AD7893BR-2 ,LC2MOS 12-Bit, Serial 6 us ADC in 8-Pin Packagespecifications such as lin-The part provides high speed serial data and serial clock lines,earity, ..
AD7893SQ/10 ,LC2MOS 12-Bit, Serial 6 us ADC in 8-Pin Packagespecifications such as lin-The part provides high speed serial data and serial clock lines,earity, ..
AD7893SQ-10 ,LC2MOS 12-Bit, Serial 6 us ADC in 8-Pin PackageCHARACTERISTICS (V = +5 V, AGND = DGND = 0 V, REF IN = +2.5 V)DDA, B SParameter Versions Version Un ..
AD7893SQ-10 ,LC2MOS 12-Bit, Serial 6 us ADC in 8-Pin PackageGENERAL DESCRIPTION1. Fast, 12-Bit ADC in 8-Pin PackageThe AD7893 is a fast, 12-bit ADC that operat ..
AD7893SQ-2 ,LC2MOS 12-Bit, Serial 6 us ADC in 8-Pin PackageSpecifications subject to change without notice.–2–REV. EAD78931, 2TIMING
AD7894AR-2 ,5 V, 14-Bit Serial, 5 ms ADC in SO-8 PackageSPECIFICATIONSl 1Parameter A Versions B Versions Units Test Conditions/Comments2DYNAMIC PERFORMANCE ..
ADM489ARZ , Full-Duplex, Low Power, Slew Rate Limited, EIA RS-485 Transceivers
ADM489ARZ , Full-Duplex, Low Power, Slew Rate Limited, EIA RS-485 Transceivers
ADM5170AN ,Octal, RS-232/RS-423 Line DriverSpecifications subject to change without notice.REV. 0–2–ADM5170ABSOLUTE MAXIMUM RATINGS* ORDERING ..
ADM5170AP ,Octal, RS-232/RS-423 Line DriverFEATURESFUNCTIONAL BLOCK DIAGRAMEight Single Ended Line Drivers in One PackageMeets EIA Standard RS ..
ADM5170JN ,Octal, RS-232/RS-423 Line DriverCHARACTERISTICSunless otherwise noted.)Parameter Min Typ Max Units Test Conditions/CommentsOutput S ..
ADM5170JP ,Octal, RS-232/RS-423 Line DriverSpecifications T to T unless otherwise noted.)MIN MAXParameter Min Typ Max Units Test Conditions/Co ..
AD7893AN-10-AD7893AN-2-AD7893AN-5-AD7893AR10-AD7893AR-10-AD7893AR-2-AD7893AR-3-AD7893AR-5-AD7893BN-10-AD7893BN-2-AD7893BR-10-AD7893BR-2-AD7893SQ/10-AD7893SQ-10-AD7893SQ-2
LC2MOS 12-Bit, Serial 6 us ADC in 8-Pin Package
FUNCTIONAL BLOCK DIAGRAM
AGND
VDD
DGNDSCLK
CONVST
VIN
SDATA
REF IN
*AD7893-5, AD7893-10, AD7893-3REV.E
LC2MOS 12-Bit, Serial 6 ms
ADC in 8-Pin Package
FEATURES
Fast 12-Bit ADC with 6 ms Conversion Time
8-Pin Mini-DlP and SOIC
Single Supply Operation
High Speed, Easy-to-Use, Serial Interface
On-Chip Track/Hold Amplifier
Selection of Input Ranges610 V for AD7893-10
62.5 V for AD7893-3
0 V to +2.5 V for AD7893-2
0 V to +5 V for AD7893-5
Low Power: 25 mW typ
GENERAL DESCRIPTIONThe AD7893 is a fast, 12-bit ADC that operates from a single
+5 V supply and is housed in a small 8-pin mini-DIP and 8-pin
SOIC. The part contains a 6μs successive approximation A/D
converter, an on-chip track/hold amplifier, an on-chip clock and
a high speed serial interface.
Output data from the AD7893 is provided via a high speed,
serial interface port. This two-wire serial interface has a serial
clock input and a serial data output with the external serial clock
accessing the serial data from the part.
In addition to traditional dc accuracy specifications such as lin-
earity, full-scale and offset errors, the AD7893 is also specified
for dynamic performance parameters, including harmonic dis-
tortion and signal-to-noise ratio.
The part accepts an analog input range of ±10 V (AD7893-10),2.5 V (AD7893-3), 0V to +5V (AD7893-5) or 0 V to +2.5 V
(AD7893-2) and operates from a single +5 V supply, consuming
only 25 mW typical.
