Rainbow Electronics MAX1383 User Manual
General Description
The MAX1377/MAX1379/MAX1383 feature two simultaneous-sampling, low-power, 12-bit ADCs with serial
interface and internal voltage reference. Fast sampling
rate, low power dissipation, and excellent dynamic performance make the MAX1377/MAX1379/MAX1383
ideal for industrial process control, motor control, and
RF applications.
Conversion results are available through a SPI™-/
QSPI™-/MICROWIRE™-/DSP-compatible interface with
independent serial digital outputs for each channel. The
serial outputs allow twice as much data to be transferred
at the given clock rate. The conversion results for both
ADCs can also be output on a single digital output for
microcontrollers (µCs) and DSPs with only a single serial
input available.
The MAX1377 operates from a 2.7V to 3.6V analog supply and the MAX1379/MAX1383 operate from a 4.75V
to 5.25V analog supply. A separate 1.8V to AVDD digital supply allows interfacing to low voltage logic without
the use of level translators.
Two power-down modes, partial and full, allow the
MAX1377/MAX1379 and MAX1383 (full power-down only)
to save power between conversions. Partial power-down
mode reduces the supply current to 2mA while leaving
the reference enabled for quick power-up. Full powerdown mode reduces the supply current to 1µA.
The MAX1377/MAX1379 inputs accept voltages
between zero and the reference voltage or ±V
REF
/2.
The MAX1383 offers an input voltage range of ±10V,
which is ideal for industrial and motor-control applications. The input to each of the ADCs supports either a
true-differential input or two single-ended inputs.
The MAX1377/MAX1379/MAX1383 are available in a
20-pin TQFN package, and are specified for the automotive (-40°C to +125°C) temperature range.
Applications
Motor Control
Communications
Data Acquisition
Bill Validation
Portable Instruments
Features
o Dual, Simultaneous-Sampling, 12-Bit Successive
Approximation Register (SAR) ADCs
o 2 x 2 Mux Inputs or Two Differential Inputs
o 1.25Msps Sampling Rate per ADC
o Internal or External Reference
o Excellent Dynamic Performance
70dB SINAD (MAX1377)
71dB SINAD (MAX1379/MAX1383)
84dBc/SFDR
1MHz Full-Linear Bandwidth
o 2.7V to 3.6V Low-Power Operation (MAX1377)
50mW (Normal Operation)
6mW (Partial Power-Down)
3µW (Full Power-Down)
o 4.75V to 5.25V Low-Power Operation (MAX1379)
90mW (Normal Operation)
10mW (Partial Power-Down)
5µW (Full Power-Down)
o 20MHz, SPI-Compatible, 3-Wire Serial Interface
User-Selectable Single (0.625Msps max) or Dual
Outputs (1.25Msps max)
o Input Range: ±10V (MAX1383), 0–V
REF
or
±V
REF
/2 (MAX1377/MAX1379)
o Small 20-Pin TQFN Package
MAX1377/MAX1379/MAX1383
Dual, 12-Bit, 1.25Msps Simultaneous-Sampling
ADCs with Serial Interface
________________________________________________________________
Maxim Integrated Products
1
19-4126; Rev 0; 7/08
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.
Pin Configuration
Ordering Information
+
Denotes a lead-free/RoHS-compliant package.
*
EP = Exposed pad.
**
Future product—contact factory for availability.
SPI/QSPI are trademarks of Motorola, Inc.
MICROWIRE is a trademark of National Semiconductor Corp.
