TLE2682

The TLE2682 offers the advantages of JFET-input operational amplifiers and rail-to-rail common-mode input voltage range with the convenience of single-supply operation. By combining a switched-capacitor voltage converter with a dual operational amplifier in a single package, Texas Instruments now gives circuit designers
new options for conditioning low-level signals in single-supply systems.

The TLE2682 features two high-speed, high-output drive JFET-input operational amplifiers with a switchedcapacitor building block. Using two external capacitors, the switched-capacitor network can be configured as a voltage inverter generating a negative supply voltage capable of sourcing up to 100 mA. This supply functions not only as the amplifier's negative rail but is also available to drive external circuitry. In this configuration, the amplifier common-mode input voltage range extends from the positive rail to below ground, thus providing true rail-to-rail inputs from a single supply. Furthermore, the outputs can swing to and below ground while sinking

over 25 mA. This feature was previously unavailable in operational amplifier circuits. The TLE2682 operational amplifier section has output stages that can drive 20-mA loads to 2.3 V with a 5-V rail. With a 2-mA load, the output swing extends to 3.9 V.

This amplifier design features a 25-V/ms minimum slew rate, which results in a high-power bandwidth. Settling time to 0.1% of a 10-V step (1-kW/100-pF load) is approximately 400 ns. Gain-bandwidth product is typically 10 MHz with an 8-MHz minimum. The TLE2682 offers significant speed and noise advantages at a low 1.5-mA typical supply current per channel.

The TLE2682 features a shutdown pin (FB/SD), which can be used to disable the switched-capacitor section. When disabled, the switched-capacitor voltage converter block draws less then 150 mA from the power supply, VIN.

The switched-capacitor voltage converter block also provides an on-board regulator; with the addition of an external divider, a well-regulated output voltage is easily obtained. The internal oscillator runs at a nominal frequency of 25 kHz. This can be synchronized to an external clock signal or can be varied using an external capacitor. A 2.5-V reference is brought out to VREF for use with the on-board regulator or external circuitry. Additional filtering can be added to minimize switching noise.

The TLE2682 is characterized for operation over the industrial temperature range of 40°C to 85°C. This device is available in a 16-pin wide-body surface-mount package.