Rainbow Electronics MAX1448 User Manual
General Description
The MAX1448 +3V, 10-bit analog-to-digital converter
(ADC) features a fully differential input, a pipelined 10stage ADC architecture with wideband track-and-hold
(T/H), and digital error correction incorporating a fully
differential signal path. The ADC is optimized for lowpower, high dynamic performance in imaging and digital communications applications. The converter
operates from a single +2.7V to +3.6V supply, consuming only 120mW while delivering a 59dB (typ) signal-tonoise ratio (SNR) at a 20MHz input frequency. The fully
differential input stage has a -3dB 400MHz bandwidth
and may be operated with single-ended inputs. In addition to low operating power, the MAX1448 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.
Lower speed, pin-compatible versions of the MAX1448
are also available. Please refer to the MAX1444 data
sheet for a 40Msps version and to the MAX1446 data
sheet for a 60Msps version.
The MAX1448 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 5mm x 5mm 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
59dB SNR at f
IN
= 20MHz
74dBc SFDR at f
IN
= 20MHz
♦ Low Power
40mA (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
MAX1448
10-Bit, 80Msps, Single +3.0V, Low-Power
ADC with Internal Reference
________________________________________________________________ Maxim Integrated Products 1
Functional Diagram
19-5400; Rev 0; 9/00
For free samples and the latest literature, visit www.maxim-ic.com or phone 1-800-998-8800.
For small orders, phone 1-800-835-8769.
EVALUATION KIT
AVAILABLE
Ordering Information
Pin Configuration appears at end of data sheet.
PART TEMP. RANGE PIN-PACKAGE
MAX1448EHJ -40°C to +85°C 32 TQFP
CLK
IN+
MAX1448
CONTROL
10
D
OUTPUT
T/H
IN-
PD
REF
PIPELINE ADC
REF SYSTEM +
BIAS
E
DRIVERS
C
V
GND
D9–D0
OV
OGND
DD
DD
REFINREFOUT REFP COM REFN OE
MAX1448
10-Bit, 80Msps, Single +3.0V, Low-Power
ADC with Internal Reference
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(VDD= +3.0V, OVDD= +2.0V; 0.1µF and 1.0µF capacitors from REFP, REFN, and COM to GND; V
REFIN
= +2.048V, REFOUT
connected to REFIN through a 10kΩ resistor, V
IN
= 2Vp-p (differential with respect to COM), CL≈ 15pF at digital outputs (Note 5),
f
CLK
= 83.3MHz (50% duty cycle), 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.
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
Junction Temperature......................................................+150°C
Storage Temperature Range ............................-60°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
DC ACCURACY
Resolution 10 Bits
Integral Nonlinearity INL fIN = 7.47MHz ±0.7 ±2.2 LSB
Differential Nonlinearity DNL f
Offset Error <±1 ±1.7 %FS
Gain Error 0 ±2%FS
ANALOG INPUT
Input Differential Range V
Common-Mode Voltage Range V
Input Resistance R