PART TEMP RANGE PIN-PACKAGE
MAX1377ATP+ -40°C to +125°C 20 TQFN-EP*
MAX1379ATP+ -40°C to +125°C 20 TQFN-EP*
MAX1383ATP+** -40°C to +125°C 20 TQFN-EP*
TOP VIEW
S/D
SEL
AGND
AIN1B
AIN1A
16
17
18
19
20
CNVST
CS
15 14 12 11
MAX1377
MAX1379
MAX1383
(EXPOSED PAD)*
+
DOUT1
SCLK
13
DOUT2
V
10
L
DGND
9
8
U/B
AIN2B
7
AIN2A
6
12
REFSEL
*CONNECT PAD TO AGND
45
3
REF
RGND
TQFN
AGND
AVDD
MAX1377/MAX1379/MAX1383
Dual, 12-Bit, 1.25Msps Simultaneous-Sampling
ADCs with Serial Interface
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.
AVDD to AGND ........................................................-0.3V to +6V
V
L
to DGND ..............................................................-0.3V to +6V
SCLK, CS, CNVST, U/B, S/D, SEL,
REFSEL to DGND.......................................-0.3V to (V
L
+ 0.3V)
DOUT_ to DGND...........................................-0.3V to (V
L
+ 0.3V)
AIN1A, AIN1B, AIN2A, AIN2B to AGND
MAX1377/MAX1379 .............................-0.3V to (AVDD + 0.3V)
MAX1383 ..............................................................-12V to +12V
RGND to AGND.....................................................-0.3V to +0.3V
RGND to DGND.....................................................-0.3V to +0.3V
DGND to AGND.....................................................-0.3V to +0.3V
Maximum Current into Any Pin (except power-supply pins).....50mA
Continuous Power Dissipation (T
A
= +70°C)
20-Pin Thin QFN (derate 34.5mW/°C above +70°C) ...2758.6mW
Operating Temperature Range .........................-40°C to +125°C
Junction Temperature......................................................+150°C
Storage Temperature Range .............................-60°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
ELECTRICAL CHARACTERISTICS—MAX1377
(V
AVDD
= 2.7V to 3.6V, VL= 1.8V to AVDD, f
SCLK
= 20MHz (50% duty cycle), V
REF
= 2.048V, REFSEL = VL, S/D = DGND, C
REF
=
1µF; T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at TA= +25°C.)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
DC ACCURACY
Resolution 12 Bits
Relative Accuracy INL (Note 1) -1.25 +1.25 LSB
Differential Nonlinearity DNL -1 +1.5 LSB
Offset Error ±8 LSB
Offset-Error Matching ±12 LSB
Gain Error (Note 2) ±6 LSB
Gain-Error Matching (Note 2) ±6 LSB
Gain Temperature Coefficient ±2 ppm/oC
DC Input Isolation
DYNAMIC SPECIFICATIONS (f
Signal-to-Noise Plus Distortion SINAD
Signal-to-Noise Ratio SNR
Total Harmonic Distortion THD Up to the 5th harmonic -84 -74 dB
Spurious-Free Dynamic Range SFDR -86 -76 dB
Intermodulation Distortion IMD f
Full-Power Bandwidth -3dB point 5 MHz
Full-Linear Bandwidth (S/N + D) > 68dB, 1V input 1 MHz
CONVERSION RATE (Figure 4)
