Product Description

The REF200AU combines three precision analog building blocks — two independent 100µA current sources and a 1:1 current mirror — into a single 8-SOIC package. All three sections are dielectrically isolated from each other and from the package substrate, ensuring complete electrical independence. The current sources are two-terminal devices that function equally well as current sources or current sinks, depending on how they are connected in circuit.

Unlike conventional current references, the REF200AU requires no external power supply — it is entirely self-biasing from the voltage across its terminals. This eliminates ground-loop issues and simplifies two-wire current-loop designs. The FET-cascoded output topology provides high dynamic output impedance for stable regulation even with fluctuating load voltages. Laser trimming at wafer probe ensures each section meets the ±0.5% accuracy specification before packaging.

Key Applications

• RTD & Thermistor Excitation — Precision 100µA bias for Pt100/Pt1000 temperature sensors

• Strain Gauge Bridges — Stable excitation current for load cells and pressure transducers

• 4–20mA Current Loops — Floating current source for industrial transmitters and process control

• Medical Instrumentation — Low-drift bias for ECG/EEG front-ends and patient monitors

• ATE & Semiconductor Test — Programmable reference current for parametric characterization

• Battery-Powered Devices — Zero quiescent supply draw for ultra-low-power portable designs

One 100µA current source drives a Pt100 RTD directly. The voltage developed across the sensor (10mV at 0°C, ~13.85mV at 100°C) is read by a differential ADC. No bridge resistors required — the floating source eliminates common-mode errors. Accuracy depends only on the REF200AU's ±0.5% current tolerance.

Both current sources are paralleled for 200µA output, feeding a XTR111 V-to-I converter's reference input. The floating topology means the REF200AU draws its operating voltage from the loop supply itself — no separate regulator needed. Total quiescent budget: zero additional current from the loop.

Connect a current source's output to the current mirror input. The mirror replicates 100µA with 1:1 ratio, sinking from a positive rail into a load to ground. Useful for discharging timing capacitors in ramp generators, or biasing PNP differential pairs in precision analog stages.

Two REF200AU current sources provide matched 100µA bias to each leg of a strain gauge bridge. The dielectric isolation between sections ensures no crosstalk. Combined with a precision ADC, this yields microstrain-level resolution in load cell and pressure sensor applications.

Multiple REF200AU sources are stacked in parallel: N devices × 200µA (both channels) = N × 200µA total. For 1mA: five REF200AU ICs in parallel. The laser-trimmed accuracy means current sharing is inherently balanced — no ballast resistors needed.

For semiconductor parametric test systems, the REF200AU provides a stable 100µA reference to force across DUT pins. The 2.5V–40V compliance range accommodates most logic families and analog ICs. Multiple REF200AU ICs per pin-electronics card give per-channel calibration references.

Same REF200AU in tape & reel (2,500 pcs/reel) for automated assembly

Programmable 1µA–10mA current source with adjustable tempco, TO-92-3

10V precision voltage reference, 2.5ppm/°C drift, 8-SOIC

Precision V-to-I converter/transmitter for 4–20mA current loops

16-bit digital current/power monitor with I²C, measures REF200AU output

Same dual current source/sink in through-hole PDIP-8 package

Green (RoHS + no Br/Sb) tape & reel, 2,500 pcs/reel

Ultra-low-noise LDO, complements REF200AU in precision analog rails