This section presents application-relevant information of some of the popular A/D converter IC type numbers, as it is not possible to give a detailed description of each one of them. The type numbers included for this purpose are ADC0800, ADC0808, ADC80, ADC84, ICL7106/ICL7107 and AD 7820.

ADC-0800 is a successive approximation type eight-bit A/D converter. The internal architecture of ADC-0800 is shown in Fig. 12.41. The digital output is in complementary form and is also tristate to permit bussing on common data lines. Its salient features include ratiometric conversion, no missing codes, tristate outputs and a conversion time of 50 µs (typical), ±1-LSB linearity and a clock frequency range of 50–800 kHz.

ADC 0808 is an eight-bit CMOS successive approximation type A/D converter. The device has an eight-channel multiplexer and a microprocessor-compatible control logic. Salient features of the device include eight-bit resolution, no missing codes, a conversion time of 100 µs (typical), stand-alone operation or easy interface to all microprocessors, a 0–5 V analogue input range with a single 5 V supply and latched tristate outputs.

ADC-80/AD ADC-80 is a 12-bit A/D converter of the successive approximation type. It has an on-chip clock generator, reference and comparator. AD ADC80 is pin-to-pin compatible with industry-standard ADC-80. The salient features of the device include low cost, ±0.012% linearity, a conversion time of 25 µs (max.), ±12V or ±15V operation, guaranteed no missing codes over a temperature range from −25°C to +85°C and a maximum power dissipation of 595 mW.

ADC-84 and ADC-85 families of 10-bit (ADC 84-10 and ADC 85-10) and 12-bit (ADC 84-12 and ADC 85-12) converters are complete A/D converters like the industry-standard ADC-80, with an internal clock (1.9 MHz in the case of the 10-bit converters and 1.35 MHz in the case of the 12-bit converters), comparator, reference (6.3 V) and input buffer amplifier. These have a conversion time of 10 µs (for 12-bit operation) and 6 µs (for 10-bit operation).

AD 7820 is a µP-compatible, eight-bit A/D converter built around half-flash architecture. It incorporates internal sample-and-hold circuitry, which eliminates the need for an external sample-and-hold circuit for signals having slew rates of less than 100 mV/µs. Other features include a 1.36 µs conversion time, a single +5 V supply and tristate buffered outputs.

ICL7106 and ICL7107 are the most commonly used A/D converter ICs for digital panel meter (DPM) and digital voltmeter (DVM) applications, with the former used with LCD and the latter used with LED displays. The two types are high-performance, low-power A/D converter ICs of the dual-slope integrating type from Intersil, containing all the necessary building blocks such as a clock generator, a reference, seven-segment decoders, display drivers, etc., for directly driving seven-segment displays.

Salient features include low cost, low power consumption (typically less than 10 mW), low noise (less than 15 µV peak to peak), true polarity at zero for precise null detection, true differential input and reference, and a rollover error of less than one count. The reference voltage is set to be half the full-scale analogue input.