The AD667 is a complete voltage output, 12-bit monolithDigital-to-analog convertersA high stability embedded Zener reference and double-buffered input latch are included. The converter uses 12 precision, high-speed, bipolar current guide switches and a laser-trimmed thin-film resistor network to provide fast settling time and high accuracy.
Microprocessor compatibility is achieved through on-chip double-buffered latches. Input latches can interface directly with 4-, 8-, 12-, or 16-bit buses. Therefore, the 12-bit data from the first-level latch can be transferred to the second-level latch to avoid spurious analog output values. The latch can respond to short strobe pulses of 100 ns, allowing it to be used with the fastest microprocessors available.
The versatility and high performance of the AD667 is the result of an advanced switching design, high speed bipolar manufacturing processes, and proven laser wafer trimming (LWT). The device is trimmed at the wafer stage with a maximum linearity error of ±1/4 LSBs (K, B) at +25°C and ±1/2 LSBs over the entire operating temperature range.
The chip's undersurface (embedded) Zener diode provides a low noise reference with long-term stability and excellent temperature drift characteristics that outperform the best discrete reference diodes. The laser trimming process has excellent linearity and can also be used to adjust the absolute value of the voltage reference and its temperature coefficient. As a result, the AD667 has wide temperature range performance with a maximum linearity error of ±1/2 LSBs and guaranteed monotonicity over temperature. The full-scale gain temperature coefficient is typically 5 ppm/°C.
The AD667 is divided into five grades based on performance. The AD667J and AD667K are specified over the 0°C to +70°C temperature range and are available in 28-lead injection molded DIP (N) or PLCC (P) packages. The AD667S grade is specified over the -55°C to +125°C temperature range and is available in a ceramic DIP (D) or LCC (E) package. The AD667A and AD667B are specified over the –25°C to +85°C temperature range and are available in a 28-lead hermetically sealed ceramic DIP (D) package.