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