Single and Multichannel, Synchronous Voltage-to-Frequency Converters

The AD7741/AD7742 are a new generation of synchronous voltage-to-frequency converters (VFCs). The AD7741 is a single-channel version in an 8-lead package (SOIC/DIP) and the AD7742 is a multichannel version in a 16-lead package (SOIC/DIP). No user trimming is required to achieve the specified performance.

The AD7741 has a single buffered input whereas the AD7742 has four buffered inputs that may be configured as two fully-differential inputs or three pseudo-differential inputs. Both parts include an on-chip +2.5 V bandgap reference that provides the user with the option of using this internal reference or an external reference.

The AD7741 has a single-ended voltage input range from 0 V to REFIN. The AD7742 has a differential voltage input range from –VREF to +VREF. Both parts operate from a single +5 V supply consuming typically 6 mA, and also contain a power down feature that reduces the current consumption to less than 35 μA.

Applications

* Low Cost Analog-to-Digital Conversion

* Signal Isolation

* AD7742 is obsolete

* AD7741: One Single-Ended Input Channel

* AD7742: Two Differential or Three Pseudo-Differential Input Channels

* Integral Nonlinearity of 0.012% at fOUT(Max) = 2.75 MHz (AD7742) and at fOUT(Max) = 1.35 MHz (AD7741)

* Single +5 V Supply Operation