General Description
The MAX1294/MAX1296 low-power, 12-bit analog-to-
digital converters (ADCs) feature a successive-approxi-
mation ADC, automatic power-down, fast wake-up
(2s), an on-chip clock, +2.5V internal reference, and a
high-speed 12-bit parallel interface. They operate with
a single +5V analog supply.
Power consumption is only 10mW at the maximum sam-
pling rate of 420ksps. Two software-selectable power-
down modes enable the MAX1294/MAX1296 to be shut
down between conversions; accessing the parallel
interface returns them to normal operation. Powering
down between conversions can reduce supply below
10A at lower sampling rates.
Both devices offer software-configurable analog inputs for
unipolar/bipolar and single-ended/pseudo-differential
operation. In single-ended mode, the MAX1294 has six
input channels and the MAX1296 has two (three input
channels and one input channel, respectively, when in
pseudo-differential mode).
Excellent dynamic performance and low power, com-
bined with ease of use and small package size, make
these converters ideal for battery-powered and data-
acquisition applications or for other circuits with demand-
ing power-consumption and space requirements.
The MAX1294/MAX1296 tri-states INT when CS goes
high. Refer to MAX1266/MAX1268 if tri-stating INT is not
desired.
The MAX1294 is offered in a 28-pin QSOP package, while
the MAX1296 is available in a 24-pin QSOP. For pin-com-
patible +3V, 12-bit versions, see the MAX1295/MAX1297.
Applications
Industrial Control Systems
Data Logging
Energy Management
Patient Monitoring
Data-Acquisition Systems
Touchscreens
Features
o 12-Bit Resolution, 0.5 LSB Linearity
o Single +5V Operation
o Internal +2.5V Reference
o Software-Configurable Analog Input Multiplexer
6-Channel Single-Ended/
3-Channel Pseudo-Differential (MAX1294)
2-Channel Single-Ended/
1-Channel Pseudo-Differential (MAX1296)
o Software-Configurable Unipolar/Bipolar
Analog Inputs
o Low Current
2.8mA (420ksps)
1.0mA (100ksps)
400A (10ksps)
2A (Shutdown)
o Internal 6MHz Full-Power Bandwidth Track/Hold
o Parallel 12-Bit Interface
o Small Footprint
28-Pin QSOP (MAX1294)
24-Pin QSOP (MAX1296)
MAX1294/MAX1296
420ksps, +5V, 6-/2-Channel, 12-Bit ADCs
with +2.5V Reference and Parallel Interface
________________________________________________________________ Maxim Integrated Products
1
19-1533; Rev 2; 12/02
PART
MAX1294ACEI
MAX1294BCEI
0C to +70C
0C to +70C
TEMP RANGE
PIN-PACKAGE
28 QSOP
28 QSOP
Ordering Information
Pin Configurations
INL
(LSB)
0.5
1
Typical Operating Circuits appear at end of data sheet.
24
23
22
21
20
19
18
17
16
15
14
13
1
2
3
4
5
6
7
8
9
10
11
12
D10
D11
V
DD
REF
REFADJ
GND
COM
CH0
CH1
CS
CLK
WR
RD
INT
D0
D1
D2
D3
D4
D5
D6
D7
D8
D9
QSOP
TOP VIEW
MAX1296
Pin Configurations continued at end of data sheet.
MAX1294AEEI
-40C to +85C
28 QSOP
0.5
MAX1294BEEI
-40C to +85C
28 QSOP
1
EVALUATION KIT
AVAILABLE
MAX1296ACEG
MAX1296BCEG
MAX1296AEEG
-40C to +85C
0C to +70C
0C to +70C
24 QSOP
24 QSOP
24 QSOP
0.5
MAX1296BEEG
-40C to +85C
24 QSOP
1
0.5
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim's website at www.maxim-ic.com.
