Rainbow Electronics MAX1420 User Manual

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

General Description

The MAX1420, +3.3V, 12-bit analog-to-digital converter
(ADC) features a fully-differential input, pipelined, 12­stage ADC architecture with wideband track-and-hold
(T/H) and digital error correction, incorporating a fully­differential signal path. The MAX1420 is optimized for
low-power, high dynamic performance applications in
imaging and digital communications. The converter
operates from a single +3.3V supply, and consumes
only 221mW. The fully-differential input stage has a
small signal -3dB bandwidth of 400MHz and may be
operated with single-ended inputs.

An internal +2.048V precision bandgap reference sets
the full-scale range of the ADC. A flexible reference
structure accommodates an internal reference, or
externally applied buffered or unbuffered reference for
applications that require increased accuracy and a dif­ferent input voltage range.

In addition to low operating power, the MAX1420 fea­tures two power-down modes: reference power-down
and shutdown mode. In reference power-down, the
internal bandgap reference is deactivated, which
results in a typical 2mA supply current reduction. A full
shutdown mode is available to maximize power savings
during idle periods.

The MAX1420 provides parallel, offset binary, CMOS­compatible three-state outputs.

The MAX1420 is available in a 7mm ✕7mm, 48-pin
TQFP package, and is specified over the commercial
(0°C to +70°C) and the extended industrial (-40°C to
+85°C) temperature range.

Pin-compatible lower speed versions of the MAX1420
are also available. Please refer to the MAX1421 data
sheet for 40Msps and the MAX1422 data sheet for
20Msps.

________________________Applications

Medical Ultrasound Imaging
CCD Pixel Processing
IR Focal Plane Arrays
Radar
IF & Baseband Digitization

Features

♦ +3.3V Single Power Supply

♦ 67dB SNR at f

IN

= 5MHz

♦ 66dB SNR at f

IN

= 15MHz

♦ Internal +2.048V Precision Bandgap Reference

♦ Differential, Wideband Input T/H Amplifier

♦ Power-Down Modes:

218mW (Reference Shutdown Mode)
10µW (Shutdown Mode)

♦ Space-Saving 48-Pin TQFP Package

MAX1420

12-Bit, 60Msps, +3.3V, Low-Power ADC

with Internal Reference

________________________________________________________________ Maxim Integrated Products 1

Pin Configuration

19-1981; Rev 0; 5/01

Ordering Information

Functional diagram appears at end of data sheet.

PART TEMP. RANGE PIN-PACKAGE

MAX1420CCM 0°C to +70°C 48 TQFP
MAX1420ECM -40°C to +85°C 48 TQFP

AGND

AVDDCML

REFN

REFP

REFIN

AGND

AV

AV
AGND
AGND

INP

INN
AGND
AGND

AV
AV

AGND

AVDDAGNDPDOE

4847464544434241403938

1

2

DD

3

DD

4

5

6

7

8

9

10

DD

11

DD

12

MAX1420

D11

D10

37

36

D9
D8

35

D7

34

D6

33

DV

32

DV

31

DGND

30

DGND

29

D5

28

D4

27

D3

26

D2

25

DD

DD

1314151617181920212223

AGND

DDAVDD

AV

CLK

AGND

48-TQFP

CLK

AGND

DD

AV

DV

24

DD

D0

D1

DGND

MAX1420

12-Bit, 60Msps, +3.3V, Low-Power ADC
with Internal Reference

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(V

AVDD

= V

DVDD

= +3.3V, AGND = DGND = 0, VIN= ±1.024V, differential input voltage at -0.5dB FS, internal reference, f

CLK

=

62.5MHz (50% duty cycle), digital output load C

L

≈ 10pF, TA= T

MIN

to T

MAX

, unless otherwise noted. 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.

AVDD, DVDDto AGND..............................................-0.3V to +4V

DV

DD

, AVDDto DGND..............................................-0.3V to +4V

DGND to AGND.....................................................-0.3V to +0.3V

INP, INN, REFP, REFN, REFIN,

CML, CLK, CLK ....................(AGND - 0.3V) to (AV

DD

+ 0.3V)

D0–D11, OE, PD .....................(DGND - 0.3V) to (DV

DD

+ 0.3V)

Continuous Power Dissipation (T

A

= +70°C)