Input Capacitance C
CONVERSION RATE
Maximum Clock Frequency f
Data Latency 5.5 Cycles
DYNAMIC CHARACTERISTICS (f
Signal-to-Noise Plus Distortion
(up to 5th harmonic)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
DIFF
COM
IN
IN
CLK
= 83.3MHz, 4096-point FFT)
CLK
SINAD
= 7.47M H z, no m i ssi ng cod es g uar anteed ±0.4 ±1.0 LSB
IN
Differential or single-ended inputs ±1.0 V
Switched capacitor load 25 kΩ
fIN = 7.47MHz 56.5 59.1
fIN = 20MHz 56 59Signal-to-Noise Ratio SNR
= 39.9MHz (Note 1) 58.5
f
IN
fIN = 7.47MHz 55.8 59
fIN = 20MHz 55.3 58.8
f
= 39.9MHz (Note 1) 58
IN
80 MHz
VDD/2
± 0.5
5pF
V
dB
dB
MAX1448
10-Bit, 80Msps, Single +3.0V, Low-Power
ADC with Internal Reference
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS (continued)
(VDD= +3.0V, OVDD= +2.0V; 0.1µF and 1.0µF capacitors from REFP, REFN, and COM to GND; V
REFIN
= +2.048V, REFOUT
connected to REFIN through a 10kΩ resistor, V
IN
= 2Vp-p (differential with respect to COM), CL≈ 15pF at digital outputs (Note 5),
f
CLK
= 83.3MHz (50% duty cycle), TA= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
=
+25°C.)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Spurious-Free Dynamic
Range
SFDR
fIN = 7.47MHz 61 74
fIN = 20MHz 61 74
= 39.9MHz (Note 1) 73
f
IN
fIN = 7.47MHz 74
Third-Harmonic Distortion HD3
Intermodulation Distortion
Two-Tone
Third-Order Intermodulation
Distortion
Total Harmonic Distortion
(first 5 harmonics)
IMD
IM3
THD
fIN = 20MHz 74
= 39.9MHz (Note 1) 73
f
IN
f
= 24MHz at -6.5dB FS, f
1
TT
-6.5dB FS (Note 2)
f
= 24MHz at -6.5dB FS, f
1
= 26MHz at
2
= 26MHz at
2
-6.5dB FS (Note 2)
fIN = 7.47MHz -72 -60
fIN = 20MHz -70 -60
= 39.9MHz (Note 1) -69
f
IN
Small-Signal Bandwidth Input at -20dB FS, differential inputs 500 MHz
Full-Power Bandwidth FPBW Input at -0.5dB FS, differential inputs 400 MHz
Aperture Delay t
Aperture Jitter t
AD
AJ
Overdrive Recovery Time For 1.5 × full-scale input 2 ns
Differential Gain ±1 %
Differential Phase ±0.25 degrees
Output Noise IN+ = IN- = COM 0.2 LSB
INTERNAL REFERENCE
Reference Output Voltage REFOUT
Reference Temperature
Coefficient
TC
REF
Load Regulation 1.25 mV/mA
EXTERNAL REFERENCE
Positive Reference REFP V
Negative Reference REFN V
Differential Reference Voltage ∆V
REFIN Resistance R
D IGIT A L IN PU T S
( C LK, P D , OE)
Input High Threshold V
REF
REFIN
IH
= +2.048V 2.012 V
REFIN
= +2.048V 0.988 V
REFIN
V
REFP
CLK
PD, OE
- V
REFN
, V
= +2.048V 0.98 1.024 1.07 V
REFIN
0.8 x
V
DD
0.8 x
OV
D D
dBc
dBc
-74 dBc
-74 dBc
dBc
1ns
2ps
2.048
±1%
RMS
V
60 ppm/°C
>50 MΩ
V
RMS
Note 1: SNR, SINAD, THD, SFDR and HD3 are based on an analog input voltage of -0.5dB FS 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: With REFIN driven externally, REFP, COM, and REFN are left floating while powered down.
Note 5: Equivalent dynamic performance is obtainable over full OV
DD
range with reduced CL.
