Maxim MAX1295BEEI, MAX1295BCEI, MAX1295AEEI, MAX1295ACEI, MAX1297BEEG Datasheet

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General Description
The MAX1295/MAX1297 low-power, 12-bit analog-to­digital converters (ADCs) feature a successive-approxi­mation ADC, automatic power-down, fast wake-up (2µs), on-chip clock, +2.5V internal reference, and high-speed 12-bit parallel interface. They operate with a single +2.7V to +3.6V analog supply.
Power consumption is only 5.4mW at the maximum sampling rate of 265ksps. Two software-selectable power-down modes enable the MAX1295/MAX1297 to be shut down between conversions; accessing the par­allel interface returns them to normal operation. Powering down between conversions can reduce sup­ply current below 10µA 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 MAX1295 has six input channels and the MAX1297 has two (three input channels and one input channel, respectively, when in pseudo-differential mode).
Excellent dynamic performance and low power combined with ease of use and small package size make these con­verters ideal for battery-powered and data-acquisition applications or for other circuits with demanding power­consumption and space requirements. The MAX1295 is offered in a 28-pin QSOP package, while the MAX1297 comes in a 24-pin QSOP. For pin-compatible +5V, 12-bit versions, refer to the MAX1294/MAX1296 data sheet.
Applications
Industrial Control Systems Data Logging Energy Management Patient Monitoring Data-Acquisition Systems Touchscreens
Features
12-Bit Resolution, ±0.5LSB Linearity+3V Single-Supply OperationInternal +2.5V ReferenceSoftware-Configurable Analog Input Multiplexer
6-Channel Single-Ended/ 3-Channel Pseudo-Differential (MAX1295)
2-Channel Single-Ended/ 1-Channel Pseudo-Differential (MAX1297)
Software-Configurable Unipolar/Bipolar
Analog Inputs
Low Current
1.8mA (265ksps)
1.0mA (100ksps) 400µA (10ksps) 2µA (shutdown)
Internal 3MHz Full-Power Bandwidth Track/HoldParallel 12-Bit InterfaceSmall Footprint
28-Pin QSOP (MAX1295) 24-Pin QSOP (MAX1297)
MAX1295/MAX1297
265ksps, +3V, 6-/2-Channel, 12-Bit ADCs
with +2.5V Reference and Parallel Interface
________________________________________________________________
Maxim Integrated Products
1
19-1530; Rev 0; 9/99
EVALUATION KIT
AVAILABLE
28 QSOP ±10°C to +70°CMAX1295BCEI
INL
(LSB)
±0.528 QSOP
PIN-PACKAGETEMP. RANGE
0°C to +70°C
MAX1295ACEI
PART
Ordering Information
Pin Configurations
Typical Operating Circuits appear at end of data sheet.
Pin Configurations continued at end of data sheet.
28 QSOP ±0.5-40°C to +85°CMAX1295AEEI 28 QSOP ±1-40°C to +85°CMAX1295BEEI
24 QSOP ±0.5-40°C to +85°CMAX1297AEEG 24 QSOP ±1-40°C to +85°CMAX1297BEEG
24 QSOP ±10°C to +70°CMAX1297BCEG
±0.524 QSOP0°C to +70°C
MAX1297ACEG
TOP VIEW
1
D9
2
D8
3
D7
4
D6
5
D5
D4
D3
D2
D1
D0
INT
RD
WR
CLK
MAX1295
6
7
8
9
10
11
12
13
14
QSOP
28
27
26
25
24
23
22
21
20
19
18
17
16
15
D10
D11
V
DD
REF
REFADJ
GND
COM
CH0
CH1
CH2
CH3
CH4
CH5
CS
MAX1295/MAX1297
265ksps, +3V, 6-/2-Channel, 12-Bit ADCs with +2.5V Reference and Parallel Interface
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(VDD= +2.7V to +3.6V, COM = GND, REFADJ = VDD, V
REF
= +2.5V, 4.7µF capacitor at REF pin, f
CLK
= 4.8MHz (50% duty cycle),
T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at TA= +25°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.
