MAXIM MAX11045ETN+

19-5036; Rev 0; 10/09
KIT
ATION
EVALU
E
L
B
A
AVAIL
4-/6-/8-Channel, 16-Bit,
Simultaneous-Sampling ADCs
†
The MAX11044/MAX11045/MAX11046 16-bit ADCs
offer 4, 6, or 8 independent input channels. Featuring
independent track and hold (T/H) and SAR circuitry,
these parts provide simultaneous sampling at 250ksps
for each channel.
The MAX11044/MAX11045/MAX11046 accept a ±5V
input. All inputs are overrange protected with internal
±20mA input clamps providing overrange protection
with a simple external resistor. Other features include a
4MHz T/H input bandwidth, internal clock, and internal
or external reference. A 20MHz, 16-bit, bidirectional,
parallel interface provides the conversion results and
accepts digital configuration inputs.
The MAX11044/MAX11045/MAX11046 operate with a
4.75V to 5.25V analog supply and a separate flexible 2.7V
to 5.25V digital supply for interfacing with the host without a
level shifter. The MAX11044/MAX11045/MAX11046
are available in a 56-pin TQFN package and operate over
the extended -40°C to +85°C temperature range.
Applications
Automatic Test Equipment
Power-Factor Monitoring and Correction
Power-Grid Protection
Multiphase Motor Control
Vibration and Waveform Analysis
Features
♦
♦
♦
♦
♦
♦
♦
♦
♦
♦
♦
4-/6-/8-Channel 16-Bit ADC
Single Analog and Digital Supply
High-Impedance Inputs Up to 1GΩ
On-Chip T/H Circuit for Each Channel
Fast 3µs Conversion Time
High Throughput: 250ksps for All 8 Channels
16-Bit, High-Speed, Parallel Interface
Internal Clocked Conversions
10ns Aperture Delay
100ps Channel-to-Channel T/H Matching
Low Drift, Accurate 4.096V Internal Reference
Providing an Input Range of ±5V
♦ External Reference Range of 3.0V to 4.25V,
Allowing Full-Scale Input Ranges of ±4.0V to ±5.2V
♦ 56-Pin TQFN Package (8mm x 8mm)
♦ Evaluation Kit Available
Ordering Information
PART
PIN-PACKAGE
56 TQFN-EP*
4
MAX11045ETN+
56 TQFN-EP*
6
MAX11046ETN+
56 TQFN-EP*
8
Note: All devices are specified over the -40°C to +85°C operating
temperature range.
+Denotes a lead(Pb)-free/RoHS-compliant package.
*EP = Exposed pad.
8 x 16-BIT REGISTERS
16-BIT ADC
DB4
DB3
DB0
RD
CH1
AVDD
24 AVDD
23 AGNDS
AGNDS 48
SHDN
22 RDC
MAX11044
MAX11045
MAX11046
DVDD 51
21 DGND
20 DVDD
WR 52
19 SHDN
CS 53
18 CONVST
17 EOC
RD 54
DB15 55
*EP
+
16 DB0
15 DB1
9
10 11 12 13 14
DB2
8
DB3
7
DB4
6
DB5
5
DB6
4
DB7
3
DVDD
2
DB9
DGND
1
DB10
RDC
DB11
DB14 56
REF
BUF
EXT REF
AGND
25 AGND
AVDD 47
DB12
BANDGAP
REFERENCE
CONVST
EOC
INT REF
REFIO
WR
CS
INTERFACE
AND
CONTROL
CH2
AGND 46
DB13
AGND
MAX11044
MAX11045
MAX11046
AGNDS
26 CH0
CH7 45
DGND 50
AGNDs
REFIO
27 AGNDS
AGNDS 44
RDC 49
CONFIGURATION
REGISTERS
CH4
AGNDS
CH5
AGND
28 RDC
RDC 43
DGND
S/H
16-BIT ADC
DB8
CLAMP
S/H
AVDD
42 41 40 39 38 37 36 35 34 33 32 31 30 29
DB15
CLAMP
BIDIRECTIONAL DRIVERS
CH7
DVDD
CH6
TOP VIEW
AVDD
CH3
Pin Configuration
Functional Diagram
RDC
†Patent pending.
CH0
CHANNELS
MAX11044ETN+
TQFN
8mm x 8mm
________________________________________________________________ Maxim Integrated Products
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.
1
MAX11044/MAX11045/MAX11046
General Description
MAX11044/MAX11045/MAX11046
4-/6-/8-Channel, 16-Bit,
Simultaneous-Sampling ADCs
ABSOLUTE MAXIMUM RATINGS
AVDD to AGND ........................................................-0.3V to +6V
DVDD to AGND and DGND .....................................-0.3V to +6V
DGND to AGND.....................................................-0.3V to +0.3V
AGNDS to AGND...................................................-0.3V to +0.3V
CH0–CH7 to AGND ...............................................-7.5V to +7.5V
REFIO, RDC to AGND ..................................-0.3V to the lower of
(AVDD + 0.3V) and +6V
EOC, WR, RD, CS, CONVST to AGND.........-0.3V to the lower of
(DVDD + 0.3V) and +6V
DB0–DB15 to AGND ....................................-0.3V to the lower of
(DVDD + 0.3V) and +6V
Maximum Current into Any Pin Except AVDD, DVDD, AGND,
DGND ...........................................................................±50mA
Continuous Power Dissipation
56-Pin TQFN (derate 36mW/°C above +70°C) ..........2222mW
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°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.
