Datasheet
Multi-Output Power Supplies with VCOM Amplifier
and High-Voltage Gamma Reference for LCD TVs
MAX17126/MAX17126A
16 _____________________________________________________________________________________
Pin Description
PIN NAME FUNCTION
1 VREF_I Gamma Reference Input
2 VOP Operational Amplifier Power Supply
3 OGND Operational Amplifier Power Ground
4 OPP Operational Amplifier Noninverting Input
5 OPN Operational Amplifier Inverting Input
6 OPO Operational Amplifier Output
7 PGOOD
Input voltage power-good open-drain output pulled high to VL or 3.3V through 10kI resistor.
8 GVOFF
High-Voltage Switch-Control Block Timing Control Input. See the High-Voltage Switch Control
section for details.
9 EN Enable Input. Enable is high, turns on step-up converter and positive charge pump.
10 FB2
Step-Down Regulator Feedback Input. Connect FB2 to GND to select the step-down converter’s 3.3V
fixed mode. For adjustable mode, connect FB2 to the center of a resistive voltage-divider between the
step-down regulator output (OUT) and GND to set the step-down regulator output voltage. Place the
resistive voltage-divider within 5mm of FB2.
11 OUT Step-Down Regulator Output Voltage Sense. Connect OUT to step-down regulator output.
12 N.C. Not Connected
13, 14 LX2
Step-Down Regulator Switching Node. LX2 is the source of the internal n-channel MOSFET connected
between IN2 and LX2. Connect the inductor and Schottky catch diode to both LX2 pins and minimize
the trace area for lowest EMI.
15 BST
Step-Down Regulator Bootstrap Capacitor Connection. Power supply for high-side gate driver. Connect
a 0.1FF ceramic capacitor from BST to LX2.
16, 17 IN2
Step-Down Regulator Power Input. Drain of the internal n-channel MOSFET connected between IN2
and LX2.
18, 44 GND Analog Ground
19 VDET
Voltage-Detector Input. Connects VDET to the center of a resistor voltage-divider between input voltage
and GND to set the trigger point of PGOOD.
20 INVL
Internal 5V Linear Regulator and the Startup Circuitry Power Supply. Bypass V
INVL
to GND with 0.22FF
close to the IC.
21 VL
5V Internal Linear Regulator Output. Bypass VL to GND with 1FF minimum. Provides power for the
internal MOSFET driving circuit, the PWM controllers, charge-pump regulators, logic, and reference
and other analog circuitry. Provides 25mA load current when all switching regulators are enabled. VL is
active whenever input voltage is high enough.
22 FSEL
Frequency Select Pin. Connect FSEL to VL or INVL or float FSEL pin for 750kHz operation. Connect to
GND for 500kHz operation.
23 CLIM
Boost Current-Limit Setting Input. Connects a resistor from CLIM to GND to set current limit for boost
converter.
24 SS
Soft-Start Input. Connects a capacitor from SS to GND to set the soft-start time for the step-up convert-
er. A 5FA current source starts to charge C
SS
when GD is done. See the Step-Up Regulator External
pMOS Pass Switch section for description. SS is internally pulled to GND through 1kI resistance when
EN is low OR when VL is below its UVLO threshold.
25, 26 LX1
Step-Up Regulator Power-MOSFET n-Channel Drain and Switching Node. Connects the inductor and
Schottky catch diode to both LX1 pins and minimizes the trace area for lowest EMI.
27, 28 PGND Step-Up Regulator Power Ground
29 GD_I
Step-Up Regulator External pMOS Pass Switch Source Input. Connects to the cathode of the step-up
regulator Schottky catch diode.