48-Pin TQFP (derate 12.5mW/°C above +70°C)........1000mW

Operating Temperature Ranges

MAX1420CCM ....................................................0°C to +70°C

MAX1420ECM .................................................-40°C to +85°C

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

Storage Temperature Range .............................-65°C to +150°C

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

DC ACCURACY

Resolution RES 12 Bits

Differential Nonlinearity DNL

Integral Nonlinearity INL TA = T

Mid-scale Offset MSO -3 .75 3 %FSR

Mid-scale Offset Temperature
Coefficient

Gain Error GE

Gain Error Temperature
Coefficient

DYNAMIC PERFORMANCE (f

Signal-to-Noise Ratio SNR

Spurious-Free Dynamic Range SFDR

Total Harmonic Distortion THD

Signal-to-Noise and Distortion SINAD

Effective Number of Bits ENOB

Two-Tone
Intermodulation Distortion

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

MSOTC

GETC

= 60MHz, 4096-point FFT)

CLK

IMD

TA = +25°C, no missing codes -1 1

T

= T

A

Internal reference (Note 1) -5 ±0.1 5

E xter nal r efer ence ap p l i ed to RE FIN
( N ote 2)

E xter nal r efer ence ap p li ed to RE FP ,
CML, and REFN (Note 3)

External reference applied to REFP,
CML, and REFN (Note 3)

fIN = 5MHz 67

f

IN

fIN = 5MHz 72

f

IN

fIN = 5MHz -70

f

IN

fIN = 5MHz 64.5

f

IN

fIN = 5MHz 10.4

f

IN

f

IN1

f

IN2

to T

MIN

to T

MIN

= 15MHz, TA =+25°C6266

= 15MHz, TA =+25°C6472

= 15MHz, TA =+25°C -69 -62

= 15MHz, TA =+25°C 58.5 63

= 15MHz 10.2

= 11.566036MHz,
= 13.4119138MHz (Note 4)

MAX

MAX

±0.5

±2 LSB

-4

3 x 10

-5 ±0.2 5

-1.5 1.5

100 x 106 %/°C

-74 dBc

LSB

%/°C

%FSR

dB

dB

dB

dB

Bits

MAX1420

12-Bit, 60Msps, +3.3V, Low-Power ADC

with Internal Reference

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS (continued)

(V

AVDD

= V

DVDD

= +3.3V, AGND = DGND = 0, VIN= ±1.024V, differential input voltage at -0.5dB FS, internal reference, f

CLK

=

62.5MHz (50% duty cycle), digital output load C

L

≈ 10pF, TA= T

MIN

to T

MAX

, unless otherwise noted. Typical values are at

T

A

= +25°C.)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Differential Gain DG ±1%
Differential Phase DP ±0.25 degrees

ANALOG INPUTS (INP, INN, CML)

Input Resistance R

Input Capacitance C

Common-Mode Input Level
(Note 5)

Common-Mode Input Voltage
Range (Note 5)

Differential Input Range V

Small-Signal Bandwidth BW

Large-Signal Bandwidth FPBW

V

V

CMVR

IN

IN

CML

IN

-3dB

-3dB

Overvoltage Recovery OVR 1.5 ✕ FS input 1

Either input to ground 22 kΩ

Either input to ground 4 pF

V

AVDD

✕

0.5

V

CML

± 5%

V

- V

INP

(Note 6) ±V

INN

DIFF

V

V

V

(Note 7) 400 MHz

(Note 7) 150 MHz

Clock
Cycle

INTERNAL REFERENCE (REFIN bypassed with 0.22µF in parallel with 1nF)

Common-Mode Reference
Voltage

Positive Reference Voltage V

Negative Reference Voltage V

Differential Reference Voltage V

Differential Reference
Temperature Coefficient

REFTC ±100 ppm/°C

V

CML

REFP

REFN

DIFF

At CML

At REFP

At REFN

V

= V

DIFF

REFP

- V

REFN

V

AVDD

✕

0.5

V

CML

+ 0.512

V

CML

- 0.512

1.024 ±5% V

V

V

V

EXTERNAL REFERENCE (REFIN = +2.048V)

REFIN Input Resistance R

REFIN Input Capacitance C

REFIN Reference Input Voltage V

Differential Reference Voltage V

EXTERNAL REFERENCE (V

= AGND, reference voltage applied to REFP, REFN, and CML)

REFIN

REFP, REFN, CML Input Current I

REFP, REFN, CML Input
Capacitance

IN

IN

REFIN

DIFF

IN

C

IN

(Note 8) 5 kΩ

10 pF

2.048
±10%

V

DIFF

= (V

REFP

- V

REFN

✕

)

0.95

V

RE F IN

V

/2

RE F IN

/2

1.05

V

REFIN

✕

/2

-200 200 µA

15 pF

V

V

MAX1420

12-Bit, 60Msps, +3.3V, Low-Power ADC
with Internal Reference

4 _______________________________________________________________________________________