The AD7893 is fabricated in Analog Devices’ Linear Compat-
ible CMOS (LC2MOS) process, a mixed technology process
that combines precision bipolar circuits with low power CMOS
logic. The part is available in a small, 8-pin, 0.3" wide, plastic or
hermetic dual-in-line package (mini-DIP) and in an 8-pin, small
outline IC (SOIC).
PRODUCT HIGHLIGHTSFast, 12-Bit ADC in 8-Pin Package
The AD7893 contains a 6μs ADC, a track/hold amplifier,
control logic and a high speed serial interface, all in an 8-pin
package. This offers considerable space saving over alterna-
tive solutions.Low Power, Single Supply Operation
The AD7893 operates from a single +5 V supply and con-
sumes only 25 mW. This low power, single supply operation
makes it ideal for battery powered or portable applications.High Speed Serial Interface
The part provides high speed serial data and serial clock lines,
allowing for an easy, two-wire serial interface arrangement.
AD7893–SPECIFICATIONSDYNAMIC PERFORMANCE
(VDD = +5 V, AGND = DGND = 0 V, REF IN = +2.5 V. All specifications TMIN to TMAX unless
otherwise noted.)
TIMING CHARACTERISTICS1, 2NOTES
1Sample tested at +25°C to ensure compliance. All input signals are measured with tr = tf = 1 ns (10% to 90% of +5 V) and timed from a voltage level of +1.6 V.
2See Figure 5.
3Measured with the load circuit of Figure 1 and defined as the time required for an output to cross 0.8 V or 2.4 V.
4Derived from the measured time taken by the data outputs to change 0.5 V when loaded with the circuit of Figure 1. The measured number is then extrapolated back
to remove the effects of charging or discharging the 50 pF capacitor. This means that the time, t5, quoted in the timing characteristics is the true bus relinquish time
of the part and, as such, is independent of external bus loading capacitances.
(VDD = +5 V, AGND = DGND = 0 V, REF IN = +2.5V)
ABSOLUTE MAXIMUM RATINGS*(TA = +25°C unless otherwise noted)
VDD to AGND . . . . . . . . . . . . . . . . . . . . . . . . . –0.3V to +7 V
VDD to DGND . . . . . . . . . . . . . . . . . . . . . . . . . –0.3V to +7 V
Analog Input Voltage to AGND
AD7893-10, AD7893-5 . . . . . . . . . . . . . . . . . . . . . . . ±17 V
AD7893-2, AD7893-3 . . . . . . . . . . . . . . . . . . . –5V, +10 V
Reference Input Voltage to AGND . . . –0.3 V to VDD + 0.3 V
Digital Input Voltage to DGND . . . . . –0.3 V to VDD + 0.3 V
Digital Output Voltage to DGND . . . . –0.3 V to VDD + 0.3 V
Operating Temperature Range
Commercial (A, B Versions) . . . . . . . . . . . –40°C to +85°C
Extended (S Version) . . . . . . . . . . . . . . . . –55°C to +125°C
Storage Temperature Range . . . . . . . . . . . . –65°C to +150°C
Junction Temperature . . . . . . . . . . . . . . . . . . . . . . . . . +150°C
Plastic DIP Package, Power Dissipation . . . . . . . . . . 450 mW
θJA Thermal Impedance . . . . . . . . . . . . . . . . . . . . . 130°C/W
Lead Temperature (Soldering, 10 sec) . . . . . . . . . . . +260°C
Cerdip Package, Power Dissipation . . . . . . . . . . . . . . 450 mW
θJA Thermal Impedance . . . . . . . . . . . . . . . . . . . . . 125°C/W
Lead Temperature (Soldering, 10 sec) . . . . . . . . . . . +300°C
SOIC Package, Power Dissipation . . . . . . . . . . . . . . . 450 mW
θJA Thermal Impedance . . . . . . . . . . . . . . . . . . . . . 170°C/W
Lead Temperature, Soldering
Vapor Phase (60 sec) . . . . . . . . . . . . . . . . . . . . . . +215°C
Infrared (15 sec) . . . . . . . . . . . . . . . . . . . . . . . . . .+220°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 listed in the operational
sections of this specification is not implied. Exposure to absolute maximum rating
conditions for extended periods may affect device reliability.
OUTPUT
PIN
+2.1V
1.6mA
200µA
50pFFigure 1.Load Circuit for Access Time and Bus
Relinquish Time
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
the AD7893 features 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.
AD7893
PIN FUNCTION DESCRIPTION
PIN CONFIGURATION
DIP and SOIC
REF IN
VIN
AGND
SCLK
DGND
SDATA
VDD
CONVST
ORDERING GUIDE
Relative AccuracyRelative accuracy or endpoint nonlinearity is the maximum
deviation from a straight line passing through the endpoints of
the ADC transfer function.
