19-1684; Rev 2; 10/10
KIT
ATION
EVALU
BLE
AVAILA
400ksps/300ksps, Single-Supply, Low-Power, 8-Channel,
Serial 12-Bit ADCs with Internal Reference
General Description
The MAX1280/MAX1281 12-bit ADCs combine an 8-chan-
nel analog-input multiplexer, high-bandwidth track/hold,
and serial interface with high conversion speed and low
power consumption. The MAX1280 operates from a single
+4.5V to +5.5V supply; the MAX1281 operates from a sin-
gle +2.7V to +3.6V supply. Both devices’ analog inputs
are software configurable for unipolar/bipolar and single-
ended/pseudo-differential operation.
The 4-wire serial interface connects directly to
SPI™/QSPI™/MICROWIRE™ devices without external
logic. A serial strobe output allows direct connection to
TMS320-family digital signal processors. The MAX1280/
MAX1281 use an external serial-interface clock to per-
form successive-approximation analog-to-digital con-
versions. Both parts feature an internal +2.5V reference
and a reference-buffer amplifier with a ±1.5% voltage-
adjustment range. An external reference with a 1V to
V
DD1
range may also be used.
The MAX1280/MAX1281 provide a hard-wired
SHDN
pin and four software-selectable power modes (normal
operation, reduced power, fast power-down, and full
power-down). These devices can be programmed to
automatically shut down at the end of a conversion or to
operate with reduced power. When using the power-
down modes, accessing the serial interface automatical-
ly powers up the devices, and the quick turn-on time
allows them to be powered down between all conver-
sions. This technique can cut supply current to under
100µA at reduced sampling rates.
The MAX1280/MAX1281 are available in 20-pin TSSOP
packages. These devices are higher-speed versions of
the MAX146/MAX147 (for more information, see the
respective data sheet).
Features
♦
8-Channel Single-Ended or 4-Channel
Pseudo-Differential Inputs
♦
Internal Multiplexer and Track/Hold
♦
Single-Supply Operation
+4.5V to +5.5V (MAX1280)
+2.7V to +3.6V (MAX1281)
♦
Internal +2.5V Reference
♦
400ksps Sampling Rate (MAX1280)
♦
Low Power 2.5mA (400ksps)
1.3mA (Reduced-Power Mode)
0.9mA (Fast Power-Down Mode)
2µA (Full Power-Down)
♦
SPI/QSPI/MICROWIRE/TMS320-Compatible
4-Wire Serial Interface
♦
Software-Configurable Unipolar or Bipolar Inputs
♦
20-Pin TSSOP Package
MAX1280/MAX1281
Ordering Information
PART
MAX1280BCUP+
MAX1280BEUP+
MAX1281BCUP+
TEMP
RANGE
0°C to +70°C
-40°C to +85°C
0°C to +70°C
PIN-
PACKAGE
20 TSSOP
20 TSSOP
20 TSSOP
INL
(LSB)
±1
±1
±1
±1
MAX1281BEUP+
-40°C to +85°C
20 TSSOP
+Denotes
a lead(Pb)-free/RoHS-compliant package.
Pin Configuration
TOP VIEW
+
CH0 1
CH1 2
CH2 3
CH3 4
CH4 5
CH5 6
CH6 7
CH7 8
COM 9
SHDN 10
20 V
DD1
19 V
DD2
18 SCLK
Applications
Portable Data Logging
Data Acquisition
Medical Instruments
Battery-Powered Instruments
Pen Digitizers
Process Control
MAX1280
MAX1281
17
CS
16 DIN
15 SSTRB
14 DOUT
13 GND
12 REFADJ
11 REF
SPI and QSPI are trademarks of Motorola, Inc.
MICROWIRE is a trademark of National Semiconductor Corp.
TSSOP
________________________________________________________________
Maxim Integrated Products
1
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.