ELECTRICAL CHARACTERISTICS (continued)

(V

AVDD

= V

DVDD

= +3.3V, AGND = DGND = 0, VIN= ±1.024V, differential input voltage at -0.5dB FS, internal reference, f

CLK

=

62.5MHz (50% duty cycle), digital output load C

L

≈ 10pF, TA= T

MIN

to T

MAX

, unless otherwise noted. Typical values are at

T

A

= +25°C.)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Differential Reference Voltage
Range

CML Input Voltage Range V

REFP Input Voltage Range V

REFN Input Voltage Range V

V

DIFF

CML

REFP

REFN

V

DIFF

= V

REFP

- V

REFN

1.024
±10%

1.65

±10%

V

CML

V

DIFF

V

CML

V

DIFF

V

V

+
/2

-

/2

V

V

DIGITAL INPUTS (CLK, CLK, PD, OE)

x

Input Logic High V

Input Logic Low V

IH

IL

0.7

V

DVDD

0.3

V

DVDD

V

x

V

CLK, CLK ±330

Input Current

PD -20 20

µA

OE -20 20

Input Capacitance 10 pF

DIGITAL OUTPUTS (D0–D11)

Output Logic High V

Output Logic Low V

OH

OL

IOH = 200µA

DVDD

- 0.5

IOL = -200µA 0 0.5 V

V

DVDD

V

V

Three-State Leakage -10 10 µA

Three-State Capacitance 2pF

POWER REQUIREMENTS

Analog Supply Voltage V

Digital Supply Voltage V

Analog Supply Current I

Analog Supply Current with
Internal Reference in Shutdown

AVDD

DVDD

AVDD

REFIN

Analog Shutdown Current PD = D

Digital Supply Current I

DVDD

Digital Shutdown Current PD = V

Power Dissipation P

Power Dissipation with Internal
Reference in Shutdown (Note 8)

P

DISS

DISS

Analog power dissipation 221 258 mW

REFIN = AGND 218 251 mW

= AGND 66 76 mA

VDD

DVDD

3.135 3.3 3.465 V

2.7 3.3 3.63 V

67 78 mA

10 20 µA

8mA

20 µA

MAX1420

12-Bit, 60Msps, +3.3V, Low-Power ADC

with Internal Reference

_______________________________________________________________________________________ 5

Note 1: Internal reference, REFIN bypassed to AGND with a combination of 0.22µF in parallel with 1nF capacitor.
Note 2: External +2.048V reference applied to REFIN.
Note 3: Internal reference disabled. V

REFIN

= 0, V

REFP

= +2.162V, V

CML

= +1.65V, and V

REFN

= +1.138V.

Note 4: IMD is measured with respect to either of the fundamental tones.
Note 5: Specifies the common-mode range of the differential input signal supplied to the MAX1420.
Note 6: V

DIFF

= V

REFP

- V

REFN

.

Note 7: Input bandwidth is measured at a 3dB level.
Note 8: V

REFIN

is internally biased to +2.048V through a 10kΩ resistor.

Note 9: Measured as the ratio of the change in mid-scale offset voltage for a ±5% change in V

AVDD

, using the internal reference.

ELECTRICAL CHARACTERISTICS (continued)

(V

AVDD

= V

DVDD

= +3.3V, AGND = DGND = 0, VIN= ±1.024V, differential input voltage at -0.5dB FS, internal reference, f

CLK

=

62.5MHz (50% duty cycle), digital output load C

L

≈ 10pF, TA= T

MIN

to T

MAX

, unless otherwise noted. Typical values are at

T

A

= +25°C.)

Typical Operating Characteristics

(V

AVDD

= V

DVDD

= +3.3V, AGND = DGND = 0, VIN= ±1.024V, differential input voltage at -0.5dB FS, f

CLK

= 60.006MHz (50% duty

cycle), digital output load CL= 10pF, TA= T

MIN

to T

MAX

, unless otherwise noted. Typical values are at TA= +25°C.)

