The MAX1213 is a monolithic, 12-bit, 170Msps analogto-digital converter (ADC) optimized for outstanding
dynamic performance at high-IF frequencies up to
300MHz. The product operates with conversion rates
up to 170Msps while consuming only 975mW.
At 170Msps and an input frequency up to 250MHz, the
MAX1213 achieves a spurious-free dynamic range
(SFDR) of 71.4dBc. Its excellent signal-to-noise ratio
(SNR) of 65.5dB at 10MHz remains flat (within 3dB) for
input tones up to 250MHz. This ADC yields an excellent
low-noise floor of -68dBFS, which makes it ideal for
wideband applications such as cable head-end
receivers and power-amplifier predistortion in cellular
base-station transceivers.
The MAX1213 requires a single 1.8V supply. The analog
input is designed for either differential or single-ended
operation and can be AC- or DC-coupled. The ADC also
features a selectable on-chip divide-by-2 clock circuit,
which allows the user to apply clock frequencies as high
as 340MHz. This helps to reduce the phase noise of the
input clock source. A low-voltage differential signal
(LVDS) sampling clock is recommended for best performance. The converter’s digital outputs are LVDS compatible and the data format can be selected to be either
two’s complement or offset binary.
The MAX1213 is available in a 68-pin QFN package
with exposed paddle (EP) and is specified over the
industrial (-40°C to +85°C) temperature range.
Pin-compatible 8-bit and 10-bit versions of the MAX1213
are also available. Refer to the MAX1121 (8 bits,
250Msps), MAX1122 (10 bits, 170Msps), MAX1123 (10
bits, 210Msps), and the MAX1124 (10 bits, 250Msps)
data sheets for more information. See Table 2.
Applications
Base-Station Power-Amplifier Linearization
Cable Head-End Receivers
Wireless and Wired Broadband Communication
Communications Test Equipment
Radar and Satellite Subsystems
internal reference, digital output pins differential R
L
= 100Ω ±1%, TA= T
MIN
to T
MAX
, unless otherwise noted. ≥+25°C guaranteed by
production test, <+25°C guaranteed by design and characterization. Typical values are at T
A
= +25°C.)
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.
AVCCto AGND ..................................................... -0.3V to +2.1V
OV
CC
to OGND .................................................... -0.3V to +2.1V
AV
CC
to OVCC...................................................... -0.3V to +2.1V
AGND to OGND ................................................... -0.3V to +0.3V
Analog Inputs to AGND ...........................-0.3V to (AV
CC
+ 0.3V)
All Digital Inputs to AGND........................-0.3V to (AV
CC
+ 0.3V)
REFIO, REFADJ to AGND ........................-0.3V to (AV
CC
+ 0.3V)
All Digital Outputs to OGND ....................-0.3V to (OV
CC
+ 0.3V)
ESD on All Pins (Human Body Model) .............................±2000V
fIN = 10MHz, TA = +25°C6465.5
fIN = 65MHz, TA = +25°C6465.2
fIN = 190MHz 64
f
= 250MHz62.8
IN
fIN = 10MHz, TA = +25°C6465.4
fIN = 65MHz, TA = +25°C63.564.9
fIN = 190MHz 62.9
fIN = 250MHz 62.3
fIN = 10MHz, TA = +25°C7785
fIN = 65MHz, TA = +25°C7378
fIN = 190MHz69.7
= 250MHz71.4
f
IN
fIN = 10MHz, TA = +25°C-85-77
fIN = 65MHz, TA = +25°C-78-73
fIN = 190MHz-69.7
fIN = 250MHz-71.4
f
= 209MHz at -7dBFS,
IN1
f
= 210MHz at -7dBFS
IN2
f
= 22MHz ±1MHz,
NOTCH
noise BW = 35MHz, A
RL = 100Ω ±1%1.1251.310V
= -9.1dBFS
IN
1.15 ±0.25V
11
±25%
5pF
-66.7dBc
62.2dB
P-P
kΩ
dB
dB
dBc
dBc
MAX1213
1.8V, 12-Bit, 170Msps ADC for
Broadband Applications
= -1dBFS; see each TOC for detailed information on test conditions, differential input drive, differential sine-wave clock input drive, 0.1µF capacitor on REFIO, internal reference, digital output pins
differential R
= -1dBFS; see each TOC for detailed information on test conditions, differential input drive, differential sine-wave clock input drive, 0.1µF capacitor on REFIO, internal reference, digital output pins
differential R
L
= 100Ω, TA= +25°C.)
