The MAX1183 is a 3V, dual 10-bit analog-to-digital converter (ADC) featuring fully differential wideband trackand-hold (T/H) inputs, driving two pipelined, nine-stage
ADCs. The MAX1183 is optimized for low-power, high
dynamic performance applications in imaging, instrumentation, and digital communication applications. This ADC
operates from a single 2.7V to 3.6V supply, consuming
only 120mW while delivering a typical signal-to-noise ratio
(SNR) of 59.6dB at an input frequency of 20MHz and a
sampling rate of 40Msps. The T/H driven input stages
incorporate 400MHz (-3dB) input amplifiers. The converters may also be operated with single-ended inputs. In
addition to low operating power, the MAX1183 features a
2.8mA sleep mode as well as a 1µA power-down mode to
conserve power during idle periods.
An internal 2.048V precision bandgap reference sets
the full-scale range of the ADC. A flexible reference
structure allows the use of this internal or an externally
derived reference, if desired for applications requiring
increased accuracy or a different input voltage range.
The MAX1183 features parallel, CMOS-compatible
three-state outputs. The digital output format can be set
to two’s complement or straight offset binary through a
single control pin. The device provides for a separate
output power supply of 1.7V to 3.6V for flexible interfacing. The MAX1183 is available in a 7mm ✕7mm, 48-pin
TQFP package, and is specified for the extended
industrial (-40°C to +85°C) temperature range.
Pin-compatible lower and higher speed versions of the
MAX1183 are also available. See Table 2 at end of data
sheet for a list of pin-compatible versions. Refer to the
MAX1180 data sheet for 105Msps, the MAX1181 data
sheet for 80Msps, the MAX1182 data sheet for 65Msps,
and the MAX1184 data sheet for 20Msps. In addition to
these speed grades, this family includes a multiplexed
output version, for which digital data is presented timeinterleaved and on a single, parallel 10-bit output port.
Applications
High-Resolution Imaging
I/Q Channel Digitization
Multichannel IF Sampling
Instrumentation
Video Application
Ultrasound
Features
♦ Single 3V Operation
♦ Excellent Dynamic Performance:
(VDD= 3V, OVDD= 2.5V, 0.1µF and 1.0µF capacitors from REFP, REFN, and COM to GND, REFOUT connected to REFIN through a
10kΩ resistor, V
IN
= 2V
P-P
(differential with respect to COM), CL= 10pF at digital outputs (Note 1), f
CLK
= 40MHz, TA= T
MIN
to T
MAX
,
unless otherwise noted. Typical values are at T
A
= +25°C.) (Note 2)
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
VDD, OVDDto GND .............................................. -0.3V to +3.6V
OGND to GND.......................................................-0.3V to +0.3V
INA+, INA-, INB+, INB- to GND ...............................-0.3V to V
DD
REFIN, REFOUT, REFP, REFN,
COM, CLK to GND .................................-0.3V to (V
(VDD= 3V, OVDD= 2.5V, 0.1µF and 1.0µF capacitors from REFP, REFN, and COM to GND, REFOUT connected to REFIN through a
10kΩ resistor, V
IN
= 2V
P-P
(differential with respect to COM), CL= 10pF at digital outputs (Note 1), f
CLK
= 40MHz, TA= T
MIN
to T
MAX
,
unless otherwise noted. Typical values are at T
A
= +25°C.) (Note 2)
Note 1: Equivalent dynamic performance is obtainable over full OVDDrange with reduced CL.
Note 2: Specifications at ≥ +25°C are guaranteed by production test and < +25°C are guaranteed by design and characterization.
Note 3: SNR, SINAD, THD, SFDR, and HD3 are based on an analog input voltage of -0.5dBFS referenced to a 1.024V full-scale
input voltage range.
Note 4: Intermodulation distortion is the total power of the intermodulation products relative to the individual carrier. This number is
6dB better, if referenced to the two-tone envelope.
