Inside

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• 16-bit Sigma Delta Analog Interface Circuit
• Power Distribution Devices Meet USB Specification
• Single-chip cellphone baseband power supply
• 300 mW stereo audio power amplifier offers 0.06% THD+N
• Single, high-speed MOSFET drivers in SOT=23 packages
• Wide input voltage, hign output drive CMOS op amps
• Single channel self-calibrating op amp
• Adjustable inverting DC-DC converter

Adjustable inverting DC-DC converter

Product Features

• Adjustable negative output @ 200 mA
• 2.7 V to 9 V input range
• 160 kHz current mode PWM controller
• Power down mode 1 µA
• 78% typical efficiency
• Operating temperature -40°C to 85°C

The TPS6755 inverting DC-DC converter provides negative supplies up to 200 mA. The device gives power supply designers a simple solution to inverting a positive low voltage input to a obtain a negative output. The device is a current mode pulse width modulator (PWM) with a P-channel MOSFET power switch. The TPS6755 offers a low 1.8 mA supply current, 78% (typical) efficiency, and simple design requirements. These features make it useful in applications requiring small layout areas and battery-saving performance. Typical applications include computer peripherals, hard disk drives and a variety of handheld and portable designs.

The 200 mA negative output voltage is adjustable to between -2.7 and -9 volts, depending on the input voltage level. Minimum input voltage is 2.7 V. The sum of the input voltage and the absolute value of the output voltage may not exceed 11.7 V. A logic enabled shutdown mode reduces battery drain to just 10 µA.

Required external components include a 10 µH inductor, output and input filter capacitors, reference filter capacitor, a Schottky rectifier and two resistors for setting the output voltage, as shown in the diagram below. A 160-kHz oscillator lets you use small surface mount components and simplifies noise filtering techniques.

Soft start, which causes the output voltage to increase at a controlled rate, may be implemented with the addition of one capacitor. Other features include an internal 1.2 V reference capable of sourcing 125 µA to external loads. The TPS6755 also has over-current limiting and an undervoltage lockout that prevents turn-on of the MOSFET power switch during power up.

The TPS6755 is designed to be pin-compatible with the MAX755 inverting PWM regulator and is offered in 8-pin plastic DIP and SOIC packages.

• TPS6755ID
• TPS6755IP