MAX1448
10-Bit, 80Msps, Single +3.0V, Low-Power
ADC with Internal Reference
4 _______________________________________________________________________________________
ELECTRICAL CHARACTERISTICS (continued)
(VDD= +3.0V, OVDD= +2.0V; 0.1µF and 1.0µF capacitors from REFP, REFN, and COM to GND; V
REFIN
= +2.048V, REFOUT
connected to REFIN through a 10kΩ resistor, V
IN
= 2Vp-p (differential with respect to COM), CL≈ 15pF at digital outputs (Note 5),
f
CLK
= 83.3MHz (50% duty cycle), TA= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
=
+25°C.)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Input Low Threshold V
IL
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
HYST
I
IH
I
IL
IN
OL
OH
LEAK
CLK
PD, OE
VIH = VDD = OV
DD
VIL = 0 ±5
I
= 200µA 0.2 V
SINK
OV
-
I
SOURCE
OE = OV
= 200µA
DD
DD
0.2
0.2 x
V
D D
V
0.2 x
OV
D D
0.1 V
±5
µA
5pF
V
±10 µA
Three-State Output Capacitance C
OUT
OE = OV
DD
5pF
POWER REQUIREMENTS
Analog Supply Voltage V
Output Supply Voltage OV
Analog Supply Current I
Output Supply Current I
DD
DD
VDD
OVDD
Power-Supply Rejection PSRR
Operating, fIN = 20MHz at -0.5dB FS 40 47 mA
Shutdown, clock idle, PD = OE = OV
DD
Operating, CL = 15pF, fIN = 20MHz at
-0.5dB FS
Shutdown, clock idle, PD = OE = OV
DD
Offset ±0.2 mV/V
Gain ±0.1 %/V
2.7 3.0 3.6 V
1.7 3.0 3.6 V
415µA
8mA
110µA
TIMING CHARACTERISTICS
CLK Rise to Output Data Valid t
OE Fall to Output Enable t
OE Rise to Output Disable t
ENABLE
DISABLE
CLK Pulse Width High t
CLK Pulse Width Low t
Wake-Up Time t
DO
CH
CL
WAKE
Figure 6 (Note 3) 5 8 ns
Figure 5 10 ns
Figure 5 15 ns
Figure 6, clock period 12ns 6±1 ns
Figure 6, clock period 12ns 6±1 ns
(Note 4) 1.5 µs
MAX1448
10-Bit, 80Msps, Single +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
= 83.3MHz, CL≈ 10pF, TA= +25°C, unless oth-
erwise noted.)
(f
IN
0
-10
-20
-30
-40
-50
-60
AMPLITUDE (dB)
-70
-80
-90
-100
01015205 2530354045
(f
IN
0
-10
-20
-30
-40
-50
-60
AMPLITUDE (dB)
-70
-80
-90
-100
01015205 2530354045
SPURIOUS-FREE DYNAMIC RANGE vs.
80
75
70
65
60
SFDR (dBc)
55
50
45
40
110100
FFT PLOT
= 7.5MHz, 8192-POINT FFT,
DIFFERENTIAL INPUT)
SFDR = 75.5dBc
SNR = 59.3dB
THD = -73.9dBc
SINAD = 59.2dB
2ND HARMONIC
3RD HARMONIC
ANALOG INPUT FREQUENCY (MHz)
FFT PLOT
= 7.5MHz, 8192-POINT FFT,
SINGLE-ENDED INPUT)
SFDR = 72.2dBc
SNR = 58.7dB
THD = -70.8dBc
SINAD = 58.4dB
2ND HARMONIC
3RD HARMONIC
ANALOG INPUT FREQUENCY (MHz)
ANALOG INPUT FREQUENCY
DIFFERENTIAL
SINGLE-ENDED
ANALOG INPUT FREQUENCY (MHz)
MAX1448-01
MAX1448-04
MAX1448-07
FFT PLOT
= 20MHz, 8192-POINT FFT,
(f
IN
DIFFERENTIAL INPUT)
0
-10
-20
-30
-40
-50
-60
AMPLITUDE (dB)
-70
-80
-90
-100
01015205 2530354045
ANALOG INPUT FREQUENCY (MHz)
SFDR = 75.2dBc
SNR = 59dB
THD = -71.8dBc
SINAD = 58.7dB
2ND HARMONIC
3RD HARMONIC
FFT PLOT
= 20MHz, 8192-POINT FFT,
(f
IN
SINGLE-ENDED INPUT)
0
-10
-20
-30
-40
-50
-60
AMPLITUDE (dB)
-70
-80
-90
-100
01015205 2530354045
ANALOG INPUT FREQUENCY (MHz)
SFDR = 67.2dBc
SNR = 58.6dB
THD = -66.5dBc
SINAD = 58dB
2ND HARMONIC
3RD HARMONIC
SIGNAL-TO-NOISE RATIO vs.