Differential NonlinearityThis is the difference between the measured and the ideal 1LSB
change between any two adjacent codes in the ADC.
Positive Full-Scale Error (AD7893-10)This is the deviation of the last code transition (01 . . . 110 to
01 . . . 111) from the ideal 4 × REF IN – 1 LSB (AD7893-10
±10 V range) after the Bipolar Zero Error has been adjusted out.
Positive Full-Scale Error (AD7893-3)This is the deviation of the last code transition (01 . . . 110 to
01 . . . 111) from the ideal (REF IN – 1 LSB) after the
Bipolar Zero Error has been adjusted out.
Positive Full-Scale Error (AD7893-5)This is the deviation of the last code transition (11 . . . 110 to
11 . . . 111) from the ideal (2 × REF IN – 1 LSB) after the Uni-
polar Offset Error has been adjusted out.
Positive Full-Scale Error (AD7893-2)This is the deviation of the last code transition (11 . . . 110 to
11 . . . 111) from the ideal (REF IN – 1 LSB) after the Unipolar
Offset Error has been adjusted out.
Bipolar Zero Error (AD7893-10, 610 V; AD7893-3, 62.5 V)This is the deviation of the midscale transition (all 0s to all 1s)
from the ideal 0 V (AGND).
Unipolar Offset Error (AD7893-2, AD7893-5)This is the deviation of the first code transition (00 . . . 000 to
00 . . . 001) from the ideal 1 LSB.
Negative Full-Scale Error (AD7893-10)This is the deviation of the first code transition (10 . . . 000 to
10 . . . 001) from the ideal –4 × REF IN + 1 LSB (AD7893-10
±10 V range) after Bipolar Zero Error has been adjusted out.
Negative Full-Scale Error (AD7893-3)This is the deviation of the first code transition (10 . . . 000 to
10 . . . 001) from the ideal (–REF IN + 1 LSB) after Bipolar
Zero Error has been adjusted out.
Track/Hold Acquisition TimeTrack/Hold acquisition time is the time required for the output
of the track/hold amplifier to reach its final value, within
±1/2LSB, after the end of conversion (the point at which the
track/hold returns to track mode). It also applies to situations
where there is a step input change on the input voltage applied
to the VIN input of the AD7893. This means that the user must
wait for the duration of the track/hold acquisition time after the
end of conversion or after a step input change to VIN before
starting another conversion, to ensure that the part operates to
specification.
TERMINOLOGY
Signal to (Noise + Distortion) RatioThis is the measured ratio of signal to (noise + distortion) at the
output of the A/D converter. The signal is the rms amplitude of
the fundamental. Noise is the rms sum of all nonfundamental
signals up to half the sampling frequency (fS/2), excluding dc.
The ratio is dependent upon the number of quantization levels
in the digitization process; the more levels, the smaller the quan-
tization noise. The theoretical signal to (noise + distortion) ratio
for an ideal N-bit converter with a sine wave input is given by:
Signal to (Noise + Distortion) = (6.02N + 1.76) dB
Thus for a 12-bit converter, this is 74 dB.
Total Harmonic DistortionTotal harmonic distortion (THD) is the ratio of the rms sum of
harmonics to the fundamental. For the AD7893, it is defined as:
where V1 is the rms amplitude of the fundamental and V2, V3,
V4, V5 and V6 are the rms amplitudes of the second through the
sixth harmonics.
Peak Harmonic or Spurious NoisePeak harmonic or spurious noise is defined as the ratio of the
rms value of the next largest component in the ADC output
spectrum (up to fS/2 and excluding dc) to the rms value of the
fundamental. Normally, the value of this specification is deter-
mined by the largest harmonic in the spectrum, but for parts
where the harmonics are buried in the noise floor, it will be a
noise peak.
Intermodulation DistortionWith inputs consisting of sine waves at two frequencies, fa and
fb, any active device with nonlinearities will create distortion
products at sum and difference frequencies of mfa ± nfb where
m, n = 0, 1, 2, 3, etc. Intermodulation terms are those for
which neither m nor n are equal to zero. For example, the second
order terms include (fa + fb) and (fa – fb), while the third order
terms include (2 fa + fb), (2 fa – fb), (fa + 2 fb) and (fa – 2 fb).
The AD7893 is tested using the CCIF standard where two
input frequencies near the top end of the input bandwidth are
used. In this case, the second and third order terms are of differ-
ent significance. The second order terms are usually distanced
in frequency from the original sine waves, while the third order
terms are usually at a frequency close to the input frequencies.