Minimum Conversion Time t
Maximum Throughput Rate
Minimum Throughput Rate for
Full Bandwidth Signal
= 500kHz, 2V
IN
CONV
AIN1A to AIN1B, AIN2A to AIN2B 80
AIN1A to AIN2A, AIN1B to AIN2B 80
sine wave, 1.25Msps, 20MHz f
P-P
Unipolar 66 69.5
Bipolar 67 70
Unipolar 66 70
Bipolar 67 70
= 103.5kHz, f
IN1
16 clock cycles per conversion (Note 3) 0.800 µs
Dual output mode, S/D = 0 1.25
Single output mode, S/D = 1 0.625
(Note 4) 10 ksps
)
SCLK
= 113.5kHz -78 dB
IN2
dB
dB
dB
Msps
MAX1377/MAX1379/MAX1383
Dual, 12-Bit, 1.25Msps Simultaneous-Sampling
ADCs with Serial Interface
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS—MAX1377 (continued)
(V
AVDD
= 2.7V to 3.6V, VL= 1.8V to AVDD, f
SCLK
= 20MHz (50% duty cycle), V
REF
= 2.048V, REFSEL = VL, S/D = DGND, C
REF
=
1µF; T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at TA= +25°C.)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Track-and-Hold Acquisition Time t
Aperture Delay 2ns
Aperture-Delay Matching 2ns
Aperture Jitter (Note 5) 30 ps
External Clock Frequency f
ANALOG INPUTS (AIN1A, AIN1B, AIN2A, AIN2B)
Input Range U/B = 0, V
Differential Input Range U/B = 1, V
Absolute Voltage Range 0 AVDD V
DC Leakage Current ±1 µA
Input Impedance 34 kΩ
Input Capacitance At each analog input 16 pF
EXTERNAL REFERENCE (REFSEL = 1)
Absolute Input Voltage Range V
Input Capacitance 50 pF
DC Leakage Current ±1 µA
Input Current Time averaged at maximum throughput rate 800 µA
INTERNAL REFERENCE (REFSEL = 0)
Reference Voltage Level 2.028 2.048 2.068 V
Load Regulation
Voltage Temperature Coefficient ±50.0 ppm/oC
DIGITAL INPUTS (SCLK, CNVST, U/B, S/D, SEL, REFSEL)
Input-Voltage Low V
Input-Voltage High V
Input Leakage Current I
DIGITAL OUTPUT (DOUT1, DOUT2)
Output Load Capacitance C
Output-Voltage Low V
Output-Voltage High V
Output Leakage Current I
POWER REQUIREMENTS
Analog Supply Voltage AVDD 2.7 3.0 3.6 V
Digital Supply Voltage V
ACQ
SCLK
REF
IL
IH
IL
DOUT
OL
OH
OL
L
- RGND 0 V
AIN_A
- V
AIN_A
I
I
For stated timing performance 30 pF
I
I
High-impedance mode (Figure 9) ±0.2 µA
= 0 to 1mA 1
SOURCE
= 0 to 50µA 1
SINK
= 5mA 0.4 V
SINK
= 1mA, VL ≥ 2.7V
SOURCE
AIN_B
125 ns
-V
/2 +V
REF
1.0
0.7 x
V
L
V
L
- 0.5V
1.8 AVDD V
AVDD
+ 0.05
0.3 x
20 MHz
REF
REF
V
±10 µA
/2 V
L
V
V
mV/mA
V
V
V
MAX1377/MAX1379/MAX1383
Dual, 12-Bit, 1.25Msps Simultaneous-Sampling
ADCs with Serial Interface
4 _______________________________________________________________________________________
ELECTRICAL CHARACTERISTICS—MAX1377 (continued)
(V
AVDD
= 2.7V to 3.6V, VL= 1.8V to AVDD, f
SCLK
= 20MHz (50% duty cycle), V
REF
= 2.048V, REFSEL = VL, S/D = DGND, C
REF
=
1µF; T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at TA= +25°C.)