SNR/SINAD vs. ANALOG INPUT AMPLITUDE
(f
SAMPLE
= 170.0053MHz, fIN = 65.1113MHz)
MAX1213 toc10
ANALOG INPUT AMPLITUDE (dBFS)
SNR/SINAD (dB)
-5-10-15-20-25
38
44
50
56
62
68
32
-300
SNR
SINAD
SFDR vs. ANALOG INPUT AMPLITUDE
(f
SAMPLE
= 170.0053MHz, fIN = 65.1113MHz)
MAX1213 toc11
ANALOG INPUT AMPLITUDE (dBFS)
SFDR (dBc)
-5-10-15-20-25
55
60
65
70
75
80
50
-300
HD2/HD3 vs. ANALOG INPUT AMPLITUDE
(f
SAMPLE
= 170.0053MHz, fIN = 65.1113MHz)
MAX1213 toc12
ANALOG INPUT AMPLITUDE (dBFS)
HD2/HD3 (dBc)
-5-10-15-20-25
-90
-80
-70
-60
-50
-100
-300
HD3
HD2
SNR/SINAD vs. f
SAMPLE
(fIN = 65MHz, AIN = -1dBFS)
MAX1213 toc13
f
SAMPLE
(MHz)
SNR/SINAD (dB)
1701405080110
61
62
63
64
65
66
67
68
60
20200
SNR
SINAD
SFDR vs. f
SAMPLE
(fIN = 65MHz, AIN = -1dBFS)
MAX1213 toc14
f
SAMPLE
(MHz)
SFDR (dBc)
1701405080110
55
60
65
70
75
80
85
90
50
20200
HD2/HD3 vs. f
SAMPLE
(fIN = 65MHz, AIN = -1dBFS)
MAX1213 toc15
f
SAMPLE
(MHz)
HD2/HD3 (dBc)
180160120 14060 80 10040
-105
-100
-95
-90
-85
-80
-75
-70
-65
-60
-110
20200
HD3
HD2
MAX1213
1.8V, 12-Bit, 170Msps ADC for
Broadband Applications
= -1dBFS; see each TOC for detailed information on test conditions, differential input drive, differential sine-wave clock input drive, 0.1µF capacitor on REFIO, internal reference, digital output pins
differential R
L
= 100Ω, TA= +25°C.)
TOTAL POWER DISSIPATION vs. f
SAMPLE
(fIN = 65MHz, AIN = -1dBFS)
MAX1213 toc16
f
SAMPLE
(MHz)
P
DISS
(mW)
180160120 14060 80 10040
910
920
930
940
950
960
970
980
990
1000
900
20200
INL vs. DIGITAL OUTPUT CODE
(1,048,576-POINT DATA RECORD)
MAX1213 toc17
DIGITAL OUTPUT CODE
INL (LSB)
358430722048 25601024 1536512
-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1.0
-1.0
04096
fIN = 13.0015039MHz
DNL vs. DIGITAL OUTPUT CODE
(1,048,576-POINT DATA RECORD)
MAX1213 toc18
DIGITAL OUTPUT CODE
DNL (LSB)
358430722048 25601024 1536512
-0.4
-0.3
-0.2
-0.1
0
0.1
0.2
0.3
0.4
0.5
-0.5
04096
fIN = 13.0015039MHz
HD2/HD3 vs. TEMPERATURE
(f
SAMPLE
= 170MHz, AIN = -2dBFS)
MAX1213 toc21b
TEMPERATURE (°C)
HD2/HD3 (dBc)
6035-1510
-95
-90
-85
-80
-70
-75
-65
-60
-100
-4085
HD3
HD2
fIN = 65MHz
GAIN (dB)
SFDR (dBc)
GAIN BANDWIDTH PLOT
= 170.0053MHz, AIN = -1dBFS)
(f
SAMPLE
1
0
-1
-2
-3
-4
-5
-6
-7
101000
ANALOG INPUT FREQUENCY (MHz)
100
SFDR vs. TEMPERATURE
= 170MHz, AIN = -2dBFS)
(f
SAMPLE
82
81
80
79
78
77
76
75
74
73
72
-4085
TEMPERATURE (°C)
fIN = 65MHz
603510-15
MAX1213 toc19
MAX1213 toc21a
SNR/SINAD vs. TEMPERATURE
= 170MHz, AIN = -2dBFS)
(f
SAMPLE
67
66
65
64
SNR/SINAD (dB)
63
62
61
SNR
SINAD
fIN = 65MHz
-4085
TEMPERATURE (°C)
6035-1510
MAX1213 toc20
MAX1213
1.8V, 12-Bit, 170Msps ADC for
Broadband Applications
= -1dBFS; see each TOC for detailed information on test conditions, differential input drive, differential sine-wave clock input drive, 0.1µF capacitor on REFIO, internal reference, digital output pins
differential R
L
= 100Ω, TA= +25°C.)
