independent
enable functions and UV/OV/OC/OT protection. A programmable switching frequency ranging from 100kHz to
2MHz helps to optimize the inductor size while the strong gate driver delivers up to 20A for the buck output.
Key Features
▪Wide input range: 18V to 80V
▪High light-load efficiency in pulse skipping DEM operation
▪Programmable soft-start
▪Optional DEM/PWM operation
▪Optional CC/HICCUP OCP protection
▪Supports pre-bias output with soft-start
▪PGOOD indicator
▪OVP, OTP, and UVP protection
▪Back-biased from output to improve efficiency
Specifications
The ISL81806EVAL1Z dual-phase evaluation board is designed for high current applications. The current rating of
the ISL81806EVAL1Z is limited by the FETs and inductor selected. The ISL81806EVAL1Z electrical ratings are
shown in Table 1.
Ordering Information
Related Literature
For a full list of related documents, visit our website:
▪ISL81806 device page
Table 1. ISL81806EVAL1Z Electrical Ratings
Parameter Rating
Input Voltage 18V to 80V
Switching Frequency 500kHz
Output Voltage 12V
Output Current 20A
Average Current OCP Setting Point 25A (Constant Current Setting Point)
Pulse by Pulse OCP Setting Point 20.5A (Each phase)
Hiccup OCP Setting point 24.5A (Each phase)
Part Number Description
ISL81806EVAL1Z High Voltage Dual Phase Buck Controller GaN FETs Evaluation Board
ISL81806EVAL1Z
Evaluation Board

X0119392 Rev.1.1 Page 2 May 13, 2021 ISL81806EVAL1Z User Manual
Figure 1. ISL81806EVAL1Z Block Diagram
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X0119392 Rev.1.1 Page 3
May 13, 2021
ISL81806EVAL1Z User Manual
1. Functional Description
The ISL81806EVAL1Z is the same test board used by Renesas application engineers and IC designers to
evaluate the performance of the ISL81806. The board provides an easy and complete evaluation of all the IC and
board functions.
As shown in Figure 3, 18V to 80V VIN is supplied to VIN and GND. The regulated 12V output on VOUT and GND
can supply up to 20A to the load. Because of the high power efficiency, the evaluation board can run at 20A
continuously with airflow 1700LFM at room ambient temperature conditions.
1.1 Recommended Testing Equipment
The following materials are recommended for testing:
▪0V to 80V power supply with at least 20A source current capability
▪Electronic loads capable of sinking current up to 30A
▪Digital Multimeter (DMMs)
▪100MHz quad-trace oscilloscope
1.2 Operating Range
The input voltage range is from 18V to 80V for an output voltage of 12V. If the output voltage is set to a lower
value, the minimum VIN can be reset to a lower value by changing the ratio of R10 and R11. The minimum EN
threshold that VIN can be set to is 4.5V.
The rated load current is 20A with the OCP point set at 20.5A at room ambient temperature conditions. The
operating temperature range of this board is -40°C to +85°C.
Note: Airflow is needed for higher temperature conditions.
1.3 Quick Test Guide
1. Ensure that the circuit is correctly connected to the power supply and electronic loads before applying any
power. See Figure 3 for the proper setup.
2. Turn on the power supply.
3. Adjust the input voltage (VIN) within the specified range and observe the output voltage. The output voltage
variation should be within 3%.
4. Adjust the load current within the specified range and observe the output voltage. The output voltage variation
should be within 3%.
5. Use an oscilloscope to observe output voltage ripple and phase node ringing. For accurate measurement, see
Figure 2 for the proper test setup.
Figure 2. Proper Probe Setup to Measure Output Ripple
Output Capacitor
or Power FET

X0119392 Rev.1.1 Page 4
May 13, 2021
ISL81806EVAL1Z User Manual
Figure 3. Proper Test Setup
A
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X0119392 Rev.1.1 Page 5
May 13, 2021
ISL81806EVAL1Z User Manual
2. Board Design
2.1 PCB Layout Guidelines
Careful attention to the Printed Circuit Board (PCB) layout requirements is necessary for the successful
implementation of an ISL81806 based DC/DC converter. The ISL81806 switches at a high frequency; therefore,
the switching times are short. At these switching frequencies, even the shortest trace has significant impedance
and the peak gate drive current rises significantly in an extremely short time. The transition speed of the current
from one device to another causes voltage spikes across the interconnecting impedances and parasitic circuit
elements. These voltage spikes can degrade efficiency, generate EMI, and increase device voltage stress and
ringing. Careful component selection and proper PCB layout minimize the magnitude of these voltage spikes.