ANALOG INPUT FREQUENCY
62
61
60
DIFFERENTIAL
59
58
SNR (dB)
57
56
55
54
110100
ANALOG INPUT FREQUENCY (MHz)
SINGLE-ENDED
UNDERSAMPLING FFT PLOT
= 50MHz, 8192-POINT FFT,
(f
IN
DIFFERENTIAL INPUT)
0
SFDR = 65.8dBc
-10
MAX1448-02
SNR = 58dB
THD = -65.1dBc
-20
SINAD = 57.2dB
-30
-40
-50
2ND HARMONIC
-60
3RD HARMONIC
AMPLITUDE (dB)
-70
-80
-90
-100
01015205 2530354045
ANALOG INPUT FREQUENCY (MHz)
TWO-TONE INTERMODULATION
(8192-POINT IMD,
DIFFERENTIAL INPUT)
0
f1 = 24MHz AT -6.5dB FS
-10
= 26MHz AT -6.5dB FS
f
MAX1448-05
2
3RD IMD = -74dBc
-20
-30
-40
-50
-60
AMPLITUDE (dB)
-70
-80
-90
-100
01015205 2530354045
ANALOG INPUT FREQUENCY (MHz)
TOTAL HARMONIC DISTORTION vs.
ANALOG INPUT FREQUENCY
-50
MAX1448-08
-55
-60
-65
THD (dBc)
-70
-75
-80
SINGLE-ENDED
DIFFERENTIAL
110100
ANALOG INPUT FREQUENCY (MHz)
MAX1448-03
MAX1448-06
MAX1448-09
MAX1448
10-Bit, 80Msps, Single +3.0V, Low-Power
ADC with Internal Reference
6 _______________________________________________________________________________________
S
Typical Operating Characteristics (continued)
(VDD= +3.0V, OVDD= +2.7V, internal reference, differential input at -0.5dB FS, f
CLK
= 83.3MHz, CL≈ 10pF, TA= +25°C, unless oth-
erwise noted.)
SIGNAL-TO-NOISE PLUS DISTORTION vs.
ANALOG INPUT FREQUENCY
65
62
59
SINAD (dB)
56
53
DIFFERENTIAL
SINGLE-ENDED
MAX1448-10
FULL-POWER INPUT BANDWIDTH vs.
ANALOG INPUT FREQUENCY
(SINGLE-ENDED)
6
4
2
0
-2
AMPLITUDE (dB)
-4
-6
MAX1448-11
MALL-SIGNAL INPUT BANDWIDTH vs.
6
4
2
0
-2
AMPLITUDE (dB)
-4
-6
ANALOG INPUT FREQUENCY
(SINGLE-ENDED)
VIN = 100mVp-p
MAX1448-12
MAX1448-14
MAX1448-17
-8
1 10 100 1000
ANALOG INPUT FREQUENCY (MHz)
TOTAL HARMONIC DISTORTION
vs. INPUT POWER (f
-50
-55
-60
-65
THD (dBc)
-70
-75
-80
-15 -9-12 -6 -3 0
INPUT POWER (dB FS)
= 20MHz)
IN
SIGNAL-TO-NOISE RATIO
vs. TEMPERATURE
70
fIN = 20MHz
66
62
MAX1448-15
MAX1448-18
MAX1448-16
-8
1 10 100 1000
ANALOG INPUT FREQUENCY (MHz)
SIGNAL-TO-NOISE RATIO
vs. INPUT POWER (f
65
60
55
SNR (dB)
50
45
40
-15 -9-12 -6 -3 0
INPUT POWER (dB FS)
= 20MHz)
IN
SPURIOUS-FREE DYNAMIC RANGE
vs. TEMPERATURE
84
fIN = 20MHz
80
76
50
110100
ANALOG INPUT FREQUENCY (MHz)
SPURIOUS-FREE DYNAMIC RANGE
vs. INPUT POWER (f
80
75
70
65
SFDR (dBc)
60
55
50
-15 -9-12 -6 -3 0
INPUT POWER (dB FS)
= 20MHz)
IN
MAX1448-13
SIGNAL-TO-NOISE PLUS DISTORTION
vs. INPUT POWER (f
65
60
55
= 20MHz)
IN
SINAD (dB)
50
45
40
-15 -9-12 -6 -3 0
INPUT POWER (dB FS)
SFDR (dBc)
72
68
64
-40 10-15 35 60 85
TEMPERATURE (°C)
SNR (dB)
58
54
50
-40 10-15 35 60 85
TEMPERATURE (°C)
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