MAX8758EVKIT Maxim Integrated Products, MAX8758EVKIT Datasheet - Page 3

• Manufacturer Part Number: MAX8758EVKIT
• Description: Display Modules & Development Tools MAX8758 KIT MAX8758 KIT
• Manufacturer: Maxim Integrated Products

Specifications of MAX8758EVKIT

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

between 640kHz and 1.2MHz, but the circuit is config-
ured to operate at 1.2MHz.
As configured and with no load on the charge pumps,
the step-up switching regulator (VMAIN) generates a
+8.5V output and can provide at least 350mA from
+2.6V input. It also provides at least 410mA from 3V
input and 600mA from 4.5V input. The step-up switch-
ing-regulator output voltage can be adjusted up to
+13V with other feedback resistors. For details, see the
Output-Voltage Selection section.
The GON consists of two positive charge-pump stages
to generate approximately +23V and can provide more
than 20mA. The GOFF consists of a single negative
charge-pump stage to generate approximately -8V and
can provide more than 20mA. Loading the GON charge
pump reduces the available output current on VMAIN
by three times the GON load current. Loading the
GOFF reduces the available VMAIN by the amount of
the GOFF current.
The operational-amplifier output VCOM is set to +4.25V
and can source or sink approximately 150mA. These
outputs can be reconfigured to other voltages with volt-
age-divider resistors. See the Output-Voltage Selection
section for details.
The high-voltage switch between the SRC and GON pins
can be used to delay the VP startup. The VP voltage is
connected to the switch source (SRC) and the switch
drain (GON) is used as an output. The startup delay time
is set with an external capacitor at the DLP pin.
The switch between the SRC and GON pins and the
switch between the GON and DRN pins can be con-
trolled by jumpers JU2 and JU4 or by an external
Table 2. On-Board, High-Voltage Switch Control Using JU2 and JU4
Installed, CTL connected to
LDO
Not installed, CTL connected
to GND through R9
Not installed, CTL driven
externally
Installed, CTL connected to
LDO
Not installed, CTL pulled to
GND through R9
Not installed, CTL driven
externally
JU2 SHUNT LOCATION
_______________________________________________________________________________________
Pins 2 and 3, MODE connected
to LDO
Pins 2 and 3, MODE connected
to LDO
Pins 2 and 3, MODE connected
to LDO
Pins 1 and 2, MODE connected
to timing capacitor C21
Pins 1 and 2, MODE connected
to timing capacitor C21
Pins 1 and 2, MODE connected
to timing capacitor C21
JU4 SHUNT LOCATION
MAX8758 Evaluation Kit
GON connected to SRC pin, SRC = VP
GON connected to DRN pin, GON is discharged through R10
GON connected to SRC when CTL is logic-high and connected
to DRN when CTL is logic-low
GON connected to SRC pin, SRC = VP
GON connected to DRN pin and discharged through R10 after
delay set by C21
GON connected to SRC on rising edge of CTL; C21 begins
charging on falling edge of CTL; when MODE reaches 2.5V,
GON connects to DRN
TTL-logic source connected to the CTL pad and JU4.
See Table 2 for switch states, and refer to the High-
Voltage Switch Control section in the MAX8758 data
sheet for further information about the high-voltage
switches connected to the GON pin.
The MAX8758 EV kit features an option to choose the
step-up regulator switching frequency. Jumper JU1
selects the switching frequency. Table 1 lists the selec-
table jumper options. The EV kit is configured for
1.2MHz operation. Optimum performance at lower fre-
quencies may require a larger inductor value. Refer to
the Step-Up Regulator Inductor Selection section in the
MAX8758 data sheet for more information.
The MAX8758 EV kit features an option to control the
high-voltage switches between SRC, GON, and DRN
on the MAX8758. GON can be connected to SRC (con-
nected to VP, the positive charge-pump output) or can
be allowed to discharge through DRN (connected to a
Table 1. Jumper JU1 Functions
LOCATION
(default)
Installed
SHUNT
None
Switching Frequency Selection (FREQ)
Connected to GND
Connected to VIN
High-Voltage Switch Control
GON OUTPUT
through R7
FREQ PIN
Jumper Selection
(CTL and MODE)
FREQUENCY
SWITCHING
1.2MHz
640kHz
3