ELECTRICAL CHARACTERISTICS
(AVDD = +4.75V to +5.25V, DVDD = +2.70V to +5.25V, VAGNDS = VAGND = VDGND = 0V, VREFIO = internal reference, CRDC = 4 x
33µF, CREFIO = 0.1µF, CAVDD = 4 x 0.1µF || 10µF, CDVDD = 3 x 0.1µF || 10µF; all digital inputs at DVDD or DGND, unless otherwise
noted, fSAMPLE = 250ksps. TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
STATIC PERFORMANCE (Note 1)
Resolution
N
16
(Note 2)
Integral Nonlinearity
Differential Nonlinearity
INL
DNL
>-2
(Note 3)
±0.8
<+2
±0.7
(Note 4)
> -1
(Note 5)
> -1
(Note 3)
No Missing Codes
Bits
±0.5
< +1.2
±0.7
< +1.5
LSB
LSB
±0.45
16
Offset Error
Bits
±0.002
Channel Offset Matching
Offset Temperature Coefficient
±0.01
%FSR
±0.01
%FSR
±2.4
µV/°C
Gain Error
±0.03
%FSR
Positive Full-Scale Error
±0.02
%FSR
Negative Full-Scale Error
±0.02
%FSR
Positive Full-Scale Error Matching
±0.02
%FSR
Negative Full-Scale Error Matching
±0.02
%FSR
±0.03
%FSR
Channel Gain-Error Matching
Between all channels
Gain Temperature Coefficient
±0.8
ppm/°C
92.3
dB
DYNAMIC PERFORMANCE (Note 6)
Signal-to-Noise Ratio
SNR
fIN = 10kHz, full-scale input
91
Signal-to-Noise and Distortion Ratio
SINAD
fIN = 10kHz, full-scale input
90.5
92
dB
Spurious-Free Dynamic Range
SFDR
fIN = 10kHz, full-scale input
95
106
dB
Total Harmonic Distortion
THD
fIN = 10kHz, full-scale input
-105
-95
dB
fIN = 60Hz, full scale and ground on
adjacent channel (Note 7)
-126
-100
dB
Channel-to-Channel Crosstalk
2
_______________________________________________________________________________________
4-/6-/8-Channel, 16-Bit,
Simultaneous-Sampling ADCs
(AVDD = +4.75V to +5.25V, DVDD = +2.70V to +5.25V, VAGNDS = VAGND = VDGND = 0V, VREFIO = internal reference, CRDC = 4 x
33µF, CREFIO = 0.1µF, CAVDD = 4 x 0.1µF || 10µF, CDVDD = 3 x 0.1µF || 10µF; all digital inputs at DVDD or DGND, unless otherwise
noted, fSAMPLE = 250ksps. TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
±1.22 x
VREFIO
V
+1
µA
ANALOG INPUTS (CH0–CH7)
Input-Voltage Range
(Note 8)
Input Leakage Current
-1
Input Capacitance
15
Input-Clamp Protection Current
Each input simultaneously
pF
-20
+20
mA
1
250
ksps
1000
µs
TRACK AND HOLD
Throughput Rate
Per channel, 8 channels in 4µs
Acquisition Time
tACQ
1
-3dB point
Full-Power Bandwidth
4
-0.1dB point
MHz
> 0.2
Aperture Delay
10
Aperture-Delay Matching
100
ns
ps
Aperture Jitter
50
psRMS
INTERNAL REFERENCE
REFIO Voltage
VREF
4.073
REFIO Temperature Coefficient
4.096
4.119
±5
V
ppm/°C
EXTERNAL REFERENCE
Input Current
REF Voltage-Input Range
VREF
-10
+10
µA
3.00
4.25
V
REF Input Capacitance
15
pF
DIGITAL INPUTS (DB0–DB15, RD, WR, CS, CONVST)
Input Voltage High
VIH
VDVDD = 2.7V to 5.25V
Input Voltage Low
VIL
VDVDD = 2.7V to 5.25V
Input Capacitance
CIN
Input Current
IIN
VIN = 0V or VDVDD
Output Voltage High
VOH
ISOURCE = 1.2mA
Output Voltage Low
VOL
ISINK = 1mA
2
V
0.8
10
V
pF
±10
µA
DIGITAL OUTPUTS (DB0–DB15, EOC)
Three-State Leakage Current
DB0–DB15, VRD ≥ VIH or VCS ≥ VIH
Three-State Output Capacitance
DB0–DB15, VRD ≥ VIH or VCS ≥ VIH
VDVDD 0.4
V
0.25
0.4
V
10
µA
15
pF
POWER SUPPLIES
Analog Supply Voltage
AVDD
Digital Supply Voltage
DVDD
Analog Supply Current
IAVDD
4.75
5.25
V
2.70
5.25
V
MAX11046, AVDD = 5V
MAX11045, AVDD = 5V
48
42
MAX11044, AVDD = 5V
36
mA
_______________________________________________________________________________________
3
MAX11044/MAX11045/MAX11046
ELECTRICAL CHARACTERISTICS (continued)
MAX11044/MAX11045/MAX11046
4-/6-/8-Channel, 16-Bit,
Simultaneous-Sampling ADCs
ELECTRICAL CHARACTERISTICS (continued)
(AVDD = +4.75V to +5.25V, DVDD = +2.70V to +5.25V, VAGNDS = VAGND = VDGND = 0V, VREFIO = internal reference, CRDC = 4 x
33µF, CREFIO = 0.1µF, CAVDD = 4 x 0.1µF || 10µF, CDVDD = 3 x 0.1µF || 10µF; all digital inputs at DVDD or DGND, unless otherwise
noted, fSAMPLE = 250ksps. TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.)
PARAMETER
SYMBOL
Digital Supply Current
Shutdown Current
Power-Supply Rejection Ratio
IDVDD
MAX
UNITS
MAX11046, DVDD = 3.3V (Note 9)
CONDITIONS
MIN
TYP
7.3
mA
MAX11045, DVDD = 3.3V (Note 9)
6.3
mA
MAX11044, DVDD = 3.3V (Note 9)
5.5
mA
IDVDD
10
IAVDD
12
PSRR
VAVDD = 4.9V to 5.1V (Note 10)
CONVST Rise to EOC
tCON
Conversion time (Note 11)
Acquisition Time
tACQ
µA
LSB
±3
TIMING CHARACTERISTICS (Note 9)
1
3
µs
1000
µs
CS Rise to CONVST Rise
tQ
CONVST Rise to EOC Rise
t0
EOC Fall to CONVST Fall
t1
CONVST mode B0 = 0 only (Note 12)
0
ns
CONVST Low Time
t2
CONVST mode B0 = 1 only
20
ns
CS Fall to WR Fall
t3
0
ns
WR Low Time
t4
20
ns
CS Rise to WR Rise
t5
0
ns
Input Data Setup Time
t6
10
ns
Input Data Hold Time
t7
1
ns
CS Fall to RD Fall
t8
0
ns
RD Low Time
t9
30
ns
RD Rise to CS Rise
t10
0
ns
RD High Time
t11
10
ns
RD Fall to Data Valid
t12
RD Rise to Data Hold Time
t13
Sample quiet time (Note 11)
500
ns
47
140
35
(Note 12)
5
ns
ns
ns
Note 1: See the Definitions section at the end of the data sheet.
Note 2: INL is guaranteed at AVDD = 5.25V, for +25°C < TA < +85°C. See the Input Range and Protection section and Typical
Operating Characteristics.
Note 3: TA = -40°C.
Note 4: DNL at code > 8192 or < 57343 (offset binary encoded), or code > -24576 or < +24575 (two’s complement), is guaranteed
at AVDD = 5.25V, for +25°C < TA < +85°C. See the Input Range and Protection section and Typical Operating
Characteristics.
