MAX17010ETL+T Maxim Integrated Products, MAX17010ETL+T Datasheet - Page 13

• Manufacturer Part Number: MAX17010ETL+T
• Description: IC LCD DISPLAY BIAS 40-TQFN
• Manufacturer: Maxim Integrated Products

Specifications of MAX17010ETL+T

• Applications: LCD Monitor, Notebook Display
• Current - Supply: 50µA
• Voltage - Supply: 1.8 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 40-TQFN Exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Internal-Switch Boost Regulator with Integrated
The MAX17010 includes an internal 4V linear regulator.
SUP is the input of the linear regulator. The input voltage
range is between 5V and 18V. The output of the linear
regulator (VL) is set to 4V (typ). The regulator powers all
the internal circuitry including the MOSFET gate driver.
Bypass the VL pin to AGND with a 0.22µF or greater
ceramic capacitor. SUP should be directly connected to
the output of the step-up regulator. This feature signifi-
cantly improves the efficiency at low input voltages.
The MAX17010 features bootstrapping operation. In nor-
mal operation, the internal linear regulator supplies
power to the internal circuitry. The input of the linear reg-
ulator (SUP) should be directly connected to the output
of the step-up regulator. The MAX17010 is enabled when
the input voltage at SUP is above 1.4V and the fault latch
is not set. After being enabled, the regulator starts open-
loop switching to generate the supply voltage for the
linear regulator. Step-up switching is inhibited if the step-
up output voltage (V
SUP input. The internal reference block turns on when the
VL voltage exceeds 2.7V (typ). When the reference volt-
age reaches regulation, the PWM controller and the cur-
rent-limit circuit are enabled and the step-up regulator
enters soft-start. During soft-start, the main step-up regu-
lator directly limits the peak inductor current, allowing
from zero up to the full current-limit value in 128 equal
current steps. The maximum load current is available
after the output voltage reaches regulation (which ter-
minates soft-start), or after the soft-start timer expires in
approximately 3ms. The soft-start routine minimizes the
inrush current and voltage overshoot, and ensures a
well-defined startup behavior.
During steady-state operation, the MAX17010 monitors
the FB voltage. If the FB voltage does not exceed 1V
(typ), the MAX17010 activates an internal fault timer. If
there is a continuous fault for the fault-timer duration,
the MAX17010 sets the fault latch, shutting down all the
outputs except VL. Once the fault condition is removed,
cycle the input voltage to clear the fault latch and reac-
tivate the device. The fault-detection circuit is disabled
during the soft-start time.
The MAX17010 monitors the SUP voltage for undervolt-
age and overvoltage conditions. If the SUP voltage is
below 1.4V (typ) or above 19V (typ), the MAX17010 dis-
ables the gate driver of the step-up regulator and pre-
vents the internal MOSFET from switching. The SUP
undervoltage and overvoltage conditions do not set the
fault latch.
______________________________________________________________________________________
MAIN
High-Voltage Level Shifter and Op Amp
Bootstrapping and Soft-Start
) exceeds the voltage on the
Linear Regulator (VL)
Fault Protection
The MAX17010 has an op amp that is typically used to
drive the LCD backplane (VCOM) and/or the gamma-
correction-divider string. The op amp features ±150mA
output short-circuit current, 45V/µs slew rate, and
12MHz bandwidth. While the op amp is a rail-to-rail
input and output design, its accuracy is significantly
degraded for input voltages within 1V of its supply rails
(SUP and VGND).
The op amp limits short-circuit current to approximately
±150mA if the output is directly shorted to SUP or to
AGND. If the short-circuit condition persists, the junction
temperature of the IC rises until it reaches the thermal-
shutdown threshold (+160°C typ). Once the junction
temperature reaches the thermal-shutdown threshold, an
internal thermal sensor immediately sets the thermal fault
latch, shutting off all the IC’s outputs except VL. The
device remains inactive until the input voltage is cycled.
The op amp is typically used to drive the LCD back-
plane (VCOM) or the gamma-correction-divider string.
The LCD backplane consists of a distributed series
capacitance and resistance, a load that can be easily
driven by the op amp. However, if the op amp is used
in an application with a pure capacitive load, steps
must be taken to ensure stable operation.
As the op amp’s capacitive load increases, the amplifier’s
bandwidth decreases and the gain peaking increases. A
5Ω to 50Ω small resistor placed between VCOM and the
capacitive load reduces peaking but also reduces the
gain. An alternative method of reducing peaking is to
place a series RC network (snubber) in parallel with the
capacitive load. The RC network does not continuously
load the output or reduce the gain.
The MAX17010 includes eight logic-level to high-volt-
age level-shifting buffers, which can buffer eight logic
inputs (A1–A8) and shift them to a desired level (Y1–Y8)
to drive TFT-LCD row logic. The driver outputs, Y1–Y8,
swing between their power-supply rails, according to
the input-logic level on A1–A8. The driver output is
GOFF when its respective input is logic low, and GON_
when its respective input is logic high. These eight dri-
ver channels are grouped for different high-level sup-
plies. A1–A6 are supplied from GON1, and A7 and A8
are supplied from GON2. GON1 and GON2 can be tied
together to make A1–A8 use identical supplies.
High-Voltage Level-Shifting Scan Driver
Driving Pure Capacitive Load
Short-Circuit Current Limit
Op Amps
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