Renesas ISL9123xIIx-EVZ User manual

Evaluation Board Manual
R16UZ0031EU0101 Rev.1.01 Page 1
Jul 26, 2023 © 2022-2023 Renesas Electronics
The ISL9123xIIx-EVZ platform allows quick
evaluation of the high-performance features of the
ISL9123, ISL9123A, and ISL9123B buck regulator.
The ISL9123 is a highly integrated buck switching
regulator that accepts input voltages above the
regulated output voltage. It features a remarkably low
quiescent current consumption, excellent efficiency,
and an I2C interface that allows access its internal
registers for output voltage and operation mode
control.
Features
▪Small, compact design
▪I2C interface for programmable VOUT, slew rate and
various operation modes (Forced Bypass
(ISL9123/A only), Auto-PFM, Forced PWM)
▪Connectors, test points, and jumpers for easy
probing
Specifications
The board operates with the following conditions:
▪Input voltage rating from 1.8V to 5.5V
▪Programmable output voltage range of 0.4V to
5.375V (ISL9123/A), and to 1.180V (ISL9123B),
and selectable transition slew rate through I2C
interface
▪Up to 600mA output current (VIN > 2.5V)
▪Operating temperature range: -40°C to +85°C
Figure 1. ISL9123xIIx-EVZ Block Diagram
VOUT
VOUT
VIN
VIN
GND
LX
VSW
EN
GND GND
SDA
SCL
I
2
C
VSW
ISL9123xIIx-EVZ

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ISL9123xIIx-EVZ Evaluation Board Manual
Contents
1. Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1 Operational Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.2 Setup and Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.3 Evaluation Software Installation and Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2. Board Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.1 ISL9123xIIx-EVZ (WLCSP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.1.1 Board Image . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.1.2 Circuit Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.1.3 Bill of Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.1.4 Board Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
2.2 Layout Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
3. Ordering Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
4. Revision History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

R16UZ0031EU0101 Rev.1.01 Page 3
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ISL9123xIIx-EVZ Evaluation Board Manual
1. Functional Description
The evaluation board (EVB) provides a simple platform to evaluate the feature-rich ISL9123/A/B buck regulator.
The board regulates to the device default output voltage after start-up. The output voltage can be programmed by
I2C. Each evaluation board is optimized to perform best with the ISL9123/A/B IC series. The input power and load
connections are provided through multi-pin connectors for high-current operations.
The evaluation board is shown in Board Design. Ta ble 1 lists the test points and jumpers for the boards. The
ISL9123 internal registers can be accessed by I2C through the on-board jumper header J5, and its mode control
register configures the part into the various operation modes. See the Evaluation Software Installation and Use to
configure the board output voltage and operation modes.
1.1 Operational Characteristics
The VIN range is 1.8V to 5.5V while the adjustable VOUT range is 0.4V to 5.375V (ISL9123/A) and to 1.180V
(ISL9123B). The IOUT range of the board is 0 to 600mA. The operating ambient temperature range is -40°C to
+85°C.
1.2 Setup and Configuration
Use the following procedures to configure and power-up the board for proper operation. During the power-on
process, the expected waveforms are shown in Figure 2.
1. Connect the power supply to J1, with voltage setting between 1.8V and 5.5V but higher than output voltage
setting for buck mode operation.
2. Connect the electronic load to J2.
3. Place the scope probes on VOUT test point and other test points of interest.
4. Ensure that the EN pin jumper (J4) is pulled up to VIN.
5. Turn on the power supply. At the end of the soft-start sequence, the ISL9123/A/B is operating in Regulation
mode at the default output voltage setting. Note: A minimum effective output capacitance of 6µF is required.
Table 1. Description of Test Points and Jumpers
Test Points Description
J1 Header for connecting input power
J2 Header for connecting external load
J4 Header for the EN pin, J4 = GND disables the part output; J4 = VIN enables the part output
J5 Header for connecting I2C interface
J1 S+/S- VIN Kelvin connection for efficiency measurements
J2 S+/S- VOUT Kelvin connection for efficiency measurements
TP1 Through Hole Mount PCB test point for LX
TP2 Through Hole Mount PCB test point for VSW (Auxiliary output). Do not use for ISL9123B.
TP3 Through Hole Mount PCB test point for VOUT
TP4 Single Turret Terminal test point for VIN
TP5 Single Turret Terminal test point for VOUT
TP6 Single Turret Terminal test point for GND
TP7 Single Turret Terminal test point for GND
TP8 Single Turret Terminal test point for GND