Note 5: Digital outputs settle to V
IH
, VIL. Parameter guaranteed by design.
Note 6: With REFIN driven externally, REFP, COM, and REFN are left floating while powered down.
Typical Operating Characteristics
(VDD= 3V, OVDD= 2.5V, V
REFIN
= 2.048V, differential input at -0.5dBFS, f
CLK
= 40.0006MHz, CL≈ 10pF, TA= +25°C, unless
otherwise noted.)
-100
-80
-90
-60
-70
-40
-50
-30
-10
-20
0
04682101214181620
FFT PLOT CHA (DIFFERENTIAL INPUT,
8192-POINT DATA RECORD)
MAX1183 toc01
ANALOG INPUT FREQUENCY (MHz)
AMPLITUDE (dB)
f
CLK
= 40.0006MHz
f
INA
= 7.5343MHz
f
INB
= 6.1475MHz
A
INA
= -0.498dBFS
HD3
HD2
CHA
-100
-80
-90
-60
-70
-40
-50
-30
-10
-20
0
04682101214181620
FFT PLOT CHB (DIFFERENTIAL INPUT,
8192-POINT DATA RECORD)
MAX1183 toc02
ANALOG INPUT FREQUENCY (MHz)
AMPLITUDE (dB)
f
CLK
= 40.0006MHz
f
INB
= 6.1475MHz
f
INA
= 7.5343MHz
A
INB
= -0.534dBFS
HD3
HD2
CHB
-100
-80
-90
-60
-70
-40
-50
-30
-10
-20
0
04682101214181620
FFT PLOT CHA (DIFFERENTIAL INPUT,
8192-POINT DATA RECORD)
MAX1183 toc03
ANALOG INPUT FREQUENCY (MHz)
AMPLITUDE (dB)
f
CLK
= 40.0006MHz
f
INA
= 24.9662MHz
f
INB
= 19.888MHz
A
INA
= -0.552dBFS
HD3
HD2
CHA
CLK Pulse Width Hight
CLK Pulse Width Lowt
Wake-Up Timet
CHANNEL-TO-CHANNEL MATCHING
Crosstalkf
Gain Matchingf
Phase Matchingf
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS
WAKE
CH
CL
Figure 3, clock period: 25ns
Figure 3, clock period: 25ns
Wake up from sleep mode (Note 6)0.41
Wake up from shutdown (Note 6)1.5
= 20MHz at -0.5dBFS-70dB
INA or B
= 20MHz at -0.5dBFS0.02±0.2dB
INA or B
= 20MHz at -0.5dBFS0.25Degrees
INA or B
12.5
±3.8
12.5
±3.8
ns
ns
µs
MAX1183
Dual 10-Bit, 40Msps, 3V, Low-Power ADC with
Internal Reference and Parallel Outputs
1COMCommon-Mode Voltage Input/Output. Bypass to GND with a ≥ 0.1µF capacitor.
2, 6, 11,
14, 15
3, 7, 10,
13, 16
4INA+Channel A Positive Analog Input. For single-ended operation connect signal source to INA+.
5INA-Channel A Negative Analog Input. For single-ended operation connect INA- to COM.
8INB-Channel B Negative Analog Input. For single-ended operation connect INB- to COM.
9INB+Channel B Positive Analog Input. For single-ended operation connect signal source to INB+.
