AD7886

a FEATURES 750 kHz/1 MHz Throughput Rate 1 ␮ s/750 ns Conversion Time 12-Bit No Missed Codes Over Temperature 67 dB SNR at 100 kHz Input Frequency Low Power—250 mW typ Fast Bus Access Time—57 ns max APPLICATIONS Digital Signal Processing Speech Recognition and Synthesis Spectrum Analysis DSP Servo Control LC2MOS 12-Bit, 750 kHz/1 MHz, Sampling ADC AD7886 FUNCTIONAL BLOCK DIAGRAM VDD R3 VIN1 10k R4 VIN2 10k +5REF R1 9k SUM R2 6.3k VREF 4096 RESISTOR DAC AGND – + T/H 3.5k R5 CLOCK OSCILLATOR AND TIMER CONTROL TIMER BUSY CS RD CONVST 4-BIT LATCH 15 COMPARATORS AND 4-BIT FLASH LOGIC DB11 4-BIT LATCH THREE STATE OUTPUTS DB0 4-BIT LATCH SEGMENT SELECT AD7886 VSS DGND GENERAL DESCRIPTION The AD7886 is a 12-bit ADC with a sample-and-hold amplifier offering high speed performance combined with low power dissipation. The AD7886 is a triple pass flash ADC that uses 15 comparators in a 4-bit flash technique to achieve 12-bit accuracy in 1 µs/750 ns conversion time. An on-chip clock oscillator provides the appropriate timing for each of the three conversion stages, eliminating the need for any external clocks. Acquisition time of the sample-and-hold amplifier gives a resulting throughput rate of 750 kHz/1 MHz.* The AD7886 operates from ± 5 V power supplies. Pin-strappable inputs offer a choice of three analog input ranges: 0 V to 5 V, 0 V to 10 V or ± 5 V. In addition to the traditional dc accuracy specifications such as linearity, offset and full-scale errors, the AD7886 is also sp...