AD7828BR ,LC2MOS High Speed 4- & 8-Channel 8-Bit ADCsfeatures a per channelconversion rate of 2.5 µ s per channel and the parts have a built-sampling fr ..
AD7828BRS ,LC2MOS High Speed 4- & 8-Channel 8-Bit ADCsspecifications T to T unless otherwise noted.
AD7828CQ ,LC2MOS High Speed 4- & 8-Channel 8-Bit ADCsSPECIFICATIONSnoted. All
AD7828KN ,LC2MOS High Speed 4- & 8-Channel 8-Bit ADCsSpecifications subject to change without notice.–2–REV. DAD7824/AD78281(V = 5 V; V (+) = 5 V; V (–) ..
AD7828KP ,LC2MOS High Speed 4- & 8-Channel 8-Bit ADCsSPECIFICATIONSnoted. All
AD7828LN ,LC2MOS High Speed 4- & 8-Channel 8-Bit ADCsGENERAL DESCRIPTION PRODUCT HIGHLIGHTSThe AD7824 and AD7828 are high-speed, multichannel, 8-bit 1. ..
ADM213ARS ,0.1 uF, +5 V Powered CMOS RS-232 Drivers/ReceiversGENERAL DESCRIPTION active-high receiver enable control. Two receivers of theThe ADM2xx family of l ..
ADM213ARZ-REEL , 0.1 μF, 5 V Powered CMOS RS-232 Drivers/Receivers
ADM213EAR ,EMI/EMC Compliant, +-15 kV ESD Protected, RS-232 Line Drivers/Receiversspecifications and operate at data rates up to 230 kbps.The ADM207E and ADM208E are available in 24 ..
ADM213EARS ,EMI/EMC Compliant, +-15 kV ESD Protected, RS-232 Line Drivers/Receiversspecifications T to T unless otherwise noted.)CC MIN MAXParameter Min Typ Max Units Test Conditions ..
ADM213EARU ,EMI/EMC Compliant, +-15 kV ESD Protected, RS-232 Line Drivers/Receiversspecifications and operate at data rates up to 230 kbps.The ADM207E and ADM208E are available in 24 ..
ADM2209E ,World抯 Smallest Dual-Port 6 Tx/10 Rx RS-232CHARACTERISTICSMaximum Data Rate 920 kbps C = 150 pF, V = 5 V – 5% OnlyL STBY = 150 pF460 kbps CL = ..
AD7824BQ-AD7824CQ-AD7824KN-AD7824KR-AD7824LN-AD7824TQ-AD7824UQ-AD7828BQ-AD7828BR-AD7828BRS-AD7828CQ-AD7828KN-AD7828KP-AD7828LN-AD7828LP
LC2MOS High Speed 4- & 8-Channel 8-Bit ADCs
REV.D
LC2MOS High Speed
4- & 8-Channel 8-Bit ADCs
FUNCTIONAL BLOCK DIAGRAM
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
GENERAL DESCRIPTIONThe AD7824 and AD7828 are high-speed, multichannel, 8-bit
ADCs with a choice of 4 (AD7824) or 8 (AD7828) multiplexed
analog inputs. A half-flash conversion technique gives a fast
conversion rate of 2.5 µs per channel and the parts have a built-
in 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.
Microprocessor interfacing of the parts is simple, using standard
Chip Select (CS) and Read (RD) signals to initiate the conver-
sion and read the data from the three-state data outputs. The
half-flash 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.
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-lead “skinny” DIP, while the
AD7828 is available in a 0.6" wide, 28-lead DIP and in 28-
terminal surface mount packages.
PRODUCT HIGHLIGHTS4- or 8-channel input multiplexer gives cost-effective space-
saving multichannel ADC system.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.Built-in track-hold function allows handling of 4- or 8-
channels up to 10 kHz bandwidth (157 mV/µs slew rate).Tight total unadjusted error spec and channel-to-channel
matching eliminate the need for user trims.Single 5 V supply simplifies system power requirements.Fast, easy-to-use digital interface allows connection to most
popular microprocessors with minimal external components.
No clock signal is required for the ADC.
AD7824/AD7828–SPECIFICATIONS(VDD = 5 V, VREF(+) = 5 V, VREF(–) = GND = O V unless otherwise
noted. All specifications TMIN to TMAX unless otherwise noted. Specifications apply for Mode 0.)ACCURACY
REFERENCE INPUT
NOTESTemperature ranges are as follows:K, L Versions; 0°C to 70°C
B, C Versions; –40°C to +85°C
T, U Versions; –55°C to +125°CTotal Unadjusted Error includes offset, full-scale and linearity errors.Sample tested at 25°C by Product Assurance to ensure compliance.RDY is an open drain output.See Typical Performance Characteristics.
Specifications subject to change without notice.
TIMING CHARACTERISTICS1(VDD = 5 V; VREF(+) = 5 V; VREF(–) = GND = 0 V unless otherwise noted)NOTES
1Sample tested at 25°C to ensure compliance. All input control signals are specified with tr = tf = 20 ns (10% to 90% of 5 V) and timed from a voltage level of 1.6 V.