12CLKConverter Clock Input
17T/B
18SLEEP
19PD
20OE
21D9BThree-State Digital Output, Bit 9 (MSB), Channel B
22D8BThree-State Digital Output, Bit 8, Channel B
23D7BThree-State Digital Output, Bit 7, Channel B
24D6BThree-State Digital Output, Bit 6, Channel B
25D5BThree-State Digital Output, Bit 5, Channel B
26D4BThree-State Digital Output, Bit 4, Channel B
27D3BThree-State Digital Output, Bit 3, Channel B
28D2BThree-State Digital Output, Bit 2, Channel B
29D1BThree-State Digital Output, Bit 1, Channel B
30D0BThree-State Digital Output, Bit 0 (LSB), Channel B
31, 34OGNDOutput Driver Ground
32, 33OV
35D0AThree-State Digital Output, Bit 0 (LSB), Channel A
36D1AThree-State Digital Output, Bit 1, Channel A
37D2AThree-State Digital Output, Bit 2, Channel A
38D3AThree-State Digital Output, Bit 3, Channel A
39D4AThree-State Digital Output, Bit 4, Channel A
40D5AThree-State Digital Output, Bit 5, Channel A
V
DD
GNDAnalog Ground
DD
Analog Supply Voltage. Bypass each supply pin to GND with a 0.1µF capacitor.
The analog supply accepts an input range of 2.7V to 3.6V.
T/B selects the ADC digital output format.
High: Two’s complement.
Low: Straight offset binary.
Sleep Mode Input.
High: Deactivates the two ADCs, but leaves the reference bias circuit active.
Low: Normal operation.
Power-Down Input.
High: Power-down mode.
Low: Normal operation.
Output Enable Input.
High: Digital outputs disabled.
Low: Digital outputs enabled.
Output Driver Supply Voltage. Bypass each supply pin to OGND with a 0.1µF capacitor.
The output driver supply accepts an input range of 1.7V to 3.6V.
MAX1183
Detailed Description
The MAX1183 uses a nine-stage, fully differential,
pipelined architecture (Figure 1) that allows for highspeed conversion while minimizing power consumption. Samples taken at the inputs move progressively
through the pipeline stages every half-clock cycle.
Including the delay through the output latch, the total
clock-cycle latency is five clock cycles.
One-and-a-half bit (2-comparator) flash ADCs convert
the held-input voltages into a digital code. The digital-
to-analog converters (DACs) convert the digitized
results back into analog voltages, which are then subtracted from the original held-input signals. The resulting
error signals are then multiplied by two, and the residues
are passed along to the next pipeline stages where the
process is repeated until the signals have been
processed by all nine stages. Digital error correction
compensates for ADC comparator offsets in each of
these pipeline stages and ensures no missing codes.
Dual 10-Bit, 40Msps, 3V, Low-Power ADC with
Internal Reference and Parallel Outputs
44D9AThree-State Digital Output, Bit 9 (MSB), Channel A
45REFOUT
46REFINReference Input. V
47REFP
48REFN
—EPExposed Pad. Connect to analog ground.
Internal Reference Voltage Output. May be connected to REFIN through a resistor or a resistor
divider.
= 2 x (V
REFIN
Positive Reference Input/Output. Conversion range is ± (V
REFP
- V
). Bypass to GND with a >1nF capacitor.
REFN
REFP
- V
REFN
).
Bypass to GND with a > 0.1µF capacitor.
Negative Reference Input/Output. Conversion range is ± (V
REFP
- V
REFN
).
Bypass to GND with a > 0.1µF capacitor.
V
IN
T/H
FLASH
ADC
1.5 BITS
STAGE 1STAGE 2
T/H
Σ
DAC
DIGITAL CORRECTION LOGIC
V
OUT
x2
2-BIT FLASH
ADC
STAGE 8
10
STAGE 9
V
IN
T/H
FLASH
ADC
1.5 BITS
STAGE 1STAGE 2
T/H
Σ
DAC
DIGITAL CORRECTION LOGIC
V
OUT
x2
2-BIT FLASH
ADC
STAGE 8STAGE 9
10
V
INA
D9A–D0A
V
= INPUT VOLTAGE BETWEEN INA+ AND INA- (DIFFERENTIAL OR SINGLE ENDED)
INA
= INPUT VOLTAGE BETWEEN INB+ AND INB- (DIFFERENTIAL OR SINGLE ENDED)
V
INB
V
INB
D9B–D0B
Input Track-and-Hold (T/H) Circuits
Figure 2 displays a simplified functional diagram of the
input track-and-hold (T/H) circuits in both track-and-hold
mode. In track mode, switches S1, S2a, S2b, S4a, S4b,
S5a, and S5b are closed. The fully differential circuits
sample the input signals onto the two capacitors (C2a
and C2b) through switches S4a and S4b. S2a and S2b
set the common mode for the amplifier input, and open
simultaneously with S1, sampling the input waveform.