SNR/SINAD vs. SUPPLY VOLTAGE
(f
IN
= 65.1113MHz, AIN = -1dBFS)
MAX1213 toc22
SUPPLY VOLTAGE (V)
SNR/SINAD (dB)
2.22.11.7 1.81.92.0
61
62
63
64
65
66
67
68
60
1.62.3
AVCC = OV
CC
INTERNAL REFERENCE
vs. SUPPLY VOLTAGE
MAX1213 toc23
SUPPLY VOLTAGE (V)
V
REFIO
(V)
2.22.12.01.91.81.7
1.2400
1.2410
1.2420
1.2430
1.2440
1.2390
1.62.3
MEASURED AT REFIO
REFADJ = AV
CC
= OV
CC
t
PDL/tCPDL
vs. TEMPERATURE
MAX1213 toc24
TEMPERATURE (°C)
t
PDL
/t
CPDL
(dBc)
6035-1510
2
1
3
4
5
6
0
-4085
t
PDL
t
CPDL
NPR vs. ANALOG INPUT POWER
MAX1213 toc25
ANALOG INPUT POWER (dBFS)
NPR (dB)
-8-9-10-11-12-13-14-15
49
53
57
61
65
45
-16-7
f
NOTCH
= 22MHz ±1MHz
NOISE-POWER RATIO PLOT
(WIDE NOISE BANDWIDTH: 50MHz)
MAX1213 toc26
ANALOG INPUT FREQUENCY (MHz)
NPR (dB)
30 3540452551015 20
-80
-70
-60
-50
-40
-30
-20
-10
-90
0
f
NOTCH
= 22MHz
50
NOISE-POWER RATIO PLOT
(NARROW NOISE BANDWIDTH: 35MHz)
MAX1213 toc27
ANALOG INPUT FREQUENCY (MHz)
NPR (dB)
5
1015
25302035
-80
-70
-60
-50
-40
-30
-20
-10
-90
0
f
NOTCH
= 22MHz
MAX1213
1.8V, 12-Bit, 170Msps ADC for
Broadband Applications
8INPPositive Analog Input Terminal
9INNNegative Analog Input Terminal
17CLKDIV
22CLKP
23CLKN
26, 45, 61OGNDDigital Converter Ground. Ground connection for digital circuitry and output drivers.
27, 28, 41, 44, 60OV
29D0NComplementary Output Bit 0 (LSB)
30D0PTrue Output Bit 0 (LSB)
31D1NComplementary Output Bit 1
32D1PTrue Output Bit 1
33D2NComplementary Output Bit 2
34D2PTrue Output Bit 2
35D3NComplementary Output Bit 3
36D3PTrue Output Bit 3
AV
CC
AGNDAnalog Converter Ground
CC
Analog Supply Voltage. Bypass each pin with a parallel combination of 0.1µF and 0.22µF
capacitors for best decoupling results.
Reference Input/Output. With REFADJ pulled high, this I/O port allows an external reference
source to be connected to the MAX1213. With REFADJ pulled low, the internal 1.24V bandgap
reference is active.
Reference Adjust Input. REFADJ allows for FSR adjustments by placing a resistor or trim
potentiometer between REFADJ and AGND (decreases FSR) or REFADJ and REFIO (increases
FSR). If REFADJ is connected to AVCC, the internal reference can be overdriven with an
external source connected to REFIO. If REFADJ is connected to AGND, the internal reference is
used to determine the FSR of the data converter.
Clock Divider Input. This LVCMOS-compatible input controls which speed the converter’s
digital outputs are updated with. CLKDIV has an internal pulldown resistor.
CLKDIV = 0: ADC updates digital outputs at one-half the input clock rate.
CLKDIV = 1: ADC updates digital outputs at input clock rate.
True Clock Input. This input requires an LVDS-compatible input level to maintain the converter’s
excellent performance.
Complementary Clock Input. This input requires an LVDS-compatible input level to maintain the
converter’s excellent performance.
Digital Supply Voltage. Bypass with a 0.1µF capacitor for best decoupling results.
MAX1213
1.8V, 12-Bit, 170Msps ADC for
Broadband Applications
37D4NComplementary Output Bit 4
38D4PTrue Output Bit 4
39D5NComplementary Output Bit 5
40D5PTrue Output Bit 5
42DCLKN
43DCLKP
46D6NComplementary Output Bit 6
47D6PTrue Output Bit 6
48D7NComplementary Output Bit 7
49D7PTrue Output Bit 7
50D8NComplementary Output Bit 8
51D8PTrue Output Bit 8
52D9NComplementary Output Bit 9
53D9PTrue Output Bit 9
54D10NComplementary Output Bit 10
55D10PTrue Output Bit 10
56D11NComplementary Output Bit 11 (MSB)
57D11PTrue Output Bit 11 (MSB)
58ORN
59ORP
Complementary Clock Output. This output provides an LVDS-compatible output level and can
be used to synchronize external devices to the converter clock.