ELECTRICAL CHARACTERISTICS—MAX1379
(V
AVDD
= 4.75V to 5.25V, VL= 3V, f
SCLK
= 20MHz (50% duty cycle), V
REF
= 4.096V, REFSEL = VL, S/D = DGND, C
REF
= 1µF; TA=
T
MIN
to T
MAX
, unless otherwise noted. Typical values are at TA= +25°C.)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Analog Supply Current I
Average Static Supply Current 810mA
Digital Supply Current I
Power-Supply Rejection PSR V
DC ACCURACY
Resolution 12 Bits
Relative Accuracy INL (Note 1) -1.25 +1.25 LSB
Differential Nonlinearity DNL -1 +1 LSB
Offset Error ±8 LSB
Offset-Error Matching ±9 LSB
Gain Error (Note 2) ±6 LSB
Gain-Error Matching (Note 2) ±9 LSB
Gain Temperature Coefficient ±2 ppm/oC
DC Input Isolation
DYNAMIC SPECIFICATIONS (f
Signal-to-Noise Plus Distortion SINAD
Signal-to-Noise Ratio SNR
Total Harmonic Distortion THD Up to the 5th harmonic -84 -76 dB
Spurious-Free Dynamic Range SFDR -84 -76 dB
Intermodulation Distortion IMD f
Full-Power Bandwidth -3dB point 5 MHz
Full-Linear Bandwidth (S/N + D) > 68dB, 1V input 1 MHz
CONVERSION RATE (Figure 6)
Minimum Conversion Time t
Maximum Throughput Rate
Minimum Throughput Rate for
Full Bandwidth Signal
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
AVDD
VL
= 500kHz , 4V
IN
CONV
Normal operation 13 15
Partial power-down mode (Note 5) 2
Full power-down mode (Note 5) 1 5 µA
f
= 20MHz, VL = 3V, CL = 30pF 1 1.5 mA
SCLK
= 3V ±10%, full-scale input ±0.2 ±3 mV
AVDD
AIN1A to AIN1B, AIN2A to AIN2B 80
AIN1A to AIN2A, AIN1B to AIN2B 80
sine wave, 1.25Msps, 20MHz f
P-P
Unipolar 69 70
Bipolar 70 71
Unipolar 70 71
Bipolar 70 72
= 103.5kHz, f
IN1
16 clock cycles per conversion (Note 3) 0.8 µs
Dual-output mode, S/D = 0 1.25
Single-output mode, S/D = 1 0.625
(Note 4) 10 ksps
= 113.5kHz -78 dB
IN2
)
SCLK
mA
dB
dB
dB
Msps
MAX1377/MAX1379/MAX1383
Dual, 12-Bit, 1.25Msps Simultaneous-Sampling
ADCs with Serial Interface
_______________________________________________________________________________________ 5
ELECTRICAL CHARACTERISTICS—MAX1379 (continued)
(V
AVDD
= 4.75V to 5.25V, VL= 3V, f
SCLK
= 20MHz (50% duty cycle), V
REF
= 4.096V, REFSEL = VL, S/D = DGND, C
REF
= 1µF; TA=
T
MIN
to T
MAX
, unless otherwise noted. Typical values are at TA= +25°C.)
Track-and-Hold Acquisition Time t
Aperture Delay 2ns
Aperture-Delay Matching 2ns
Aperture Jitter (Note 5) 30 ps
External Clock Frequency f
ANALOG INPUTS (AIN1A, AIN1B, AIN2A, AIN2B)
Input Range U/B = 0, V
Differential Input Range U/B = 1, V
Absolute Voltage Range 0 AVDD V
DC Leakage Current ±1 µA
Input Impedance 34 kΩ
Input Capcitance At each analog input 16 pF
EXTERNAL REFERENCE (REFSEL = 1)
Absolute Input Voltage Range V
Input Capacitance 50 pF
DC Leakage Current ±1 µA
Input Current Time averaged at maximum throughput rate 800 µA
INTERNAL REFERENCE (REFSEL = 0)
Reference Voltage Level 4.086 4.096 4.106 V
Load Regulation
Voltage Temperature Coefficient ±50.0 ppm/oC
DIGITAL INPUTS (SCLK, CNVST, U/B, S/D, SEL, REFSEL)
Input-Voltage Low V
Input-Voltage High V
Input Leakage Current I
DIGITAL OUTPUT (DOUT1, DOUT2)
Output Load Capacitance C
Output-Voltage Low V
Output-Voltage High V
Output Leakage Current I
POWER REQUIREMENTS
Analog Supply Voltage AVDD 4.25 5.0 5.25 V
Digital Supply Voltage V
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
ACQ
SCLK
REF
I
SOURCE
= 0 to 50µA 1
I
SINK
IL
IH
IL
DOUT
OH
OL
For stated timing performance 30 pF
I
OL
L
= 5mA 0.4 V
SINK
I
SOURCE
High-impedance mode (Figure 9) ±0.2 µA
125 ns
- RGND 0 V
AIN_A
- V
AIN_A
= 0 to 1mA 1
= 1mA, VL ≥ 2.7V
AIN_B
-V
/2 + V
REF
1.0
0.7 x
V
L
V
-
L
0.5V
1.8 AVDD V
20 MHz
REF
/2
R E F
AVDD
+ 0.05
mV/mA
0.3 x
V
L
±10 µA
V
V
V
V
V
MAX1377/MAX1379/MAX1383
Dual, 12-Bit, 1.25Msps Simultaneous-Sampling
ADCs with Serial Interface
6 _______________________________________________________________________________________
ELECTRICAL CHARACTERISTICS—MAX1379 (continued)
(V
AVDD
= 4.75V to 5.25V, VL= 3V, f
SCLK
= 20MHz (50% duty cycle), V
REF
= 4.096V, REFSEL = VL, S/D = DGND, C
REF
= 1µF; TA=
T
MIN
to T
MAX
, unless otherwise noted. Typical values are at TA= +25°C.)