Three sets of components are critical when using the ISL81806 DC/DC converter:
▪Controller
▪Switching power components
▪Small-signal components
The switching power components are the most critical to the layout because they switch a large amount of energy,
which tends to generate a large amount of noise. The critical small-signal components are those connected to
sensitive nodes or those supplying critical bias currents. A multilayer PCB is recommended.
Complete the following steps to optimize the PCB layout.
1. Place the input capacitors, GaN FETs, inductor, and output capacitor first. Isolate these power components on
dedicated areas of the board with their ground terminals adjacent to one another. Place the input and output
high frequency decoupling ceramic capacitors very close to the GaN FETs.
2. If signal components and the IC are placed separately from the power train, Renesas recommends using full
ground planes in the internal layers with shared SGND and PGND to simplify the layout design. Otherwise, use
separate ground planes for the power ground and the small signal ground. Connect the SGND and PGND
together close to the IC. Note: DO NOT connect them together anywhere else.
3. Keep the loop formed by the input capacitor, the top FET, and the bottom FET as small as possible.
4. Ensure the current paths from the input capacitor to the FETs, the power inductor, and the output capacitor are
as short as possible with maximum allowable trace widths.
5. Place the PWM controller IC close to the FETs Gates. Especially the high side FET. The FETs gate drive
connections should be short and wide. Place the IC over a quiet ground area. Avoid switching ground loop
currents in this area.
6. Place the VDD bypass capacitor very close to the VDD pin of the IC and connect its ground end to the PGND
pin. Connect the PGND pin to the ground plane by a via.
Note: DO NOT connect the PGND pin directly to the SGND EPAD.
7. Place the gate drive components (BOOT diodes and BOOT capacitors) together near the controller IC.
8. Place the output capacitors as close to the load as possible. Use short, wide copper regions to connect output
capacitors to load to avoid inductance and resistances.
9. Use copper filled polygons or wide, short traces to connect the junction of the upper FET, lower FET, and output
inductor. Keep the PHASE nodes connection to the IC short. Note: DO NOT unnecessarily oversize the copper
islands for the PHASE nodes. Because the phase nodes are subjected to high dv/dt voltages, the stray
capacitor formed between these islands and the surrounding circuitry tends to couple switching noise.
10. Create a separate small analog ground plane near the IC. Connect the SGND pin to this plane. Connect all
small signal grounding paths including feedback resistors, current monitoring resistors and capacitors,
