MCP2036-I/SL Microchip

V DET+ 13 14 NC NC 15 16 V REF MCP2036 Inductive Sensor Analog Front End Device Features Description Complete Inductance Measurement System: The MCP2036 Inductive Sensor Analog Front End (AFE) combines all the necessary analog functions for - Low-Impedance Current Driver a complete inductance measurement system. - Sensor/Reference Coil Multiplexer The device includes : - High-Frequency Detector Operating Voltage: 2.7 to 5.5V High-frequency, current-mode coil driver for exciting the sensor coil. Low-Power Standby Mode Synchronous detector for converting AC sense Gain and Frequency set by external passive voltages into DC levels. components Output amplifier/filter to improve resolution and limit noise. Typical Applications Virtual ground reference generator for single Harsh environment inductive keyboards supply operation. Inductive rotational sensor interface The device is available in 14-pin PDIP, SOIC and Inductive displacement sensor interface 16-pin QFN packages: Inductive force sensor interface Package Types MCP2036 14-pin PDIP, SOIC MCP2036 16-pin QFN V 1 14 V REF DET+ V LREF 2 13 DET- V LBTN 3 12 DETOUT LREF 1 12 V DET- V DD V 4 11 SS 2 LBTN 11 V DETOUT Reserved DRVOUT 5 10 V DD 3 10 V SS CS DRVIN 6 9 DRVOUT 4 9 Reserved CLK REFSEL 7 8 2009 Microchip Technology Inc. DS22186A-page 1 5 DRVIN CLK 6 REFSEL 7 CS 8MCP2036 high-frequency triangular waveform present on the 1.0 FUNCTIONAL DESCRIPTION DRVIN input, and amplifies it into the pulsed DC current The MCP2036 measures a sensor coils impedance by for exciting the series combination of the sensor coils. exciting the coil with a pulsed DC current and The AC voltages generated across the coils, are then measuring the amplitude of the resulting AC voltage capacitively coupled into the LBTN and LREF inputs. waveform. The drive current is generated by the An input resistance of 2K between the inputs and the on-chip current amplifier/driver which takes the virtual ground offsets the AC input voltages up to the signal ground generated by the reference voltage generator, as shown in Figure 1-1. LREF LBTN CLK Input MUX Op. Amp. Block V 1 0 DET+ REFSEL 10K + V DETOUT 10K V SS - Mixer V DET- V DD Key Inductor Driver Voltage V REF Reference DRVIN DRVOUT CS FIGURE 1-1: MCP2036 Block Diagram DS22186A-page 2 2009 Microchip Technology Inc.