400ksps/300ksps, Single-Supply, Low-Power, 8-Channel,
Serial 12-Bit ADCs with Internal Reference
MAX1280/MAX1281
ABSOLUTE MAXIMUM RATINGS
V
DD_
to GND ............................................................ -0.3V to +6V
V
DD1
to V
DD2
........................................................ -0.3V to +0.3V
CH0–CH7, COM to GND.......................... -0.3V to (V
DD1
+ 0.3V)
REF, REFADJ to GND .............................. -0.3V to (V
DD1
+ 0.3V)
Digital Inputs to GND .............................................. -0.3V to +6V
Digital Outputs to GND ............................ -0.3V to (V
DD2
+ 0.3V)
Digital Output Sink Current .................................................25mA
Continuous Power Dissipation (T
A
= +70°C)
20-Pin TSSOP (derate 7.0mW/°C above +70°C) .........559mW
Operating Temperature Ranges
MAX128_BCUP .................................................. 0°C to +70°C
MAX128_BEUP ............................................... -40°C to +85°C
Storage Temperature Range ............................ -60°C to +150°C
Lead Temperature (soldering, 10s) ................................ +300°C
Soldering Temperature (reflow) ...................................... +260°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—MAX1280
(V
DD1
= V
DD2
= +4.5V to +5.5V, COM = GND, f
SCLK
= 6.4MHz, 50% duty cycle, 16 clocks/conversion cycle (400ksps), external
+2.5V at REF, REFADJ = V
DD1
, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
DC ACCURACY
(Note 1)
Resolution
Relative Accuracy (Note 2)
Differential Nonlinearity
Offset Error
Gain Error (Note 3)
Gain-Error Temperature
Coefficient
Channel-to-Channel Offset-Error
Matching
±0.8
±0.1
INL
DNL
No missing codes over temperature
12
±1.0
±1.0
±6.0
±7.0
Bits
LSB
LSB
LSB
LSB
ppm/°C
LSB
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
DYNAMIC SPECIFICATIONS
(100kHz sine-wave input, 2.5Vp-p, 400ksps, 6.4MHz clock, bipolar input mode)
Signal-to-Noise plus Distortion
Ratio
Total Harmonic Distortion
Spurious-Free Dynamic Range
Intermodulation Distortion
Channel-to-Channel Crosstalk
(Note 4)
Full-Power Bandwidth
Full-Linear Bandwidth
CONVERSION RATE
Conversion Time (Note 5)
Track/Hold Acquisition Time
Aperture Delay
Aperture Jitter
Serial Clock Frequency
Duty Cycle
f
SCLK
0.5
40
t
CONV
t
ACQ
10
<50
6.4
60
2.5
468
µs
ns
ns
ps
MHz
%
SINAD
THD
SFDR
IMD
f
IN1
= 99kHz, f
IN2
= 102kHz
f
IN
= 200kHz, V
IN
= 2.5Vp-p
-3dB point
SINAD > 68dB
Up to the 5th harmonic
70
-81
80
76
-78
6
350
dB
dB
dB
dB
dB
MHz
kHz
2
_______________________________________________________________________________________
400ksps/300ksps, Single-Supply, Low-Power, 8-Channel,
Serial 12-Bit ADCs with Internal Reference
ELECTRICAL CHARACTERISTICS—MAX1280 (continued)
(V
DD1
= V
DD2
= +4.5V to +5.5V, COM = GND, f
SCLK
= 6.4MHz, 50% duty cycle, 16 clocks/conversion cycle (400ksps), external
