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TPL0401 128-Taps Single-Channel Digital Potentiometer With I2C Interface Evaluation Module



  • Works with low-cost MSP430-based LaunchPad platform
  • Simple GUI to control EVM
  • EVM can operate in three different modes
    • Adjustable voltage reference mode
    • Variable gain mode
  • Board is entirely powered by USB

Texas Instruments  TPL0401EVM

The TPL0401 is an I2C bus-controlled, single-channel, linear-taper digital potentiometer with 128 wiper positions. TPL0401A/B have an end-to-end resistance of 10 kΩ and the low terminal is internally connected to ground. The position of the wiper can be adjusted using an I2C interface. The TPL0401 is available in a 6-pin SC-70 package with a specified temperature range of -40°C to 125°C. The part has 10-kΩ end-to-end resistance and can operate with a supply-voltage range of 2.7 V to 5.5 V.

The TPL0401EVM is designed to operate with the Texas Instruments LaunchPad (MSP-EXP430G2). The TPL0401EVM comes with a preprogrammed MSP430G2553 microcontroller, which is to be inserted in the DIP socket on the LaunchPad. The LaunchPad can be purchased separately at http://www.ti.com/launchpad.

The TPL0401EVM has three different evaluation modes:

Mode 1 – LED mode: This is the standard mode the TPL0401 comes up in when powered up. In this mode, the TPL0401 devices are used to control the color mixing on the RGB LEDs. The DPOTs are used to set the current limit for the TLC59108 LED driver. This mode is an auto-run mode that does not have any GUI control. The flashing lights and color mixing is controlled by the keys on the board and other TI products on the board.

Mode 2 – Adjustable voltage reference mode: In this mode, the TPL0401 is used in conjunction with an LMV321 op amp as an adjustable voltage reference circuit.

Mode 3 – Variable gain mode: In this mode, the TPL0401 is configured as part of a variable gain noninverting amplifier. The gain of the amplifier can be controlled by a digital interface. This mode can be used to evaluate the bandwidth of the TPL0401.

The EVM is operated by connecting the LaunchPad to a PC that has Windows&#8482 (with .NET) via the USB port. Other standard lab equipment such as signal generator, multimeter, spectrum analyzer, etc., may be required for detailed analysis of the TPL0401 performance using this EVM.