As a result, the second and third order terms are specified sepa-
rately. The calculation of the intermodulation distortion is per
the THD specification where it is the ratio of the rms sum of the
individual distortion products to the rms amplitude of the fun-
damental expressed in dBs.
THD(dB)=20log1
AD7893
CONVERTER DETAILSThe AD7893 is a fast, 12-bit single supply A/D converter. It
provides the user with signal scaling (AD7893-10), track/hold,
A/D converter and serial interface logic functions on a single
chip. The A/D converter section of the AD7893 consists of a
conventional successive-approximation converter based on an
R-2R ladder structure. The signal scaling on the AD7893-10,
AD7893-5 and AD7893-3 allows the part to handle ±10 V, 0V
to +5V and ±2.5 V input signals, respectively, while operating
from a single +5V supply. The AD7893-2 accepts an analog in-
put range of 0 V to +2.5 V. The part requires an external +2.5 V
reference. The reference input to the part is buffered on-chip.
A major advantage of the AD7893 is that it provides all of the
above functions in an 8-pin package, either 8-pin mini-DIP or
SOIC. This offers the user considerable space saving advantages
over alternative solutions. The AD7893 typically consumes onlymW, making it ideal for battery-powered applications.
Conversion is initiated on the AD7893 by pulsing the CONVST
input. On the rising edge of CONVST, the on-chip track/hold
goes from track-to-hold mode and the conversion sequence is
started. The conversion clock for the part is generated internally
using a laser-trimmed clock oscillator circuit. Conversion time
for the AD7893 is 6μs, and the track/hold acquisition time is
1.5μs. To obtain optimum performance from the part, the read
operation should not occur during the conversion or during
600 ns prior to the next conversion. This allows the part to op-
erate at throughput rates up to 117 kHz and to achieve data
sheet specifications. The part can operate at higher throughput
rates (up to 133 kHz) with slightly degraded performance (see
Timing and Control section).
CIRCUIT DESCRIPTION
Analog Input SectionThe AD7893 is offered as four part types: the AD7893-10,
which handles a ±10 V input voltage range; the AD7893-3,
which handles a ±2.5 V input voltage range; the AD7893-5,
which handles a 0V to +5 V input range; and the AD7893-2,
which handles a 0V to +2.5V input voltage range.
Figure 2 shows the analog input section for the AD7893-10,
AD7893-5 and AD7893-3. The analog input range of the
AD7893-10 is ±10 V into an input resistance of typically 33 kΩ.
The analog input range of the AD7893-3 is ±2.5 V into an input
resistance of typically 12 kΩ. The input range on the AD7893-5 is
0 V to +5 V into an input resistance of typically 11 kΩ. This in-
put is benign with no dynamic charging currents, as the resistor
stage is followed by a high input impedance stage of the track/hold
AGND
VIN
REF INamplifier. For the AD7893-10, R1 = 30 kΩ; R2 = 7.5 kΩ and
R3 = 10 kΩ. For the AD7893-3, R1 = R2 = 6.5 kΩ, and R3
is open circuit. For the AD7893-5, R1 and R3 = 5 kΩ while
R2 is open-circuit.
For the AD7893-10 and AD7893-3, the designed code transi-
tions occur on successive integer LSB values (i.e., 1 LSB, 2 LSBs,
3 LSBs . . .). Output coding is twos complement binary withLSB = FS/4096. The ideal input/output transfer function for
the AD7893-10 and AD7893-3 is shown in Table I.
Table I.Ideal Input/Output Code Table for the AD7893-10/
AD7893-3NOTESFSR is full-scale range and is 20 V (AD7893-10) and = 5 V (AD7893-3) with
REF IN = +2.5 V.1 LSB = FSR/4096 = 4.883 mV (AD7893-10) and 1.22 mV (AD7893-3) with
REF IN = +2.5 V.
For the AD7893-5, the designed code transitions occur again on
successive integer LSB values. Output coding is straight (natural)
binary with 1 LSB = FS/4096 = 5 V/4096 = 1.22 mV. The ideal
input/output transfer function for the AD7893-5 is shown in
Table II.
The analog input section for the AD7893-2 contains no biasing
resistors, and the VIN pin drives the input directly to the track/
hold amplifier. The analog input range is 0 V to +2.5 V into a
high impedance stage, with an input current of less than
500nA. This input is benign, with no dynamic charging cur-
rents. Once again, the designed code transitions occur on suc-
cessive integer LSB values. Output coding is straight (natural)
binary with 1 LSB = FS/4096 = 2.5 V/4096 = 0.61 mV. Table
II also shows the ideal input/output transfer function for the
AD7893-2.
Table II.Ideal Input/Output Code Table for
AD7893-2/AD7893-5
