Member of the Pin-Compatible
CommsDAC Product Family
125 MSPS Update Rate
12-Bit Resolution
Spurious Free Dynamic Range (SFDR) to
Nyquist at 40 MHz Output: 60 dBc
1 ns Setup/Hold Time
Differential Scalable Current Outputs: 2 mA
to 20 mA
On-Chip 1.2 V Reference
3 V and 5 V CMOS-Compatible Digital
Interface
Straight Binary or Twos Complement Input
Power Dissipation: 175 mW at 5 V, Sleep
Mode: 25 mW at 5 V
Package: 28-Pin SOIC and TSSOP

description
The THS5661A is a 12-bit resolution digital-to-analog converter (DAC) specifically optimized for digital data
transmission in wired and wireless communication systems. The 12-bit DAC is a member of the CommsDAC
series of high-speed, low-power CMOS digital-to-analog converters. The CommsDAC family consists of pin
compatible 14-, 12-, 10-, and 8-bit DACs. All devices offer identical interface options, small outline package, and
pinout. The THS5661A offers superior ac and dc performance while supporting update rates up to 125 MSPS.
The THS5661A operates from an analog and digital supply of 3 V to 5.5 V. Its inherent low power dissipation
of 175 mW ensures that the device is well-suited for portable and low-power applications. Lowering the full-scale
current output reduces the power dissipation without significantly degrading performance. The device features
a SLEEP mode, which reduces the standby power to approximately 25 mW, thereby optimizing the power
consumption for system needs.
The THS5661A is manufactured in Texas Instruments advanced high-speed mixed-signal CMOS process. A
current-source-array architecture combined with simultaneous switching shows excellent dynamic
performance. On-chip edge-triggered input latches and a 1.2 V temperature-compensated bandgap reference
provide a complete monolithic DAC solution. The digital supply range of 3 V to 5.5 V supports 3 V and 5 V CMOS
logic families. Minimum data input setup and hold times allow for easy interfacing with external logic. The
THS5661A supports both a straight binary and twos complement input word format, enabling flexible interfacing
with digital signal processors.
The THS5661A provides a nominal full-scale differential output current of 20 mA and >300 kΩ output
impedance, supporting both single-ended and differential applications. The output current can be directly fed
to the load (e.g., external resistor load or transformer), with no additional external output buffer required. An
accurate on-chip reference and control amplifier allows the user to adjust this output current from 20 mA down
to 2 mA, with no significant degradation of performance. This reduces power consumption and provides 20 dB
gain range control capabilities. Alternatively, an external reference voltage and control amplifier may be applied
in applications using a multiplying DAC. The output voltage compliance range is 1.25 V.