19-4126; Rev 1; 2/09
Dual, 12-Bit, 1.25Msps Simultaneous-Sampling
ADCs with Serial Interface
General Description
The MAX1377/MAX1379/MAX1383 feature two simulta-
neous-sampling, low-power, 12-bit ADCs with serial
interface and internal voltage reference. Fast sampling
rate, low power dissipation, and excellent dynamic per-
formance 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 sup-
ply and the MAX1379/MAX1383 operate from a 4.75V
to 5.25V analog supply. A separate 1.8V to AVDD digi-
tal 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 power-
down 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 applica-
tions. 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 automo-
tive (-40°C to +125°C) temperature range.
Features
♦
Dual, Simultaneous-Sampling, 12-Bit Successive
Approximation Register (SAR) ADCs
♦
2 x 2 Mux Inputs or Two Differential Inputs
♦
1.25Msps Sampling Rate per ADC
♦
Internal or External Reference
♦
Excellent Dynamic Performance
70dB SINAD (MAX1377)
71dB SINAD (MAX1379/MAX1383)
84dBc/SFDR
1MHz Full-Linear Bandwidth
♦
2.7V to 3.6V Low-Power Operation (MAX1377)
50mW (Normal Operation)
6mW (Partial Power-Down)
3µW (Full Power-Down)
♦
4.75V to 5.25V Low-Power Operation (MAX1379)
90mW (Normal Operation)
10mW (Partial Power-Down)
5µW (Full Power-Down)
♦
4.75V to 5.25V Low-Power Operation (MAX1383)
280mW (Normal Operation)
2.5µW (Full Power-Down)
♦
20MHz, SPI-Compatible, 3-Wire Serial Interface
User-Selectable Single (0.625Msps max) or Dual
Outputs (1.25Msps max)
♦
Input Range: ±10V (MAX1383), 0–V
REF
or
±V
REF
/2 (MAX1377/MAX1379)
♦
Small 20-Pin TQFN Package
SPI/QSPI are trademarks of Motorola, Inc.
MICROWIRE is a trademark of National Semiconductor Corp.
MAX1377/MAX1379/MAX1383
Functional Diagram
AVDD
AIN1A
MAX1377
MAX1379
MAX1383
OUTPUT
BUFFER
DOUT1
V
L
AIN1B
MUX
T/H
12-BIT
SAR
ADC1
Applications
REF
CS
SERIAL
INTERFACE
AND TIMING
A=1
CNVST
SCLK
Motor Control
Communications
Data Acquisition
Bill Validation
Portable Instruments
REFSEL
RGND
INTERNAL
REFERENCE
CONTROL
LOGIC
U/B
S/D
Ordering Information
PART
MAX1377ATP+
MAX1379ATP+
MAX1383ATP+
TEMP RANGE
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
PIN-PACKAGE
20 TQFN-EP*
20 TQFN-EP*
20 TQFN-EP*
AIN2B
AIN2A
MUX
T/H
12-BIT
SAR
ADC2
V
L
OUTPUT
BUFFER
DOUT2
SEL
AGND
DGND
+Denotes
a lead(Pb)-free/RoHS-compliant package.
*EP
= Exposed pad.
Pin Configuration appears at end of data sheet.
1
________________________________________________________________
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.
Dual, 12-Bit, 1.25Msps Simultaneous-Sampling
ADCs with Serial Interface
MAX1377/MAX1379/MAX1383
ABSOLUTE MAXIMUM RATINGS
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
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—MAX1377
(V
AVDD
= 2.7V to 3.6V, V
L
= 1.8V to AVDD, f
SCLK
= 20MHz (50% duty cycle), V
REF
= 2.048V, REFSEL = V
L
, S/D = DGND, C
REF
=
1µF; T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
DC ACCURACY
Resolution
Relative Accuracy
Differential Nonlinearity
Offset Error
Offset-Error Matching
Gain Error
Gain-Error Matching
Gain Temperature Coefficient
DC Input Isolation
AIN1A to AIN1B, AIN2A to AIN2B
AIN1A to AIN2A, AIN1B to AIN2B
Unipolar
Bipolar
Unipolar
Bipolar
Up to the 5th harmonic
f
IN1
= 103.5kHz, f
IN2
= 113.5kHz
-3dB point
(S/N + D) > 68dB, 1V input
t
CONV
