MAXIM MAX1121 Technical data

General Description

The MAX1121 is a monolithic 8-bit, 250Msps analog-to­digital converter (ADC) optimized for outstanding
dynamic performance at high IF frequencies up to
500MHz. The product operates with conversion rates of
up to 250Msps while consuming only 477mW.

At 250Msps and an input frequency of 100MHz, the
MAX1121 achieves a spurious-free dynamic range
(SFDR) of 68dBc. Its excellent signal-to-noise ratio
(SNR) of 48.9dB at 10MHz remains flat (within 0.5dB)
for input tones up to 500MHz. This makes the MAX1121
ideal for wideband applications such as digital predis­tortion in cellular base-station transceiver systems.

The MAX1121 requires a single 1.8V supply. The ana­log input is designed for either differential or single­ended 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 500MHz. This helps to reduce the
phase noise of the input clock source. A differential
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 MAX1121 is available in a 68-pin QFN with
exposed pad (EP) and is specified over the industrial
(-40°C to +85°C) temperature range.

For pin-compatible, higher resolution versions of the
MAX1121, refer to the MAX1122 (170Msps), the
MAX1123 (210Msps), and the MAX1124 (250Msps)
data sheets.

Applications

Wireless and Wired Broadband Communication

Digital Oscilloscopes

Digital Predistortion Receivers

Communications Test Equipment

Radar and Satellite Subsystems Antenna Array
Processing

Instrumentation

Features

♦ 250Msps Conversion Rate

♦ SNR = 48.8dB/48.7dB at f

IN

= 100MHz/500MHz

♦ SFDR = 68dBc/63.8dBc at f

IN

= 100MHz/500MHz

♦ Single 1.8V Supply

♦ 477mW Power Dissipation at 250Msps

♦ On-Chip Track-and-Hold and Internal Reference

♦ On-Chip Selectable Divide-by-2 Clock Input

♦ LVDS Digital Outputs with Data Clock Output

♦ Evaluation Kit Available (Order MAX1124EVKIT)

MAX1121

1.8V, 8-Bit, 250Msps Analog-to-Digital Converter
with LVDS Outputs for Wideband Applications

E

Pin Configuration

Ordering Information

19-3077; Rev 2; 8/08

For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.

________________________________________________________________

Maxim Integrated Products

1

*

EP = Exposed pad.

PART TEMP RANGE PIN-PACKAGE

MAX1121EGK -40°C to +85°C 68 QFN-EP*

TOP VIEW

CC

CC

AVCCOGND

OVCCORP

ORN

D7P

D7N

D6P

D6N

D5P

D5N

5253

51 D4P

50

49

48 D3N

47

46

45

44

43

42

41

40

39

38

37

36

35

AV

CC

AGND

REFIO

REFADJ

AGND

AV

CC

AGND

INP

INN

AGND

AV

CC

AV

CC

AV

CC

AV

CC

AGND

AGND

CLKDIV 17

T/B

68

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

EP

AV

64

656667

5859606162 5455565763

MAX1121

AGND

AGND

AGND

AV

D4N

D3P

D2P

D2N

OGND

OV

CC

DCLKP

DCLKN

OV

CC

D1P

D1N

D0P

D0N

N.C.

N.C.

PART TEMP RANGE PIN-PACKAG

MAX1121EGK -40°C to +85°C 68 QFN-EP*

2322212019 2726252418 2928 323130

CC

AV

CLKP

AGND

CLKN

AGND

AGND

CC

CC

AGND

CC

AV

OGND

N.C.

N.C.

OV

OV

N.C.

N.C.

N.C.

3433

N.C.

MAX1121

1.8V, 8-Bit, 250Msps Analog-to-Digital Converter
with LVDS Outputs for Wideband Applications

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

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)

Digital Inputs to AGND.............................-0.3V to (AV

CC

+ 0.3V)

REF, REFADJ to AGND............................-0.3V to (AV

CC

+ 0.3V)

Digital Outputs to OGND.........................-0.3V to (OV

CC

+ 0.3V)

ESD on All Pins (Human Body Model).............................±2000V

Continuous Power Dissipation (T

A

= +70°C)

68-Pin QFN (derate 41.7mW/°C above +70°C) .........3333mW

Operating Temperature Range ...........................-40°C to +85°C

Junction Temperature......................................................+150°C

Storage Temperature Range .............................-60°C to +150°C

Lead Temperature (soldering, 10s) .................................+300°C

Maximum Current into Any Pin............................................50mA

ELECTRICAL CHARACTERISTICS

(AVCC= OVCC= 1.8V, V

AGND

= V

OGND

= 0, f

SAMPLE

= 250MHz, differential sine-wave clock input drive, 0.1µF capacitor on REFIO,

internal reference, digital output pins differential R

L

= 100Ω ±1%, CL= 5pF, 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.)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

