New to Microchip’s Linear Product Line is a family of operational amplifiers optimized for high speed, low noise and distortion, single-supply operation with rail-to-rail output and an input that includes the negative rail.
Well then….what’s so special about mCal?
The internal mCal circuitry, when activated, starts a delay timer (to wait for the op amp to settle to its new bias point), then calibrates the input offset voltage (VOS). The mCal circuitry is triggered at power-up (and after some power brown out events) by the internal POR, and by the memory’s Parity Detector. The power up time, when the mCal circuitry triggers the calibration sequence, is 200 ms (typical).
What applications benefit from mCal?
The following are a few examples of applications that benefit from mCal and low offset performance.
POWER DRIVER WITH HIGH GAIN: The figure below shows a power driver with high gain (1 + R2/R1). The MCP651/2/5 op amp’s short circuit current makes it possible to drive significant loads. The calibrated input offset voltage supports accurate response at high gains. R3 should be small, and equal to R1||R2, in order to minimize the bias current induced offset.
OPTICAL DETECTOR AMPLIFIER: The figure below shows a transimpedance amplifier, using the MCP651 op amp, in a photo detector circuit. The photo detector is a capacitive current source. The op amp’s input common mode capacitance (5 pF, typical) acts in parallel with CD. RF provides enough gain to produce 10 mV at VOUT. CF stabilizes the gain and limits the transimpedance bandwidth to about 1.1 MHz. RF’s parasitic capacitance (e.g., 0.2 pF for a 0805 SMD) acts in parallel with CF.
More about this new product family: Click Here
More about Eval Boards that support this product family: Click Here
May 21, 2009
Cool!