GENERAL DESCRIPTION

The 1B22 is an isolated voltage-to-current converter that incorporates transformer isolation to achieve high performance and automated surface mount manufacturing for low cost and increased reliability. Designed for industrial applications, it is especially suited for harsh environments with extremely high common-mode interference. With programmable inputs and outputs, the 1B22 provides an unbeatable combination of versatility and performance in a compact plastic package.

Functionally, the V/I converter consists of four basic sections: input conditioning, modulator/demodulator, isolated loop supply and current source (Figure 1). The 1B22 is pin programmable for 0 V to +5 V or 0 V to +10 V inputs and 0 to 20 mA or 4 to 20 mA outputs using an internal resistor network. It can also be set by an external resistor to accept 0 V to +1 V to 0 V to +10 V inputs. Transformer coupling provides 1500 V rms galvanic isolation between the inputs and the current loop. Nonlinearity is an excellent ±0.05 max.

FEATURES

Internal Isolated Loop Supply Drives 1000 Ω Load

Pin Programmable Inputs: 0 V to +5 V or 0 V to +10 V

Pin Programmable Outputs: 4 to 20 mA or 0 to 20 mA

High CMV Isolation: 1500 V RMS

Normal-Mode Output Protection: 240 V RMS

High Accuracy

Low Offset Tempco: ±300 nA/°C

Low Gain Tempco: ±50 ppm/°C

Low Nonlinearity: ±0.02

High CMR: 90 dB min

Small Package: 1.0 x 2.10 x 0.35

Meets IEEE STD 472: CMV Transient Protection (SWC)

APPLICATIONS

Multichannel Process Control

D/A Converter—Current Loop Interface

Analog Transmitters and Controllers

Remote Data Acquisition Systems