TIMING CHARACTERISTICS (Figures 6, 10)
V
AVDD
= 4.25V to 5.25V, VL= 1.8V to AVDD, V
REF
= 4.096V, f
SCLK
= 20MHz for MAX1379, 50% duty cycle, CL= 30pF, TA= T
MIN
to
T
MAX
, unless otherwise noted. Typical values are at TA= +25°C.)
Note 1: Relative accuracy is the deviation of the analog value at any code from its theoretical value after the gain error and the offset
error have been nulled.
Note 2: Offset nulled.
Note 3: Conversion time is defined as the number of clock cycles (16) multiplied by the clock period. Clock has 50% duty cycle.
Note 4: At sample rates below 10ksps, the input full linear bandwidth is reduced to 5kHz.
Note 5: SCLK and CNVST not switching during measurement.
Analog Supply Current I
Average Static Current 910mA
Digital Supply Current I
Power-Supply Rejection PSR V
SCLK Clock Period t
SCLK Duty Cycle tCH/t
SCLK Pulse-Width High t
SCLK Pulse-Width Low t
SCLK Rise to DOUT_ Transition t
DOUT_ Remains Valid After
SCLK
CNVST Fall to SCLK Fall t
CNVST Pulse Width t
Power-Up Time; Full Power-Down t
SEL to CNVST Fall t
SEL Hold to CNVST Fall 10 ns
CS Fall To CNVST Fall t
Restart Time; Partial Power-Down t
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
PARAMETER SYMBOL CONDITION MIN TYP MAX UNITS
Normal operation 16 18
AVDD
VL
CP
CH
CL
DOUT
t
DHOLD
SETUP
CSW
PWR-UP
SEL_SETUP
CST
RCV
Partial power-down mode (Note 5) 2
Full power-down mode (Note 5) 5 µA
f
= 20MHz, VL = 5V, CL = 30pF 2 3
SCLK
f
= 20MHz, VL = 3V, CL = 30pF 1
SCLK
= 5V ±10%, full-scale input ±0.2 ±3 mV
AVDD
CL
CL = 30pF, VL = 5V 14
CL = 30pF, VL = 3V 17
CL = 30pF, VL = 1.8V 24
CL = 30pF 10 ns
External load on REF < 3µF 2 ms
External load on REF < 3µF 2 ms
No external load 16 Cycles
50 ns
45 55 %
22.5 ns
22.5 ns
4ns
20 ns
100 120 ns
mA
mA
ns
MAX1377/MAX1379/MAX1383
Dual, 12-Bit, 1.25Msps Simultaneous-Sampling
ADCs with Serial Interface
_______________________________________________________________________________________ 7
Typical Operating Characteristics
(V
AVDD
= 5V/3V, VL= 3V, f
SCLK
= 20MHz, TA= +25°C, unless otherwise noted.)