True Clock Output. This output provides an LVDS-compatible output level and can be used to
synchronize external devices to the converter clock.
Complementary Output for Out-of-Range Control Bit. If an out-of-range condition is detected,
bit ORN flags this condition by transitioning low.
True Output for Out-of-Range Control Bit. If an out-of-range condition is detected, bit ORP flags
this condition by transitioning high.
Two’s Complement or Binary Output Format Selection. This LVCMOS-compatible input controls
68T/B
—EP
the digital output format of the MAX1213. T/B has an internal pulldown resistor.
The MAX1213 uses a fully differential pipelined architecture that allows for high-speed conversion, optimized accuracy, and linearity while minimizing power
consumption and die size.
Both positive (INP) and negative/complementary analog input terminals (INN) are centered around a common-mode voltage of 1.365V, and accept a differential
analog input voltage swing of ±0.371V each, resulting in
a typical differential full-scale signal swing of 1.485V
P-P
.
Inputs INP and INN are buffered prior to entering each
T/H stage and are sampled when the differential sampling clock signal transitions high.
Each pipeline converter stage converts its input voltage
to a digital output code. At every stage, except the last,
the error between the input voltage and the digital output code is multiplied and passed along to the next
pipeline stage. Digital error correction compensates for
ADC comparator offsets in each pipeline stage and
ensures no missing codes. The result is a 12-bit parallel
digital output word in user-selectable two’s complement
or offset binary output formats with LVDS-compatible
output levels. See Figure 1 for a more detailed view of
the MAX1213 architecture.
Analog Inputs (INP, INN)
INP and INN are the fully differential inputs of the
MAX1213. Differential inputs usually feature good
rejection of even-order harmonics, which allows for
enhanced AC performance as the signals are progressing through the analog stages. The MAX1213
analog inputs are self-biased at a common-mode voltage of 1.365V and allow a differential input voltage
swing of 1.485V
P-P
(Figure 2). Both inputs are self-
biased through 2kΩ resistors, resulting in a typical differential input resistance of 4kΩ. It is recommended to
drive the analog inputs of the MAX1213 in AC-coupled
configuration to achieve best dynamic performance.
See the Single-Ended, AC-Coupled Analog Input section for a detailed discussion of this configuration.
Figure 1. Simplified MAX1213 Block Diagram
Figure 2. Simplified Analog Input Architecture and Allowable
Input Voltage Range
CLKDIV
CLKP
CLKN
INP
INN
2.2kΩ
CLOCKDIVIDER
CONTROL
2.2kΩ
INPUT
BUFFER
COMMON-MODE
BUFFER
CLOCK
MANAGEMENT
T/H
REFERENCE
REFIO REFADJ
DCLKP
DCLKN
12-BIT PIPELINE
QUANTIZER
CORE
INP
2.2kΩ
TO COMMON MODE
MAX1213
LVDS
DATA PORT
D0P/N–D11P/N
12
ORP
ORN
TO COMMON MODE
INP
P-P
1.485V
DIFFERENTIAL FSR
INN
+371mV
-371mV
+371mV
-371mV
COMMON-MODE
VOLTAGE (1.365V)
COMMON-MODE
VOLTAGE (1.365V)
2.2kΩ
AV
INN
AGND
CC
P-P
742mV
P-P
742mV
MAX1213
1.8V, 12-Bit, 170Msps ADC for
Broadband Applications
The MAX1213 features an internal 1.24V bandgap reference circuit (Figure 3), which in combination with an internal reference-scaling amplifier determines the FSR of the
MAX1213. Bypass REFIO with a 0.1µF capacitor to
AGND. To compensate for gain errors or increase the
ADC’s FSR, the voltage of this bandgap reference can be
indirectly adjusted by adding an external resistor (e.g.,
100kΩ trim potentiometer) between REFADJ and AGND
or REFADJ and REFIO. See the Applications Information
section for a detailed description of this process.
To disable the internal reference, connect REFADJ to
AVCC. In this configuration, an external, stable reference must be applied to REFIO to set the converter’s
full scale. To enable the internal reference, connect
REFADJ to AGND.
