Rainbow Electronics MAX1444 User Manual

General Description

The MAX1444 10-bit, +3V analog-to-digital converter
(ADC) features a pipelined 10-stage ADC architecture
with fully differential wideband track-and-hold (T/H)
input and digital error correction incorporating a fully
differential signal path. This ADC is optimized for low­power, high dynamic performance applications in
imaging and digital communications. The MAX1444
operates from a single +2.7V to +3.6V supply, consum­ing only 57mW while delivering a 59.5dB signal-to­noise ratio (SNR) at a 20MHz input frequency. The fully
differential input stage has a 400MHz -3dB bandwidth
and may be operated with single-ended inputs. In addi­tion to low operating power, the MAX1444 features a
5µA power-down mode for idle periods.

An internal +2.048V precision bandgap reference is
used to set the ADC full-scale range. A flexible refer­ence structure allows the user to supply a buffered,
direct, or externally derived reference for applications
requiring increased accuracy or a different input volt­age range.

Higher speed, pin-compatible versions of the MAX1444
are also available. Please refer to the MAX1446 data
sheet (60Msps) and the MAX1448 data sheet
(80Msps).

The MAX1444 has parallel, offset binary, CMOS-com­patible three-state outputs that can be operated from
+1.7V to +3.6V to allow flexible interfacing. The device
is available in a 5x5mm 32-pin TQFP package and is
specified over the extended industrial (-40°C to +85°C)
temperature range.

________________________Applications

Ultrasound Imaging

CCD Imaging

Baseband and IF Digitization

Digital Set-Top Boxes

Video Digitizing Applications

Features

♦ Single +3.0V Operation

♦ Excellent Dynamic Performance

59.5dB SNR at f

IN

= 20MHz

74dBc SFDR at fIN= 20MHz

♦ Low Power

19mA (Normal Operation)
5µA (Shutdown Mode)

♦ Fully Differential Analog Input

♦ Wide 2V

p-p Differential Input Voltage Range

♦ 400MHz -3dB Input Bandwidth

♦ On-Chip +2.048V Precision Bandgap Reference

♦ CMOS-Compatible Three-State Outputs

♦ 32-Pin TQFP Package

♦ Evaluation Kit Available

MAX1444

10-Bit, 40Msps, +3.0V, Low-Power

ADC with Internal Reference

________________________________________________________________ Maxim Integrated Products 1

Pin Configuration

19-1745; Rev 0; 7/00

For free samples and the latest literature, visit www.maxim-ic.com or phone [phone].
For small orders, phone [phone].

EVALUATION KIT

AVAILABLE

Ordering Information

Functional Diagram appears at end of data sheet.

PART TEMP. RANGE PIN-PACKAGE

MAX1444EHJ -40°C to +85°C 32 TQFP

TOP VIEW

REFIN

GND

REFOUT

REFP

32 28

D0

D1

D2

D3

293031

27

25

26

COM

V

GND

GND

IN+

1REFN

2

3

DD

4

5

6

7

IN-

8GND

9

V

MAX1444

CLK

14

13

15

PD

GND

10

DD

DD

V

GND

24 D4

OGND

23

22

T.P.

21

OV

DD

20

D5

19

D6

18

D7

17

D8

1611 12

OE

D9

TQFP

MAX1444

10-Bit, 40Msps, +3.0V, Low-Power
ADC with Internal Reference

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VDD= +3.0V, OVDD= +2.7V; 0.1µF and 1.0µF capacitors from REFP, REFN, and COM to GND; V

REFIN

= +2.048V, REFOUT con-

nected to REFIN through a 10kΩ resistor, V

IN

= 2Vp-p (differential w.r.t. COM), CL= 10pF at digital outputs, f

CLK

= 40MHz (50% duty

cycle), T

A

= T

MIN

to T

MAX

, unless otherwise noted. Typical values are at TA= +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.

VDD, OVDDto GND ...............................................-0.3V to +3.6V

OGND to GND.......................................................-0.3V to +0.3V

IN+, IN- to GND........................................................-0.3V to V

DD

REFIN, REFOUT, REFP,

REFN, and COM to GND.........................-0.3V to (V

DD

+ 0.3V)

OE, PD, CLK to GND..................................-0.3V to (V

DD

+ 0.3V)

D9–D0 to GND.........................................-0.3V to (OV

DD

+ 0.3V)

Continuous Power Dissipation (T

A

= +70°C)