MAX1294/MAX1296
420ksps, +5V, 6-/2-Channel, 12-Bit ADCs
with +2.5V Reference and Parallel Interface
2
_______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(V
DD
= +5V 10%, COM = GND, REFADJ = V
DD
, V
REF
= +2.5V, 4.7F capacitor at REF pin, f
CLK
= 7.6MHz (50% duty cycle),
T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25C.)
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.
V
DD
to GND ..............................................................-0.3V to +6V
CH0CH5, COM to GND ............................-0.3V to (V
DD
+ 0.3V)
REF, REFADJ to GND.................................-0.3V to (V
DD
+ 0.3V)
Digital Inputs to GND ...............................................-0.3V to +6V
Digital Outputs (D0D11, INT) to GND.......-0.3V to (V
DD
+ 0.3V)
Continuous Power Dissipation (T
A
= +70C)
24-Pin QSOP (derate 9.5mW/C above +70C)..........762mW
28-Pin QSOP (derate 8.00mW/C above +70C)........667mW
Operating Temperature Ranges
MAX1294_C_ _/MAX1296_C_ _ .........................0C to +70C
MAX1294_E_ _/MAX1296_E_ _ ......................-40C to +85C
Storage Temperature Range .............................-65C to +150C
Lead Temperature (soldering, 10s) .................................+300C
External acquisition or external clock mode
Internal acquisition/internal clock mode
MAX129_A
External acquisition/internal clock mode
External clock mode
-3dB rolloff
SINAD > 68dB
f
IN
= 175kHz (Note 4)
f
IN1
= 49kHz, f
IN2
= 52kHz
MAX129_B
No missing codes over temperature
CONDITIONS
ns
25
Aperture Delay
ns
400
t
ACQ
T/H Acquisition Time
3.2
3.6
4
2.5
3.0
3.5
s
2.1
t
CONV
Conversion Time (Note 5)
MHz
6
Full-Power Bandwidth
kHz
350
Full-Linear Bandwidth
dB
-78
Channel-to-Channel Crosstalk
dB
76
IMD
Intermodulation Distortion
dB
-80
SFDR
Spurious-Free Dynamic Range
Total Harmonic Distortion
(including 5th-order harmonic)
dB
-80
THD
0.5
INL
Relative Accuracy (Note 2)
Bits
12
RES
Resolution
dB
67
70
SINAD
Signal-to-Noise Plus Distortion
LSB
0.2
Channel-to-Channel Offset
Matching
ppm/C
2.0
Gain Temperature Coefficient
LSB
1
LSB
1
DNL
Differential Nonlinearity
LSB
4
Offset Error
LSB
4
Gain Error (Note 3)
UNITS
MIN
TYP
MAX
SYMBOL
PARAMETER
Internal acquisition/internal clock mode
External acquisition or external clock mode
<200
ps
<50
Aperture Jitter
MHz
0.1
7.6
f
CLK
External Clock Frequency
%
30
70
Duty Cycle
DC ACCURACY (Note 1)
DYNAMIC SPECIFICATIONS (f
IN(sine wave)
= 50kHz, V
IN
= 2.5V
P-P
, 420ksps, external f
CLK
= 7.6MHz, bipolar input mode)
CONVERSION RATE
I
DD
MAX1294/MAX1296
420ksps, +5V, 6-/2-Channel, 12-Bit ADCs
with +2.5V Reference and Parallel Interface
_______________________________________________________________________________________
3
ELECTRICAL CHARACTERISTICS (continued)
(V
DD
= +5V 10%, COM = GND, REFADJ = V
DD
, V
REF
= +2.5V, 4.7F capacitor at REF pin, f
CLK
= 7.6MHz (50% duty cycle),
T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25C.)
