ANALOGIC TECH 사의 AAT3123   로 0~20mA 의 정전류를 만들수 있다.
(제어가 간단하다..)

특징은 아래와 같다.


? Dual Mode 1x and 1.5x Charge Pump for
Maximum Efficiency
? Drives Low-VF & High-VF Type LEDs
? Up to 6 20mA Outputs
? 32 Position Logarithmic Scale with Digital
Control
? Simple Serial Control™ (S2Cwire™) interface
? Low Noise Constant Frequency Operation
? 1MHz Switching Frequency
? Small Application Circuit
? Regulated Output Current
? Automatic Soft-Start
? VIN Range: 2.7V to 5.5V
? No Inductors
? Iq < 1μA in Shutdown
? Temperature Range -40 to 85°C.
? 16 pin 4x4 QFN package (AAT3124)
? 12 pin TSOPJW-12 package (AAT3123)