Switches S4a and S4b are then opened before switches S3a and S3b connect capacitors C1a and C1b to
the output of the amplifier and switch S4c is closed.
The resulting differential voltages are held on capacitors C2a and C2b. The amplifiers are used to charge
capacitors C1a and C1b to the same values originally
held on C2a and C2b. These values are then presented
to the first-stage quantizers and isolate the pipelines
from the fast-changing inputs. The wide input bandwidth
T/H amplifiers allow the MAX1183 to track-and-sample/hold analog inputs of high frequencies (> Nyquist).
The ADC inputs (INA+, INB+, INA- and INB-) can be
driven either differentially or single-ended. Match the
impedance of INA+ and INA-, as well as INB+ and INBand set the common-mode voltage to midsupply
(V
DD
/2) for optimum performance.
Analog Inputs and Reference
Configurations
The full-scale range of the MAX1183 is determined by
the internally generated voltage difference between
REFP (VDD/2 + V
REFIN
/4) and REFN (VDD/2 -
V
REFIN
/4). The full-scale range for both on-chip ADCs is
adjustable through the REFIN pin, which is provided for
this purpose. REFOUT, REFP, COM (VDD/2), and REFN
are internally buffered low-impedance outputs.
The MAX1183 provides three modes of reference
operation:
• Internal reference mode
• Buffered external reference mode
• Unbuffered external reference mode
In internal reference mode, connect the internal reference output REFOUT to REFIN through a resistor (e.g.,
10kΩ) or resistor divider, if an application requires a
reduced full-scale range. For stability and noise filtering
purposes, bypass REFIN with a >10nF capacitor to
GND. In internal reference mode, REFOUT, COM, REFP,
and REFN become low-impedance outputs.
In buffered external reference mode, adjust the reference
voltage levels externally by applying a stable and accurate voltage at REFIN. In this mode, COM, REFP, and
REFN become outputs. REFOUT may be left open or
connected to REFIN through a >10kΩ resistor.
In unbuffered external reference mode, connect REFIN
to GND. This deactivates the on-chip reference buffers
for REFP, COM, and REFN. With their buffers shut
down, these nodes become high impedance and may
be driven through separate external reference sources.
Clock Input (CLK)
The MAX1183’s CLK input accepts CMOS-compatible
clock signals. Since the interstage conversion of the
device depends on the repeatability of the rising and
falling edges of the external clock, use a clock with low
jitter and fast rise and fall times (< 2ns). In particular,
sampling occurs on the rising edge of the clock signal,
requiring this edge to provide lowest possible jitter. Any
significant aperture jitter would limit the SNR performance of the on-chip ADCs as follows:
where fINrepresents the analog input frequency and
tAJis the time of the aperture jitter.
Clock jitter is especially critical for undersampling
applications. The clock input should always be considered as an analog input and routed away from any analog input or other digital signal lines.
The MAX1183 clock input operates with a voltage threshold set to VDD/2. Clock inputs with a duty cycle other
than 50% must meet the specifications for high and low
periods as stated in the Electrical Characteristics.
System Timing Requirements
Figure 3 depicts the relationship between the clock
input, analog input, and data output. The MAX1183
samples at the rising edge of the input clock. Output
data for channels A and B is valid on the next rising
edge of the input clock. The output data has an internal
latency of five clock cycles. Figure 4 also determines
the relationship between the input clock parameters
and the valid output data on channels A and B.
