19-1685; Rev 0; 5/00
300ksps/400ksps, Single-Supply, Low-Power,
8-Channel, Serial 10-Bit ADCs with Internal Reference
General Description
The MAX1080/MAX1081 10-bit analog-to-digital convert-
ers (ADCs) combine an 8-channel analog-input multiplex-
er, high-bandwidth track/hold (T/H), and serial interface
with high conversion speed and low power consumption.
The MAX1080 operates from a single +4.5V to +5.5V sup-
ply; the MAX1081 operates from a single +2.7V to +3.6V
supply. Both devices’ analog inputs are software config-
urable for unipolar/bipolar and single-ended/pseudo-dif-
ferential operation.
The 4-wire serial interface connects directly to
SPI™/QSPI™ and MICROWIRE™ devices without external
logic. A serial strobe output allows direct connection to
TMS320-family digital signal processors. The MAX1080/
MAX1081 use an external serial-interface clock to perform
successive-approximation analog-to-digital conversions.
The devices feature an internal +2.5V reference and a ref-
erence-buffer amplifier with a ±1.5% voltage-adjustment
range. An external reference with a 1V to V
DD1
range may
also be used.
The MAX1080/MAX1081 provide a hard-wired
SHDN
pin
and four software-selectable power modes (normal opera-
tion, reduced power (REDP), fast power-down (FASTPD),
and full power-down (FULLPD)). 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
automatically powers up the devices, and the quick turn-
on time allows them to be shut down between all conver-
sions. This technique can cut supply current below 100mA
at lower sampling rates.
The MAX1080/MAX1081 are available in a 20-pin TSSOP
package. These devices are higher-speed versions of the
MAX148/MAX149. For more information, refer to the
respective data sheet.
Features
o
8-Channel Single-Ended or 4-Channel
Pseudo-Differential Inputs
o
Internal Multiplexer and Track/Hold
o
Single-Supply Operation
+4.5V to +5.5V (MAX1080)
+2.7V to +3.6V (MAX1081)
o
Internal +2.5V Reference
o
400ksps Sampling Rate (MAX1080)
o
Low Power: 2.5mA (400ksps)
1.3mA (REDP)
0.9mA (FASTPD)
2µA (FULLPD)
o
SPI/QSPI/MICROWIRE/TMS320-Compatible 4-Wire
Serial Interface
o
Software-Configurable Unipolar or Bipolar Inputs
o
20-Pin TSSOP Package
MAX1080/MAX1081
Ordering Information
PART
MAX1080ACUP
MAX1080BCUP
MAX1080AEUP
TEMP.
RANGE
0°C to +70°C
0°C to +70°C
-40°C to +85°C
PIN-
PACKAGE
20 TSSOP
20 TSSOP
20 TSSOP
INL
(LSB)
±1/2
±1
±1/2
Ordering Information continued at end of data sheet.
Pin Configuration
TOP VIEW
CH0 1
CH1 2
CH2 3
CH3 4
CH4 5
CH5 6
CH6 7
CH7 8
20 V
DD1
19 V
DD2
18 SCLK
Applications
Portable Data Logging
Data Acquisition
Medical Instruments
Battery-Powered Instruments
Pen Digitizers
Process Control
MAX1080
MAX1081
17
CS
16 DIN
15 SSTRB
14 DOUT
13 GND
12 REFADJ
11 REF
Typical Operating Circuit appears at end of data sheet.
SPI and QSPI are trademarks of Motorola, Inc.
MICROWIRE is a trademark of National Semiconductor Corp.
COM 9
SHDN 10
TSSOP
________________________________________________________________
Maxim Integrated Products
1
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.
300ksps/400ksps, Single-Supply, Low-Power,
8-Channel, Serial 10-Bit ADCs with Internal Reference
MAX1080/MAX1081
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
MAX108_ _CUP ................................................. 0°C to +70°C
MAX108_ _EUP............................................... -40°C to +85°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—MAX1080
(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
MAX1080A
MAX1080B
No missing codes over temperature
10
±0.5
±1.0
±1.0
±3.0
±3.0
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 > 58dB
Up to the 5th harmonic
60
-70
70
76
-78
6
350
dB
dB
dB
dB
dB
MHz
kHz
2
_______________________________________________________________________________________
300ksps/400ksps, Single-Supply, Low-Power,
8-Channel, Serial 10-Bit ADCs with Internal Reference
MAX1080/MAX1081
ELECTRICAL CHARACTERISTICS—MAX1080 (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
1.4
+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
±100
V
DD1
- 1.0
±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 mode, f
SCLK
= 0
V
_______________________________________________________________________________________
3
300ksps/400ksps, Single-Supply, Low-Power,
8-Channel, Serial 10-Bit ADCs with Internal Reference
MAX1080/MAX1081
ELECTRICAL CHARACTERISTICS—MAX1080 (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
Normal operating mode (Note 10)
Supply Current
I
VDD1+
I
VDD2
PSR
V
DD1
=
V
DD2
=
5.5V
Reduced-power mode (Note 11)
Fast power-down mode (Note 11)
Full power-down mode (Note 11)
Power-Supply Rejection
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—MAX1081
(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
MAX1081A
MAX1081B
No missing codes over temperature
10
±0.5
±1.0
±1.0
±3.0
±3.0
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 > 58dB
Up to the 5th harmonic
60
-70
70
76
-78
3
250
dB
dB
dB
dB
dB
MHz
kHz
4
_______________________________________________________________________________________
300ksps/400ksps, Single-Supply, Low-Power,
8-Channel, Serial 10-Bit ADCs with Internal Reference
ELECTRICAL CHARACTERISTICS—MAX1081 (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)
Buffer Voltage Gain
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 mode, f
SCLK
= 0
1.0
200
For small adjustments, from 1.22V
To power down the internal reference
1.4
+2.05
2.05
V
DD1
+
50mV
350
320
5
µA
TC V
REF
0 to 0.75mA output load
4.7
0.01
1.22
±100
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
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
MAX1080/MAX1081
_______________________________________________________________________________________
5