-120

-80

-100

-40

-60

-20

0

030

FFT PLOT (8192-POINT DATA RECORD)

DIFFERENTIAL INPUT

MAX1420 toc01

ANALOG INPUT FREQUENCY (MHz)

AMPLITUDE (dB)

10 1552025

HD2

HD3

fIN = 5.5449583MHz

-120

-80

-100

-40

-60

-20

0

030

FFT PLOT (8192-POINT DATA RECORD)

DIFFERENTIAL INPUT

MAX1420 toc02

ANALOG INPUT FREQUENCY (MHz)

AMPLITUDE (dB)

10 1552025

HD2

HD3

fIN = 13.4119138MHz

-120

-80

-100

-40

-60

-20

0

030

FFT PLOT (8192-POINT DATA RECORD)

DIFFERENTIAL INPUT

MAX1420 toc03

ANALOG INPUT FREQUENCY (MHz)

AMPLITUDE (dB)

10 1552025

HD2

HD3

fIN = 37.701219MHz

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Power Dissipation In Shutdown P

DISS

PD = V

DVDD

10 µW

Power-Supply Rejection Ratio PSRR (Note 9) ±1 mV/V

TIMING CHARACTERISTICS

Maximum Clock Frequency f

Clock High t

Clock Low t

CLK

CH

CL

Figure 6, clock period 16.667ns 8.33 ns

Figure 6, clock period 16.667ns 8.33 ns

60 MHz

Pipeline Delay (Latency) Figure 6 7

Aperture Delay t

Aperture Jitter t

Data Output Delay t

Bus Enable Time t

Bus Disable Time t

AD

AJ

OD

BE

BD

Figure 10 2 ns

Figure 10 2 ps

Figure 6 5 10 14 ns

Figure 5 5 ns

Figure 5 5 ns

f

CLK

cycles

MAX1420

12-Bit, 60Msps, +3.3V, Low-Power ADC
with Internal Reference

6 _______________________________________________________________________________________

Typical Operating Characteristics (continued)

(V

AVDD

= V

DVDD

= +3.3V, AGND = DGND = 0, VIN= ±1.024V, differential input voltage at -0.5dB FS, f

CLK

= 60.006MHz (50% duty

cycle), digital output load C

L

= 10pF, TA= T

MIN

to T

MAX

, unless otherwise noted. Typical values are at TA= +25°C.)

-120

-80

-100

-40

-60

-20

0

030

TWO-TONE IMD PLOT

(8192-POINT DATA RECORD)

DIFFERENTIAL INPUT

MAX1420 toc04

ANALOG INPUT FREQUENCY (MHz)

AMPLITUDE (dB)

10 1552025

f

IN1

f

IN1

= 11.566036MHz

f

IN2

= 13.4119138MHz

A

IN1

= A

IN2

= -6.5dB FS
TWO TONE
ENVELOPE: -0.5dB FS

f

IN2

IMD3

IMD2

IMD2

IMD3

85

45

110100

SPURIOUS-FREE DYNAMIC RANGE

vs. ANALOG INPUT FREQUENCY

53

MAX1420 toc08

ANALOG INPUT FREQUENCY (MHz)

SFDR (dB)

61

69

77

MAX1420 toc09

-10

0

20

10

50

60

40

30

70

SNR (dB)

-70 -50 -40-60

-30

-20 -10 0

INPUT POWER (dB FS)

SIGNAL-TO-NOISE RATIO

vs. INPUT POWER (f

IN

= 15MHz)

-80

-60

-70

-40

-50

-30

-20

MAX1420 toc11

THD (dB)

TOTAL HARMONIC DISTORTION

vs. INPUT POWER (f

IN

= 15MHz)

-70 -50 -40-60

-30

-20 -10 0

INPUT POWER (dB FS)

20

40

30

60

50

70

80

MAX1420 toc12

SFDR (dB)

SPURIOUS-FREE DYNAMIC RANGE

vs. INPUT POWER (f

IN

= 15MHz)

-70 -50 -40-60

-30

-20 -10 0

INPUT POWER (dB FS)

-50

-80
110100

TOTAL HARMONIC DISTORTION
vs. ANALOG INPUT FREQUENCY

-74

MAX1420 toc07

ANALOG INPUT FREQUENCY (MHz)

THD (dB)

-68

-62

-56

MAX1420 toc10

-10

0

80

SINAD (dB)

-70 -50 -40-60

-30

-20 -10 0

INPUT POWER (dB FS)

SIGNAL-TO-NOISE + DISTORTION
vs. INPUT POWER (f

IN

= 15MHz)

10

40

30

20

70

60

50

70

50

110100

SIGNAL-TO-NOISE RATIO

vs. ANALOG INPUT FREQUENCY

54

MAX1420 toc05

ANALOG INPUT FREQUENCY (MHz)

SNR (dB)

58

62

66

70

50

1 10 100

SIGNAL-TO-NOISE + DISTORTION

vs. ANALOG INPUT FREQUENCY

54

MAX1420 toc06

ANALOG INPUT FREQUENCY (MHz)

SINAD (dB)

58

62

66