+2.5V at REF, REFADJ = V
DD1
, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
SYMBOL
CONDITIONS
Unipolar, V
COM
= 0
V
CH_
Bipolar, V
COM
or V
CH_
= V
REF
/2,
referenced to COM or CH_
On/off leakage current, V
CH_
= 0 or V
DD1
±0.001
18
V
REF
T
A
= +25°C
2.480
2.500
30
TC V
REF
0 to 1mA output load
4.7
0.01
1.22
For small adjustments, from 1.22V
To power down the internal reference
1.33
2.05
1.0
200
V
DD1
+
50mV
350
320
5
3.0
0.8
0.2
V
IN
= 0 or V
DD2
15
I
SINK
= 5mA
I
SOURCE
= 1mA
CS
= 5V
CS
= 5V
15
4
±10
0.4
±1
µA
mA
±50
V
DD1
±15
0.1
2.0
10
10
2.520
MIN
TYP
MAX
V
REF
±V
REF
/2
±1
V
µA
pF
V
mA
ppm/°C
mV/mA
µF
µF
V
mV
V
V/V
UNITS
ANALOG INPUTS
(CH7–CH0, COM)
Input Voltage Range, Single-
Ended and Differential (Note 6)
Multiplexer Leakage Current
Input Capacitance
INTERNAL REFERENCE
REF Output Voltage
REF Short-Circuit Current
REF Output Temperature
Coefficient
Load Regulation (Note 7)
Capacitive Bypass at REF
Capacitive Bypass at REFADJ
REFADJ Output Voltage
REFADJ Input Range
REFADJ Buffer Disable
Threshold
Buffer Voltage Gain
EXTERNAL REFERENCE
(Reference buffer disabled, reference applied to REF)
REF Input Voltage Range
(Note 8)
V
REF
= 2.500V, f
SCLK
= 6.4MHz
REF Input Current
DIGITAL INPUTS
(DIN, SCLK,
CS, SHDN)
Input High Voltage
Input Low Voltage
Input Hysteresis
Input Leakage
Input Capacitance
DIGITAL OUTPUTS
(DOUT, SSTRB)
Output Voltage Low
Output Voltage High
Three-State Leakage Current
Three-State Output Capacitance
V
OL
V
OH
I
L
C
OUT
V
V
µA
pF
V
INH
V
INL
V
HYST
I
IN
C
IN
V
V
V
µA
pF
V
REF
= 2.500V, f
SCLK
= 0
In power-down, f
SCLK
= 0
V
MAX1280/MAX1281
_______________________________________________________________________________________
3
400ksps/300ksps, Single-Supply, Low-Power, 8-Channel,
Serial 12-Bit ADCs with Internal Reference
MAX1280/MAX1281
ELECTRICAL CHARACTERISTICS—MAX1280 (continued)
(V
DD1
= V
DD2
= +4.5V to +5.5V, COM = GND, f
SCLK
= 6.4MHz, 50% duty cycle, 16 clocks/conversion cycle (400ksps), external
+2.5V at REF, REFADJ = V
DD1
, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
POWER SUPPLY
Positive Supply Voltage
(Note 9)
V
DD1
,
V
DD2
Operating mode (Note 10)
Supply Current
Supply Current
Power-Supply Rejection
PSR
I
VDD1 +
I
VDD2
V
DD1
=
V
DD2
= 5.5V
Reduced-power mode (Note 11)
Fast power-down (Note 11)
Full power-down (Note 11)
V
DD1
= V
DD2
= 5V ±10%, midscale input
4.5
2.5
1.3
0.9
2
±0.5
5.5
4.0
2.0
1.5
10
±2.0
µA
mV
mA
V
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
ELECTRICAL CHARACTERISTICS—MAX1281
(V
DD1
= V
DD2
= +2.7V to +3.6V, COM = GND, f
SCLK
= 4.8MHz, 50% duty cycle, 16 clocks/conversion cycle (300ksps), external
+2.5V at REF, REFADJ = V
DD1
, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
DC ACCURACY
(Note 1)
Resolution
Relative Accuracy (Note 2)
Differential Nonlinearity
Offset Error
Gain Error (Note 3)
Gain-Error Temperature