32-Pin TQFP (derate 11.1mW/°C above +70°C)...........889mW

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

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

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

DC ACCURACY

Resolution 10 bits

Integral Nonlinearity INL fIN = 7.51MHz ±0.6 ±1.9 LSB

Differential Nonlinearity DNL

Offset Error <±0.1 ±1.7 % FS

Gain Error 0 ±2% FS

ANALOG INPUT

Input Differential Range V

Common-Mode
Voltage Range

Input Resistance R

Input Capacitance C

CONVERSION RATE

Maximum Clock Frequency f

Data Latency 5.5 cycles

DYNAMIC CHARACTERISTICS (f

Signal-To-Noise Ratio SNR

Signal-To-Noise And Distortion
(Up to 5th harmonic)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

CLK

f

= 7.51MHz, no missing codes

IN

guaranteed

DIFF

V

COM

CLK

= 40MHz, 4096-point FFT)

SINAD

Differential or single-ended inputs ±1.0 V

Switched capacitor load 50 kΩ

IN

IN

fIN = 7.51MHz 57.5 59.5

fIN = 19.91MHz 57 59.5

= 39.9MHz (Note 1) 58.5

f

IN

fIN = 7.51MHz 57 59.4

fIN = 19.91MHz 56.7 59

f

= 39.9MHz (Note 1) 58.3

IN

fIN = 7.51MHz 67 75

fIN = 19.91MHz 66 74Spurious-Free Dynamic Range SFDR

= 39.9 MHz (Note 1) 72.5

f

IN

40 MHz

±0.4 ±1.0 LSB

VDD/2

±0.5

5pF

V

dB

dB

dBc

MAX1444

10-Bit, 40Msps, +3.0V, Low-Power

ADC with Internal Reference

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS (continued)

(VDD= +3.0V, OVDD= +2.7V; 0.1µF and 1.0µF capacitors from REFP, REFN, and COM to GND; V

REFIN

= +2.048V, REFOUT con-

nected to REFIN through a 10kΩ resistor, V

IN

= 2Vp-p (differential w.r.t. COM), CL= 10pF at digital outputs, f

CLK

= 40MHz (50% duty

cycle), T

A

= T

MIN

to T

MAX

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

PARAMETER

SYMBOL

CONDITIONS

MIN

TYP

MAX

UNITS

fIN = 7.51MHz -75

fIN = 19.91MHz -74

Third-Harmonic Distortion HD3

f

IN

= 39.9MHz (Note 1)

dBc

Two-Tone Intermodulation
Distortion

IMD

f

1

= 11.5MHz at -6.5dBFS

f

2

= 13.5MHz at -6.5dBFS

(Note 2)

-76

dBc

Third-Order Intermodulation
Distortion

IM3

f

1

= 11.5MHz at -6.5dBFS

f

2

= 13.5MHz at -6.5dBFS

(Note 2)

-76

dBc

fIN = 7.51MHz

-65

fIN = 19.91MHz

-65

Total Harmonic Distortion
(First 5 Harmonics)

THD

f

IN

= 39.9MHz (Note 1) -70

dBc

Small-Signal Bandwidth Input at -20dBFS, differential inputs

MHz

Full-Power Bandwidth FPBW Input at -0.5dBFS, differential inputs

MHz

Aperture Delay t

AD

1ns

Aperture Jitter t

AJ

2

ps

RMS

Overdrive Recovery Time For 1.5 × full-scale input 2 ns

Differential Gain ±1%

Differential Phase

degree

Output Noise IN+ = IN- = COM 0.2

LS B

RM S

INTERNAL REFERENCE

Reference Output Voltage

2.048 ±1% V

Reference Temperature
Coefficient

60

p p m/°C

Load Regulation

mV/mA

EXTERNAL REFERENCE

Positive Reference REFP V

REFIN

= +2.048V

V

Negative Reference REFN V

REFIN

= +2.048V

V

Differential Reference Voltage

V

REFP

– V

REFN

, V

REFIN

= +2.048V

V

REFIN Resistance

MΩ

DIGITAL INPUTS (CLK, PD, OE)

CLK

0.8 ×

Input High Threshold V

IH

PD, OE

0.8 ×

V

CLK

0.2 ×

Input Low Threshold V

IL

PD, OE

0.2 ×

V

REFOUT

TC

REF

∆V

R

REFIN

REF

0.98 1.024 1.07

V

OV

-72.5

-73.8

-72.2

500

400

±0.25

1.25

2.012

0.988

>50

DD

DD

V

OV

DD

DD

MAX1444

10-Bit, 40Msps, +3.0V, Low-Power
ADC with Internal Reference

4 _______________________________________________________________________________________

ELECTRICAL CHARACTERISTICS (continued)

(VDD= +3.0V, OVDD= +2.7V; 0.1µF and 1.0µF capacitors from REFP, REFN, and COM to GND; V

REFIN

= +2.048V, REFOUT con-

nected to REFIN through a 10kΩ resistor, V

IN

= 2Vp-p (differential w.r.t. COM), CL= 10pF at digital outputs, f

CLK

= 40MHz (50% duty

cycle), T

A

= T

MIN

to T

MAX

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

Note 1: 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 2: 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 3: Digital outputs settle to V

IH

/ VIL.

