19-3430; Rev 0; 10/04
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 boost-
ed output voltage (VMAIN) up to 13V using ultra-small
inductors and ceramic capacitors. The low-power
BiCMOS control circuitry and the low on-resistance
(0.35Ω) of the integrated power MOSFET allows effi-
ciency up to 93%.
The dual charge pumps independently regulate one
positive output (VPOS) and one negative output (VNEG).
These low-power outputs use external diode and
capacitor stages (as many stages as required) to regu-
late output voltages up to +40V and down to -40V. A
proprietary regulation algorithm minimizes output rip-
ple, as well as capacitor sizes for both charge pumps.
For both the MAX1748 and MAX8726, the supply
sequence is VMAIN first, VNEG next, and finally VPOS.
The MAX1748 soft-starts each supply as soon as the
previous supply finishes. The MAX8726 adds a delay
between the startups of VMAIN and VNEG and also
between VNEG and VPOS.
The MAX1748/MAX8726 are available in the ultra-thin
TSSOP package (1.1mm max height).
TFT Active-Matrix LCD Displays
Passive-Matrix LCD Displays
Digital Still Cameras
Typical Operating Circuit appears at end of data sheet.
♦ Three Integrated DC-DC Converters
♦ 1MHz Current-Mode PWM Boost Regulator
Up to +13V Main High-Power Output
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)
-40°C to +85°C
-40°C to +85°C
A "+" SIGN WILL REPLACE THE FIRST PIN INDICATOR ON LEAD-FREE PACKAGES.
________________________________________________________________ Maxim Integrated Products 1
For free samples and the latest literature, visit www.maxim-ic.com or phone 1-800-998-8800.
For small orders, phone 1-800-835-8769.