19-1155; Rev 5; 8/10
KIT
ATION
EVALU
BLE
AVAILA
+2.7V, Low-Power,
12-Bit Serial ADCs in 8-Pin SO
________________________________Features
♦
Single-Supply Operation:
+2.7V to +3.6V (MAX1240)
+2.7V to +5.25V (MAX1241)
♦
12-Bit Resolution
♦
Internal 2.5V Reference (MAX1240)
♦
Small Footprint: 8-Pin PDIP/SO Packages
♦
Low Power: 3.7µW (73ksps, MAX1240)
3mW (73ksps, MAX1241)
66µW (1ksps, MAX1241)
5µW (power-down mode)
♦
Internal Track/Hold
♦
SPI/QSPI/MICROWIRE 3-Wire Serial Interface
♦
Internal Clock
__________________General Description
The MAX1240/MAX1241 low-power, 12-bit analog-to-
digital converters (ADCs) are available in 8-pin pack-
ages. The MAX1240 operates with a single +2.7V to
+3.6V supply, and the MAX1241 operates with a single
+2.7V to +5.25V supply. Both devices feature a 7.5µs
successive-approximation ADC, a fast track/hold
(1.5µs), an on-chip clock, and a high-speed, 3-wire ser-
ial interface.
Power consumption is only 37mW (V
DD
= 3V) at the
73ksps maximum sampling speed. A 2µA shutdown
mode reduces power at slower throughput rates.
The MAX1240 has an internal 2.5V reference, while the
MAX1241 requires an external reference. The MAX1241
accepts signals from 0V to V
REF
, and the reference
input range includes the positive supply rail. An exter-
nal clock accesses data from the 3-wire interface,
which connects directly to standard microcontroller I/O
ports. The interface is compatible with SPI™, QSPI™,
and MICROWIRE™.
Excellent AC characteristics and very low power com-
bined with ease of use and small package size make
these converters ideal for remote-sensor and data-
acquisition applications, or for other circuits with
demanding power consumption and space require-
ments. The MAX1240/MAX1241 are available in 8-pin
PDIP and SO packages.
MAX1240/MAX1241
Ordering Information
PART*
MAX1240ACPA+
MAX1240BCPA+
MAX1240CCPA+
MAX1240ACSA+
MAX1240BCSA+
MAX1240CCSA+
MAX1240CC/D
MAX1240AESA/V+**
TEMP RANGE
0°C to +70°C
0°C to +70°C
0°C to +70°C
0°C to +70°C
0°C to +70°C
0°C to +70°C
0°C to +70°C
-40°C to +85°C
PIN-
PACKAGE
8 PDIP
8 PDIP
8 PDIP
8 SO
8 SO
8 SO
Dice*
8 SO
INL
(LSB)
±1/2
±1
±1
±1/2
±1
±1
±1
±1/2
Applications
Battery-Powered Systems
Portable Data Logging
Isolated Data Acquisition
Process Control
Instrumentation
MAX1240BESA/V+
-40°C to +85°C 8 SO
±1
Ordering Information continued at end of data sheet.
*Dice
are specified at T
A
= +25°C, DC parameters only.
**Future
product—contact factory for availability.
/V denotes an automotive qualified part.
+Denotes
a lead(Pb)-free/RoHS-compliant package.
Functional Diagram
V
DD
1
Pin Configuration
TOP VIEW
V
DD
AIN
1
2
8
7
SCLK
CS
DOUT
GND
CS
SCLK
SHDN
7
8
3
CONTROL
LOGIC
INT
CLOCK
OUTPUT
SHIFT
REGISTER
6
DOUT
SHDN 3
REF 4
MAX1240
MAX1241
6
5
AIN
2
T/H
2.5V REFERENCE
(MAX1240 ONLY)
12-BIT
SAR
REF
4
MAX1240
MAX1241
5
GND
PDIP/SO
SPI and QSPI are trademarks of Motorola, Inc. MICROWIRE is a trademark of National Semiconductor Corp.
________________________________________________________________
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.
+2.7V, Low-Power,
12-Bit Serial ADCs in 8-Pin SO
MAX1240/MAX1241
ABSOLUTE MAXIMUM RATINGS
V
DD
to GND .............................................................-0.3V to +6V
AIN to GND................................................-0.3V to (V
DD
+ 0.3V)
REF to GND ...............................................-0.3V to (V
DD
+ 0.3V)
Digital Inputs to GND...............................................-0.3V to +6V
DOUT to GND............................................-0.3V to (V
DD
+ 0.3V)
DOUT Current ..................................................................±25mA
Continuous Power Dissipation (T
A
= +70°C)
Plastic DIP (derate 9.09mW/°C above +70°C) ...........727mW
SO (derate 5.88mW/°C above +70°C)........................471mW
CERDIP (derate 8.00mW/°C above +70°C)................640mW
Operating Temperature Ranges
MAX1240_C_A/MAX1241_C_A .........................0°C to +70°C
MAX1240_E_ A/MAX1241_E_ A .....................-40°C to +85°C
MAX1240_MJA/MAX1241_MJA ...................-55°C to +125°C
Storage Temperature Range............................-60°C to +150°C
Lead Temperature (soldering, 10s) ................................+300°C
Soldering Temperature (reflow)
PDIP, SO .....................................................................+260°C
CDIP ...........................................................................+250°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
(V
DD
= +2.7V to +3.6V (MAX1240); V
DD
= +2.7V to +5.25V (MAX1241); 73ksps, f
SCLK
= 2.1MHz (50% duty cycle); MAX1240—4.7µF
capacitor at REF pin, MAX1241—external reference; V
REF
= 2.500V applied to REF pin; T
A
= T
MIN
to T
MAX
; unless otherwise noted.)
