MAX1748, MAX8726 Triple-Output TFT-LCD DC-DC Converters

Status

Active: In Production.

Description

FULL DATA SHEET (PDF, 228kB)
Download

The MAX1748/MAX8726 triple-output DC-DC converters in a low-profile TSSOP package provide the regulated voltages required by active-matrix, thin-film transistor (TFT) liquid-crystal displays (LCDs). One high-power DC-DC converter and two low-power charge pumps convert the +3.3V to +5V input supply voltage into three independent output voltages.

The primary 1MHz DC-DC converter generates a boosted output voltage (V_MAIN) up to 13V using ultra-small inductors and ceramic capacitors. The low-power BiCMOS control circuitry and the low on-resistance (0.35��) of the integrated power MOSFET allows efficiency up to 93%.

The dual charge pumps independently regulate one positive output (V_POS) and one negative output (V_NEG). These low-power outputs use external diode and capacitor stages (as many stages as required) to regulate output voltages up to +40V and down to -40V. A proprietary regulation algorithm minimizes output ripple, as well as capacitor sizes for both charge pumps.

For both the MAX1748 and MAX8726, the supply sequence is V_MAIN first, V_NEG next, and finally V_POS. The MAX1748 soft-starts each supply as soon as the previous supply finishes. The MAX8726 adds a delay between the startups of V_MAIN and V_NEG and also between V_NEG and V_POS.

The MAX1748/MAX8726 are available in the ultra-thin TSSOP package (1.1mm max height).

An evaluation kit is available: MAX1748EVKIT

Key Features		Applications/Uses
Three Integrated DC-DC Converters 1MHz Current-Mode PWM Boost Regulator Up to +13V Main High-Power Output ��1% Accuracy High Efficiency (93%) Dual Charge-Pump Outputs Up to +40V Positive Charge-Pump Output Down to -40V Negative Charge-Pump Output Internal Supply Sequencing Internal Power MOSFETs +2.7V to +5.5V Input Supply 0.1µA Shutdown Current 0.6mA Quiescent Current Internal Soft-Start Power-Ready Output Ultra-Small External Components Thin TSSOP Package (1.1mm max)		Camcorders Digital Still Cameras Passive-Matrix LCD Displays PDAs TFT Active-Matrix LCD Displays

Key Specifications: Multifunction PMICs

Part Number

Primary Topology

Monitor/Control Features

DC-DC/Power Features

LCD/LED/Flash/CCD Features

V_IN
(V)

V_OUT
(V)

Max. I_OUT
(A)

Oper. Freq.
(kHz)

Package/Pins

Smallest Available Pckg.
(mm²)

Price

min

max

min

max

��

max w/pins

See Notes

MAX1748

Step-Up

Shutdown

Fixed Freq./PWM

Internal Pwr. FETs

Soft Start

TFT Bias

2.7

5.5

2.7

0.5

1000

TSSOP/16

33.4

$3.07 @1k

See All Multifunction PMICs (83)

Diagram

Typical Operating Circuit

source��ShenZhen henlito electronic co.,ltd.

web:www.henlito.com