VDDto GND..............................................................-0.3V to +6V
CH0–CH5, COM to GND............................-0.3V to (VDD+ 0.3V)
REF, REFADJ to GND.................................-0.3V to (VDD+ 0.3V)
Digital Inputs to GND ...............................................-0.3V to +6V
Digital Outputs (D0–D11, INT) to GND.......-0.3V to (V
DD
+ 0.3V)
Continuous Power Dissipation (T
A
= +70°C)
24-Pin QSOP (derate 9.5mW/°C above +70°C)..........762mW
28-Pin QSOP (derate 8.00mW/°C above +70°C)........667mW
Operating Temperature Ranges
MAX1295_C_ _ /MAX1297_C__ ........................0°C to +70°C
MAX1295_E_ _ /MAX1297_E__ ......................-40°C to +85°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10sec) .............................+300°C
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
fIN= 125kHz (Note 4)
f
IN1
= 49kHz, f
IN2
= 52kHz
MAX129_B No missing codes over temperature
CONDITIONS
ns50Aperture Delay
ns625t
ACQ
Track/Hold Acquisition Time
3.2 3.6 4.1
2.5 3.0 3.5
µs
3.3
t
CONV
Conversion Time (Note 5)
MHz
3
Full-Power Bandwidth
kHz
250
Full-Linear Bandwidth
dB
-78
Channel-to-Channel Crosstalk
dB
76
IMDIntermodulation Distortion
dB
80
SFDRSpurious-Free Dynamic Range
dB
Total Harmonic Distortion (including 5th-order harmonic)
-78
THD
±0.5
INLRelative Accuracy (Note 2)
Bits
12
RESResolution
dB
67 70
SINADSignal-to-Noise Plus Distortion
LSB
±0.2
Channel-to-Channel Offset Matching
ppm/°C
±2.0
Gain Temperature Coefficient
LSB
±1
LSB
±1
DNLDifferential Nonlinearity
LSB
±4
Offset Error
LSB
±4
Gain Error (Note 3)
UNITSMIN TYP MAXSYMBOLPARAMETER
Internal acquisition/internal clock mode
External acquisition or external clock mode
<200
ps
<50
Aperture Jitter
MHz0.1 4.8f
CLK
External Clock Frequency
%30 70Duty Cycle
DC ACCURACY (Note 1)
DYNAMIC SPECIFICATIONS (f
IN(sine-wave)
= 50kHz, VIN= 2.5Vp-p, 265ksps, external f
CLK
= 4.8MHz, bipolar input mode)
CONVERSION RATE
MAX1295/MAX1297
265ksps, +3V, 6-/2-Channel, 12-Bit ADCs
with +2.5V Reference and Parallel Interface
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS (continued)
(VDD= +2.7V to +3.6V, COM = GND, REFADJ = VDD, V
REF
= +2.5V, 4.7µF capacitor at REF pin, f
CLK
= 4.8MHz (50% duty cycle),
T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at TA= +25°C.)
