Bidirectional controled current source module v.01 - m1

This is my second order from PCBWay factory and same as last time, i have excellent quality pcb at a low price and fairly fast delivery. This board is an improved version of the previous project. Current-Voltage measurements often require a precision bidirectional current source that can be controlled by a microcontroller. This module implements a precision bipolar current source based on a Holland pump. The basis of the module is a differential operational amplifier LT1990 (SOIC-8 case), the power of this current source is increased by two transistors (FZT651 and FZT751 in SOT-223 case) that form a current mirror. The current value is controlled in two ways: 1. DAC input; 2. PWM input. There is also a choice of reference level: 1. Vcc; 2. Vcc/2; 3. GND-Vcc range by potentiometer; 4. GND. This module has one output (±12V compilance voltage, ±100 mA recommended and ±200 mA max load capability) with two options: with galvanic isolation (via opto-relay), and without it. A bipolar ±12V PSU is required to power the module.