soft-starting capacitors, loop compensation capacitors and resistors, and EN pull-down resistors to this SGND
plane.
11. Use a pair of traces with minimum loop for the input or output current sensing connection.

X0119392 Rev.1.1 Page 6
May 13, 2021
ISL81806EVAL1Z User Manual
12. Ensure the feedback connection to the output capacitor is short and direct.
2.2 ISL81806EVAL1Z Evaluation Board
Figure 4. ISL81806EVAL1Z Evaluation Board, Top View
Figure 5. ISL81806EVAL1Z Evaluation Board, Bottom View

X0119392 Rev.1.1 Page 7 May 13, 2021 ISL81806EVAL1Z User Manual
2.3 ISL81806EVAL1Z Circuit Schematic
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X0119392 Rev.1.1 Page 8
May 13, 2021
ISL81806EVAL1Z User Manual
2.4 Bill of Materials
Qty Reference Designator Description Manufacturer Manufacturer Part
1PWB-PCB,
ISL81806EVAL1Z, REVF,
ROHS
MTL (Multilayer PCB
International)
ISL81806EVAL1ZREVFPCB
1 C65 CAP, SMD, 0603, 0.01µF,
50V, 5%, C0G/NP0, SOFT
TERMINATION, ROHS
TDK C1608C0G1H103J080AE
3 C52, C54, C55 CAP, SMD, 0603, 1000pF,
50V, 10%, X7R, ROHS
TDK C1608X7R1H102K
1 C51 CAP, SMD, 0603, 0.1µF,
100V, 10%, X7S, ROHS
TDK C1608X7S2A104K080AB
14 C16, C17, C18, C19, C20,
C21, C22, C41, C42, C43,
C44, C45, C46, C47
CAP, SMD, 0805, 22µF, 25V,
20%, X5R, LOW ESL,
ROHS
TDK C2012X5R1E226M125AC
24 C11, C12, C13, C36, C37,
C38, C39, C68, C69, C70,
C71, C72, C73, C76, C77,
C79, C81, C82, C83, C84,
C85, C86, C87, C88
CAP, SMD, 0805, 1µF, 100V,
10%, X7S, ROHS
TDK C2012X7S2A105K125AB
1 C66 CAP-AEC-Q200, SMD,
0603, 820pF, 50V, 5%,
C0G/NP0, ROHS
TDK CGA3E2C0G1H821J080AA
4 C24, C25, C49, C50 CAP, SMD, 0402, 0.01µF,
50V, 10%, X7R, ROHS
VENKEL C0402X7R500-103KNE
1 C61 CAP, SMD, 0402, 10µF, 10V,
20%, X5R, ROHS
SAMSUNG CL05A106MP8NUB8
2 C57, C64 CAP, SMD, 0402, 2.2µF,
25V, 10%, X5R, ROHS
TDK C1005X5R1E225K050BC
0 C15, C40 CAP, SMD, 0402, DNP-
PLACE HOLDER, ROHS
1 C62 CAP, SMD, 0603, 10µF, 16V,
10%, X5R, ROHS
MURATA GRM188R61C106KAALD
1 C53 CAP, SMD, 0603, 10µF, 25V,
20%, X5R, ROHS
TDK C1608X5R1E106M080AC
1 C59 CAP, SMD, 0603, 0.027µF,
50V, 10%, X7R, ROHS
VENKEL C0603X7R500-273KNE
1 C74 CAP, SMD, 0603, 47pF, 50V,
5%, C0G, NP0, ROHS
AVX 06035A470JAT2A
1 C58 CAP, SMD, 0603, 560pF,
50V, 5%, C0G, ROHS
VENKEL C0603C0G500-561JNE
1 C60 CAP, SMD, 0603, 0.056µF,
50V, 10%, X7R, ROHS
MURATA GRM188R71H563KA93D
0 C56, C63 CAP, SMD, 0603, DNP-
PLACE HOLDER, ROHS
10 C1, C2, C3, C4, C5, C26,
C27, C28, C29, C30
CAP-AEC-Q200, SMD,
0603, 0.22µF, 100V, 10%,
X7S, ROHS
TAIYO YUDEN HMK107C7224KAHTE

X0119392 Rev.1.1 Page 9
May 13, 2021
ISL81806EVAL1Z User Manual
5 C6, C7, C8, C31, C32 CAP-OSCON, SMD,
10.3mm, 27µF, 100V, 20%,
30mΩ, POLYMER, ROHS
PANASONIC 100SXV27M
1 C23 CAP, SMD, 10.3mm,
1200µF, 16V, 20%, 12mΩ,
ALUM.POLYMER, ROHS
PANASONIC 16SVPK12000M
2 L1, L2 COIL-PWR INDUCTOR,
AEC-Q200, SMD, 10.5x10,
3.3µH, 14.5A, WW, ROHS
TDK SPM10065VT-3R3M-D