Clock Inputs (CLKP, CLKN)
Designed for a differential LVDS clock input drive, it is
recommended to drive the clock inputs of the MAX1213
with an LVDS-compatible clock to achieve the best
dynamic performance. The clock signal source must be
a high-quality, low-phase noise to avoid any degradation
in the noise performance of the ADC. The clock inputs
(CLKP, CLKN) are internally biased to 1.15V, accept a
typical differential signal swing of 0.5V
section for more circuit details on how to drive CLKP and
CLKN appropriately. Although not recommended, the
clock inputs also accept a single-ended input signal.
The MAX1213 also features an internal clock-management circuit (duty-cycle equalizer) that ensures that the
clock signal applied to inputs CLKP and CLKN is
processed to provide a 50% duty-cycle clock signal
that desensitizes the performance of the converter to
variations in the duty cycle of the input clock source.
Note that the clock duty-cycle equalizer cannot be
turned off externally and requires a minimum clock frequency of >20MHz to work appropriately and according to data sheet specifications.
Clock Outputs (DCLKP, DCLKN)
The MAX1213 features a differential clock output, which
can be used to latch the digital output data with an
external latch or receiver. Additionally, the clock output
can be used to synchronize external devices (e.g.,
FPGAs) to the ADC. DCLKP and DCLKN are differential
outputs with LVDS-compatible voltage levels. There is a
4.815ns delay time between the rising (falling) edge of
CLKP (CLKN) and the rising edge of DCLKP (DCLKN).
See Figure 4 for timing details.
Divide-by-2 Clock Control (CLKDIV)
The MAX1213 offers a clock control line (CLKDIV),
which supports the reduction of clock jitter in a system.
Connect CLKDIV to OGND to enable the ADC’s internal
divide-by-2 clock divider. Data is now updated at onehalf the ADC’s input clock rate. CLKDIV has an internal
pulldown resistor and can be left open for applications
that require this divide-by-2 mode. Connecting CLKDIV
to OVCCdisables the divide-by-2 mode.
Figure 3. Simplified Reference Architecture
ADC FULL SCALE = REFT-REFB
REFERENCE
1V
REFT: TOP OF REFERENCE LADDER.
REFB: BOTTOM OF REFERENCE LADDER.
BUFFER
CONTROL LINE TO
DISABLE REFERENCE BUFFER
AV
CC
REFT
REFB
REFERENCE
SCALING AMPLIFIER
G
REFIO
REFADJ
100Ω*
MAX1213
AVCC/2
0.1µF
*REFADJ MAY
BE SHORTED TO
AGND DIRECTLY
MAX1213
1.8V, 12-Bit, 170Msps ADC for
Broadband Applications
Figure 4 depicts the relationship between the clock
input and output, analog input, sampling event, and
data output. The MAX1213 samples on the rising
(falling) edge of CLKP (CLKN). Output data is valid on
the next rising (falling) edge of the DCLKP (DCLKN)
clock, but has an internal latency of 11 clock cycles.
Digital Outputs (D0P/N–D11P/N, DCLKP/N,
ORP/N) and Control Input
T
/B
Digital outputs D0P/N–D11P/N, DCLKP/N, and ORP/N
are LVDS compatible, and data on D0P/N–D11P/N is
presented in either binary or two’s-complement format
(Table 1). The T/B control line is an LVCMOS-compatible input, which allows the user to select the desired
output format. Pulling T/B low outputs data in two’s
complement and pulling it high presents data in offset
binary format on the 12-bit parallel bus. T/B has an
internal pulldown resistor and may be left unconnected
in applications using only two’s complement output for-
mat. All LVDS outputs provide a typical voltage swing
of 0.371V around a common-mode voltage of roughly
1.2V, and must be terminated at the far end of each
transmission line pair (true and complementary) with
100Ω. The LVDS outputs are powered from a separate
power supply, which can be operated between 1.7V
and 1.9V.
The MAX1213 offers an additional differential output
pair (ORP, ORN) to flag out-of-range conditions, where
out-of-range is above positive or below negative full
scale. An out-of-range condition is identified with ORP
(ORN) transitioning high (low).
Note: Although a differential LVDS output architecture
reduces single-ended transients to the supply and
ground planes, capacitive loading on the digital outputs should still be kept as low as possible. Using
LVDS buffers on the digital outputs of the ADC when
driving larger loads may improve overall performance
and reduce system-timing constraints.
Figure 4. System and Output Timing Diagram
SAMPLING EVENT
INN
SAMPLING EVENT
SAMPLING EVENTSAMPLING EVENT
INP
t
AD
CLKN
N
CLKP
t
CPDL
DCLKP
N-8
DCLKN
t
PDL
D0P/N–
D11P/N
ORP/N
t
- t
~ 0.4 x t
PDL
PDL
NOTE: THE ADC SAMPLES ON THE RISING EDGE OF CLKP. THE RISING EDGE OF DCLKP CAN BE USED TO EXTERNALLY LATCH THE OUTPUT DATA.
