MAX8728EVKIT Maxim Integrated Products, MAX8728EVKIT Datasheet - Page 4

• Manufacturer Part Number: MAX8728EVKIT
• Description: Display Modules & Development Tools MAX8728 KIT MAX8728 KIT
• Manufacturer: Maxim Integrated Products

Specifications of MAX8728EVKIT

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

(through resistor R13, jumper JU4, and diode D3) or
toward PGND (through resistor R13 and jumper JU4).
However, GON stops discharging when the voltage at
GON drops to 10 times the threshold voltage set at the
THR pin. As configured, the voltage at the THR pin is
set to 2V by voltage-divider resistors R11 and R12.
The high-voltage switches have two modes of operation
controlled by jumper JU5. The first mode has no delay,
while the second mode has an adjustable delay fea-
ture. In the first mode, GON is switched to SRC at the
rising edge of the control signal connected to the CTL
pad, and then switched to DRN at the falling edge of
the control signal. In the second mode, GON is
switched to SRC at the rising edge of the control signal.
However, at the falling edge of the control signal, GON
is not switched to DRN until the voltage at the MODE
pin reaches 0.5 x V
Description, High-Voltage Switch Control section in the
MAX8728 data sheet for additional details.
Jumper JU1 controls the shutdown pin (SHDN) of the
MAX8728 IC. The shutdown pin can also be controlled
by an external logic controller connected to the EV kit
SHDN pad. Remove the shunt from jumper JU1 before
connecting an external controller to the SHDN pad. See
Table 1 for shunt positions.
The MAX8728 EV kit features an enable input (EN).
When EN is low, the step-up regulator, the positive
charge-pump regulator, the negative charge-pump regu-
lator, and the high-voltage switch matrix are disabled
MAX8728 Evaluation Kit
Table 2. Jumper JU2 Functions (EN)
4
controller connected
_______________________________________________________________________________________
(external logic
Not installed
Not installed
LOCATION
to EN pad)
(default)
SHUNT
1-2
2-3
External logic controller
Unconnected; pulled
REF
Shutdown Mode ( SHDN )
CONNECTED TO
high internally
Jumper Selection
. Refer to the Detailed
EN PIN
GND
C10
Enable Input (EN)
Set by C10
No delay
No delay
DELAY
—
and the step-down regulator operates in its power-saving
skip mode.
On the rising edge of EN, the step-down regulator
enters its fixed-frequency mode, and the step-up,
charge pumps and switch matrix begin their startup
sequence (refer to the Power-Up Sequence section in
the MAX8728 IC data sheet).
The EN pin includes a 5µA current source, which,
together with capacitor C10 from EN to ground, can
provide a startup delay for the above blocks.
Jumper JU2 controls the enable pin (EN) of the
MAX8728 IC. The enable pin can also be controlled by
an external logic controller connected to the EV kit’s EN
pad. Remove the shunt from jumper JU2 before connect-
ing an external controller to the EN pad. See Table 2 for
shunt positions.
Table 1. JU1 Jumper Selection (SHDN)
SHUNT POSITION
mode (after delay)
Fixed-frequency
Fixed-frequency
(external logic
connected to
REGULATOR
STEP-DOWN
Controlled by
external logic
Not installed
Not installed
SHDN pad)
controller
Skip mode
EV KIT’S
controller
Installed
(default)
mode
Enabled (after delay)
Disabled
Enabled
Controlled by external logic controller
CONNECTED TO
POSITIVE AND NEGATIVE CHARGE-
(through resistor
External logic
EV KIT’S STEP-UP REGULATOR,
SHDN PIN
controller
GND
HIGH-VOLTAGE SWITCH
R3)
VL
PUMP REGULATORS,
Enabled
Shutdown mode
SHDN driven by
external logic
controller,
shutdown is
active low
FUNCTION
EV KIT