a FEATURES 4- or 8-Analog Input Channels Built-In Track/Hold Function 10 kHz Signal Handling on Each Channel Fast Microprocessor Interface Single +5 V Supply Low Power: 50 mW Fast Conversion Rate, 2.5 s/Channel Tight Error Specification: 1/2 LSB
LC2MOS High Speed 4- & 8-Channel 8-Bit ADCs AD7824/AD7828 FUNCTIONAL BLOCK DIAGRAM
The AD7824 and AD7828 are high-speed, multichannel, 8-bit ADCs with a choice of 4 (AD7824) or 8 (AD7828) multiplexed analog inputs. A halflash conversion technique gives a fast conversion rate of 2.5 µs per channel and the parts have a builtin track/hold function capable of digitizing full-scale signals of 10 kHz (157 mV/µs slew rate) on all channels. The AD7824 and AD7828 operate from a single +5 V supply and have an analog input range of 0 V to +5 V, using an external +5 V reference.
1. 4- or 8-channel input multiplexer gives cost-effective spacesaving multichannel ADC system.
Microprocessor interfacing of the parts is simple, using standard Chip Select (CS) and Read (RD) signals to initiate the conversion and read the data from the three-state data outputs. The halflash conversion technique means that there is no need to generate a clock signal for the ADC. The AD7824 and AD7828 can be interfaced easily to most popular microprocessors.
4. Tight total unadjusted error spec and channel-to-channel matching eliminate the need for user trims.
2. Fast conversion rate of 2.5 µs/channel features a per channel sampling frequency of 100 kHz for the AD7824 or 50 kHz for the AD7828. 3. Built-in track-hold function allows handling of 4- or 8channels up to 10 kHz bandwidth (157 mV/µs slew rate).
5. Single +5 V supply simplifies system power requirements. 6. Fast, easy-to-use digital interface allows connection to most popular microprocessors with minimal external components. No clock signal is required for the ADC.
The AD7824 and AD7828 are fabricated in an advanced, all ion-implanted, Linear-Compatible CMOS process (LC2MOS) and have low power dissipation of 40 mW (typ). The AD7824 is available in a 0.3" wide, 24-pin “skinny” DIP, while the AD7828 is available in a 0.6" wide, 28-pin DIP and in 28terminal surface mount packages.
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