SAMPLE
WITH t
N-8
SAMPLE
= 1/f
SAMPLE
t
LATENCY
N+1
N-7
N-7N-1
t
CH
N+8
t
CPDL
t
CL
N+9
N
- t
PDL
N
N+1
N+1
MAX1213
1.8V, 12-Bit, 170Msps ADC for
Broadband Applications
The MAX1213 supports a full-scale adjustment range of
10% (±5%). To decrease the full-scale signal range, an
external resistor value ranging from 13kΩ to 1MΩ may
be added between REFADJ and AGND. A similar
approach can be taken to increase the ADC’s full-scale
signal range. Adding a variable resistor, potentiometer,
or predetermined resistor value between REFADJ and
REFIO increases the FSR of the data converter. Figure
6a shows the two possible configurations and their
impact on the overall full-scale range adjustment of the
MAX1213. Do not use resistor values of less than 13kΩ
to avoid instability of the internal gain regulation loop
for the bandgap reference. See Figure 6b for the
results of the adjustment range for a selection of resistors used to trim the full-scale range of the MAX1213.
Table 1. MAX1213 Digital Output Coding
Figure 5. Simplified LVDS Output Architecture
Figure 6a: Circuit Suggestions to Adjust the ADC’s Full-Scale
Range
Figure 6b: FS Adjustment Range vs. FS Adjustment Resistor
The MAX1213 dynamic performance depends on the
use of a very clean clock source. The phase noise floor
of the clock source has a negative impact on the SNR
performance. Spurious signals on the clock signal
source also affect the ADC’s dynamic range. The preferred method of clocking the MAX1213 is differentially
with LVDS- or PECL-compatible input levels. The fast
data transition rates of these logic families minimize the
clock-input circuitry’s transition uncertainty, thereby
improving the SNR performance. To accomplish this, a
50Ω reverse-terminated clock signal source with low
phase noise is AC-coupled into a fast differential
receiver such as the MC100LVEL16 (Figure 7). The
receiver produces the necessary PECL output levels to
drive the clock inputs of the data converter.
Transformer-Coupled, Differential Analog
Input Drive
In general, the MAX1213 provides the best SFDR and
THD with fully differential input signals and it is not re-
commended to drive the ADC inputs in single-ended
configuration. In differential input mode, even-order
harmonics are usually lower since INP and INN are balanced, and each of the ADC inputs only requires half
the signal swing compared to a single-ended configuration. Wideband RF transformers provide an excellent
solution to convert a single-ended signal to a fully differential signal, required by the MAX1213 to reach its
optimum dynamic performance.
A secondary-side termination of a 1:1 transformer (e.g.,
Mini-Circuit’s ADT1-1WT) into two separate 24.9Ω ±1%
resistors (use tight resistor tolerances to minimize
effects of imbalance; 0.5% would be an ideal choice)
placed between top/bottom and center tap of the transformer is recommended to maximize the ADC’s dynamic range. This configuration optimizes THD and SFDR
performance of the ADC by reducing the effects of
transformer parasitics. However, the source impedance combined with the shunt capacitance provided
by a PC board and the ADC’s parasitic capacitance
limit the ADC’s full-power input bandwidth to approximately 600MHz.
To further enhance THD and SFDR performance at
high-input frequencies (>100MHz), a second transformer (Figure 8) should be placed in series with the
single-ended-to-differential conversion transformer.
This transformer reduces the increase of even-order
harmonics at high frequencies.
Single-Ended, AC-Coupled Analog Inputs
Although not recommended, the MAX1213 can be used
in single-ended mode (Figure 9). Analog signals can be
AC-coupled to the positive input INP through a 0.1µF
capacitor and terminated with a 49.9Ω resistor to AGND.
The negative input should be reverse terminated with
24.9Ω resistors and AC-grounded with a 0.1µF capacitor.
Grounding, Bypassing, and
Board Layout Considerations
The MAX1213 requires board layout design techniques
suitable for high-speed data converters. This ADC provides separate analog and digital power supplies. The
analog and digital supply voltage pins accept input
voltage ranges of 1.7V to 1.9V. Although both supply
types can be combined and supplied from one source,
it is recommended to use separate sources to cut down
on performance degradation caused by digital switching currents, which can couple into the analog supply
network. Isolate analog and digital supplies (AVCCand
OVCC) where they enter the PC board with separate
networks of ferrite beads and capacitors to their corresponding grounds (AGND, OGND).