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ISL9123xIIx-EVZ Evaluation Board Manual
Therefore, depending on the performance specifications of the capacitor, an additional output capacitor might
be required for higher output voltage settings.
6. Monitor the output voltage start-up sequence on the scope. The waveforms should look similar to those shown
in Figure 2.
7. Turn on the electronic load.
8. Measure the output voltage with the voltmeter. The voltage should regulate within the datasheet specification
limits.
9. To determine efficiency, measure input and output voltages at the Kelvin sense test points (S+ and S-), which
are part of J1 and J2 headers. The bench power supply can be connected to the VIN and GND headers on J1.
The electronic load can be connected to the VOUT and GND headers on J2. Measure the input and output
currents. Calculate the efficiency based on these measurements.
10. VSW (auxiliary output) should be left floating if not connected to a load. Refer the part datasheet for additional
information on VSW pin. Leave floating for ISL9123B.
Figure 2. ISL9123/A Start-Up with VIN = 3.6V and VOUT = 1.8V
Figure 3. ISL9123B Start-Up with VIN = 3.6V and VOUT = 0.88V
EN(2 V/D iv)
LX(2 V /D iv)
V
OUT
(1V/D iv)
I
IN
(20m A/Div)
100µs/Div
LX (2V/Div)
VOUT (1V/Div)
IIN (20mA/Div)
EN (2V/Div)
200µs/Div
VOUT (200mV/Div)
LX (1V/Div)
EN (500mV/Div)
200µs/Div
IIN (5mA/Div)

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ISL9123xIIx-EVZ Evaluation Board Manual
1.3 Evaluation Software Installation and Use
The ISL9123 evaluation software and evaluation software manual are available for download from the Renesas
website.
1. Save the evaluation software executable file and install the evaluation software (see the evaluation software
manual). When the evaluation software launches, (see the Setup and Configuration and) connect the power
supply, DC load, and other test equipment to the evaluation board; next, apply power.
2. The ISL9123/A/B has various control registers. See the ISL9123/A and ISL9123B datasheets for detailed
register descriptions.
3. Register RO_REG1 (Address: 0x02) provides chip identification information. The Get IC INFO_RO_REG1
button reads from this read-only register.
4. To change the output voltage, use the VSET Control slider in the VSET register (Address: 0x11) panel and
perform a Write REG operation. The output voltage ramps up at the slew rate specified in the DVSRATE setting
of CONV_CFG register. If the modified output voltage is lower than the initial value, its ramp down rate depends
on the applied load and output capacitance. The Read REG button provides the contents of the register, so
adjust the slider accordingly.
5. Register INTFLG_REG (Address: 0x03) contains the fault flags. The background color changes from green to
red: when (1) a fault occurs, and (2) this register is read using either the Check Fault button or the READ ALL
button. Each bit is set by a fault event and cleared when read. When the bit is cleared after reading, the
background color changes from red back to green.
6. Register CONV_CFG (Address: 0x12) contains crucial converter configuration bits. Selecting the Write (or
Read) button writes (or reads) the entire CONV_CFG register in one go.
7. Use EN_AND bit to disable the converter through I2C by toggling the Soft Start EN_AND button from Soft
Start enabled to Soft Start inhibit.
8. Selecting the Soft DSCHG enabled button presents a soft discharge resistor on the output pin, when the
converter is disabled through I2C using the EN_AND bit and VIN is still HIGH. By default, the Soft DSCHG
disabled button is selected. (ISL9123/B only)
9. Use the DVSRATE drop-down list to modify the dynamic voltage scaling rate for voltage ramp up, when output
voltage is modified using the VSET register.
10. Use the FMODE drop-down list to select one of the forced operating modes: Normal (Auto-PFM, default),
Forced PWM, and Forced Bypass (ISL9123/A only).
11. Use the CTRL Type drop-down list to select the control mode between Type I and Type II error amplifier.
12. Register INTFLG_MASK (Address: 0x13) contains additional features influencing the part behavior. Selecting
the Write (or Read) button writes (or reads) the entire INTFLG_MASK register in one go.
13. Use the OC_FAULT drop-down to select the over-current handling mechanism for the part.
14. Use the EN_OR drop-down list to enable a push-button ON functionality for the EN pin.

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ISL9123xIIx-EVZ Evaluation Board Manual
Figure 4. ISL9123 Evaluation Software Window
Figure 5. ISL9123A Evaluation Software Window

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ISL9123xIIx-EVZ Evaluation Board Manual
Figure 6. ISL9123B Evaluation Software Window

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ISL9123xIIx-EVZ Evaluation Board Manual
2. Board Design
2.1 ISL9123xIIx-EVZ (WLCSP)
2.1.1 Board Image
Figure 7. ISL9123xIIx-EVZ Evaluation Board (Top)