CONDITIONS
UNITS
MIN
TYP
MAX
SYMBOL
PARAMETER
Shutdown mode
V
REF
= 2.5V, f
SAMPLE
= 420ksps
0 to 0.5mA output load
To power down the internal reference
For small adjustments
On/off-leakage current, V
IN
= 0 or V
DD
Unipolar, V
COM
= 0
Bipolar, V
COM
= V
REF
/ 2
2
A
200
300
I
REF
V
1.0
V
DD
+
50mV
V
REF
REF Input Voltage Range
F
4.7
10
Capacitive Bypass at REF
F
0.01
1
Capacitive Bypass at REFADJ
mV/mA
0.2
Load Regulation (Note 7)
V
V
DD
- 1
REFADJ High Threshold
mV
100
REFADJ Input Range
ppm/C
20
TC
REF
REF Temperature Coefficient
mA
15
REF Short-Circuit Current
V
2.49
2.5
2.51
REF Output Voltage
pF
12
C
IN
Input Capacitance
A
0.01
1
Multiplexer Leakage Current
V
0 V
REF
V
IN
Analog Input Voltage Range
Single-Ended and Differential
(Note 6)
-V
REF
/2
+V
REF
/2
CS = V
DD
I
SOURCE
= 1mA
I
SINK
= 1.6mA
V
IN
= 0 or V
DD
A
0.1
1
I
LEAKAGE
Three-State Leakage Current
V
V
DD
- 0.5
V
OH
Output Voltage High
V
0.4
V
OL
Output Voltage Low
pF
15
C
IN
Input Capacitance
A
0.1
1
I
IN
Input Leakage Current
mV
200
V
HYS
Input Hysteresis
V
0.8
V
IL
Input Voltage Low
V
4.0
V
IH
Input Voltage High
CS = V
DD
V
4.5
5.5
V
DD
Analog Supply Voltage
pF
15
C
OUT
Three-State Output Capacitance
3.3
3.6
REF Input Current
A
External reference
2.8
3.1
External reference
0.5
0.8
mA
Internal reference
1.0
1.2
Power-Supply Rejection
PSR
V
DD
= 5V 10%, full-scale input
0.3
0.9
mV
Positive Supply Current
I
DD
Shutdown mode
2
10
A
ANALOG INPUTS
INTERNAL REFERENCE
EXTERNAL REFERENCE AT REF
DIGITAL INPUTS AND OUTPUTS
POWER REQUIREMENTS
Internal reference
Operating mode,
f
SAMPLE
= 420ksps
Standby mode
MAX1294/MAX1296
420ksps, +5V, 6-/2-Channel, 12-Bit ADCs
with +2.5V Reference and Parallel Interface
4
_______________________________________________________________________________________
t
TR
10
40
ns
C
LOAD
= 20pF, Figure 1
RD Rise to Output Disable
WR to CLK Fall Setup Time
t
CWS
60
ns
ns
CLK Pulse Width High
ns
CLK Period
t
CH
40
RD Fall to Output Data Valid
t
DO
10
50
ns
RD Fall to INT High Delay
t
INT1
50
ns
CS Fall to Output Data Valid
t
DO2
100
ns
C
LOAD
= 20pF, Figure 1
C
LOAD
= 20pF, Figure 1
C
LOAD
= 20pF, Figure 1
t
CP
132
CLK Pulse Width Low
t
CL
40
ns
Data Valid to WR Rise Time
t
DS
40
ns
WR Rise to Data Valid Hold Time
t
DH
0
ns
CLK Fall to WR Hold Time
t
CWH
40
ns
CS to CLK or WR Setup Time
t
CSWS
40
ns
CLK or WR to CS Hold Time
t
CSWH
0
ns
CS Pulse Width
t
CS
100
ns
WR Pulse Width (Note 8)
t
WR
60
ns
t
TC
10
60
ns
C
LOAD
= 20pF, Figure 1
PARAMETER
SYMBOL
MIN
TYP
MAX
UNITS
CONDITIONS
CS Rise to Output Disable
Note 1: Tested at V
DD
= +5V, COM = GND, unipolar single-ended input mode.
Note 2: Relative accuracy is the deviation of the analog value at any code from its theoretical value after offset and gain errors have
been removed.
Note 3: Offset nulled.
Note 4: On channel is grounded; sine wave applied to off channels.