16 clock cycles per conversion (Note 3)
Dual output mode, S/D = 0
Single output mode, S/D = 1
(Note 4)
1.25
0.625
10
66
67
66
67
(Note 2)
(Note 2)
±2
80
80
69.5
70
70
70
-84
-86
-78
5
1
0.800
-74
-76
INL
DNL
(Note 1)
12
-1.25
-1
+1.25
+1.5
±8
±12
±6
±6
Bits
LSB
LSB
LSB
LSB
LSB
LSB
ppm/
o
C
dB
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
DYNAMIC SPECIFICATIONS (f
IN
= 500kHz, 2V
P-P
sine wave, 1.25Msps, 20MHz f
SCLK
)
Signal-to-Noise Plus Distortion
Signal-to-Noise Ratio
Total Harmonic Distortion
Spurious-Free Dynamic Range
Intermodulation Distortion
Full-Power Bandwidth
Full-Linear Bandwidth
CONVERSION RATE (Figure 4)
Minimum Conversion Time
Maximum Throughput Rate
Minimum Throughput Rate for
Full Bandwidth Signal
µs
Msps
ksps
SINAD
SNR
THD
SFDR
IMD
dB
dB
dB
dB
dB
MHz
MHz
2
_______________________________________________________________________________________
Dual, 12-Bit, 1.25Msps Simultaneous-Sampling
ADCs with Serial Interface
ELECTRICAL CHARACTERISTICS—MAX1377 (continued)
(V
AVDD
= 2.7V to 3.6V, V
L
= 1.8V to AVDD, f
SCLK
= 20MHz (50% duty cycle), V
REF
= 2.048V, REFSEL = V
L
, S/D = DGND, C
REF
=
1µF; T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
Track-and-Hold Acquisition Time
Aperture Delay
Aperture-Delay Matching
Aperture Jitter
External Clock Frequency
Input Range
Differential Input Range
Absolute Voltage Range
DC Leakage Current
Input Impedance
Input Capacitance
EXTERNAL REFERENCE (REFSEL = 1)
Absolute Input Voltage Range
Input Capacitance
DC Leakage Current
Input Current
INTERNAL REFERENCE (REFSEL = 0)
Reference Voltage Level
Load Regulation
Voltage Temperature Coefficient
DIGITAL INPUTS (SCLK, CNVST,
U/B,
S/D, SEL, REFSEL)
Input-Voltage Low
Input-Voltage High
Input Leakage Current
DIGITAL OUTPUT (DOUT1, DOUT2)
Output Load Capacitance
Output-Voltage Low
Output-Voltage High
Output Leakage Current
POWER REQUIREMENTS
Analog Supply Voltage
Digital Supply Voltage
AVDD
V
L
2.7
1.8
3.0
3.6
AVDD
V
V
C
DOUT
V
OL
V
OH
I
OL
For stated timing performance
I
SINK
= 5mA
I
SOURCE
= 1mA, V
L
≥
2.7V
High-impedance mode (Figure 9)
V
L
- 0.5V
±0.2
30
0.4
pF
V
V
µA
V
IL
V
IH
I
IL
0.7 x
V
L
±10
0.3 x
V
L
V
V
µA
I
SOURCE
= 0 to 1mA
I
SINK
= 0 to 50µA
2.028
2.048
1
1
±50.0
2.068
V
mV/mA
ppm/
o
C
Time averaged at maximum throughput rate
800
V
REF
1.0
50
±1
AVDD
+ 0.05
V
pF
µA
µA
At each analog input
34
16
f
SCLK
U/B
= 0, V
AIN_A
- RGND
U/B
= 1, V
AIN_A
- V
AIN_B
0
-V
REF
/2
0
(Note 5)
SYMBOL
t
ACQ
CONDITIONS
MIN
TYP
125
2
2
30
20
V
REF
+V
REF
/2
AVDD
±1
MAX
UNITS
ns
ns
ns
ps
MHz
V
V
V
µA
kΩ
pF
MAX1377/MAX1379/MAX1383
ANALOG INPUTS (AIN1A, AIN1B, AIN2A, AIN2B)
_______________________________________________________________________________________
3
Dual, 12-Bit, 1.25Msps Simultaneous-Sampling
ADCs with Serial Interface
MAX1377/MAX1379/MAX1383
ELECTRICAL CHARACTERISTICS—MAX1377 (continued)
(V
AVDD
= 2.7V to 3.6V, V
L
= 1.8V to AVDD, f
SCLK
= 20MHz (50% duty cycle), V
REF
= 2.048V, REFSEL = V
L
, S/D = DGND, C
REF
=
1µF; T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
Analog Supply Current
Average Static Supply Current
Digital Supply Current
Power-Supply Rejection
I
VL
PSR
f
SCLK
= 20MHz, V
L
= 3V, C
L
= 30pF
V
AVDD
= 3V ±10%, full-scale input
SYMBOL
I
AVDD
CONDITIONS
Normal operation
Partial power-down mode (Note 5)
Full power-down mode (Note 5)
MIN
TYP
13
2
1
8
1