Note 5: DNL at code ≤ 8192 or ≥ 57343 (offset binary encoded), or code ≤ -24576 or ≥ +24575 (2’s complements), is guaranteed
at AVDD = 5.25V, for +25°C < TA < +85°C. See the Input Range and Protection section and Typical Operating
Characteristics.
Note 6: AC dynamics are guaranteed at AVDD = 5.25V, for +25°C < TA < +85°C. See the Input Range and Protection section and
Typical Operating Characteristics.
Note 7: Tested with alternating channels modulated at full scale and ground.
Note 8: See the Input Range and Protection section for more details.
Note 9: CLOAD = 30pF on DB0–DB15 and EOC. Inputs (CH0–CH7) alternate between full scale and zero scale. fCONV = 250ksps.
All data is read out.
Note 10: Defined as the change in positive full scale caused by a ±2% variation in the nominal supply voltage.
Note 11: It is recommended that RD, WR, and CS are kept high for the quiet time (tQ) and conversion time (tCON).
Note 12: Guaranteed by design.
4
_______________________________________________________________________________________
4-/6-/8-Channel, 16-Bit,
Simultaneous-Sampling ADCs
0.2
VAVDD = 5.25V
VDVDD = 3.3V
fSAMPLE = 250ksps
TA = +25°C
VRDC = 4.096V
-0.6
32768
24576
16384
8192
65536
0
-0.8
-1.0
MAX DNL
0
MIN DNL
-0.5
4.75
4.85
5.15
5.25
MAX DNL
MAX11046 STATIC
40
IAVDD (mA)
0.5
VAVDD = 5.25V
VDVDD = 3.3V
fSAMPLE = 250ksps
VRDC = 4.096V
TA = +25°C
fSAMPLE = 250ksps
MAX11046 CONVERTING
MAX11044 toc05
45
MAX11044 toc04
1.0
-0.5
5.05
VAVDD (V)
ANALOG SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX INL
MIN DNL
4.95
OUTPUT CODE (DECIMAL)
1.5
0
VDVDD = 3.3V
fSAMPLE = 250ksps
TA = +25°C
VRDC = 4.096V
MIN INL
-1.5
INL AND DNL
vs. TEMPERATURE
INL AND DNL (LSB)
0.5
-1.0
65536
-0.4
57344
32768
24576
16384
8192
-0.2
OUTPUT CODE (DECIMAL)
MAX11045 CONVERTING
35
MAX11045 STATIC
MAX11044 CONVERTING
30
-1.0
MIN INL
MAX11044 STATIC
25
-1.5
10
35
60
85
4.95
5.05
5.15
ANALOG SUPPLY CURRENT
vs. TEMPERATURE
DIGITAL SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX11046 STATIC
5.25
12
10
TA = +25°C
fSAMPLE = 250ksps
MAX11046 CONVERTING
8
IDVDD (mA)
MAX11045 CONVERTING
35
4.85
VAVDD (V)
MAX11046 CONVERTING VAVDD = 5.0V
fSAMPLE = 250ksps
40
4.75
TEMPERATURE (°C)
MAX11044 toc07
45
-15
MAX11044 toc06
-40
IAVDD (mA)
0
-0.8
-1.0
49152
-0.6
40960
VAVDD = 5.25V
VDVDD = 3.3V
fSAMPLE = 250ksps
TA = +25°C
VRDC = 4.096V
-0.4
0
57344
0
MAX INL
1.0
INL AND DNL (LSB)
0.4
0.2
DNL (LSB)
0.4
1.5
MAX11044 toc02
0.6
49152
0.6
0.8
40960
0.8
INL (LSB)
1.0
MAX11044 toc01
1.0
-0.2
INL AND DNL
vs. ANALOG SUPPLY VOLTAGE
DIFFERENTIAL NONLINEARITY vs. CODE
MAX11044 toc03
INTEGRAL NONLINEARITY vs. CODE
MAX11045 STATIC
6
MAX11045 CONVERTING
4
MAX11044 CONVERTING
MAX11044/MAX11045/
MAX11046 STATIC
30
2
MAX11044 CONVERTING
MAX11044 STATIC
25
0
-40
-15
10
35
TEMPERATURE (°C)
60
85
2.75
3.25
3.75
4.25
4.75
5.25
VDVDD (V)
_______________________________________________________________________________________
5
MAX11044/MAX11045/MAX11046
Typical Operating Characteristics
(AVDD = 5V, DVDD = 3.3V, TA = +25°C, fSAMPLE = 250ksps, internal reference, unless otherwise noted.)
Typical Operating Characteristics (continued)
(AVDD = 5V, DVDD = 3.3V, TA = +25°C, fSAMPLE = 250ksps, internal reference, unless otherwise noted.)
