The LT ®1946A is a fixed frequency step-up DC/DC converter containing an internal 1.5A, 36V switch. Capable of generating 12V at 430mA from a 5V input, the LT1946A is ideal for powering large TFT-LCD panels. The LT1946A switches at 2.7MHz, allowing the use of tiny, low profile inductors and low value ceramic capacitors. Loop com- pensation can be either internal or external, giving the user flexibility in setting loop compensation and allowing opti- mized transient response with low ESR ceramic output capacitors. Soft-start is controlled with an external capaci- tor which determines the input current ramp rate during start up. The 8-lead MSOP package and high switching frequency ensure a low profile overall solution less than 1.1mm high.
The LT1946A is a 2.7 MHz boost DC/DC converter with an internal 1.5 A, 36 V switch, soft‑start function and adjustable output up to 35 V, suitable for powering large TFT‑LCD panels. It is offered in a thermally‑enhanced 8‑lead MSOP package with an exposed pad for improved heat dissipation.
The document includes absolute maximum ratings, electrical characteristics, pin descriptions, typical performance curves, recommended inductors and capacitors, and compensation guidelines. Application examples such as triple‑output TFT supplies and SEPIC topologies are provided to aid designers.
| Switching Frequency | 2.7 MHz (typical) |
|---|---|
| Maximum Input Voltage | 16 V |
| Internal Switch Current Rating | 1.5 A |
| Package | 8‑Lead MSOP (Thermally Enhanced) |
| Soft‑Start Output | 12 V at 430 mA from 5 V input |
The LT1946A operates at a typical switching frequency of 2.7 MHz.
The maximum operating voltage is 16 V.
A soft‑start capacitor on the SS pin charges with 4 µA, allowing the device to generate 12 V at 430 mA from a 5 V input during start‑up.
It is supplied in a small thermally enhanced 8‑lead MSOP package with an exposed pad.