Figure 8. Analog Input Configuration with Back-to-Back Transformers and Secondary-Side Termination
Figure 9. Single-Ended AC-Coupled Analog Input Configuration
SINGLE-ENDED
INPUT TERMINAL
0.1µF
ADT1-1WT
ADT1-1WT
25Ω
25Ω
0.1µF
AV
OV
CC
CC
10Ω
INP
D0P/N–D11P/N
MAX1213
INN
10Ω
12
AGND
OGND
OV
AV
CC
CC
SINGLE-ENDED
INPUT TERMINAL
50Ω
25Ω
0.1µF
0.1µF
INP
INN
MAX1213
AGND
D0P/N–D11P/N
12
OGND
MAX1213
1.8V, 12-Bit, 170Msps ADC for
Broadband Applications
To achieve optimum performance, provide each supply
with a separate network of a 47µF tantalum capacitor
and parallel combinations of 10µF and 1µF ceramic
capacitors. Additionally, the ADC requires each supply
pin to be bypassed with separate 0.1µF ceramic
capacitors (Figure 10). Locate these capacitors directly
at the ADC supply pins or as close as possible to the
MAX1213. Choose surface-mount capacitors, whose
preferred location should be on the same side as the
converter to save space and minimize the inductance.
If close placement on the same side is not possible,
these bypassing capacitors may be routed through
vias to the bottom side of the PC board.
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 analog and digital
ground 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 dynamic currents that may need to
travel long distances before they are recombined at a
common-source ground, resulting in large and undesirable ground loops, are a major concern with this
approach. Ground loops can degrade the input noise
by coupling back to the analog front end of the converter, resulting in increased spurious activity, leading to
decreased noise performance.
Alternatively, all ground pins could share the same
ground plane, if the ground plane is sufficiently isolated
from any noisy, digital systems ground. To minimize the
coupling of the digital output signals from the analog
input, segregate the digital output bus carefully from the
analog input circuitry. To further minimize the effects of
digital noise coupling, ground return vias can be positioned throughout the layout to divert digital switching
currents away from the sensitive analog sections of the
ADC. This approach does not require split ground
planes, but can be accomplished by placing substantial
ground connections between the analog front end and
the digital outputs.
The MAX1213 is packaged in a 68-pin QFN-EP package (package code: G6800-4), providing greater
design flexibility, increased thermal dissipation, and
optimized AC performance of the ADC. The exposed
paddle (EP) must be soldered down to AGND.
In this package, the data converter die is attached to
an EP lead frame with the back of this frame exposed
at the package bottom surface, facing the PC board
side of the package. This allows a solid attachment of
the package to the board with standard infrared (IR)
flow soldering techniques.
Thermal efficiency is one of the factors for selecting a
package with an exposed pad for the MAX1213. The
exposed pad improves thermal and ensures a solid
ground connection between the DAC and the PC
board’s analog ground layer.
Considerable care must be taken when routing the digital output traces for a high-speed, high-resolution data
converter. It is essential to keep trace lengths at a minimum and place minimal capacitive loading—less than
5pF—on any digital trace to prevent coupling to sensitive analog sections of the ADC. It is recommended
running the LVDS output traces as differential lines with
100Ω characteristic impedance from the ADC to the
LVDS load device.
Figure 10. Grounding, Bypassing, and Decoupling Recommendations for MAX1213
BYPASSING-ADC LEVEL
AV
CC
OV
CC
BYPASSING-BOARD LEVEL
AV
CC
0.1µF0.1µF
AGND
MAX1213
AGND
OGND
OGND
D0P/N–D11P/N
12
NOTE: EACH POWER-SUPPLY PIN (ANALOG
AND DIGITAL) SHOULD BE DECOUPLED WITH
AN INDIVIDUAL 0.1µF CAPACITOR AS CLOSE
AS POSSIBLE TO THE ADC.
1µF
1µF
10µF
OV
CC
10µF47µF
47µF
ANALOG POWERSUPPLY SOURCE
DIGITAL/OUTPUT
DRIVER POWERSUPPLY SOURCE
MAX1213
1.8V, 12-Bit, 170Msps ADC for
Broadband Applications
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 end points of the transfer function, once
offset and gain errors have been nullified. However, the
static linearity parameters for the MAX1213 are measured using the histogram method with an input frequency of 10MHz.
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. The
MAX1213’s DNL specification is measured with the histogram method based on a 10MHz input tone.
Dynamic Parameter Definitions
Aperture Jitter
Figure 11 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
rising edge of the sampling clock and the instant when
an actual sample is taken (Figure 11).