MAX11044
CONVERTING
2.4
VDVDD = 3.3V
fSAMPLE = 250ksps
CDBxx = 15pF
MAX11044/MAX11045/
MAX11046 STATIC
2
-15
10
35
60
IDVDD
1
0
-40
IAVDD
3
-15
10
35
60
3.25
3.75
4.25
4.75
AVDD AND DVDD (V)
TEMPERATURE (°C)
INTERNAL REFERENCE VOLTAGE
vs. TEMPERATURE
4.112
MAX11044 toc10
4.09520
TA = +25°C
4.09515
VAVDD = 5.0V
4.108
4.104
VRDC
VREFIO (V)
VREF (V)
IDVDD
2.75
85
INTERNAL REFERENCE VOLTAGES
vs. SUPPLY VOLTAGE
4.09505
UPPER TYPICAL LIMIT
4.100
4.096
4.092
4.09500
LOWER TYPICAL LIMIT
4.088
VREFIO
4.09495
4.084
4.080
4.09490
4.75
4.85
4.95
5.05
5.15
-40
5.25
-15
10
35
60
VAVDD (V)
TEMPERATURE (°C)
OFFSET ERROR AND OFFSET ERROR
MATCHING vs. SUPPLY VOLTAGE
OFFSET ERROR AND OFFSET ERROR
MATCHING vs. TEMPERATURE
TA = +25°C
0.006
85
0.010
MAX11044 toc12
0.010
VAVDD = 5.0V
VREFIO = 4.096V
0.006
OFFSET ERROR MATCHING
OFFSET ERROR MATCHING
ERRORS (%FS)
ERRORS (%FS)
MAX11044 toc09A
2
0
-40
TEMPERATURE (°C)
4.09510
IAVDD
3
1
0
85
4
MAX11044 toc13
1.2
4
TA = +25°C
MAX11044 toc11
MAX11045 CONVERTING
VAVDD = 5.0V
VDVDD = 3.3V
SHUTDOWN CURRENT (µA)
4.8
5
MAX11044 toc09
6.0
5
SHUTDOWN CURRENT (µA)
MAX11046 CONVERTING
MAX11044 toc08
7.2
3.6
ANALOG AND DIGITAL SHUTDOWN
CURRENT vs. SUPPLY VOLTAGE
ANALOG AND DIGITAL SHUTDOWN
CURRENT vs. TEMPERATURE
DIGITAL SUPPLY CURRENT
vs. TEMPERATURE
IDVDD (mA)
MAX11044/MAX11045/MAX11046
4-/6-/8-Channel, 16-Bit,
Simultaneous-Sampling ADCs
0.002
-0.002
0.002
-0.002
OFFSET ERROR
OFFSET ERROR
-0.006
-0.006
-0.010
-0.010
4.75
4.85
4.95
5.05
VAVDD (V)
6
5.15
5.25
-40
-15
10
35
TEMPERATURE (°C)
_______________________________________________________________________________________
60
85
5.25
4-/6-/8-Channel, 16-Bit,
Simultaneous-Sampling ADCs
GAIN ERROR AND GAIN ERROR
MATCHING vs. TEMPERATURE
VAVDD = 5.0V
GAIN ERROR MATCHING
-0.003
0.002
-0.002
OFFSET ERROR
MATCHING
4.95
5.05
5.15
-140
-40
5.25
-15
10
35
60
85
0
100
MAX11044 toc17
95
-80
fIN = 10kHz
fSAMPLE = 250ksps
TA = +25°C
VRDC = 4.096V
VIN = -0.025dB FROM FS
94
SNR AND SINAD (dB)
MAGNITUDE (dB)
-60
75
125
SIGNAL-TO-NOISE RATIO AND
SIGNAL-TO-NOISE AND DISTORTION
RATIO vs. TEMPERATURE
fIN1 = 9838Hz
fIN2 = 10235Hz
fSAMPLE = 250ksps
TA = +25°C
VAVDD = 5.0V
VRDC = 4.096V
VIN = -0.01dBFS
-40
50
FREQUENCY (kHz)
TWO-TONE IMD PLOT
-20
25
TEMPERATURE (°C)
VAVDD (V)
0
-80
MAX11044 toc18
4.85
-60
-120
-0.010
4.75
-40
-100
-0.006
-0.005
fIN = 10kHz
fSAMPLE = 250ksps
TA = +25°C
VAVDD = 5.0V
-20
MAGNITUDE (dB)
ERRORS (%FS)
SNR
93
92
-100
91
SINAD
-120
90
-140
7.2
8.0
8.8
9.6
10.4
11.2
12.0
10
35
60
TEMPERATURE (°C)
TOTAL HARMONIC DISTORTION
vs. TEMPERATURE
SNR AND SINAD
vs. ANALOG SUPPLY VOLTAGE
-103.5
-104.0
-104.5
SNR
92.5
92.0
91.5
fIN = 10kHz
fSAMPLE = 250ksps
TA = +25°C
VRDC = 4.096V
VIN = -0.025dB FROM FS
SINAD
91.0
-105.0
85
93.0
MAX11044 toc19
fIN = 10kHz
fSAMPLE = 250ksps
TA = +25°C
VRDC = 4.096V
VIN = -0.025dB FROM FS
SNR AND SINAD (dB)
THD (dB)
-15
FREQUENCY (kHz)
-102.5
-103.0
-40
12.8
MAX11044 toc20
ERRORS (%FS)
0
OFFSET ERROR
0.006
0.003
0
MAX11044 toc15
TA = +25°C
GAIN ERROR
FFT PLOT
0.010
MAX11044 toc14
0.005
MAX11044 toc16
GAIN ERROR AND GAIN ERROR
MATCHING vs. SUPPLY VOLTAGE
90.5
-40
-15
10
35
TEMPERATURE (°C)
60
85
4.75
4.85
4.95
5.05
5.15
5.25
VAVDD (V)
_______________________________________________________________________________________
7
MAX11044/MAX11045/MAX11046
Typical Operating Characteristics (continued)
(AVDD = 5V, DVDD = 3.3V, TA = +25°C, fSAMPLE = 250ksps, internal reference, unless otherwise noted.)
Typical Operating Characteristics (continued)
(AVDD = 5V, DVDD = 3.3V, TA = +25°C, fSAMPLE = 250ksps, internal reference, unless otherwise noted.)
SIGNAL-TO-NOISE AND DISTORTION
RATIO vs. FREQUENCY
94
-90
fSAMPLE = 250ksps
TA = +25°C
VRDC = 4.096V
VIN = -0.025dB FROM FS
86
84
-105
-105
-110
-115
82
5.05
5.15
5.25
0.1
VAVDD (V)
1
0.1
100
10
fIN = 60kHz
fSAMPLE = 250ksps
TA = +25°C
VRDC = 4.096V
VIN = -0.025dB FROM FS
INACTIVE CHANNEL AT GND
-110
-120
-130
200,000
NUMBER OF OCCURRENCES
VCHX = 0V
VAVDD = 5.0V
fSAMPLE = 250ksps
TA = +25°C
150,000
100,000
50,000
-140
0
0.1
1
10
32765
CROSSTALK (dB)
MAX11044 toc24
-90
100
FREQUENCY (kHz)
OUTPUT CODE (DECIMAL)
CONVERSION TIME
vs. ANALOG SUPPLY VOLTAGE
2.99
CONVERSION TIME (µs)
2.98
2.97
2.96
2.95
MAX11044 toc27
2.99
CONVERSION TIME (µs)
CONVERSION TIME vs. TEMPERATURE
3.00
MAX11044 toc26
3.00
2.98
2.97
2.96
2.95
2.94
2.94
2.93
2.93
2.92
2.92
4.75
4.85
4.95
5.05
VAVDD (V)
8
100
10
OUTPUT NOISE HISTOGRAM WITH
INPUT CONNECTED TO GND
CROSSTALK vs. FREQUENCY
-100
1
FREQUENCY (kHz)
FREQUENCY (kHz)
MAX11044 toc25
4.95
32768
4.85
32767
4.75
-100
32766
-104
88
-95
32771
fIN = 10kHz
fSAMPLE = 250ksps
TA = +25°C
VRDC = 4.096V
VIN = -0.025dB FROM FS
-103
90
32770
SINAD (dB)
-102
THD (dB)
92
-101
fSAMPLE = 250ksps
TA = +25°C
VRDC = 4.096V
VIN = -0.025dB FROM FS
-85
32769
-100
THD vs. INPUT FREQUENCY
-80
MAX11044 toc22
96
MAX11044 toc21
-99
MAX11044 toc23
TOTAL HARMONIC DISTORTION
vs. ANALOG SUPPLY VOLTAGE
THD (dB)
MAX11044/MAX11045/MAX11046
4-/6-/8-Channel, 16-Bit,
Simultaneous-Sampling ADCs
5.15
5.25
-40
-15
10
35
TEMPERATURE (°C)
_______________________________________________________________________________________
60
85
4-/6-/8-Channel, 16-Bit,
Simultaneous-Sampling ADCs
PIN
NAME
1
DB13
16-Bit Parallel Data Bus Digital Output Bit 13
FUNCTION
2
DB12
16-Bit Parallel Data Bus Digital Output Bit 12
3
DB11
16-Bit Parallel Data Bus Digital Output Bit 11
4
DB10
16-Bit Parallel Data Bus Digital Output Bit 10
5
DB9
16-Bit Parallel Data Bus Digital Output Bit 9
6
DB8
16-Bit Parallel Data Bus Digital Output Bit 8
7, 21, 50
DGND
Digital Ground
8, 20, 51
DVDD
Digital Supply. Bypass to DGND with a 0.1µF capacitor at each DVDD input.
