MAX8798AETX+T Maxim Integrated Products, MAX8798AETX+T Datasheet - Page 17

• Manufacturer Part Number: MAX8798AETX+T
• Description: Display Drivers Internal-Switch Boos t Regulator with Int
• Manufacturer: Maxim Integrated Products

Specifications of MAX8798AETX+T

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Table 1. Component List
Table 2. Component Suppliers
The MAX8798 typical application circuit (Figure 2) gener-
ates a +8V source-driver supply and approximately +20V
and -12V gate-driver supplies for TFT displays. The input-
voltage range for the IC is from +1.8V to +5.5V; however,
the Figure 2 circuit is designed to operate from 2.2V to
3.6V. Table 1 lists recommended components and Table
2 lists contact information of component suppliers.
DESIGNATION
Fairchild Semiconductor
Sumida Corp.
TDK Corp.
Toshiba American Electronic Components, Inc.
Integrated 3-Channel Scan Driver for TFT LCDs
C21, C22
D2–D5
C1
D1
L1
Typical Application Circuit
10μF, 6.3V X5R ceramic capacitor (1206)
TDK C3216X5ROJ106M
4.7μF, 10V X5R ceramic capacitors (1206)
TDK C3216X5R1A475M
3A, 30V Schottky diode (M-flat)
Toshiba CMS02
200mA, 100V, dual, ultra-fast diodes (SOT23)
Fairchild MMBD4148SE
3.6μH, 1.8A inductor
Sumida CM0611BHPNP-3R6MC
SUPPLIER
______________________________________________________________________________________
Internal-Switch Boost Regulator with
DESCRIPTION
408-822-2000
847-545-6700
847-803-6100
949-455-2000
PHONE
The MAX8798 contains a high-performance step-up
switching regulator; one high-speed operational ampli-
fier; one three-channel, high-voltage level-shifting scan
driver for active-matrix TFT LCDs; and an I
VCOM calibrator. Figure 3 shows the MAX8798 func-
tional diagram.
The step-up regulator employs a current-mode, fixed-
frequency PWM architecture to maximize loop band-
width and provide fast transient response to pulsed
loads found in source drivers of TFT LCD panels. The
high switching frequency (1.2MHz) allows the use of
low-profile inductors and ceramic capacitors to minimize
the thickness of LCD panel designs. The integrated
high-efficiency MOSFET and the IC’s built-in digital
soft-start functions reduce the number of external com-
ponents required while controlling inrush current. The
output voltage can be set from V
nal resistive voltage-divider.
The regulator controls the output voltage and the power
delivered to the output by modulating the duty cycle (D)
of the internal power MOSFET in each switching cycle.
The duty cycle of the MOSFET is approximated by:
408-822-2102
847-545-6720
847-390-4405
949-859-3963
FAX
D
≈
Detailed Description
V
MAIN
V
www.fairchildsemi.com
www.sumida.com
www.component.tdk.com
www.toshibaamerica.com/taec
MAIN
−
Step-Up Regulator
V
IN
IN
to 18V with an exter-
WEBSITE
2
C-controlled
17