Evaluation Board Hardware; Quick Start Instructions; Factory Settings; Jumper Selection - Analog Devices ADD8754-EVAL Manual

EVALUATION BOARD HARDWARE

QUICK START INSTRUCTIONS

Follow these steps to begin using the ADD8754 evaluation board:
1. Connect ground to at least one of the 10 pins labeled GND.
2. Connect a 5 V power supply to at least one of the two pins
labeled VIN.
3. Apply a 2.5 V to 5 V digital control signal on VFLK. This
control signal determines when VGH_M is at GPM_H or
GPM_L. See the Gate Pulse Modulator section to determine
a typical waveform.
After these steps are completed, users can probe the precon-
figured output voltages and waveforms.

FACTORY SETTINGS

The ADD8754-EVAL arrives fully assembled and ready to use.
The factory voltage settings are detailed in Table 1. See the
Quick Start Instructions section for power-up instructions.
Table 1. Factory Settings
1
Test Point Value Description
2
BOOST_OUT 9.8 V Step-up output voltage
LDO_OUT 3.3 V LDO output voltage
VCOM 4.9 V VCOM output voltage
VGH_M 28 V Gate pulse modulation output
VDD_1 9.8 V GPM low ramp voltage
VGL −5 V Gate low voltage
1
Actual voltages may differ slightly (±3%).
2 Soft start time is 100 μs when VIN = 5 V and 500 μs when VIN = 3.3 V.

JUMPER SELECTION

The jumper pins are listed and described in this section.
JP1— SHDN Control
If the JP1 jumper is shorted, the SHDN pin is shorted to ground,
causing the ADD8754 to shut down. When the jumper is
opened, the ADD8754 continues to operate normally. If
external shutdown control is desired, remove this jumper.
JP2—FREQ Select
If the JP2 jumper is shorted, the ADD8754 operates at a 650 kHz
internal switching frequency. If this jumper is open, the device
operates at 1.2 MHz. See the ADD8754 data sheet for details.
JP3—LDO Output Select
The JP3 jumper has three positions (3.3 V, 2.85 V, and 2.5 V) for
setting the LDO output voltage. Table 2 illustrates the proper
jumper configuration.
Table 2. LDO Output Voltage Jumper Selection
Jumper Position
Short Pin 2 and Pin 3
Open all pins
Short Pin 1 and Pin 2
JP4—VCOM Buffer Mode
When the JP4 jumper is shorted, the VCOM negative input and
output are shorted together. This configures VCOM as a unity
gain buffer. Remove this jumper if external VCOM feedback is
desired.
JP5—VDPM from Step-Up
When the JP5 jumper is shorted, the step-up output connects
to VDPM. This enables GPM and requires no external signal
on VDPM. Remove this jumper if an external VDPM control
is desired.
JP6—VCOM Supply from Step-Up
When the JP6 jumper is shorted, the VCOM supply (VDD_2) is
connected to the step-up output. This eliminates the need for an
external VCOM supply voltage. If the use of an external VCOM
power supply is desired, remove this jumper and connect a power
supply to VDD_2.
JP7—VGH from Positive Charge Pump
When the JP7 jumper is shorted, GPM receives its VGH voltage
from the positive charge pump. If an external VGH voltage is
desired, remove this jumper to drive the VGH pin externally.
Rev. A | Page 3 of 12
ADD8754-EVAL
Description
LDO_OUT = 3.3 V, see Figure 2.
LDO_OUT = 2.85 V, see Figure 3.
LDO_OUT = 2.5 V, see Figure 4.
JP3
Figure 2. JP3 Short Pin 2 and Pin 3
JP3
Figure 3. JP3 Open All Pins
JP3
Figure 4. JP3 Short Pin1 and Pin 2