Note 4: REFIN is driven externally. REFP, COM, and REFN are left floating while powered down.

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Input Hysteresis V

Input Leakage

Input Capacitance C

DIGITAL OUTPUTS (D9–D0)

Output Voltage Low V

Output Voltage High V

Three-State Leakage Current I

Three-State Output Capacitance C

POWER REQUIREMENTS

Analog Supply Voltage V

Output Supply Voltage OV

Analog Supply Current I

Output Supply Current I

Power Supply Rejection PSRR

TIMING CHARACTERISTICS

CLK Rise to Output Data Valid t

OE Fall to Output Enable t
OE Rise to Output Disable t

CLK Pulse Width High t

CLK Pulse Width Low t

Wake-up Time t

HYST

I

I

LEAK

OUT

VDD

OVDD

VIH = VDD = OV

IH

VIL = 0 ±5

IL

IN

I

OL

OH

= 200µA 0.2 V

SINK

I

SOURCE

OE = OV
OE = OV

DD

DD

DD

= 200µA

DD

DD

Operating, fIN = 19.91MHz at -0.5dBFS 19 25 mA
Shutdown, clock idle, PD = OE = OV

DD

Operating, fIN = 19.91MHz at -0.5dBFS 4.5 mA
Shutdown, clock idle, PD = OE = OV

DD

Offset ±0.1 mV/V

Gain ±0.1 %/V

DO

ENABLE

DISABLE

CH

WAKE

Figure 6, (Note 3) 5 8 ns

Figure 5 10 ns

Figure 5 15 ns

Figure 6, clock period 25ns 12.5 ±3.8 ns

Figure 6, clock period 25ns 12.5 ±3.8 ns

CL

(Note 4) 1.7 µs

0.1 V

±5

5pF

OV

DD

- 0.2

±10 µA

5pF

2.7 3.0 3.6 V

1.7 3.0 3.6 V

415µA

110µA

µA

V

MAX1444

10-Bit, 40Msps, +3.0V, Low-Power

ADC with Internal Reference

_______________________________________________________________________________________ 5

Typical Operating Characteristics

(VDD= +3.0V, OVDD= +2.7V, internal reference, differential input at -0.5dB FS, f

CLK

= 40MHz, CL≈ 10pF, TA= +25°C, unless other-

wise noted.)

-10

-20

-30

-40

-50

-60

AMPLITUDE (dB)

-70

-80

-90

-100

-10

-20

-30

-40

-50

-60

AMPLITUDE (dB)

-70

-80

-90

-100

FFT PLOT (fIN = 7.51MHz,

8192-POINT FFT, DIFFERENTIAL INPUT)

0

0 2 4 6 8101214161820

ANALOG INPUT FREQUENCY (MHz)

SINAD = 59dB
SNR = 59.3dB
THD = -71.6dBc
SFDR = 73dBc

3RD HARMONIC

2ND HARMONIC

FFT PLOT (fIN = 7.51MHz,

8192-POINT FFT, SINGLE-ENDED INPUT)

0

0 2 4 6 8101214161820

ANALOG INPUT FREQUENCY (MHz)

SINAD = 59.7dB
SNR = 60dB
THD = -71.8dBc
SFDR = 75dBc

3RD HARMONIC

2ND HARMONIC

MAX1444-01

MAX1444-04

FFT PLOT (fIN = 19.91MHz,

8192-POINT FFT, DIFFERENTIAL INPUT)

0

SINAD = 58.9dB

-10

SNR = 59.1dB
THD = -72.8dBc

-20
SFDR = 75.2dBc

-30

-40

-50

-60

2ND HARMONIC

AMPLITUDE (dB)

-70

-80

-90

-100
0 2 4 6 8101214161820

ANALOG INPUT FREQUENCY (MHz)

3RD HARMONIC

FFT PLOT (fIN = 19.91MHz,

8192-POINT FFT, SINGLE-ENDED INPUT)

0

SINAD = 59.1dB

-10

SNR = 59.2dB
THD = -74.6dBc

-20
SFDR = 77.6dBc

-30

-40

-50

2ND HARMONIC

-60

AMPLITUDE (dB)

-70

-80

-90

-100
0 2 4 6 8101214161820

ANALOG INPUT FREQUENCY (MHz)

3RD HARMONIC

FFT PLOT (fIN = 47MHz,

8192-POINT FFT, DIFFERENTIAL INPUT)

MAX1444-02

0

-10

-20

-30

-40

-50

-60

AMPLITUDE (dB)

-70

-80

-90

-100
0 5 10 15 20 25

2ND HARMONIC

ANALOG INPUT FREQUENCY (MHz)

SINAD = 58.1dB
SNR = 58.4dB
THD = -69.7dBc
SFDR = 72.4dBc

3RD HARMONIC

FULL-POWER INPUT BANDWIDTH vs.