9
DB7
16-Bit Parallel Data Bus Digital Output Bit 7
10
DB6
16-Bit Parallel Data Bus Digital Output Bit 6
11
DB5
16-Bit Parallel Data Bus Digital Output Bit 5
12
DB4
16-Bit Parallel Data Bus Digital Output Bit 4
13
DB3
16-Bit Parallel Data Bus Digital I/O Bit 3
14
DB2
16-Bit Parallel Data Bus Digital I/O Bit 2
15
DB1
16-Bit Parallel Data Bus Digital I/O Bit 1
16
DB0
16-Bit Parallel Data Bus Digital I/O Bit 0
17
EOC
Active-Low, End-of-Conversion Output. EOC goes low when a conversion is completed. EOC goes high
when a conversion is initiated.
18
CONVST
19
SHDN
22, 28,
35, 43, 49
RDC
23, 27, 33,
38, 44, 48
AGNDS
24, 30,
41, 47
AVDD
Analog Supply Input. Bypass AVDD to AGND with a 0.1µF capacitor at each AVDD input.
25, 31,
40, 46
AGND
Analog Ground. Connect all AGND inputs together.
26
CH0
Channel 0 Analog Input
29
CH1
Channel 1 Analog Input
32
CH2
Channel 2 Analog Input
34
CH3
36
REFIO
37
CH4
Channel 4 Analog Input
39
CH5
Channel 5 Analog Input
Convert Start Input. The rising edge of CONVST ends sample and starts a conversion on the captured
sample. The ADC is in acquisition mode when CONVST is low and CONVST mode = 0.
Shutdown Input. If SHDN is held high, the entire device will enter and stay in a low-current state.
Contents of the configuration register are not lost when in the shutdown state.
Reference Buffer Decoupling. Connect all RDC outputs together. Bypass to AGND with at least a 80µF
total capacitance. See the Layout, Grounding, and Bypassing section.
Signal Ground. Connect all AGND and AGNDS inputs together.
Channel 3 Analog Input
External Reference Input/Internal Reference Output. Place a 0.1µF capacitor from REFIO to AGND.
_______________________________________________________________________________________
9
MAX11044/MAX11045/MAX11046
Pin Description
MAX11044/MAX11045/MAX11046
4-/6-/8-Channel, 16-Bit,
Simultaneous-Sampling ADCs
Pin Description (continued)
PIN
NAME
42
CH6
FUNCTION
45
CH7
Channel 7 Analog Input
52
WR
Active-Low Write Input. Drive WR low to write to the ADC. Configuration registers are loaded on the
rising edge of WR.
53
CS
Active-Low Chip-Select Input. Drive CS low when reading from or writing to the ADC.
54
RD
Active-Low Read Input. Drive RD low to read from the ADC. Each rising edge of RD advances the
channel output on the data bus.
55
DB15
16-Bit Parallel Data Bus Digital Out Bit 15
56
DB14
16-Bit Parallel Data Bus Digital Out Bit 14
—
EP
Channel 6 Analog Input
Exposed Pad. Internally connected to AGND. Connect to a large ground plane to maximize thermal
performance. Not intended as an electrical connection point.
Detailed Description
The MAX11044/MAX11045/MAX11046 are fast, lowpower ADCs that combine 4, 6, or 8 independent ADC
channels in a single IC. Each channel includes simultaneously sampling independent T/H circuitry that preserves relative phase information between inputs
making the MAX11044/MAX11045/MAX11046 ideal for
motor control and power monitoring. The MAX11044/
MAX11045/MAX11046 are available with ±5V input
ranges that feature ±20mA overrange, fault-tolerant
inputs. The MAX11044/MAX11045/MAX11046 operate
with a single 4.75V to 5.25V supply. A separate 2.7V to
5.25V supply for digital circuitry makes the devices
compatible with low-voltage processors.
The MAX11044/MAX11045/MAX11046 perform conversions for all channels in parallel by activating independent ADCs. Results are available through a high-speed,
20MHz, parallel data bus after a conversion time of 3µs
following the end of a sample. The data bus is bidirectional and allows for easy programming of the configuration register. The MAX11044/MAX11045/MAX11046
feature a reference buffer, which is driven by an internal
bandgap reference circuit (VREFIO = 4.096V). Drive
REFIO with an external reference or bypass with 0.1µF
capacitor to ground when using the internal reference.
Analog Inputs
Track and Hold (T/H)
To preserve phase information across all channels,
each input includes a dedicated T/H circuitry. The input
tracking circuitry provides a 4MHz small-signal bandwidth, enabling the device to digitize high-speed transient events and measure periodic signals with
10
bandwidths exceeding the ADC’s sampling rate by
using undersampling techniques. Use anti-alias filtering
to avoid high-frequency signals being aliased into the
frequency band of interest.
Input Range and Protection
The full-scale analog input voltage is a product of the reference voltage. For the MAX11044/MAX11045/
MAX11046, the full-scale input is bipolar in the range of:
±(VREFIO x
5
)
4.096
When in external reference mode, drive VREFIO with a
3.0V to 4.25V source, resulting in an input range of
±3.662V to ±5.188V, respectively.
All analog inputs are fault-protected to up to ±20mA.
The MAX11044/MAX11045/MAX11046 include an input
clamping circuit that activates when the input voltage at
the analog input is above (VAVDD + 300mV) or below
–(VAVDD + 300mV). The clamp circuit remains high
impedance while the input signal is within the range of
±VAVDD and draws little or almost no current. However,
when the input signal exceeds ±VAVDD, the clamps
begin to turn on and shunt current to/from the AVDD
supply. Consequently, to obtain the highest accuracy,
ensure that the input voltage does not exceed ±VAVDD.