DC ACCURACY

Resolution 8 Bits

Integral Nonl inearity INL (Note 1) -0.6 ±0.2 +0.6 LSB

Differential Nonlinear ity DNL No mi ssing codes (Note 1) -0.9 ±0.1 +0.9 LSB

Transfer Curve Offset VOS (Note 1) -10 +10 LSB

Offset Temperature Drift ±20 μV/°C

ANALOG INPUTS (INP, INN)

Ful l-Scale Input Voltage Range VFS (Note 1) 1100 1250 1375 mV

Ful l-Scale Range Temperature
Drift

Common-Mode Input Range VCM

Input Capacitance CIN 3 pF

Differential Input Resistance RIN 3.00 4.4 6.5 k

Ful l-Power Analog Bandwidth FPBW Figure 8 600 MHz

REFERENCE (REFIO, REFADJ)

Reference Output Voltage V

Reference Temperature Drift 90 ppm/°C

REFADJ Input High Voltage V

SAMPLING CHARACTERISTICS

Maximum Sampling Rate f

Minimum Sampling Rate f

130 ppm/°C

1.18 1.24 1.30 V

REFIO

REFADJ

SAMPLE

SAMPLE

Used to di sable the internal reference

250 MHz

20 MHz

AV

CC

0.3

1.38

±0.18

­ V

V

P-P

MAX1121

1.8V, 8-Bit, 250Msps Analog-to-Digital Converter
with LVDS Outputs for Wideband Applications

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS (continued)

(AVCC= OVCC= 1.8V, V

AGND

= V

OGND

= 0, f

SAMPLE

= 250MHz, differential sine-wave clock input drive, 0.1µF capacitor on REFIO,

internal reference, digital output pins differential R

L

= 100Ω ±1%, CL= 5pF, 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.)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Cloc k Duty Cycle Set by clock management circuit 40 to 60 %

Aperture Delay tAD 350 ps

Aperture Jitter tAJ 0.2 ps

CLOCK INPUTS (CLKP, CLKN)

Differential Clock Input

Cloc k Input Common-Mode
Voltage Range

Cloc k D ifferential Input
Resistance

Cloc k D ifferential Input
Capacitance

DYNAMIC CHARACTERISTICS (at -0.5dBFS)

Signal-to-Noise Ratio SNR

Signal-to-Noise
and Distortion

Spurious-Free
Dynamic Range

Worst Harmonics
(HD2 or HD3)

Two-Tone Intermodulation
Distortion

LVDS DIGITAL OUTPUTS (D0P/N–D7P/N, ORP/N)

Differential Output Voltage |VOD| 250 450 mV

(Note 2) 200 500 mV

R

CLK

5 pF

C

CLK

SINAD

SFDR

IMD

100

IMD

500

fIN = 10MHz, TA +25°C 47.2 48.9

fIN = 100MHz, TA +25°C 46.2 48.8

fIN = 180MHz 48.8

= 500MHz 48.7

f

IN

fIN = 10MHz, TA +25°C 47.1 48.8

fIN = 100MHz, TA +25°C 46.1 48.7

fIN = 180MHz 48.7

f

= 500MHz 48.6

IN

fIN = 10MHz, TA +25°C 60 69

fIN = 100MHz, TA +25°C 59 68

fIN = 180MHz 69.1

= 500MHz 63.8

f

IN

fIN = 10MHz -74.6

fIN = 100MHz -68.4

fIN = 180MHz -69.1

= 500MHz -63.8

f

IN

f

= 99MHz at -7dBFS,

IN1

= 101MHz at -7dBFS

f

IN2

f

= 498.5MHz at -7dBFS,

IN1

= 502.5MHz at -7dBFS

f

IN2

-70

-56

1.25

±0.25

11

±25%

k

RMS

P-P

V

dB

dB

dBc

dBc

dBc

MAX1121

1.8V, 8-Bit, 250Msps Analog-to-Digital Converter
with LVDS Outputs for Wideband Applications

4 _______________________________________________________________________________________

ELECTRICAL CHARACTERISTICS (continued)

(AVCC= OVCC= 1.8V, V

AGND

= V

OGND

= 0, f

SAMPLE

= 250MHz, differential sine-wave clock input drive, 0.1µF capacitor on REFIO,

internal reference, digital output pins differential R

L

= 100Ω ±1%, CL= 5pF, 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.)

Note 1: Static linearity and offset parameters are computed from a best-fit straight line through the code transition points. The full-

scale range is defined as 1023 x slope of the line.

Note 2: Parameter guaranteed by design and characterization; T

A

= T

MIN

to T

MAX

.