ANALOG INPUT FREQUENCY (SINGLE-ENDED)

6

MAX1444-05

4

2

0

GAIN (dB)

-2

-4

-6

-8
1 100 1000

10

ANALOG INPUT FREQUENCY (MHz)

MAX1444-03

MAX1444-06

SMALL-SIGNAL INPUT BANDWIDTH vs.

ANALOG INPUT FREQUENCY (SINGLE-ENDED)

6

VIN = 100mVp-p

4

2

0

GAIN (dB)

-2

-4

-6

-8
1 100 1000

10

ANALOG INPUT FREQUENCY (MHz)

MAX1444-07

TWO-TONE INTERMODULATION

8192-POINT IMD (DIFFERENTIAL INPUT)

0

f1 = 11.5MHz AT

-10

-6.5dB FS
= 13.5MHz AT

f

2

-20

-6.5dB FS

3RD IMD = -76dBc

-30

-40

-50

-60

AMPLITUDE (dB)

-70

-80

-90

-100
0 5 10 15 20 25

ANALOG INPUT FREQUENCY (MHz)

MAX1444-08

SPURIOUS-FREE DYNAMIC RANGE vs.

ANALOG INPUT FREQUENCY

80

75

70

65

60

SFDR (dBc)

55

50

45

40

110100

DIFFERENTIAL

SINGLE-ENDED

ANALOG INPUT FREQUENCY (MHz)

MAX1444-09

MAX1444

10-Bit, 40Msps, +3.0V, Low-Power
ADC with Internal Reference

6 _______________________________________________________________________________________

)

)

Typical Operating Characteristics (continued)

(VDD= +3.0V, OVDD= +2.7V, internal reference, differential input at -0.5dB FS, f

CLK

= 40MHz, CL≈ 10pF, TA= +25°C, unless other-

wise noted.)

SNR (dB)

SIGNAL-TO-NOISE RATIO vs.

ANALOG INPUT FREQUENCY

62

61

60

59

58

57

56

55

54

110100

DIFFERENTIAL

SINGLE-ENDED

ANALOG INPUT FREQUENCY (MHz)

MAX1444-10

-45

-50

-55

-60

THD (dBc)

-65

-70

-75

TOTAL HARMONIC DISTORTION vs.

ANALOG INPUT FREQUENCY

SINGLE-ENDED

DIFFERENTIAL

110100

ANALOG INPUT FREQUENCY (MHz)

SIGNAL-TO-NOISE PLUS DISTORTION vs.

ANALOG INPUT FREQUENCY

65

MAX1444-11

61

57

SINAD (dB)

53

49

45

1 10 100

DIFFERENTIAL

SINGLE-ENDED

ANALOG INPUT FREQUENCY (MHz)

MAX1444-12

SPURIOUS-FREE DYNAMIC RANGE

vs. ANALOG INPUT POWER

80

fIN = 19.91MHz

75

70

65

SFDR (dBc)

60

55

50

-15 -9-12 -6 -3 0
ANALOG INPUT POWER (dB FS)

SIGNAL-TO-NOISE PLUS DISTORTION

vs. ANALOG INPUT POWER

65

fIN = 19.91MHz

60

55

SINAD (dB)

50

MAX1444-13

MAX1444-16

SIGNAL-TO-NOISE RATIO

vs. ANALOG INPUT POWER

65

fIN = 19.91MHz

60

55

SNR (dB)

50

45

40

-15 -9-12 -6 -3 0
ANALOG INPUT POWER (dB FS)

SPURIOUS-FREE DYNAMIC RANGE

vs. TEMPERATURE

84

fIN = 19.91MHz

80

76

SFDR (dBc)

72

MAX1444-14

MAX1444-17

TOTAL HARMONIC DISTORTION

vs. ANALOG INPUT POWER

-50
fIN = 19.91MHz

-55

-60

-65

THD (dBc)

-70

-75

-80

-15 -9-12 -6 -3 0
ANALOG INPUT POWER (dB FS)

SIGNAL-TO-NOISE RATIO

vs. TEMPERATURE

70

fIN = 19.91MHz

66

62

SNR (dB)

58

MAX1444-15

MAX1444-18

45

40

-15 -9-12 -6 -3 0
ANALOG INPUT POWER (dB FS

68

64

-40 10-15 35 60 85
TEMPERATURE (°C

54

50

-40 10-15 356085
TEMPERATURE (°C)