Note that the input clamp circuit also has a small
amount of hysteresis and once triggered remains
engaged, shunting current to/from AVDD until the input
returns to within the convertible range by several hundredths of a volt. This effect can cause some errors at
the extremes of the transfer function if VIN is driven
beyond ±VAVDD.
______________________________________________________________________________________
4-/6-/8-Channel, 16-Bit,
Simultaneous-Sampling ADCs
RS =
where VFAULT_MAX is the maximum voltage that the
source produces during a fault condition.
Figures 2 and 3 illustrate the clamp circuit voltage-current characteristics for a source impedance R S =
1280Ω. While the input voltage is within the ±(VAVDD +
300mV) range, no current flows in the input clamps.
Once the input voltage goes beyond this voltage range,
the clamps turn on and limit the voltage at the input pin.
VFAULT _ MAX - 7V
20mA
INPUT
SIGNAL
PIN
VOLTAGE
AVDD
DVDD
DB15
CLAMP
S/H
16-BIT ADC
8 x 16-BIT REGISTERS
CH0
SOURCE
CH7
CLAMP
S/H
BIDIRECTIONAL DRIVERS
RS
DB4
DB3
DB0
16-BIT ADC
CONFIGURATION
REGISTERS
AGNDS
MAX11044
MAX11045
MAX11046
WR
RD
CS
INTERFACE
AND
CONTROL
AGND
CONVST
SHDN
EOC
INT REF
BANDGAP
REFERENCE
RDC
REF
BUF
DGND
EXT REF
REFIO
Figure 1. Required Setup for Clamp Circuit
RS = 1280Ω
VAVDD = 5V
MAX11044 fig03
20
30
MAX11044 fig02
30
RS = 1280Ω
VAVDD = 5V
20
AT CH_ INPUT
ICLAMP (mA)
ICLAMP (mA)
AT CH_ INPUT
10
AT SOURCE
0
10
AT SOURCE
0
-10
-10
-20
-20
-30
-30
-50
-30
-10
10
30
SIGNAL VOLTAGE AT SOURCE AND PIN (V)
Figure 2. Input Clamp Characteristics
50
-8
-6
-4
-2
0
2
4
6
8
SIGNAL VOLTAGE AT SOURCE AND PIN (V)
Figure 3. Input Clamp Characteristics (Zoom In)
______________________________________________________________________________________
11
MAX11044/MAX11045/MAX11046
To make use of the input clamps (see Figure 1), connect a resistor (RS) between the analog input and the
voltage source to limit the voltage at the analog input so
that the fault current into the MAX11044/MAX11045/
MAX11046 does not exceed ±20mA. Note that the voltage at the analog input pin limits to approximately 7V
during a fault condition so the following equation can
be used to calculate the value of RS:
MAX11044/MAX11045/MAX11046
4-/6-/8-Channel, 16-Bit,
Simultaneous-Sampling ADCs
Applications Information
Digital Interface
The bidirectional, parallel, digital interface, DB0–DB3,
sets the 4-bit configuration register. This interface
configures the following control signals: chip select
(CS), read (RD), write (WR), end of conversion (EOC),
and convert start (CONVST). Figures 6 and 7 and the
Timing Characteristics in the Electrical Characteristics
table show the operation of the interface. DB0–DB3,
together with the output-only DB4–DB15, also output
the 16-bit conversion result. All bits are high impedance when RD = 1 or CS = 1.
DB3 (Int/Ext Reference)
DB3 selects the internal or external reference. The POR
default = 0.
0 = internal reference, REFIO internally driven through a
10kΩ resistor, bypass with 0.1µF capacitor to AGND.
1 = external reference, drive REFIO with a high-quality
reference.
DB2 (Output Data Format)
DB2 selects the output data format. The POR default = 0.
0 = offset binary.
1 = two’s complement.
DB1 (Reserved)
Set to 0 for normal operation.
0 = normal operation.
1 = reserved; do not use.
DB0 (CONVST Mode)
DB0 selects the acquisition mode. The POR default = 0.
0 = CONVST controls the acquisition and conversion.
Drive CONVST low to start acquisition. The rising edge
of CONVST begins the conversion.
1 = acquisition mode starts as soon as the previous
conversion is complete. The rising edge of CONVST
begins the conversion.
Programming the Configuration Register
To program the configuration register, bring the CS and
WR low and apply the required configuration data on
DB3–DB0 of the bus and then raise WR once to save
changes.
12
Table 1. Configuration Register
DB3
DB2
DB1
DB0
Int/Ext
Reference
Output
Data Format
Reserved
CONVST
Mode
Starting a Conversion
CONVST initiates conversions. The MAX11044/
MAX11045/MAX11046 provide two acquisition modes
set through the configuration register. Allow a quiet time
(tQ) of 500ns prior to the start of conversion to avoid
any noise interference during readout or write operations from corrupting a sample.
In default mode (DB0 = 0), drive CONVST low to place
the MAX11044/MAX11045/MAX11046 into acquisition
mode. All the input switches are closed and the internal
T/H circuits track the respective input voltage. Keep the
CONVST signal low for at least 1µs (tACQ) to enable
proper settling of the sampled voltages. On the rising
edge of CONVST, the switches are opened and the
MAX11044/MAX11045/MAX11046 begin the conversion
on all the samples in parallel. EOC remains high until
the conversion is completed.
In the second mode (DB0 = 1), the MAX11044/
MAX11045/MAX11046 enter acquisition mode as soon
as the previous conversion is completed. CONVST rising
edge initiates the next sample and conversion sequence.
CONVST needs to be low for at least 20ns to be valid.
Provide adequate time for acquisition and the requisite
quiet time in both modes to achieve accurate sampling
and maximum performance of the MAX11044/
MAX11045/MAX11046.
Reading Conversion Results
The CS and RD are active-low, digital inputs that control the readout through the 16-bit, parallel, 20MHz data
bus (D0–D15). After EOC transitions low, read the conversion data by driving CS and RD low. Each low period of RD presents the next channel’s result. When CS
and RD are high, the data bus is high impedance. CS
may be driven high between individual channel readouts or left low during the entire 8-channel readout.
Reference
Internal Reference
The MAX11044/MAX11045/MAX11046 feature a precision, low-drift, internal bandgap reference. Bypass REFIO
with a 0.1µF capacitor to AGND to reduce noise. The
REFIO output voltage may be used as a reference for
other circuits. The output impedance of REFIO is 10kΩ.
