Charge Pump Regulator for Color TFT Panel

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Replacement Parts

Rochester Electronics is the only authorized source of Analog Devices' products that have previously been discontinued or have become obsolete. Product availability should be checked directly with Rochester Electronics.

Product Details

The ADM8839 is a charge pump regulator, used for colour TFT (Thin Film Transistor) LCD’s (Liquid Crystal Displays). The device can be used to generate 3 output voltages (+5 V ±2%, +15 V, -15 V) from a single 2.7V - 4.2V (li-ion) input supply, using charge pump technology. These voltages are then used to provide supplies for the LCD controller (5 V ±2%), and the gate drives for the transistors in the panel (+15 V and -15 V). Only a few external capacitors are needed for the charge pumps. An efficient low dropout voltage regulator also ensures that the power efficiency is high and provides a low ripple 5 V output. This LDO can be shutdown and an external LDO used to regulate the 5 V doubler output and to drive the input to the charge pump section which generates the +15 V and -15 V outputs if so required by the user.

The ADM8839 has a power save shutdown feature. The 5 V output consumes the most power, so Power Efficiency is also maximised on this output with an oscillator enabling scheme (Green Idle™). This effectively senses the load current that is flowing and turns on the charge pump only when charge needs to be delivered to the 5 V pump doubler output.

The ADM8839 is fabricated using CMOS technology for minimal power consumption. The part is packaged in a 20- lead LFCSP (Lead Frame Chip Scale Package) with a tiny 4mm x 4mm footprint.