Note 3: PSRR is measured with both analog and digital supplies connected to the same potential.

Output Offset Voltage OVOS 1.125 1.310 V

LVCMOS DIGITAL INPUTS (CLKDIV, T/B)

Digital Input Voltage Low VIL

Digital Input Voltage High V

TIMING CHARACTERISTICS

CLK to Data Propagation Delay t

CLK to DCLK Propagation Dela y t

Data Valid to DCLK Rising Edge

LVDS Output Rise-Time t

LVDS Output Fall-Time t

Output Data Pipeline Delay t

POWER REQUIREMENTS

Analog Supply Voltage Range AVCC 1.70 1.80 1.90 V

Digital Supply Voltage Range OVCC 1.70 1.80 1.90 V

Analog Supply Current

Digital Supply Current I

Total Power Dissipation P

Power-Supply Rejection Ratio
(Note 3)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

IH

Figure 4 1.5 ns

PDL

Figure 4 2.85 ns

CPDL

t

-

CPDL

t

PDL

20% to 80%, CL = 5pF 460 ps

RISE

20% to 80%, CL = 5pF 460 ps

FALL

LATENCY

fIN = 100MHz 220 290 mA

I

AVCC

fIN = 100MHz 45 75 mA

OVCC

fIN = 100MHz 477 657 mW

DISS

PSRR

Figure 4 (Note 2) 0.92 1.35 1.86 ns

8

Offset 1.6 mV/V

Gain 1.9 %FS/V

0.8 x

AV

CC

0.2 x

AV

V

CC

V

Clock

cycles

MAX1121

1.8V, 8-Bit, 250Msps Analog-to-Digital Converter
with LVDS Outputs for Wideband Applications

Typical Operating Characteristics

(AVCC= OVCC= 1.8V, V

AGND

= V

OGND

= 0, f

SAMPLE

= 250.0057MHz, -0.5dBFS; see TOCs 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.)

_______________________________________________________________________________________ 5

FFT PLOT (8192-POINT DATA RECORD,

COHERENT SAMPLING)

0

-10

-20

-30

-40

-50

AMPLITUDE (dB)

-60

-70

-80

-90
040608020 100 140120

HD3

HD2

ANALOG INPUT FREQUENCY (MHz)

FFT PLOT (8192-POINT DATA RECORD,

COHERENT SAMPLING)

0

-10
FUNDAMENTAL

-20

-30

-40

HD3

-50

AMPLITUDE (dB)

-60

HD2

-70

-80

-90

040608020 100 140120

ANALOG INPUT FREQUENCY (MHz)

HD2/HD3 vs. ANALOG INPUT FREQUENCY

= 250.0057MHz, AIN = -0.5dBFS)

(f

SAMPLE

-50

-60

-70

-80

HD2/HD3 (dBc)

-90

-100
0 500

HD2

f

IN

f

= 250.0057MHz

SAMPLE

= 11.5054MHz

f

IN

= -0.4885MHz

A

IN

SNR = 48.9dB
SFDR = 71.5dBc
HD2 = -79.2dBc
HD3 = -74.6dBc

f

= 250.0057MHz

SAMLE

= 500.516MHz

f

IN

= -0.5235MHz

A

IN

SNR = 48.8dB
SFDR = 63.8dBc
HD2 = -70.8dBc
HD3 = -63.8dBc

HD3

(MHz)

400300200100

MAX1121 toc01

MAX1121 toc04

MAX1121 toc07

FFT PLOT (8192-POINT DATA RECORD,

COHERENT SAMPLING)

0

-10

-20

-30

-40

-50

AMPLITUDE (dB)

-60

-70

-80

-90
040608020 100 140120

ANALOG INPUT FREQUENCY (MHz)

f

= 250.0057MHz

SAMPLE

= 60.0294MHz

f

IN

= -0.4885MHz

A

IN

SNR = 49dB
SFDR = 71.1dBc
HD2 = -79.5dBc
HD3 = -71.9dBc

HD3

SNR vs. ANALOG INPUT FREQUENCY

= 250.0057MHz, AIN = -0.5dBFS)

(f

SAMPLE

50

49

48

SNR (dB)

47

46

45

0 500

f

(MHz)

IN

SNR vs. ANALOG INPUT AMPLITUDE

= 250.0057MHz, fIN = 60.0294MHz)

(f

SAMPLE

50

45

40

35

SNR (dB)

30

25

20

-30 -15 -10-25 -20 -5 0
ANALOG INPUT AMPLITUDE (dBFS)

HD2

400300200100

MAX1121 toc02

MAX1121 toc05

MAX1121 toc08

FFT PLOT (8192-POINT DATA RECORD,

COHERENT SAMPLING)

