The AD9764 is the 14-bit resolution member of the TxDAC^®series of high performance, low power CMOS digital-to-analogconverters (DACs). The TxDAC^®; family, which consists of pincompatible 8-, 10-, 12-, and 14-bit DACs, is specificallyoptimized for the transmit signal path of communicationsystems. All of the devices share the same interface options,small outline package and pinout, providing an upward ordownward component selection path based on performance,resolution and cost. The AD9764 offers exceptional ac and dcperformance while supporting update rates up to 125 MSPS.

The AD9764’s flexible single-supply operating range of 2.7 V to5.5 V and low power dissipation are well suited for portable andlow power applications. Its power dissipation can be furtherreduced to a mere 45 mW with a slight degradation in performanceby lowering the full-scale current output. Also, a power-downmode reduces the standby power dissipation to approximately25 mW.

The AD9764 is manufactured on an advanced CMOS process.A segmented current source architecture is combined with aproprietary switching technique to reduce spurious componentsand enhance dynamic performance. Edge-triggered inputlatches and a 1.2 V temperature compensated bandgap referencehave been integrated to provide a complete monolithicDAC solution. Flexible supply options support +3 V and +5 VCMOS logic families.

The AD9764 is a current-output DAC with a nominal full-scaleoutput current of 20 mA and >100 kΩ output impedance.Differential current outputs are provided to support single-endedor differential applications. Matching between the twocurrent outputs ensures enhanced dynamic performance in adifferential output configuration. The current outputs may betied directly to an output resistor to provide two complementary,single-ended voltage outputs or fed directly into a transformer.The output voltage compliance range is 1.25 V.

The on-chip reference and control amplifier are configured formaximum accuracy and flexibility. The AD9764 can be drivenby the on-chip reference or by a variety of external referencevoltages. The internal control amplifier, which provides a wide(>10:1) adjustment span, allows the AD9764 full-scale currentto be adjusted over a 2 mA to 20 mA range while maintainingexcellent dynamic performance. Thus, the AD9764 may operateat reduced power levels or be adjusted over a 20 dB range toprovide additional gain ranging capabilities.

The AD9764 is available in a 28-lead SOIC package. It isspecified for operation over the industrial temperature range.

Product Highlights

1. The AD9764 is a member of the TxDAC product family that provides an upward or downward component selection path based on resolution (8 to 14 bits), performance and cost.
2. Manufactured on a CMOS process, the AD9764 uses a proprietary switching technique that enhances dynamic performance beyond that previously attainable by higher power/cost bipolar or BiCMOS devices.
3. On-chip, edge-triggered input CMOS latches readily interface to +3 V and +5 V CMOS logic families. The AD9764 can support update rates up to 125 MSPS.
4. A flexible single-supply operating range of 2.7 V to 5.5 V, and a wide full-scale current adjustment span of 2 mA to 20 mA, allows the AD9764 to operate at reduced power levels.
5. The current output(s) of the AD9764 can be easily configured for various single-ended or differential circuit topologies.

Applications

• Communication Transmit Channel:
  - Basestations
  - ADSL/HFC Modems
• Instrumentation

At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.