0
-20
-40
-60
AMPLITUDE (dB)
-80
-100
-120
0 100 200 300 400 500 600
0
-20
-40
-60
AMPLITUDE (dB)
-80
MAX1377 BIPOLAR FFT
f
= 1.25MHz
SAMPLE
f
= 20MHz
SCLK
f
= 100kHz
IN
SINAD = 60.052dB
SNR = 69.073dB
THD = -92.267dB
SFDR = 93.225dB
V
= 2.048V
REF
ANALOG INPUT FREQUENCY (kHz)
MAX1377 UNIPOLAR FFT
f
= 1.25MHz
SAMPLE
f
= 20MHz
SCLK
f
= 100kHz
IN
SINAD = 69.324dB
SNR = 69.400dB
THD = -86.952dB
SFDR = 89.213dB
V
= 2.048V
REF
MAX1377 toc01
MAX1377 toc04
MAX1377 BIPOLAR FFT
0
f
= 1.25MHz
-20
-40
-60
AMPLITUDE (dB)
-80
-100
-120
0 100 200 300 400 500 600
ANALOG INPUT FREQUENCY (kHz)
MAX1377 UNIPOLAR FFT
0
-20
-40
-60
AMPLITUDE (dB)
-80
SAMPLE
f
= 20MHz
SCLK
f
= 250kHz
IN
SINAD = 68.720dB
SNR = 68.769dB
THD = -88.244dB
SFDR = 91.237dB
V
= 2.048V
REF
f
SAMPLE
f
= 20MHz
SCLK
f
= 250kHz
IN
SINAD = 68.947dB
SNR = 69.054dB
THD = -85.101dB
SFDR = 86.718dB
= 2.048V
V
REF
= 1.25MHz
MAX1377 toc02
MAX1377 toc05
MAX1377 BIPOLAR FFT
0
f
= 1.25MHz
SAMPLE
-20
-40
-60
AMPLITUDE (dB)
-80
-100
-120
= 20MHz
f
SCLK
f
= 500kHz
IN
SINAD = 68.542dB
SNR = 68.554dB
THD = -90.391dB
SFDR = 94.350dB
V
= 2.048V
REF
0 100 200 300 400 500 600
ANALOG INPUT FREQUENCY (kHz)
MAX1377 UNIPOLAR FFT
0
f
= 1.25MHz
SAMPLE
-20
f
= 20MHz
SCLK
f
= 500kHz
IN
SINAD = 68.645dB
-40
SNR = 68.715dB
THD = -83.617dB
-60
SFDR = 88.709dB
V
= 2.048V
REF
AMPLITUDE (dB)
-80
MAX1377 toc03
MAX1377 toc06
-100
-120
0 100 200 300 400 500 600
ANALOG INPUT FREQUENCY (kHz)
MAX1377 UNIPOLAR DNL
vs. OUTPUT CODE
1.0
0.8
0.6
0.4
0.2
0
DNL (LSB)
-0.2
-0.4
-0.6
-0.8
-1.0
500 3500 4000
0 45002000 2500 30001000 1500
CODE
MAX1377 toc07
-100
-120
0 100 200 300 400 500 600
ANALOG INPUT FREQUENCY (kHz)
MAX1377 BIPOLAR INL
vs. OUTPUT CODE
1.0
0.8
0.6
0.4
0.2
0
INL (LSB)
-0.2
-0.4
-0.6
-0.8
-1.0
CODE
300025001000 200015005000
3500 45004000
MAX1377 toc08
-100
-120
0 100 200 300 400 500 600
ANALOG INPUT FREQUENCY (kHz)
MAX1377 UNIPOLAR INL
vs. OUTPUT CODE
1.0
0.8
0.6
0.4
0.2
0
INL (LSB)
-0.2
-0.4
-0.6
-0.8
-1.0
CODE
MAX1377 toc09
3500 45004000300025001000 200015005000
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