MAX8790AETP+T Maxim Integrated Products, MAX8790AETP+T Datasheet - Page 9

• Manufacturer Part Number: MAX8790AETP+T
• Description: IC LED DRVR WHITE BCKLGT 20-TQFN
• Manufacturer: Maxim Integrated Products
• Type: Backlight, White LEDr

Specifications of MAX8790AETP+T

• Topology: PWM, Step-Up (Boost)
• Number Of Outputs: 6
• Internal Driver: No
• Type - Primary: Backlight
• Type - Secondary: White LED
• Frequency: 1MHz
• Voltage - Supply: 4.5 V ~ 5.5 V, 5.5 V ~ 26 V
• Voltage - Output: 5V
• Mounting Type: Surface Mount
• Package / Case: 20-TQFN Exposed Pad
• Operating Temperature: -40°C ~ 85°C
• Current - Output / Channel: 27mA
• Internal Switch(s): Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Efficiency: -
• Lead Free Status / Rohs Status: Details

PIN
11
12
13
14
15
16
17
18
19
20
EP
Current Balancing for LCD Panel Applications
NAME
CPLL
FSET
CCV
ISET
FB6
EXT
V
CS
OV
EP
IN
CC
_______________________________________________________________________________________
Six-String White LED Driver with Active
LED String 6 Cathode Connection. FB6 is the open-drain output of an internal regulator, which controls
current through FB6. FB6 can sink up to 27mA. If unused, connect FB6 to GND.
Step-Up Controller Current-Sense Input. Connect the CS input to a ground-referenced sense resistor to
measure the current in the external MOSFET switch.
External MOSFET Gate-Drive Output
Overvoltage Sense. Connect OV to the center tap of a resistive voltage-divider from V
detection threshold for voltage limiting at OV is 1.23V (typ).
5V Linear Regulator Output. V
for the external MOSFET. Bypass V
than or equal to 5.5V, connect V
V
Supply Input. V
at the pin with a 0.1µF or greater ceramic capacitor.
Step-Up Converter Compensation Pin. Connect a 0.1µF ceramic capacitor and 1.2kΩ resistor from CCV to
GND. When the MAX8790A shuts down, CCV is discharged to 0V through an internal 20kΩ resistor.
Full-Scale LED Current Adjustment Pin. The resistance from ISET to GND controls the full-scale current in
each LED string:
The acceptable resistance range is 74kΩ < R
27mA > I
PLL Free-Running Frequency Control Pin. The resistance from FSET to GND controls the PLL oscillator’s
free-running frequency, f
The capture range is 0.6 x f
754kΩ, which corresponds to a frequency range of 500Hz > f
frequency range is 100Hz to 500Hz.
Phase-Locked Loop-Compensation Capacitor Pin. The capacitance at CPLL compensates the PLL loop
response. Connect a 0.1µF ceramic capacitor from CPLL to GND.
Exposed Backside Pad. Solder to the circuit board ground plane with sufficient copper connection to
ensure low thermal resistance. See the PCB Layout Guidelines section.
CC
. When SHDN is low, the internal linear regulator is disabled.
LEDmax
IN
> 15mA. Connect ISET to V
biases the internal 5V linear regulator that powers the device. Bypass IN to GND directly
PLL
PLL
:
CC
to f
CC
provides power to the MAX8790A and is also used to bias the gate driver
PLL
CC
to IN to the disable the internal LDO and use the external 5V supply to
. The acceptable resistance range for FSET is 250kΩ < R
I
f
to GND with a ceramic capacitor of 1µF or greater. If V
LEDmax
PLL
= 1 / (10 x R
CC
ISET
= 20mA x 100kΩ/R
FUNCTION
for a default full-scale LED current of 20mA.
< 133kΩ, which corresponds to full-scale LED current of
FSET
Pin Description (continued)
x 800pF)
PLL
> 166Hz. The resulting capture
ISET
OUT
to ground. The
IN
FSET
is less
<
9