Drive only high impedance circuits or buffer externally
when using REFIO to drive external circuitry.
______________________________________________________________________________________
4-/6-/8-Channel, 16-Bit,
Simultaneous-Sampling ADCs
Reference Buffer
The MAX11044/MAX11045/MAX11046 have a built-in
reference buffer to provide a low-impedance reference
source to the SAR converters. This buffer is used in
both internal and external reference mode. The reference buffer output feeds five RDC pins. The RDC pins
should be all connected together on the PCB. The reference buffer is externally compensated and requires
at least 10µF on the RDC node. For best performance,
provide a total of at least 80µF on the RDC outputs.
Transfer Functions
Figures 8 and 9 show the transfer functions for all the
formats and devices. Code transitions occur halfway
between successive-integer LSB values.
Layout, Grounding, and Bypassing
For best performance use PCBs with ground planes.
Ensure that digital and analog signal lines are separated
from each other. Do not run analog and digital lines parallel to one another (especially clock lines), and avoid running digital lines underneath the ADC package. A single
solid GND plane configuration with digital signals routed
from one direction and analog signals from the other pro-
CS
(USER SUPPLIED)
t5
t3
vides the best performance. Connect DGND, AGND, and
AGNDS pins on the MAX11044/MAX11045/MAX11046 to
this ground plane. Keep the ground return to the power
supply for this ground low impedance and as short as
possible for noise-free operation.
To achieve the highest performance, connect all the
RDC pins (22, 28, 36, 43, and 49) to a local RDC plane
on the PCB. A total of at least 80µF of capacitance
should be placed on this RDC plane. If two capacitors
are used, place each as close as possible to pins 22
and 49. If four capacitors are used, place each as
close as possible to pins 22, 28, 43, and 49. For example, two 47µF, 10V X5R capacitors in 1210 case size
can be placed as close as possible to pins 22 and 49
will provide excellent performance. Alternatively, four
22µF, 10V X5R capacitors in 1210 case size placed as
close as possible to pins 22, 28, 43, and 49 will also
provide good performance. Ensure that each capacitor
is connected directly into the GND plane with an independent via.
If Y5U or Z5U ceramics are used, be aware of the highvoltage coefficient these capacitors exhibit and select
higher voltage rating capacitors to ensure that at least
80µF of capacitance is on the RDC plane when the
plane is driven to 4.096V by the built-in reference
buffer. For example, a 22µF X5R with a 10V rating is
approximately 20µF at 4.096V, whereas, the same
capacitor in Y5U ceramic is just 13µF. However, a Y5U
22µF capacitor with a 25V rating cap is approximately
20µF at 4.096V.
CS
(USER SUPPLIED)
t11
RD
(USER SUPPLIED)
WR
(USER SUPPLIED)
t6
t13
t12
t7
D0–D15
(USER SUPPLIED)
t10
t9
t8
t4
D0–D15
Sn
Sn + 1
CONFIGURATION
REGISTER
Figure 4. Programming Configuration-Register Timing
Requirements
Figure 5. Readout Timing Requirements
______________________________________________________________________________________
13
MAX11044/MAX11045/MAX11046
External Reference
Set the configuration register to disable the internal reference and drive REFIO with a high-quality external reference. To avoid signal degradation, ensure that the
integrated reference noise applied to REFIO is less
than 10µV in the bandwidth of up to 50kHz.
MAX11044/MAX11045/MAX11046
4-/6-/8-Channel, 16-Bit,
Simultaneous-Sampling ADCs
SAMPLE
tCON
tACQ
CONVST
t1
EOC
tO
tQ
CS
RD
D0–D15
S0
S1
S6
S7
Figure 6. Conversion Timing Diagram (DB0 = 0)
SAMPLE
tCON
tACQ
CONVST
t2
EOC
tO
tQ
CS
RD
D0–D15
S0
S1
S6
S7
Figure 7. Conversion Timing Diagram (DB0 = 1)
14
______________________________________________________________________________________
4-/6-/8-Channel, 16-Bit,
Simultaneous-Sampling ADCs
Typical Application Circuits
Power-Grid Protection
Figure 10 shows a typical power-grid protection application.
DSP Motor Control
Figure 11 shows a typical DSP motor control application.
Definitions
Integral Nonlinearity (INL)
INL is the deviation of the values on an actual transfer
function from a straight line. For these devices, this
straight line is a line drawn between the end points of
the transfer function, once offset and gain errors have
been nullified.
OUTPUT CODE (hex)
7FFE
0001
5 x VREF
4.096
ZS = 0
-5 x VREF
-FS =
4.096
+FS - (-FS)
LSB =
65,536
+FS =
Offset Error
For the MAX11044/MAX11045/MAX11046, the offset
error is defined at code transition 0x8000 to 0x8001 in
offset binary encoding and 0x0000 to 0x0001 for two’s
complement encoding. The offset code transitions
should occur with an analog input voltage of exactly 0.5
x (10/4.096) x VREF/65,536 above GND. The offset error
is defined as the deviation between the actual analog
input voltage required to produce the offset code transition and the ideal analog input of 0.5 x (10/4.096) x
VREF/65,536 above GND, expressed in LSBs.
Gain Error
Gain error is defined as the difference between the
change in analog input voltage required to produce a top
code transition minus a bottom code transition, subtracted from the ideal change in analog input voltage on
(10/4.096) x V REF x (65,534/65,536). For the
MAX11044/MAX11045/MAX11046, top code transition is
0x7FFE to 0x7FFF in two’s complement mode and
0xFFFE to 0xFFFF in offset binary mode. The bottom code
transition is 0x8000 and 0x8001 in two’s complement
FULL-SCALE
TRANSITION
FFFF
FFFE
0000
FFFF
V x 32,768
CODE = IN
VREFIO 5
4.096
FFFE
8001
OUTPUT CODE (hex)
7FFF
Differential Nonlinearity (DNL)
DNL is the difference between an actual step width and
the ideal value of 1 LSB. For these devices, the DNL of
each digital output code is measured and the worst-case
value is reported in the Electrical Characteristics table. A
DNL error specification of greater than -1 LSB guarantees no missing codes and a monotonic transfer function. For example, -0.9 LSB guarantees no missing code
while -1.1 LSB results in missing code.