4 TP1, TP2, TP3, TP4 CONN-PC PIN, W/FLANGE,
TH, 6.55mmPOST,
2.67mmTAIL, ROHS
KEYSTONE 1377-2
6 TP5, TP6, TP7, TP8, TP9,
TP10
CONN-COMPACT TEST PT,
VERTICAL, WHT, ROHS
KEYSTONE 5007
2 D6, D9 DIODE-ZENER, SMD, 0402,
5.6V, 250mW, 7%, 40Ω,
ROHS
DIODES, INC. BZT52C5V6LP-7
2 D13, D14 DIODE-SCHOTTKY, SMD,
SOD-323, 100V, 200mA,
ROHS
ON SEMICONDUCTOR NSR02100HT1G
3 D4, D7, D8 DIODE-SCHOTTKY, SMD,
2P, TUMD2M, 100V, 700mA,
ROHS
ROHM RB578VAM100TR
1 D2 LED, SMD, 0603, GREEN
CLEAR, 2V, 20mA, 574nm,
35mcd, ROHS
LITEON/VISHAY LTST-C191KGKT
1 U1 IC-80V PWM
CONTROLLER for GaN,
32P, TQFN, 5X5, ROHS
RENESAS ELECTRONICS ISL81806FRTZ
4 Q1, Q2, Q3, Q4 TRANSISTOR-GaNFET,
N-CHNL, 100V, 60A, SMD,
BUMPED-DIE, ROHS
EPC (Efficient Power
Conversion)
EPC2218
1 R10 RES, SMD, 0603, 48.7k,
1/10W, 1%, TF, ROHS
VISHAY/DALE CRCW060348K7FKEAC
1 R11 RES-AEC-Q200, SMD,
0805, 430k, 1/8W, 1%, TF,
ROHS
VISHAY/DALE CRCW0805430KFKEA
4 R2, R3, R7, R8 RES, SMD, 0402, 1Ω,
1/16W, 1%, TF, ROHS
VISHAY/DALE CRCW04021R00FKED
2 R38, R39 RES, SMD, 0402, 2.4Ω,
1/16W, 1%, TF, ROHS
VISHAY/DALE CRCW04022R40FKED
2 R21, R25 RES, SMD, 0402, 5.1Ω,
1/16W, 1%, TF, ROHS
YAGEO AC0402FR-075R1L
2 R40, R41 RES, SMD, 0402, 2k,
1/16W, 1%, TF, ROHS
PANASONIC ERJ-2RKF2001
2 R5, R9 RES, SMD, 0402, 20k,
1/16W, 1%, TF, ROHS
PANASONIC ERJ2RKF2001
2 R34, R35 RES, SMD, 0603, 2Ω,
1/10W, 1%, TF, ROHS
YAGEO 9C06031A2R00FGHFT
Qty Reference Designator Description Manufacturer Manufacturer Part

X0119392 Rev.1.1 Page 10
May 13, 2021
ISL81806EVAL1Z User Manual
1 R13 RES, SMD, 0603, 5.1Ω,
1/10W, 1%, TF, ROHS
YAGEO RC0603FR-075R1L
2 R14, R28 RES, SMD, 0603, 10k,
1/10W, 1%, TF, ROHS
VENKEL CR0603-10W-1002FT
4 R30, R32, R42, R43 RES, SMD, 0603, 100k,
1/10W, 1%, TF, ROHS
VENKEL CR0603-10W-1003FT
1 R12 RES, SMD, 0603, 200Ω,
1/10W, 1%, TF, ROHS
VENKEL CR0603-10W-2000FT
1 R15 RES, SMD, 0603, 20k,
1/10W, 1%, TF, ROHS
VENKEL CR0603-10W-2002FT
1 R19 RES, SMD, 0603, 34.8k,
1/10W, 1%, TF, ROHS
VENKEL CR0603-10W-3482FT
1 R31 RES, SMD, 0603, 36k,
1/10W, 1%, TF, ROHS
PANASONIC ERJ-3EKF3602V
1 R20 RES, SMD, 0603, 4.7k,
1/10W, 1%, TF, ROHS
YAGEO 9C06031A4701FKHFT
1 R16 RES, SMD, 0603, 487k,
1/10W, 1%, TF, ROHS
VENKEL CR0603-10W-4873FT
2 R27, R29 RES, SMD, 0603, 51k,
1/10W, 1%, TF, ROHS
YAGEO RC0603FR-0751KL
1 R22 RES, SMD, 0603, 68k,
1/10W, 1%, TF, ROHS
YAGEO RC0603FR-0768KL
1 R17 RES, SMD, 0603, 8.2k,
1/10W, 1%, TF, ROHS
ROHM MCR03EZPFX8201
0 R36, R37 RES, SMD, 0603, DNP-
PLACE HOLDER, ROHS
1 R4 RES, SMD, 0805, 5.1k,
1/8W, 1%, TF, ROHS
PANASONIC ERJ-6ENF5101V
2 R1, R6 RES-AEC-Q200, SMD,
0805-WIDE, 0.004Ω, 1W,
1%, ROHS
SUSUMU KRL2012E-M-R004-F-T5
1 R23 RES-AEC-Q200, SMD,
0603, 2.7k, 1/4W, 1%, TF,
ROHS
VISHAY/DALE RCS06032K70FKEA
4 Bottom four corners BUMPONS,
0.44inWx0.20inH,
CYLINDRICAL DOME, BLK,
ROHS
3M SJ-5003 (BLACK)
Qty Reference Designator Description Manufacturer Manufacturer Part