Digital Output Data, Output Data Format
Selection (T/B), Output Enable (
OE
)
All digital outputs, D0A–D9A (Channel A) and D0B–D9B
(Channel B) are TTL/CMOS logic-compatible. There is a
five-clock-cycle latency between any particular sample
and its corresponding output data. The output coding
can be chosen to be either straight offset binary or
two’s complement (Table 1) controlled by a single pin
(T/B). Pull T/B low to select offset binary and high to
activate two’s complement output coding. The capacitive load on the digital outputs D0A–D9A and D0B–D9B
should be kept as low as possible (<15pF) to avoid
large digital currents that could feed back into the analog portion of the MAX1183, thereby degrading its
dynamic performance. Using buffers on the digital outputs of the ADCs can further isolate the digital outputs
from heavy capacitive loads. To further improve the
dynamic performance of the MAX1183, small-series
resistors (e.g., 100Ω) may be added to the digital output paths close to the MAX1183.
Dual 10-Bit, 40Msps, 3V, Low-Power ADC with
Internal Reference and Parallel Outputs
Figure 4 displays the timing relationship between output
enable and data output valid, as well as powerdown/wake-up and data output valid.
Power-Down (PD) and Sleep
(SLEEP) Modes
The MAX1183 offers two power-save modes—sleep and
full power-down modes. In sleep mode (SLEEP = 1), only
the reference bias circuit is active (both ADCs are
disabled), and current consumption is reduced to 2.8mA.
To enter full power-down mode, pull PD high. With OE
simultaneously low, all outputs are latched at the last
value prior to the power down. Pulling OE high forces
the digital outputs into a high-impedance state.
Applications Information
Figure 5 depicts a typical application circuit containing
two single-ended to differential converters. The internal
reference provides a VDD/2 output voltage for levelshifting purposes. The input is buffered and then split
to a voltage follower and inverter. One lowpass filter per
ADC suppresses some of the wideband noise associated with high-speed op amps follows the amplifiers. The
user may select the R
ISO
and CINvalues to optimize
the filter performance, to suit a particular application.
For the application in Figure 5, a R
ISO
of 50Ω is placed
before the capacitive load to prevent ringing and
oscillation. The 22pF CINcapacitor acts as a small
bypassing capacitor.
Using Transformer Coupling
An RF transformer (Figure 6) provides an excellent solution to convert a single-ended source signal to a fully differential signal, required by the MAX1183 for optimum
performance. Connecting the center tap of the transformer to COM provides a VDD/2 DC level shift to the
input. Although a 1:1 transformer is shown, a step-up
transformer may be selected to reduce the drive requirements. A reduced signal swing from the input driver, such
as an op amp, may also improve the overall distortion.
In general, the MAX1183 provides better SFDR and
THD with fully differential input signals than singleended drive, especially for very high input frequencies.
In differential input mode, even-order harmonics are
lower as both inputs (INA+, INA- and/or INB+, INB-) are
balanced, and each of the ADC inputs only requires
half the signal swing compared to single-ended mode.
Single-Ended AC-Coupled Input Signal
Figure 7 shows an AC-coupled, single-ended application. Amplifiers like the MAX4108 provide high speed,
high bandwidth, low noise, and low distortion to maintain the integrity of the input signal.