±0.2
5
10
1.5
±3
MAX
15
UNITS
mA
µA
mA
mA
mV
ELECTRICAL CHARACTERISTICS—MAX1379
(V
AVDD
= 4.75V to 5.25V, V
L
= 3V, f
SCLK
= 20MHz (50% duty cycle), V
REF
= 4.096V, REFSEL = V
L
, S/D = DGND, C
REF
= 1µF; T
A
=
T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
DC ACCURACY
Resolution
Relative Accuracy
Differential Nonlinearity
Offset Error
Offset-Error Matching
Gain Error
Gain-Error Matching
Gain Temperature Coefficient
DC Input Isolation
AIN1A to AIN1B, AIN2A to AIN2B
AIN1A to AIN2A, AIN1B to AIN2B
Unipolar
Bipolar
Unipolar
Bipolar
Up to the 5th harmonic
f
IN1
= 103.5kHz, f
IN2
= 113.5kHz
-3dB point
(S/N + D) > 68dB, 1V input
t
CONV
16 clock cycles per conversion (Note 3)
Dual-output mode, S/D = 0
Single-output mode, S/D = 1
(Note 4)
1.25
0.625
10
69
70
70
70
(Note 2)
(Note 2)
±2
80
80
70
71
71
72
-84
-84
-78
5
1
0.8
-76
-76
INL
DNL
(Note 1)
12
-1.25
-1
+1.25
+1
±8
±9
±6
±9
Bits
LSB
LSB
LSB
LSB
LSB
LSB
ppm/
o
C
dB
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
DYNAMIC SPECIFICATIONS (f
IN
= 500kHz , 4V
P-P
sine wave, 1.25Msps, 20MHz f
SCLK
)
Signal-to-Noise Plus Distortion
Signal-to-Noise Ratio
Total Harmonic Distortion
Spurious-Free Dynamic Range
Intermodulation Distortion
Full-Power Bandwidth
Full-Linear Bandwidth
CONVERSION RATE (Figure 6)
Minimum Conversion Time
Maximum Throughput Rate
Minimum Throughput Rate for
Full Bandwidth Signal
µs
Msps
ksps
SINAD
SNR
THD
SFDR
IMD
dB
dB
dB
dB
dB
MHz
MHz
4
_______________________________________________________________________________________
Dual, 12-Bit, 1.25Msps Simultaneous-Sampling
ADCs with Serial Interface
ELECTRICAL CHARACTERISTICS—MAX1379 (continued)
(V
AVDD
= 4.75V to 5.25V, V
L
= 3V, f
SCLK
= 20MHz (50% duty cycle), V
REF
= 4.096V, REFSEL = V
L
, S/D = DGND, C
REF
= 1µF; T
A
=
T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
Track-and-Hold Acquisition Time
Aperture Delay
Aperture-Delay Matching
Aperture Jitter
External Clock Frequency
Input Range
Differential Input Range
Absolute Voltage Range
DC Leakage Current
Input Impedance
Input Capcitance
EXTERNAL REFERENCE (REFSEL = 1)
Absolute Input Voltage Range
Input Capacitance
DC Leakage Current
Input Current
INTERNAL REFERENCE (REFSEL = 0)
Reference Voltage Level
Load Regulation
Voltage Temperature Coefficient
DIGITAL INPUTS (SCLK, CNVST,
U/B,
S/D, SEL, REFSEL)
Input-Voltage Low
Input-Voltage High
Input Leakage Current
DIGITAL OUTPUT (DOUT1, DOUT2)
Output Load Capacitance
Output-Voltage Low
Output-Voltage High
Output Leakage Current
POWER REQUIREMENTS
Analog Supply Voltage
Digital Supply Voltage
AVDD
V
L
4.25
1.8
5.0
5.25
AVDD
V
V
C
DOUT
V
OL
V
OH
I
OL
For stated timing performance
I
SINK
= 5mA
I
SOURCE
= 1mA, V
L
≥
2.7V
High-impedance mode (Figure 9)
V
L
-
0.5V
±0.2
30
0.4
pF
V
V
µA
V
IL
V
IH
I
IL
0.7 x
V
L
±10
0.3 x
V
L
V
V
µA
I
SOURCE
= 0 to 1mA
I
SINK
= 0 to 50µA
4.086
4.096
1
1
±50.0
4.106
V
mV/mA
ppm/
o
C
Time averaged at maximum throughput rate
800
V
REF
1.0
50
±1
AVDD
+ 0.05
V
pF
µA
µA
At each analog input
34
16
f
SCLK
U/B
= 0, V
AIN_A
- RGND
U/B
= 1, V
AIN_A
- V
AIN_B
0
-V
REF
/2
0
(Note 5)
SYMBOL
t
ACQ
CONDITIONS
MIN
TYP
125
2
2
30
20
V
REF
+V
REF
/2
AVDD
±1
MAX
UNITS
ns
ns
ns
ps
MHz
MAX1377/MAX1379/MAX1383
ANALOG INPUTS (AIN1A, AIN1B, AIN2A, AIN2B)
V
V
µA
kΩ
pF
_______________________________________________________________________________________
5