Signal-to-Noise Ratio (SNR)
For a waveform perfectly reconstructed from digital
samples, the theoretical maximum SNR is the ratio of
the full-scale analog input (RMS value) to the RMS
quantization error (residual error). The ideal, theoretical
minimum analog-to-digital noise is caused by quantiza-
tion error only and results directly from the ADC’s resolution (N bits):
SNR
[max]
= 6.02 x N + 1.76
In reality, other noise sources such as thermal noise,
clock jitter, signal phase noise, and transfer function
nonlinearities are also contributing to the SNR calculation and should be considered when determining the
signal-to-noise ratio in ADC.
Signal-to-Noise Plus Distortion (SINAD)
SINAD is computed by taking the ratio of the RMS signal to all spectral components excluding the fundamental and the DC offset. In the case of the MAX1213,
SINAD is computed from a curve fit.
Spurious-Free Dynamic Range (SFDR)
SFDR is the ratio of RMS amplitude of the carrier frequency (maximum signal component) to the RMS value
of the next-largest noise or harmonic distortion component. SFDR is usually measured in dBc with respect to
the carrier frequency amplitude or in dBFS with respect
to the ADC’s full-scale range.
Intermodulation Distortion (IMD)
IMD is the ratio of the RMS sum of the intermodulation
products to the RMS sum of the two fundamental input
tones. This is expressed as:
The fundamental input tone amplitudes (V1and V2) are at
-7dBFS. The intermodulation products are the amplitudes
of the output spectrum at the following frequencies:
• Second-order intermodulation products: f
IN1
+ f
IN2
,
f
IN2
- f
IN1
• Third-order intermodulation products: 2 x f
IN1
- f
IN2
,
2 x f
IN2
- f
IN1
, 2 x f
IN1
+ f
IN2
, 2 x f
IN2
+ f
IN1
• Fourth-order intermodulation products: 3 x f
IN1
- f
IN2
,
3 x f
IN2
- f
IN1
, 3 x f
IN1
+ f
IN2
, 3 x f
IN2
+ f
IN1
•Fifth-order intermodulation products: 3 x f
IN1
- 2 x f
IN2
,
3 x f
IN2
-2 x f
IN1
, 3 x f
IN1
+2 x f
IN2
, 3 x f
IN2
+ 2 x f
IN1
Full-Power Bandwidth
A large -1dBFS analog input signal is applied to an
ADC and the input frequency is swept up to the point
where the amplitude of the digitized conversion result
has decreased by 3dB. The -3dB-point is defined as
full-power input bandwidth frequency of the ADC.
Figure11. Aperture Jitter/Delay Specifications
CLKP
CLKN
IMD
log
=×
20
2
VVV V
IMIMIMIMn
1
2
++++
......
2
VV
+
122
22
3
2
ANALOG
INPUT
SAMPLED
DATA (T/H)
T/H
t
AD
TRACKTRACK
t
AJ
HOLD
MAX1213
1.8V, 12-Bit, 170Msps ADC for
Broadband Applications
NPR is commonly used to characterize the return path of
cable systems where the signals are typically individual
quadrature amplitude-modulated (QAM) carriers with a
frequency spectrum similar to noise. Numerous such
carriers are operated in a continuous spectrum, generating a noise-like signal, which covers a relatively broad
bandwidth. To test the MAX1213 for NPR, a “noise-like”
signal is passed through a high-order bandpass filter to
produce an approximately square spectral pedestal of
noise with about the same bandwidth as the signals
being simulated. Following the bandpass filter, the signal
is passed through a narrow band-reject filter to produce
a deep notch at the center of the noise pedestal. Finally,
this signal is applied to the MAX1213 and its digitized
results analyzed. The RMS noise power of the signal
inside the notch is compared with the RMS noise level
outside the notch using an FFT. Note that the NPR test
requires sufficiently long data records to guarantee a
suitable number of samples inside the notch. NPR for the
MAX1213 was determined for 35MHz and 50MHz noise
bandwidth signals, simulating a typical cable signal environment (see the Typical Operating Characteristics for
test details and results).
Pin-Compatible Lower
Speed/Resolution Versions
Applications that require lower resolution and/or higher
speed can refer to other family members of the
MAX1213. Adjusting an application to a lower resolution
has been simplified by maintaining an identical pinout for
all members of this high-speed family. See Table 2 for a
selection of different resolution and speed grades.
(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
.)
68L QFN.EPS
PACKAGE OUTLINE, 68L QFN, 10x10x0.9 MM
21-0122
1
C
2
MAX1213
1.8V, 12-Bit, 170Msps ADC for
Broadband Applications
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.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________ 21
(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
.)
PACKAGE OUTLINE, 68L QFN, 10x10x0.9 MM
21-0122
1
C
2
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