Coefficient
Channel-to-Channel Offset-
Error Matching
±1.6
±0.2
INL
DNL
No missing codes over temperature
12
±1.0
±1.0
±6.0
±7.0
Bits
LSB
LSB
LSB
LSB
ppm/°C
LSB
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
DYNAMIC SPECIFICATIONS
(75kHz sine-wave input, 2.5Vp-p, 300ksps, 4.8MHz clock, bipolar input mode)
Signal-to-Noise plus
Distortion Ratio
Total Harmonic Distortion
Spurious-Free Dynamic
Range
Intermodulation Distortion
Channel-to-Channel Crosstalk
(Note 4)
Full-Power Bandwidth
Full-Linear Bandwidth
SINAD
THD
SFDR
IMD
f
IN1
= 73kHz, f
IN2
= 77kHz
f
IN
= 150kHz, V
IN
= 2.5Vp-p
-3dB point
SINAD > 68dB
Up to the 5th harmonic
70
-81
80
76
-78
3
250
dB
dB
dB
dB
dB
MHz
kHz
4
_______________________________________________________________________________________
400ksps/300ksps, Single-Supply, Low-Power, 8-Channel,
Serial 12-Bit ADCs with Internal Reference
ELECTRICAL CHARACTERISTICS—MAX1281 (continued)
(V
DD1
= V
DD2
= +2.7V to +3.6V, COM = GND, f
SCLK
= 4.8MHz, 50% duty cycle, 16 clocks/conversion cycle (300ksps), external
+2.5V at REF, REFADJ = V
DD1
, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
CONVERSION RATE
Conversion Time (Note 5)
Track/Hold Acquisition Time
Aperture Delay
Aperture Jitter
Serial Clock Frequency
Duty Cycle
ANALOG INPUTS
(CH7–CH0, COM)
Input Voltage Range, Single-
Ended and Differential (Note 6)
Multiplexer Leakage Current
Input Capacitance
INTERNAL REFERENCE
REF Output Voltage
REF Short-Circuit Current
REF Output Temperature
Coefficient
Load Regulation (Note 7)
Capacitive Bypass at REF
Capacitive Bypass at REFADJ
REFADJ Output Voltage
REFADJ Input Range
REFADJ Buffer Disable
Threshold
Buffer Voltage Gain
EXTERNAL REFERENCE
(Reference buffer disabled, reference applied to REF)
REF Input Voltage Range
(Note 8)
V
REF
= 2.500V, f
SCLK
= 4.8MHz
REF Input Current
DIGITAL INPUTS
(DIN, SCLK,
CS, SHDN)
Input High Voltage
Input Low Voltage
Input Hysteresis
Input Leakage
Input Capacitance
V
INH
V
INL
V
HYST
I
IN
C
IN
V
IN
= 0 or V
DD2
15
0.2
±1
2.0
0.8
V
V
V
µA
pF
V
REF
= 2.500V, f
SCLK
= 0
In power-down, f
SCLK
= 0
1.0
200
V
DD1
+
50mV
350
320
5
µA
V
For small adjustments, from 1.22V
To power down the internal reference
1.33
2.05
TC V
REF
0 to 0.75mA output load
4.7
0.01
1.22
±50
V
DD1
- 1
V
REF
T
A
= +25°C
2.480
2.500
15
±15
0.1
2.0
10
10
2.520
V
mA
ppm/°C
mV/mA
µF
µF
V
mV
V
V/V
Unipolar, V
COM
= 0
V
CH_
Bipolar, V
COM
or V
CH_
= V
REF
/2,
referenced to COM or CH_
On/off leakage current, V
CH_
= 0 or V
DD1
±0.001
18
V
REF
±V
REF
/2
±1
V
µA
pF
f
SCLK
Normal operating mode
0.5
40
t
CONV
t
ACQ
Normal operating mode
Normal operating mode
10
< 50
4.8
60
3.3
625
µs
ns
ns
ps
MHz
%
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
MAX1280/MAX1281
_______________________________________________________________________________________
5
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