Note 5: Conversion time is defined as the number of clock cycles times the clock period; clock has a 50% duty cycle.
Note 6: Input voltage range referenced to negative input. The absolute range for the analog inputs is from GND to V
DD
.
Note 7: External load should not change during conversion for specified accuracy.
Note 8: When bit 5 is set low for internal acquisition, WR must not return low until after the first falling clock edge of the conversion.
TIMING CHARACTERISTICS
(V
DD
= +5V 10%, COM = GND, REFADJ = V
DD
, V
REF
= +2.5V, 4.7F capacitor at REF pin, f
CLK
= 7.6MHz (50% duty cycle),
T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25C.)
3k
3k
DOUT
DOUT
V
DD
a) High-Z to V
OH
and V
OL
to V
OH
b) High-Z to V
OL
and V
OH
to V
OL
C
LOAD
20pF
C
LOAD
20pF
Figure 1. Load Circuits for Enable/Disable Times
MAX1294/MAX1296
420ksps, +5V, 6-/2-Channel, 12-Bit ADCs
with +2.5V Reference and Parallel Interface
_______________________________________________________________________________________
5
-0.5
-0.2
-0.3
-0.4
-0.1
0
0.1
0.2
0.3
0.4
0.5
0
2000
1000
3000
4000
5000
INTEGRAL NONLINEARITY
vs. DIGITAL OUTPUT CODE
MAX1294/6toc01
DIGITAL OUTPUT CODE
INL (LSB)
-0.5
-0.2
-0.3
-0.4
-0.1
0
0.1
0.2
0.3
0.4
0.5
0
2000
1000
3000
4000
5000
DIFFERENTIAL NONLINEARITY
vs. DIGITAL OUTPUT CODE
MAX1294/6toc02
DIGITAL OUTPUT CODE
DNL (LSB)
1.8
1.9
2.0
2.1
2.2
SUPPLY CURRENT vs. SUPPLY VOLTAGE
MAX1294/6 toc03
V
DD
(V)
I
DD
(mA)
4.50
5.00
4.75
5.25
5.50
R
L
=
CODE = 101010100000
1.7
1.9
1.8
2.1
2.0
2.2
2.3
-40
10
-15
35
60
85
SUPPLY CURRENT vs. TEMPERATURE
MAX1294/6 toc04
TEMPERATURE (C)
I
DD
(mA)
R
L
=
CODE = 101010100000
930
950
940
970
960
980
990
4.50
5.00
4.75
5.25
5.50
STANDBY CURRENT vs. SUPPLY VOLTAGE
MAX1294/6 toc05
V
DD
(V)
STANDBY I
DD
(
A)
930
950
940
970
960
980
990
-40
10
-15
35
60
85
STANDBY CURRENT vs. TEMPERATURE
MAX1294/6 toc06
TEMPERATURE (C)
STANDBY I
DD
(
A)
1.0
1.5
2.0
2.5
3.0
POWER-DOWN CURRENT
vs. SUPPLY VOLTAGE
MAX1294/6 toc07
V
DD
(V)
POWER-DOWN I
DD
(
A)
4.50
5.00
4.75
5.25
5.50
1.8
2.0
1.9
2.1
2.2
-40
10
-15
35
60
85
POWER-DOWN CURRENT
vs. TEMPERATURE
MAX1294/6 toc08
TEMPERATURE (C)
POWER-DOWN I
DD
(
A)
Typical Operating Characteristics
(V
DD
= +5V, V
REF
= +2.500V, f
CLK
= 7.6MHz, C
L
= 20pF, T
A
= +25C, unless otherwise noted.)
0.1
1k
100k
10
1
100
10k
1M
SUPPLY CURRENT
vs. SAMPLE FREQUENCY
MAX1294/6toc02A
f
SAMPLE
(Hz)
I
DD
(
A)
0
10
100
1000
10,000
WITH EXTERNAL REFERENCE
WITH INTERNAL REFERENCE
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