Functional Diagram
Functional Diagrams
MAX25222/MAX25222C
MAX25222/C
MAX25222/C
Switching Node of Boost Converter. Connect the boost inductor between LXP and IN.
LXP
LX
P
POSITIVE SOFT-START AND DISCHARGE
POSITIVE
SOFT
-START
AND
DISCHARGE
Boost Output and Input to Positive and Negative Charge-Pump Drivers. Bypass HVINP with a 10μF output capacitor placed close to the pin.
HVINP
HVINP
Switched Output of Boost Converter. Connect a bypass capacitor of value 2.2μF from AVDD to PGND.
AVDD
AVDD
Negative Source-Driver Output Voltage. Connect ceramic capacitors of value 0.1μF and 10μF from this pin to GND with the smallest capacitor closest to the pin.
NAVDD
N
AVDD
INVERTING REGULATOR 420kHz/2.1MHz
INV
ERTING
REGULATOR
420
kHz
/
2
.
1
MHz
DC-DC Inverting Converter Inductor/Diode Connection.
LXN
LXN
Inverting Converter Input. Connect 10μF + 0.1μF ceramic capacitors from this pin to ground for proper operation.
INN
INN
ENABLE, CONTROL AND FAULT LOGIC
ENABLE, CONTROL
AND FAULT LOGIC
Enable Input Pin. When EN is low, the device is in shutdown. When EN is taken high, the device is active. In stand-alone mode, the outputs are turned on in the stored sequence when EN goes high.
EN
EN
Logic Ground.
DGND
D
GND
POSITIVE CHARGE PUMP
POSITIVE
CHARGE PUMP
NEGATIVE CHARGE PUMP
NEGATIVE
CHARGE PUMP
Negative Charge-Pump Push-Pull Drive Output.
DN
DN
Positive Connection for Second Flying Capacitor. Connect a 22nF capacitor from FC2- to FC2+.
FC2+
FC2+
Supply Voltage for Positive Charge Pump. PGVDD is connected to HVINP by means of an internal switch when the positive charge pump is enabled. Bypass PGVDD with a ceramic capacitor of 1μF to GND.
PGVDD
PGVDD
Supply Connection for Display Bias Circuitry. Bypass IN with local 10μF and 0.1μF capacitors.
IN
IN
Output of Negative Charge-Pump Block. Connect a 1μF capacitor from this pin to GND.
VGOFF
VGOFF
Output of Positive Charge-Pump Block. Connect a 1μF capacitor from VGON to GND.
VGON
VGON
REF1
REF1
I2C Clock Pin.
SCL
S
CL
Bidirectional I2C Data Pin.
SDA
S
DA
TFT BOOST CONTROL 420kHz/2.1MHz
TFT
BOOST
CONTROL
420
kHz/2.1MHz
I2C
I
2
C
Open-Drain, Active-Low Fault Output. Connect a pullup resistor from FLTB to a logic supply ≤5V. In stand-alone mode, the duty cycle of the FLTB pin indicates an error condition, if present (see Table 4). When the serial interface is used, FLTB is either a 0 (indicating data to be read from the internal registers) or a 1.
FLTB
FLT
B
Ground Connection
GND
GND
NEGATIVE SOFT-START AND DISCHARGE
NEGATIVE
SOFT
-START
AND
DISCHARGE
Device Address Select pin. Connect to GND or V18 to Select the Device I2C Address. See the I2C address table. To use stand-alone mode (without I2C) leave the ADD pin open. In this mode, the device turns on all outputs in the programmed sequence when EN is taken high.
ADD
ADD
Bootstrap Capacitor Connection for Synchronous Rectifier Driver. Connect a 0.1μF ceramic capacitor between BST and LXP.
BST
BST
Ground Connection for Boost Switching Device and VCOM Buffer. Connect to GND using a low-impedance trace.
PGND
PGND
0.9V
0.9V
TEMP WARNING, SHUTDOWN
TEMP
WARNING
,
SHUTDOWN
Negative Supply for VCOM Buffer. Connect a ceramic capacitor of at least 1μF from VCOMN to GND.
VCOMN
VCOMN
Output of VCOM amplifier.
VCOM
VCOM
DAC
DAC
NEG. REGULATOR
NEG.
REGULATOR
Drive Output for External npn Pass Transistor for VCOMN regulator. Connect to the base of the external npn transistor.
VCB
VCB
NTC 8b ADC FOR TEMP COMPENSATION
NTC
8
b ADC FOR
TEMP
COMPENSATION
Temperature Sensor Pin. When using the temperature compensation function, connect an NTC from TEMP to GND. If unused, leave TEMP unconnected.
TEMP
TEMP
REG
REG
Output of Internal 1.8V Regulator. Connect a 1μF capacitor from V18 to GND.
V18
V18
PROGRAMMING LOGIC & NV MEMORY
PROGRAMMING
LOGIC
&
NV MEMORY
Programming Voltage. Apply a voltage of 8.5V to this pin during the programming of non-volatile registers. Connect to GND through a resistor during normal operation.
VPROG
VPROG
Negative Connection for Second Flying Capacitor. Connect a 22nF capacitor from FC2- to FC2+.
FC2-
FC2-
Positive Connection for First Flying Capacitor. Connect a 22nF capacitor from FC1- to FC1+.
FC1+
FC1+
Negative Connection for First Flying Capacitor. Connect a 22nF capacitor from FC1- to FC1+.
FC1-
FC1-
Boost Output and Input to Positive and Negative Charge-Pump Drivers. Bypass HVINP with a 10μF output capacitor placed close to the pin.
HVINP
HVINP
Reference Resistor Pin. When using the temperature compensation function, connect a resistor from RREF to GND. If unused, leave RREF unconnected.
RREF
RREF
REF2
REF2
DIAGNOSTICS
DIAGNOSTICS
Output of VCOM amplifier.
VCOM
VCOM
Supply Connection for Display Bias Circuitry. Bypass IN with local 10μF and 0.1μF capacitors.
IN
IN
Ground Connection for Charge Pumps.
CPGND
CP
GND
Negative Source-Driver Output Voltage. Connect ceramic capacitors of value 0.1μF and 10μF from this pin to GND with the smallest capacitor closest to the pin.
NAVDD
N
AVDD
Output of Internal 1.8V Regulator. Connect a 1μF capacitor from V18 to GND.
V18
V18