Typical QAM Demodulation Application
The most frequently used modulation technique for digital communications applications is probably the quadrature amplitude modulation (QAM). Typically found in
spread-spectrum-based systems, a QAM signal represents a carrier frequency modulated in both amplitude
and phase. At the transmitter, modulating the baseband signal with quadrature outputs, a local oscillator
followed by subsequent up-conversion can generate
the QAM signal. The result is an in-phase (I) and
a quadrature (Q) carrier component, where the Q
Figure 5. Typical Application for Single-Ended to Differential Conversion
+5V
INPUT
MAX4108
300Ω
+5V
-5V
300Ω
0.1µF
0.1µF
300Ω
300Ω
300Ω
300Ω
300Ω
300Ω
600Ω
600Ω
0.1µF
0.1µF
0.1µF
MAX4108
-5V
+5V
MAX4108
-5V
+5V
MAX4108
-5V
600Ω
0.1µF
0.1µF
0.1µF
600Ω
0.1µF
0.1µF
0.1µF
LOWPASS FILTER
R
IS0
50Ω
LOWPASS FILTER
R
IS0
50Ω
LOWPASS FILTER
R
IS0
50Ω
C
22pF
C
22pF
C
22pF
INA+
IN
COM
INA-
IN
MAX1183
INB+
IN
+5V
MAX4108
-5V
600Ω
0.1µF
0.1µF
600Ω
LOWPASS FILTER
R
IS0
50Ω
C
22pF
INB-
IN
INPUT
MAX4108
300Ω
+5V
-5V
300Ω
0.1µF
0.1µF
300Ω
600Ω
0.1µF
600Ω
300Ω
300Ω
component is 90 degree phase-shifted with respect to
the in-phase component. At the receiver, the QAM signal
is divided down into its I and Q components, essentially
representing the modulation process reversed. Figure 8
displays the demodulation process performed in the
analog domain, using the dual matched 3V, 10-bit ADC
(MAX1183), and the MAX2451 quadrature demodulator
to recover and digitize the I and Q baseband signals.
Before being digitized by the MAX1183, the mixed-down
signal components may be filtered by matched analog
filters, such as Nyquist or pulse-shaping filters, which
remove any unwanted images from the mixing process,
thereby enhancing the overall signal-to-noise (SNR) performance and minimizing intersymbol interference.
Grounding, Bypassing, and
Board Layout
The MAX1183 requires high-speed board layout design
techniques. Locate all bypass capacitors as close to
the device as possible, preferably on the same side as
the ADC, using surface-mount devices for minimum
inductance. Bypass V
DD
, REFP, REFN, and COM with
two parallel 0.1µF ceramic capacitors and a 2.2µF
bipolar capacitor to GND. Follow the same rules to
bypass the digital supply (OV
DD
) to OGND. Multilayer
boards with separated ground and power planes produce the highest level of signal integrity. Consider the
use of a split ground plane arranged to match the
physical location of the analog ground (GND) and the
digital output driver ground (OGND) on the ADC’s
package. The two ground planes should be joined at a
single point such that the noisy digital ground currents
do not interfere with the analog ground plane. The ideal
location of this connection can be determined experimentally at a point along the gap between the two
ground planes, which produces optimum results. Make
this connection with a low-value, surface-mount resistor
Figure 7. Using an Op Amp for Single-Ended, AC-Coupled
Input Drive
0.1µF
0.1µF
REFP
REFN
REFP
REFN
1kΩ
1kΩ
1kΩ
1kΩ
R
50Ω
0.1µF
R
50Ω
0.1µF
ISO
C
IN
22pF
R
ISO
50Ω
C
IN
22pF
ISO
C
IN
22pF
R
ISO
50Ω
C
IN
22pF
INA+
COM
INA-
MAX1183
INB+
INB-
25Ω
22pF
0.1µF
V
IN
N.C.
MINICIRCUITS
0.1µF
V
IN
N.C.
MINICIRCUITS
6
1
T1
5
2
2.2µF
43
TT1–6
6
1
T1
5
2
TT1–6
2.2µF
4
3
0.1µF
25Ω
22pF
25Ω
22pF
0.1µF
25Ω
22pF
INA+
COM
INA-
INB+
INB-
MAX1183
V
IN
MAX4108
100Ω
100Ω
V
IN
MAX4108
100Ω
100Ω
MAX1183
(1Ω to 5Ω), a ferrite bead, or a direct short. Alternatively,
all ground pins could share the same ground plane, if the
ground plane is sufficiently isolated from any noisy, digital
systems ground plane (e.g. downstream output buffer or
DSP ground plane). Route high-speed digital signal
traces away from the sensitive analog traces of either
channel. Make sure to isolate the analog input lines to
each respective converter to minimize channel-to-channel crosstalk. Keep all signal lines short and free of 90
degree turns.
