User Guide 066
UG066.0
February 23, 2016
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2
Functional Description
The ISL91107IRN-EVZ and ISL91107IRA-EVZ provide simple
platforms to demonstrate the features of the ISL91107IR
buck-boost regulator. The ISL91107IRN-EVZ is for the fixed 3.3V
output IC ISL91107IRTNZ. The ISL91107IRA-EVZ is for the
adjustable output IC ISL91107IRTAZ. The Evaluation boards have
been functionally optimized for best performance of the
ISL91107IR IC series. The input power and load connections are
provided through multi-pin connectors for high current
operations.
The ISL91107IRA-EVZ evaluation board is shown in Figures 4
and 5.
The board’s enable function is controlled by the on-board jumper
header J3. Similarly the Mode function is controlled by the on-board
jumper header J4.
The schematic of the ISL91107IRA-EVZ evaluation board is
shown in Figure 6
. The schematic for the ISL91107IRN-EVZ is
shown in Figure 7
. The PCB layout images for all layers are shown
in Figures 8 through 9. The bill of materials of the
ISL91107IRA-EVZ is shown in Table 2. The bill of materials of the
ISL91107IRN-EVZ is shown in Table 3
.
Operating Range
The V
IN
range of the boards is 1.8V to 5.5V. The adjustable V
OUT
range for the ISL91107IRA-EVZ is 1V to 5.2V. The I
OUT
range of the
boards is 0 to 2A. The operating ambient temperature range: -40°C
to +85°C.
Quick Start Guide
For the ISL91107IRA-EVZ board, the default output voltage is set
at 3.3V. If other output voltages are desired, resistor R
2
can be
set to a desired voltage as shown in Table 1 (use a resistor with
1% accuracy).
Refer to the “
Quick Setup Guide” to configure and power-up the
board for proper operation. During the power-on process, the
expected waveforms are shown in Figures 2
and 3.
Quick Setup Guide
1. Install jumper on J3, shorting EN to V
IN
.
2. Install jumper on J4, shorting MODE to V
IN
.
3. Connect power supply to J1, with voltage setting between
1.8V and 5.5V.
4. Connect electronic load to J2.
5. Place scope probes on the V
OUT
test point and other test
points of interest.
6. Turn on the power supply.
7. Monitor the output voltage start-up sequence on the scope. The
waveforms will look similar to that shown in Figures 2
and 3.
8. Turn on the electronic load.
9. Measure the output voltage with the voltmeter. The voltage
should regulate within datasheet specific limits.
10. To determine efficiency, measure input and output voltages
at J1 and J2 headers. The bench power supply can be
connected to the PVIN and GND headers on J1. The electronic
load can be connected to the V
OUT
and GND headers on J2.
Measure the input and output currents. Calculate efficiency
based on these measurements.
TABLE 1. OUTPUT VOLTAGE PROGRAMMING FOR ISL91107IRA-EVZ
DESIRED OUTPUT VOLTAGE
(V)
R
2
RESISTOR VALUE
(kΩ)
2.0 124
2.5 88.7
3.0 68.1
3.3 60.4
3.4 57.6
3.6 53.6
4.0 46.4
FIGURE 2. ISL91107IR START-UP WITH V
IN
= 2V AND V
OUT
= 3.3V
INDUCTOR CURRENT
(200mA/DIV)
V
OUT
(1V/DIV)
EN (2V/DIV)
1ms/DIV
FIGURE 3. ISL91107IR START-UP WITH V
IN
= 4V AND V
OUT
= 3.3V
1ms/DIV
INDUCTOR CURRENT
(200mA/DIV)
V
OUT
(1V/DIV)
EN (2V/DIV)
