MAX1512ETA+T Maxim Integrated Products, MAX1512ETA+T Datasheet - Page 6

• Manufacturer Part Number: MAX1512ETA+T
• Description: IC CALIBRATOR TFT VCOM 8-TDFN
• Manufacturer: Maxim Integrated Products
• Type: TFT VCOM Calibratorr

Specifications of MAX1512ETA+T

• Applications: LCD TV/Monitor
• Mounting Type: Surface Mount
• Package / Case: *
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

The MAX1512 is a solid-state alternative to mechanical
potentiometers used for adjusting the LCD backplane
voltage (VCOM) in TFT LCD displays. The MAX1512
attaches to an external resistive voltage-divider and
sinks a programmable current (I
VCOM level (Figure 1). An internal 7-bit DAC controls
the sink current and allows the user to increase or
decrease the VCOM level (Figure 2). The DAC is ratio-
metric relative to AVDD and is monotonic over all oper-
ating conditions. The user can store the DAC setting in
an internal EEPROM. On power-up, the EEPROM pre-
sets the DAC to the last stored setting. The single-wire
interface between the LCD panel and the programming
circuit adjusts the DAC, programs the EEPROM, and
provides programming power.
The resistive voltage-divider and the AVDD supply set
the maximum value of VCOM. The MAX1512 sinks cur-
rent from the voltage-divider to reduce the VCOM level.
The external resistor R
rent and the minimum value of VCOM.
EEPROM-Programmable TFT VCOM Calibrator
6
PIN
_______________________________________________________________________________________
1
2
3
4
5
6
7
8
NAME
AVDD
GND
OUT
N.C.
V
CTL
SET
CE
DD
Adjustable Sink-Current Output. OUT connects to the resistive voltage-divider between AVDD and GND that
sets the VCOM voltage. I
description.
High-Voltage Analog Supply. Connects to the panel source-driver supply rail.
No Connect. Not internally connected.
Ground
Supply Input. +2.6V to +3.6V input range.
VCOM Adjustment and EEPROM Programming Control. CTL sets the internal DAC code and programs the
EEPROM. A pulse-control method is used to adjust the VCOM level. See the VCOM Adjustment (CTL)
section. To program the DAC setting into the EEPROM as the power-on default, drive CTL to the EEPROM
programming voltage using the correct timing and voltage ramp rates. See the EEPROM Programming
(CTL) section.
Control Interface Enable. Connect CE to V
CTL input and reduce the supply current.
Full-Scale Sink-Current Adjustment Input. Connect a resistor, R
adjustable sink current. The full-scale adjustable sink current is equal to:
Detailed Description
SET
⎛
⎜
⎝
20 ×
V
sets the full-scale sink cur-
AVDD
R
SET
OUT
⎞
⎟
⎠
), which sets the
I
OUT
is equal to the current through R
OUT
lowers the divider voltage by an adjustable amount. See the SET pin
DD
Figure 1. Standard Application Circuit
to enable the CTL input. Connect CE to GND to disable the
FUNCTION
CE
CTL
SET
MAX1512
.
GND
V
V
SET
3V
DD
DD
, from SET to GND to set the full-scale
AVDD
OUT
SET
AVDD
R
25kΩ
10V
SET
Pin Description
R1
200kΩ
R2
245kΩ
VCOM
5V