Static Parameter Definitions
Integral Nonlinearity (INL)
Integral nonlinearity is the deviation of the values on an
actual transfer function from a straight line. This straight
line can be either a best straight-line fit or a line drawn
between the endpoints of the transfer function, once
offset and gain errors have been nullified. The static linearity parameters for the MAX1183 are measured using
the best straight-line fit method.
Differential Nonlinearity (DNL)
Differential nonlinearity is the difference between an
actual step width and the ideal value of 1LSB. A DNL
error specification of less than 1LSB guarantees no
missing codes and a monotonic transfer function.
Dynamic Parameter Definitions
Aperture Jitter
Figure 9 depicts the aperture jitter (tAJ), which is the
sample-to-sample variation in the aperture delay.
Aperture Delay
Aperture delay (tAD) is the time defined between the
falling edge of the sampling clock and the instant when
an actual sample is taken (Figure 9).
Signal-to-Noise Ratio (SNR)
For a waveform perfectly reconstructed from digital samples, the theoretical maximum SNR is the ratio of the fullscale analog input (RMS value) to the RMS quantization
error (residual error). The ideal, theoretical minimum analog-to-digital noise is caused by quantization error only
and results directly from the ADC’s resolution (N-Bits):
SNR
dB[max]
= 6.02 ✕ N + 1.76
In reality, there are other noise sources besides quantization noise (thermal noise, reference noise, clock jitter,
etc.). SNR is computed by taking the ratio of the RMS
signal to the RMS noise, which includes all spectral
components minus the fundamental, the first five harmonics, and the DC offset.
Dual 10-Bit, 40Msps, 3V, Low-Power ADC with
Internal Reference and Parallel Outputs
Figure 8. Typical QAM Application, Using the MAX1183
Figure 9. T/H Aperture Timing
DOWNCONVERTER
MAX2451
÷
8
SAMPLED
DATA (T/H)
0°
90°
CLK
ANALOG
INPUT
INA+
INA-
DSP
MAX1183
INB+
INB-
t
AD
t
AJ
POST-
PROCESSING
TRACKTRACK
T/H
HOLD
Signal-to-Noise Plus Distortion (SINAD)
SINAD is computed by taking the ratio of the RMS signal to all spectral components minus the fundamental
and the DC offset.
Total Harmonic Distortion (THD)
THD is typically the ratio of the RMS sum of the first four
harmonics of the input signal to the fundamental itself.
This is expressed as:
where V1is the fundamental amplitude, and V2through
V
5
are the amplitudes of the 2nd- through 5th-order
harmonics.
Spurious-Free Dynamic Range (SFDR)
SFDR is the ratio expressed in decibels of the RMS
amplitude of the fundamental (maximum signal component) to the RMS value of the next largest spurious
component, excluding DC offset.
Intermodulation Distortion (IMD)
The two-tone IMD is the ratio expressed in decibels of
either input tone to the worst 3rd-order (or higher) intermodulation products. The individual input tone levels
are backed off by 6.5dB from full scale.
Dual 10-Bit, 40Msps, 3V, Low-Power ADC with
Internal Reference and Parallel Outputs
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
18 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information
go to www.maxim-ic.com/packages
.)
Revision History
Pages changed at Rev 1: Title change—all pages,
1-13, 15-18
48L,TQFP.EPS
PACKAGE OUTLINE,
48L TQFP, 7x7x1.0mm EP OPTION
21-0065
PACKAGE OUTLINE,
48L TQFP, 7x7x1.0mm EP OPTION
21-0065
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