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ISL9123xIIx-EVZ Evaluation Board Manual
2.1.2 Circuit Schematic
2.1.3 Bill of Materials
Figure 8. ISL9123xIIx-EVZ Circuit Schematic
Qty Reference
Designator Description Manufacturer Part Number Manufacturer
1 C1 CAP, SMD, 1210, 47µF, 16V, 20%, ROHS GRM32ER61C476ME15 Murata
1 C2 CAP, SMD, 0603, 10µF, 6.3V, 20%, X5R, ROHS GRM188R60J106ME84D Murata
2C3,C4
[1] CAP, SMD, 0603, 22µF, 6.3V, 20%, X5R, ROHS GRM188R60J226ME15D Murata
2 C5, C6 CAP, SMD, 0603, DNP-PLACE HOLDER, ROHS Open Any
2J1,J2
CONN-HEADER, 1×6, BRKAWY 1×36, 2.54mm,
ROHS 68000-236 FCI
1J4
CONN-HEADER, 1×3, BRKAWY 1×36, 2.54mm,
ROHS 68000-236 FCI
1J5
CONN-HEADER, TH, 2×10, 1.27mm PITCH, R/A,
ROHS M50-3901042 Harwin Inc
1L1
COIL-PWR INDUCTOR, SMD, 0603, 1µH, 20%
1.7A, 128mΩ, ROHS DFE18SAN1R0MG0L Murata
4 R1, R2, R5, R6 RES, SMD, 0402, DNP-PLACE HOLDER, TF,
ROHS Open Any
1 R3 RES, SMD, 0402, 1MΩ, 1/16W, 1%, TF, ROHS ERJ-2RKF1004X Panasonic
1 R4 RES, SMD, 0603, 0.3Ω, 1/10W, 1%, TF, ROHS RL0603FR-070R3L Yageo
2TP1,TP3
CONN-SCOPE PROBE TEST PT, COMPACT, PCB
MNT, ROHS 131-5031-00 Tektronix
6TP2, TP4, TP5,
TP6, TP7, TP8
CONN-TURRET, TH, SWAGE MNT,
0.230 LENGTH, ROHS 2110-2-00-80-00-00-07-0 Mill-Max

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ISL9123xIIx-EVZ Evaluation Board Manual
2.1.4 Board Layout
1U1
[2]
IC, ULTRA-LOW IQ BUCK REGULATOR, 1.8V,
WLCSP, ROHS ISL9123IICZ
Renesas
Electronics
IC, ULTRA-LOW IQ BUCK REGULATOR, 3.0V,
WLCSP, ROHS ISL9123IINZ
IC, ULTRA-LOW IQ BUCK REGULATOR, 1.8V,
WLCSP, ROHS ISL9123AIICZ
IC, ULTRA-LOW IQ BUCK REGULATOR, 0.88V,
WLCSP, ROHS ISL9123BII9Z
1 J4-Pins 1-2 CONN-JUMPER, SHUNT, 2P, 2.54mmPITCH, BLK,
6mm, ROHS SPC02SYAN Sullins
1. C4 is DNP in default configuration. It is required to be populated if effective capacitance of C3 is less than 6μF at the operating output
voltage.
2. All related WLCSP packaged device(s) use the same printed circuit board design (ISL9123IIN-EVZ), with an appropriate silk screen or
label according to the unique orderable evaluation board part number.
Figure 9. ISL9123xIIx-EVZ Top Layer Silk Screen
Qty Reference
Designator Description Manufacturer Part Number Manufacturer

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ISL9123xIIx-EVZ Evaluation Board Manual
Figure 10. ISL9123xIIx-EVZ Inner Layer 2
Figure 11. ISL9123xIIx-EVZ Inner Layer 3

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Figure 12. ISL9123xIIx-EVZ Bottom Layer Silk Screen

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ISL9123xIIx-EVZ Evaluation Board Manual
2.2 Layout Guidelines
The evaluation board PCB layout is optimized for electrical and thermal performance.
▪Position the input and output capacitors as close to the IC as possible. The input currents are discontinuous in
a buck converter; therefore, it is important to place the input capacitors as close as possible.
▪Keep the ground connections of the input and output capacitors as short as possible and on the component
layer to avoid problems that are caused by high-switching currents flowing through PCB vias. If it is necessary
to use the vias, use multiple vias to minimize the effective trace inductance.
▪It is strongly advised that the second layer is a clean GND to mitigate problems that arise from long GND traces
and subsequent parasitic inductive components. Also, a clean GND shields the intermediate layers from high
power traces on the top layer.
▪After placing short input and output loops, place an inductor as close as possible to the IC. While being cautious
of any EMI concerns, ensure that the switch node traces (from LX to the inductor) are short and wide.
▪Finally, EN, SCL, SDA should be routed away from high energy and high dV/dt traces to prevent mis-triggering.
These traces can be routed through the intermediate layers.
Note: C1 and R4 are on the evaluation board to stabilize the input supply with long test leads, and they are not
required in actual system boards.
3. Ordering Information
4. Revision History
Part Number Description
ISL9123IIC-EVZ Evaluation board for ISL9123IICZ, WLCSP
ISL9123IIN-EVZ Evaluation board for ISL9123IINZ, WLCSP
ISL9123AIIC-EVZ Evaluation board for ISL9123IICZ, WLCSP
ISL9123BII9-EVZ Evaluation board for ISL9123II9Z, WLCSP
Revision Date Description
1.01 Jul 26, 2023
Added info for ISL9123A and ISL9123B devices.
Set register and bit name references to bold text.
Updated section titles and figure titles.
Updated BOM.
Updated GUI screenshot for ISL9123.
1.00 Apr 1, 2022 Initial release

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