8001
+FS =
ZS =
LSB =
FULL-SCALE
TRANSITION
-5 x VREF
4.096
+FS - (-FS)
65,536
8000
7FFF
7FFE
V x 32,768
CODE = IN
+ 32,768
VREFIO 5
4.096
0001
8000
5 x VREF
4.096
0000
-FS
0
-FS + 0.5 x LSB
+FS - 1.5 x LSB
INPUT VOLTAGE (LSB)
Figure 8. Two’s Complement Transfer Function
+FS
-FS
0
-FS + 0.5 x LSB
+FS - 1.5 x LSB
INPUT VOLTAGE (LSB)
+FS
Figure 9. Offset-Binary Transfer Function
______________________________________________________________________________________
15
MAX11044/MAX11045/MAX11046
Bypass AVDD and DVDD to the ground plane with
0.1µF ceramic chip capacitors on each pin as close as
possible to the device to minimize parasitic inductance.
Add at least one bulk 10µF decoupling capacitor to
AVDD and DVDD per PCB. Interconnect all of the
AVDD inputs and DVDD inputs using two solid power
planes. For best performance, bring the AVDD power
plane in on the analog interface side of the MAX11044/
MAX11045/MAX11046 and the DVDD power plane from
the digital interface side of the device.
For acquisition periods near minimum (1µs) use a 1nF
C0G ceramic chip capacitor between each of the channel inputs to the ground plane as close as possible to
the MAX11044/MAX11045/MAX11046. This capacitor
reduces the inductance seen by the sampling circuitry
and reduces the voltage transient seen by the input
source circuit.
MAX11044/MAX11045/MAX11046
4-/6-/8-Channel, 16-Bit,
Simultaneous-Sampling ADCs
VOLTAGE
TRANSFORMER
PHASE 1
OPT
ADC
OPT
ADC
CURRENT
TRANSFORMER
VN
NEUTRAL
ADC
IN
ADC
LOAD 1
MAX11046
LOAD 2
LOAD 3
I3
V3
I2
ADC
ADC
PHASE 2
V2
ADC
ADC
PHASE 3
Figure 10. Power-Grid Protection
16
______________________________________________________________________________________
4-/6-/8-Channel, 16-Bit,
Simultaneous-Sampling ADCs
MAX11044/MAX11045/MAX11046
DSP-BASED DIGITAL
PROCESSING ENGINE
MAX11046
16-BIT
ADC
IGBT CURRENT DRIVERS
16-BIT
ADC
16-BIT
ADC
16-BIT
ADC
16-BIT
ADC
IPHASE1
IPHASE3
IPHASE2
3-PHASE ELECTRIC MOTOR
POSITION
ENCODER
Figure 11. DSP Motor Control
______________________________________________________________________________________
17
MAX11044/MAX11045/MAX11046
4-/6-/8-Channel, 16-Bit,
Simultaneous-Sampling ADCs
mode and 0x0000 and 0x0001 in offset binary mode. For
the MAX11044/MAX11045/MAX11046, the analog input
voltage to produce these code transitions is measured
and the gain error is computed by subtracting (10/4.096)
x VREF x (65,534/65,536) from this measurement.
Signal-to-Noise Ratio (SNR)
For a waveform perfectly reconstructed from digital
samples, 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 quantization noise error only and
results directly from the ADC’s resolution (N bits):
SNR = (6.02 x N + 1.76)dB
where N = 16 bits. In reality, there are other noise
sources besides quantization noise: thermal noise, reference noise, clock jitter, etc. SNR is computed by taking the ratio of the RMS signal to the RMS noise, which
includes all spectral components not including the fundamental, the first five harmonics, and the DC offset.
Signal-to-Noise Plus Distortion (SINAD)
SINAD is the ratio of the fundamental input frequency’s
RMS amplitude to the RMS equivalent of all the other
ADC output signals:
⎡
⎤
SignalRMS
SINAD(dB) = 10 × log ⎢
⎥
(
+
)
Noise
Distortion
RMS ⎦
⎣
Effective Number of Bits (ENOB)
The ENOB indicates the global accuracy of an ADC at
a specific input frequency and sampling rate. An ideal
ADC’s error consists of quantization noise only. With an
input range equal to the full-scale range of the ADC,
calculate the ENOB as follows:
ENOB =
SINAD − 1.76
6.02
Total Harmonic Distortion (THD)
THD is the ratio of the RMS of the first five harmonics of
the input signal to the fundamental itself. This is:
expressed as:
⎡
⎤
V 22 + V 32 + V 4 2 + V 52 ⎥
THD = 20 × log ⎢
⎢
⎥
V1
⎣⎢
⎦⎥
where V1 is the fundamental amplitude and V2 through
V5 are the 2nd- through 5th-order harmonics.
18
Spurious-Free Dynamic Range (SFDR)
SFDR is the ratio of the RMS amplitude of the fundamental (maximum signal component) to the RMS value
of the next-largest frequency component.
Aperture Delay
Aperture delay (tAD) is the time delay from the sampling
clock edge to the instant when an actual sample is
taken.
Aperture Jitter
Aperture jitter (tAJ) is the sample-to-sample variation in
aperture delay.
Channel-to-Channel Isolation
Channel-to-channel isolation indicates how well each
analog input is isolated from the other channels.
Channel-to-channel isolation is measured by applying
DC to channels 1 to 7, while a -0.4dBFS sine wave at
60Hz is applied to channel 0. A 10ksps FFT is taken for
channel 0 and channel 1. Channel-to-channel isolation
is expressed in dB as the power ratio of the two 60Hz
magnitudes.
Small-Signal Bandwidth
A small -20dBFS analog input signal is applied to an
ADC in a manner that ensures that the signal’s slew
rate does not limit the ADC’s performance. The input
frequency is then swept up to the point where the
amplitude of the digitized conversion result has
decreased 3dB.
Full-Power Bandwidth
A large -0.5dBFS 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. This point is defined as fullpower input bandwidth frequency.
Positive Full-Scale Error
The error in the input voltage that causes the last code
transition of FFFE to FFFF (hex) (in default offset binary
mode) or 7FFE to 7FFF (hex) (in two’s complement mode)
from the ideal input voltage of 32,766.5 x (5/4.096) x
(VREFIO/65,536) after correction for offset error.
Negative Full-Scale Error
The error in the input voltage that causes the first code
transition of 0000 to 0001 (hex) (in default offset binary
mode) or 8000 to 8001 (hex) (in two’s complement mode)
from the ideal input voltage of -32,767.5 x (5/4.096) x
(VREFIO/65,536) after correction for offset error.
______________________________________________________________________________________
4-/6-/8-Channel, 16-Bit,
Simultaneous-Sampling ADCs
PROCESS: BiCMOS
For the latest package outline information and land patterns, go
to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in
the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status.
PACKAGE TYPE
PACKAGE CODE
DOCUMENT NO.
56 TQFN-EP
T5688+2
21-0135
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implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
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MAX11044/MAX11045/MAX11046
Package Information
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