CONDITIONS UNITSMIN TYP MAXSYMBOLPARAMETER
0 to 0.5mA output load
To power down the internal reference
For small adjustments
On/off-leakage-current, VIN= 0 or V
DD
Unipolar, V
COM
= 0
Bipolar, V
COM
= V
REF
/2
V
1.0
V
DD
+
50mV
V
REF
REF Input Voltage Range
µF
4.7 10
Capacitive Bypass at REF
µF
0.01 1
Capacitive Bypass at REFADJ
mV/mA
0.2 0.5
Load Regulation (Note 7)
V
VDD- 1
REFADJ High Threshold
mV
±100
REFADJ Input Range
mA
15
REF Short-Circuit Current
V
2.49 2.5 2.51
REF Output Voltage
pF
12
C
IN
Input Capacitance
µA
±0.01 ±1
Multiplexer Leakage Current
V
0 V
REF
Analog Input Voltage Range Single-Ended and Differential (Note 6)
-V
REF
/2 +V
REF
/2
V
IN
CS = V
DD
I
SOURCE
= 1mA
I
SINK
= 1.6mA
VIN= 0 or V
DD
V
REF
= 2.5V, f
SAMPLE
= 265ksps
µA
±0.1 ±1
I
LEAKAGE
Three-State Leakage Current
V
VDD- 0.5
V
OH
Output Voltage High
V
0.4
V
OL
Output Voltage Low
pF
15
C
IN
Input Capacitance
µA
±0.1 ±1
I
IN
Input Leakage Current
mV
200
V
HYS
Input Hysteresis
V
0.8
V
IL
Input Voltage Low
V
2.0
V
IH
Input Voltage High
µA
200 300
I
REF
REF Input Current
CS = V
DD
V
2.7 3.6
V
DD
Analog Supply Voltage
pF
15
C
OUT
Three-State Output Capacitance
Internal reference
2.3 2.6
ppm/°C
±20
TC
REF
REF Temperature Coefficient
Shutdown mode
2
External reference
1.9 2.3
0.9 1.2
Positive Supply Current
Shutdown mode
210
µA
Power-Supply Rejection PSR VDD= 2.7V to 3.6V, full-scale input
±0.4 ±0.7
mV
I
DD
0.5 0.8
mA
Operating mode, f
SAMPLE
= 265ksps
Internal reference External reference
Standby mode
CONVERSION RATE (continued)ANALOG INPUTS
INTERNAL REFERENCE
EXTERNAL REFERENCE AT REF
DIGITAL INPUTS AND OUTPUTS
POWER REQUIREMENTS
MAX1295/MAX1297
265ksps, +3V, 6-/2-Channel, 12-Bit ADCs with +2.5V Reference and Parallel Interface
4 _______________________________________________________________________________________
t
TR
20 70
nsC
LOAD
= 20pF, Figure 1
RD Rise to Output Disable
WR to CLK Fall Setup Time
t
CWS
40
ns
nsCLK Pulse Width High
nsCLK Period
t
CH
40
RD Fall to Output Data Valid
t
DO
20 70
ns
RD Fall to INT High Delay
t
INT1
100
ns
CS Fall to Output Data Valid
t
DO2
110
ns
C
LOAD
= 20pF, Figure 1
C
LOAD
= 20pF, Figure 1
C
LOAD
= 20pF, Figure 1
t
CP
208
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
60
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
20 100
nsC
LOAD
= 20pF, Figure 1
PARAMETER SYMBOL MIN TYP MAX UNITSCONDITIONS
CS Rise to Output Disable
Note 1: Tested at VDD= +3V, 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
(VDD= +2.7V to +3.6V, COM = GND, REFADJ = VDD, V
REF
= +2.5V, 4.7µF capacitor at REF pin, f
CLK
= 4.8MHz (50% duty cycle),
T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at TA= +25°C.)
Figure 1. Load Circuits for Enable/Disable Times
V
DD
3k
DOUT
6k
GND GND
a) HIGH-Z TO VOH AND VOL TO V
C 20pF
LOAD
OH
DOUT
b) HIGH-Z TO VOL AND VOH TO V
C
LOAD
20pF
OL
MAX1295/MAX1297
265ksps, +3V, 6-/2-Channel, 12-Bit ADCs
with +2.5V Reference and Parallel Interface
_______________________________________________________________________________________
5
Typical Operating Characteristics
(VDD= +3V, V
REF
= +2.500V, f
CLK
= 4.8MHz, CL= 20pF, TA = +25°C, unless otherwise noted.)
0.1
1k
100k
101100
10k
1M
SUPPLY CURRENT
vs. SAMPLE FREQUENCY
MAX1295/7-02A
f
SAMPLE
(Hz)
I
DD
(µA)
0
10
100
1000
10,000
WITH EXTERNAL REFERENCE
WITH INTERNAL REFERENCE
INTEGRAL NONLINEARITY vs.
DIGITAL OUTPUT CODE
0.5
0.4
0.3
0.2
0.1
0
INL (LSB)
-0.1
-0.2
-0.3
-0.4
-0.5 0 20001000 3000 4000 5000
DIGITAL OUTPUT CODE
SUPPLY CURRENT vs. SUPPLY VOLTAGE
2.10
2.05
2.00
(mA)
1.95
DD
I
1.90
1.85
R
L
CODE = 101010100000
=
MAX1295/7-01
MAX1295/7 toc03
DIFFERENTIAL NONLINEARITY vs.
