ALD1123E

ALD1123E/ALD1121E are monolithic quad/dual EPAD® (Electrically Programmable Analog Device) N-channel MOSFETs with electrically adjustable threshold (turn-on) voltage. The ALD1123E/ALD1121E are precision matched and adjusted
(e-trimmed) at the factory resulting in quad/dual MOSFETs that are highly matched in electrical characteristics. The ALD1123E/ALD1121E has four (4) separate source pins. SN1, SN2 share a common substrate pin V-1 which has to be connected to the most negative voltage potential. Likewise, SN3, SN4 share a common substrate pin V-2 which has to be connected to the negative voltage potential for SN3, SN4. The ALD1121E has two (2) separate source pins (SN1, SN2). Both SN1, SN2 share  common substrate pin 4 which has to be connected to the most negative voltage potential.

Using an ALD1123E/ALD1121E MOSFET array is simple and straight forward. The MOSFETs function in electrical characteristics as n-channel MOSFETs except that all the devices have exceptional matching to each other. For a given input voltage, the threshold voltage of a MOSFET device determines its drain on-current, resulting in an on-resistance characteristic that can be precisely preset and then controlled by the input voltage very accurately. Since these devices are on the same monolithic chip, they also exhibit excellent tempco matching characteristics.

ALD1123E/ALD1121E MOSFET devices have very low input currents, and as a result a very high input impedance (>10 12 Ohm). The gate voltage from a control source can drive many MOSFET inputs with practically no loading effects. Used in precision current mirror or current multiplier applications, they can be used to provide a current source over a 100 nA to 3 mA range, and with either a positive, negative or zero tempco.