0

-10

-20

-30

-40

-50

AMPLITUDE (dB)

-60

-70

-80

-90
040608020 100 140120

ANALOG INPUT FREQUENCY (MHz)

HD3

f

= 250.0057MHz

SAMPLE

= 183.5064MHz

f

IN

= -0.5245MHz

A

IN

SNR = 48.8dB
SFDR = 69.1dBc
HD2 = -77.2dBc
HD3 = -69.1dBc

SFDR vs. ANALOG INPUT FREQUENCY

= 250.0057MHz, AIN = -0.5dBFS)

(f

SAMPLE

80

74

68

SFDR (dBc)

62

56

50

0 500

f

(MHz)

IN

SFDR vs. ANALOG INPUT AMPLITUDE

= 250.0057MHz, fIN = 60.0294MHz)

(f

SAMPLE

75

70

65

60

55

50

SFDR (dBc)

45

40

35

30

-30 -15 -10-25 -20 -5 0
ANALOG INPUT AMPLITUDE (dBFS)

HD2

400300200100

MAX1121 toc03

MAX1121 toc06

MAX1121 toc09

MAX1121

1.8V, 8-Bit, 250Msps Analog-to-Digital Converter
with LVDS Outputs for Wideband Applications

6 _______________________________________________________________________________________

Typical Operating Characteristics (continued)

(AVCC= OVCC= 1.8V, V

AGND

= V

OGND

= 0, f

SAMPLE

= 250.0057MHz, -0.5dBFS; see TOCs 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.)

-90

-65

-75

-85

-70

-80

-50

-55

-60

-40

-45

-35

-30

-30 -20 -15-25 -10 -5 0

HD2/HD3 vs. ANALOG INPUT AMPLITUDE

(f

SAMPLE

= 250.0057MHz, fIN = 60.0294MHz)

MAX1121 toc10

ANALOG INPUT AMPLITUDE (dBFS)

HD2/HD3 (dBc)

HD3

HD2

SNR vs. f

SAMPLE

(fIN = 60.0294MHz, AIN = -0.5dBFS)

MAX1121 toc11

f

SAMPLE

(MHz)

SNR (dB)

60

47.0

47.5

48.0

48.5

49.0

46.5
20 260180140100 220

SFDR vs. f

SAMPLE

(fIN = 60.0294MHz, AIN = -0.5dBFS)

MAX1121 toc12

f

SAMPLE

(MHz)

SFDR (dBc)

22014010060

50

60

70

80

90

40

20 260180

HD2/HD3 vs. f

SAMPLE

(fIN = 60.03294MHz, AIN = -0.5dBFS)

MAX1121 toc13

f

SAMPLE

(MHz)

HD2/HD3 (dBc)

22018014010060

-92

-84

-76

-68

-60

-100
20 260

HD3

HD2

-80

-90

-60

-70

-40

-50

-30

-10

-20

0

TWO-TONE IMD PLOT (8192-POINT

DATA RECORD, COHERENT SAMPLING)

MAX1121 toc14

ANALOG INPUT FREQUENCY (MHz)

AMPLITUDE (dB)

040608020 100 140120

f

SAMPLE

= 250.0057MHz

f

IN1

= 99.0318MHz

f

IN2

= 101.046MHz

A

IN1

= A

IN2

= -7dBFS

IMD = -70dBc

2f

IN1

- f

IN2

2f

IN2

-

f

IN1

f

IN1

f

IN2

-0.5

-0.3

-0.4

-0.1

-0.2

0.1

0

0.2

0.4

0.3

0.5

64 96320 128 160 192 224 256

INTEGRAL NONLINEARITY

vs. DIGITAL OUTPUT CODE

MAX1121 toc15

DIGITAL OUTPUT CODE

INL (LSB)

-0.5

-0.4

-0.2

0.1

0.3

0.5

0.4

0

-0.3

-0.1

0.2

64 96320 128 160 192 224 256

DIFFERENTIAL NONLINEARITY

vs. DIGITAL OUTPUT CODE

MAX1121 toc16

DIGITAL OUTPUT CODE

DNL (LSB)

2

0

-2

-4

-6

-8

-10

-12
10 100 1000

GAIN BANDWIDTH PLOT

(f

SAMPLE

= 250.0057MHz, AIN = -0.5dBFS)

MAX1121 toc17

ANALOG INPUT FREQUENCY (MHz)

GAIN (dB)

SNR vs. TEMPERATURE (fIN = 65.0108MHz,

f

SAMPLE

= 249.856MHz, AIN = -0.5dBFS)

MAX1121 toc18

TEMPERATURE (°C)

SNR (dB)

603510-15

47.0

46.5

48.0

47.5

49.0

48.5

49.5

50.0

46.0

-40 85