DIGITAL OUTPUT CODE
0.5
0.4
0.3
0.2
0.1
0
DNL (LSB)
-0.1
-0.2
-0.3
-0.4
-0.5 0 20001000 3000 4000 5000
DIGITAL OUTPUT CODE
SUPPLY CURRENT vs. TEMPERATURE
2.2
2.1
2.0
(mA)
1.9
DD
I
1.8
1.7
R
=
L
CODE = 101010100000
MAX1295/7-02
MAX1295/7 toc04
STANDBY CURRENT vs. SUPPLY VOLTAGE
930
920
(µA)
910
DD
900
STANDBY I
890
MAX1295/7 toc05
MAX1295/7 toc07
880
2.7 3.33.0 3.6 V
(V)
DD
POWER-DOWN CURRENT
vs. TEMPERATURE
1.2
1.1
(µA)
DD
1.0
POWER-DOWN I
0.9
0.8
-40 35-15 10 60 85
TEMPERATURE (°C)
MAX1295/7 toc08
1.80
2.7 3.0 3.3 3.6 VDD (V)
1.6
-40 10-15 35 60 85
TEMPERATURE (°C)
POWER-DOWN CURRENT
STANDBY CURRENT vs. TEMPERATURE
MAX1295/7 toc06
1.50
1.25
(µA)
DD
1.00
POWER-DOWN I
0.75
0.50
2.7 3.0 3.3 3.6
930
920
(µA)
910
DD
900
STANDBY I
890
880
-40 10-15 35 8560
TEMPERATURE (°C)
vs. SUPPLY VOLTAGE
VDD (V)
MAX1295/MAX1297
265ksps, +3V, 6-/2-Channel, 12-Bit ADCs with +2.5V Reference and Parallel Interface
6 _______________________________________________________________________________________
Typical Operating Characteristics (continued)
(VDD= +3V, V
REF
= +2.500V, f
CLK
= 4.8MHz, CL= 20pF, TA = +25°C, unless otherwise noted.)
MAX1295/7-10
V
REF
(mA)
85
2.48
2.49
2.51
2.50
2.52
2.53
INTERNAL REFERENCE VOLTAGE
vs. TEMPERATURE
TEMPERATURE (°C)
-40 60
35
10
-15
-2.5
-2.0
-1.0
-1.5
-0.5
0
OFFSET ERROR vs. SUPPLY VOLTAGE
MAX1295/7 toc11
VDD (V)
OFFSET ERROR (LSB)
2.7 3.33.0 3.6
-2.5
-1.5
-2.0
-0.5
-1.0
0
0.5
-40 10-15 35 60 85
OFFSET ERROR vs. TEMPERATURE
MAX1295/7 toc12
TEMPERATURE (°C)
OFFSET ERROR (LSB)
-3.0
-1.0
-2.0
0
1.0
2.7 3.33.0 3.6
GAIN ERROR vs. SUPPLY VOLTAGE
MAX1295/7 toc13
VDD (V)
GAIN ERROR (LSB)
-2.0
-1.5
-0.5
-1.0
0
0.5
GAIN ERROR vs. TEMPERATURE
MAX1295/7 toc14
TEMPERATURE (°C)
GAIN ERROR (LSB)
-40 10-15 35 60 85
MAX1295/7-09
V
REF
(V)
3.6
2.48
2.49
2.51
2.50
2.52
2.53
INTERNAL REFERENCE VOLTAGE vs.
SUPPLY VOLTAGE
V
DD
(V)
2.7
3.33.0
-140
-120
-100
-80
-60
-40
-20
0
20
0 200 400 600 800 1000
FFT PLOT
MAX1295/7-15
FREQUENCY (kHz)
AMPLITUDE (dB)
V
DD
= 3V
f
IN
= 50kHz
f
SAMPLE
= 250ksps
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