2CL = 50 pF.
3Measured with load circuits of Figure 1 and defined as the time required for an output to cross 0.8 V or 2.4 V.
4Defined as the time required for the data lines to change 0.5 V when loaded with the circuits of Figure 2.
Specifications subject to change without notice.
Test CircuitsFigure 1.Load Circuits for Data Access Time TestFigure 2.Load Circuits for Data Hold Time Test
AD7824/AD7828Operating Temperature Range
Commercial (K, L Versions) . . . . . . . . . . . . . .0°C to 70°C
Industrial (B, C Versions) . . . . . . . . . . . . . –25°C to +85°C
Extended (T, U Versions) . . . . . . . . . . . .–55°C to +125°C
Storage Temperature Range . . . . . . . . . . . . –65°C to +150°C
Lead Temperature (Soldering, 10 secs) . . . . . . . . . . . . .300°C
Power Dissipation (Any Package) to 75°C . . . . . . . . .450 mW
Derates above 75°C by . . . . . . . . . . . . . . . . . . . . . .6 mW/°C
*Stresses above those listed under Absolute Maximum Ratings may cause
permanent damage to the device. This is a stress rating only; functional operation
of the device at these or any other conditions above those indicated in the
operational sections of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect device reliability.
ABSOLUTE MAXIMUM RATINGS*(TA = 25°C unless otherwise noted)
VDD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .0 V, 7 V
Digital Input Voltage to GND
(RD, CS, A0, A1 & A2) . . . . . . . . . . . .–0.3 V, VDD + 0.3 V
Digital Output Voltage to GND
(DB0, DB7, RDY & INT) . . . . . . . . . .–0.3 V, VDD + 0.3 V
VREF (+) to GND . . . . . . . . . . . . . . . . . .VREF (–), VDD + 0.3 V
VREF (–) to GND . . . . . . . . . . . . . . . . . . . . . . . .0 V, VREF (+)
Analog Input (Any Channel) . . . . . . . . . .–0.3 V, VDD + 0.3 V
CAUTIONESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000V readily
accumulate on the human body and test equipment and can discharge without detection.
Although these devices feature proprietary ESD protection circuitry, permanent damage may
occur on devices subjected to high-energy electrostatic discharges. Therefore, proper ESD
precautions are recommended to avoid performance degradation or loss of functionality.
PIN CONFIGURATIONS
DIP/SOIC/SSOP
PLCC
LCCC
ORDERING GUIDE
TPC 1.Conversion Time vs. Temperature
TPC 2.Accuracy vs. VREF [VREF = VREF(+) – VREF(–)]
TPC 3.Signal-Noise Ratio vs. Input Frequency
TPC 4.Power Supply Current vs. Temperature
(Not Including Reference Ladder)
TPC 5.Accuracy vs. tP
TPC 6.Output Current vs. Temperature
AD7824/AD7828
OPERATIONAL DIAGRAMThe AD7824 is a 4-channel 8-bit A/D converter and the
AD7828 is an 8-channel 8-bit A/D converter. Operational dia-
grams for both of these devices are shown in Figures 3 and 4.
The addition of just a 5 V reference allows the devices to
perform the analog-to-digital function.
Figure 3.AD7824 Operational Diagram
Figure 4.AD7828 Operational Diagram
CIRCUIT INFORMATION
BASIC DESCRIPTIONThe AD7824/AD7828 uses a half-flash conversion technique
whereby two 4-bit flash A/D converters are used to achieve an
8-bit result. Each 4-bit flash ADC contains 15 comparators
which compare the unknown input to a reference ladder to get
a 4-bit result. For a full 8-bit reading to be realized, the upper
4-bit flash, the most significant (MS) flash, performs a conver-
sion to provide the 4 most significant data bits. An internal
DAC, driven by the 4 MSBs, then recreates an analog approxi-
mation of the input voltage. This analog result is subtracted
APPLYING THE AD7824/AD7828
REFERENCE AND INPUTThe two reference inputs on the AD7824/AD7828 are fully dif-
ferential and define the zero to full-scale input range of the A/D
converter. As a result, the span of the analog input voltage for
all channels can easily be varied. By reducing the reference
span, VREF (+) – VREF (–), to less than 5 V the sensitivity of the
converter can be increased (e.g., if VREF = 2 V then 1 LSB =
7.8 mV). The input/reference arrangement also facilitates ratio-
metric operation.
This reference flexibility also allows the input channel voltage
span to be offset from zero. The voltage at VREF (–) sets the
input level for all channels which produces a digital output of
all zeroes. Therefore, although the analog inputs are not them-
selves differential, they have nearly differential-input capability
in most measurement applications because of the reference
design. Figures 5 to 7 show some of the configurations that are
possible.
Figure 5.Power Supply as Reference
Figure 6.External Reference Using the AD580, Full-Scale
Input is 2.5 V
