2 LC MOS High Speed a 4- and 8-Channel 8-Bit ADCs AD7824/AD7828 FUNCTIONAL BLOCK DIAGRAM FEATURES 4 or 8 Analog Input Channels Built-In Track-and-Hold Function V (+) DB7 4-BIT REF FLASH DB6 V () 10 kHz Signal Handling on Each Channel REF ADC DB5 (4MSB) AIN1 DB4 Fast Microprocessor Interface Single 5 V Supply 4-BIT THREE- AIN4 MUX* Low Power: 50 mW DAC STATE DRIVERS Fast Conversion Rate: 2.5 s/Channel V (+) REF 4-BIT DB3 16 Tight Error Specification: 1/2 LSB FLASH AIN8 DB2 ADC DB1 (4LSB) DB0 ADDRESS TIMING AND CONTROL INT LATCH CIRCUITRY DECODE RDY RD CS A0 A1 A2** *AD7824 4-CHANNEL MUX **AD7828 8-CHANNEL MUX A2 AD7828 ONLY GENERAL DESCRIPTION PRODUCT HIGHLIGHTS The AD7824 and AD7828 are high speed, multichannel, 8-bit 1. 4- or 8-channel input multiplexer gives cost effective, ADCs with a choice of four (AD7824) or eight (AD7828) multi- space-saving multichannel ADC system. plexed analog inputs. A half-flash conversion technique gives a fast 2. Fast conversion rate of 2.5 s/channel features a per-channel conversion rate of 2.5 s per channel, and the parts have a built-in sampling frequency of 100 kHz for the AD7824 or 50 kHz track-and-hold function capable of digitizing full-scale signals of for the AD7828. 10 kHz (157 mV/s slew rate) on all channels. The AD7824 and 3. Built-in track-and-hold function allows handling of four or AD7828 operate from a single 5 V supply and have an analog input eight channels up to 10 kHz bandwidth (157 mV/s slew rate). range of 0 V to 5 V, using an external 5 V reference. 4. Tight total unadjusted error spec and channel-to-channel Microprocessor interfacing of the parts is simple, using standard matching eliminate the need for user trims. Chip Select (CS) and Read (RD) signals to initiate the conversion and read the data from the three-state data outputs. The half-flash 5. Single 5 V supply simplifies system power requirements. conversion technique means that there is no need to generate a 6. Fast, easy-to-use digital interface allows connection to most clock signal for the ADC. The AD7824 and AD7828 can be popular microprocessors with minimal external components. interfaced easily to most popular microprocessors. No clock signal is required for the ADC. The AD7824 and AD7828 are fabricated in an advanced, all 2 ion-implanted, linear compatible CMOS process (LC MOS) and have low power dissipation of 40 mW (typ). The AD7824 is available in a 0.3 wide, 24-lead skinny DIP, while the AD7828 is available in a 0.6 wide, 28-lead DIP and in 28-terminal surface- mount packages. REV. F Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. may result from its use. No license is granted by implication or otherwise Tel: 781/329-4700 www.analog.com under any patent or patent rights of Analog Devices. Trademarks and registered trademarks are the property of their respective companies. Fax: 781/326-8703 2003 Analog Devices, Inc. All rights reserved.AD7824/AD7828SPECIFICATIONS (V = 5 V, V (+) = 5 V, V () = GND = O V, unless otherwise DD REF REF noted. All specifications T to T , unless otherwise noted. Specifications apply to Mode 0.) MIN MAX 1 Parameter K Version L Version B, T Versions C, U Versions Unit Conditions/Comments ACCURACY Resolution 8 8 8 8 Bits 2 Total Unadjusted Error 1 1/2 1 1/2 LSB max Minimum Resolution for which No Missing Codes Are Guaranteed 8 8 8 8 Bits Channel-to-Channel Mismatch 1/4 1/4 1/4 1/4 LSB max REFERENCE INPUT Input Resistance 1.0/4.0 1.0/4.0 1.0/4.0 1.0/4.0 k min/k max V (+) Input Voltage Range V ()/ V ()/ V ()/ V ()/ V min/V max REF REF REF REF REF V V V V DD DD DD DD V () Input Voltage Range GND/ GND/ GND/ GND/ V min/V max REF V (+) V (+) V (+) V (+) REF REF REF REF ANALOG INPUT Input Voltage Range V ()/ V ()/ V ()/ V ()/ V min/V max REF REF REF REF V (+) V (+) V (+) V (+) REF REF REF REF Input Leakage Current 3 3 3 3 A max Analog Input Any Channel 3 Input Capacitance 45 45 45 45 pF typ 0 V to 5 V LOGIC INPUTS RD, CS, A0, A1, and A2 V 2.4 2.4 2.4 2.4 V min INH V 0.8 0.8 0.8 0.8 V max INL I 11 1 1 A max INH I 1 1 1 1 A max INL 3 Input Capacitance 88 88 pF max Typically 5 pF LOGIC OUTPUTS DB0DB7 and INT V 4.0 4.0 4.0 4.0 V min I = 360 A OH SOURCE V 0.4 0.4 0.4 0.4 V max I = 1.6 mA OL SINK I (DB0DB7) 3 3 3 3 A max Floating State Leakage OUT 3 Output Capacitance 88 88 pF max Typically 5 pF RDY 4 V 0.4 0.4 0.4 0.4 V max I = 2.6 mA OL SINK I 3 3 3 3 A max Floating State Leakage OUT Output Capacitance 8 8 8 8 pF max Typically 5 pF 3 SLEW RATE, TRACKING 0.7 0.7 0.7 0.7 V/s typ 0.157 0.157 0.157 0.157 V/s max POWER SUPPLY V 55 5 5 V 5% for Specified DD Performance 5 I 16 16 20 20 mA max CS = RD = 2.4 V DD Power Dissipation 50 50 50 50 mW typ 80 80 100 100 mW max Power Supply Sensitivity 1/4 1/4 1/4 1/4 LSB max 1/16 LSB typ V = 5 V 5% DD NOTES 1 Temperature ranges are as follows: K, L Versions: 0C to 70C B, C Versions: 40C to +85C T, U Versions: 55C to +125C 2 Total Unadjusted Error includes offset, full-scale and linearity errors. 3 Sample tested at 25C by Product Assurance to ensure compliance. 4 RDY is an open-drain output. 5 See Typical Performance Characteristics. Specifications subject to change without notice. 2 REV. F