PARAMETER
DC ACCURACY
(Note 1)
Resolution
Relative Accuracy (Note 2)
Differential Nonlinearity
Offset Error
Gain Error (Note 3)
Gain Temperature Coefficient
DYNAMIC SPECIFICATIONS
(10kHz sine-wave input, 0V to 2.500Vp-p, 73ksps, f
SCLK
= 2.1MHz)
Signal-to-Noise Plus
Distortion Ratio
Total Harmonic Distortion
Spurious-Free Dynamic Range
Small-Signal Bandwidth
Full-Power Bandwidth
CONVERSION RATE
Conversion Time
Track/Hold Acquisition Time
Throughput Rate
Aperture Delay
Aperture Jitter
ANALOG INPUT
Input Voltage Range
Input Capacitance
2
0
16
V
REF
V
pF
t
APR
t
CONV
t
ACQ
f
SCLK
= 2.1MHz
Figure 8
30
<50
5.5
7.5
1.5
73
µs
µs
ksps
ns
ps
SINAD
THD
SFDR
MAX124_A/B
MAX124_C
Up to the 5th harmonic
MAX124_A/B
MAX124_C
-3dB rolloff
MAX124_A/B
MAX124_C
80
88
2.25
1.0
-88
70
71.5
-80
dB
dB
dB
MHz
MHz
INL
DNL
MAX124_A
MAX124_B/C
No missing codes over temperature
MAX124_A
MAX124_B/C
±0.5
±0.5
±0.5
±0.25
12
±0.5
±1.0
±1
±3.0
±4.0
±4.0
Bits
LSB
LSB
LSB
LSB
ppm/°C
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
_______________________________________________________________________________________
+2.7V, Low-Power,
12-Bit Serial ADCs in 8-Pin SO
ELECTRICAL CHARACTERISTICS (continued)
(V
DD
= +2.7V to +3.6V (MAX1240); V
DD
= +2.7V to +5.25V (MAX1241); 73ksps, f
SCLK
= 2.1MHz (50% duty cycle); MAX1240—4.7µF
capacitor at REF pin, MAX1241—external reference; V
REF
= 2.500V applied to REF pin; T
A
= T
MIN
to T
MAX
; unless otherwise noted.)
PARAMETER
REF Output Voltage
REF Short-Circuit Current
MAX1240AC/BC
REF Temperature Coefficient
MAX1240AE/BE
MAX1240AM/BM
MAX1240C
Load Regulation (Note 4)
Capacitive Bypass at REF
EXTERNAL REFERENCE
(V
REF
= 2.500V)
Input Voltage Range
Input Current
Input Resistance
REF Input Current in Shutdown
Capacitive Bypass at REF
DIGITAL INPUTS: SCLK,
CS
,
SHDN
SCLK,
CS
Input High Voltage
SCLK,
CS
Input Low Voltage
SCLK,
CS
Input Hysteresis
SCLK,
CS
Input Leakage
SCLK,
CS
Input Capacitance
SHDN
Input High Voltage
SHDN
Input Low Voltage
SHDN
Input Current
SHDN
Input Mid Voltage
SHDN
Voltage, Unconnected
SHDN
Max Allowed Leakage,
Mid Input
DIGITAL OUTPUT: DOUT
Output Voltage Low
Output Voltage High
Three-State Leakage Current
Three-State Output Capacitance
V
OL
V
OH
I
L
C
OUT
I
SINK
= 5mA
I
SINK
= 16mA
I
SOURCE
= 0.5mA
CS
= V
DD
CS
= V
DD
(Note 5)
V
DD
- 0.5
±0.01
±10
15
0.4
0.8
V
V
µA
pF
V
SM
V
FLT
SHDN
= unconnected
SHDN
= unconnected
V
IH
V
IL
V
HYST
I
IN
C
IN
V
SH
V
SL
V
SHDN
= 0V or V
DD
1.1
V
DD
/2
±100
V
IN
= 0V or V
DD
(Note 5)
V
DD
- 0.4
0.4
±4.0
V
DD
- 1.1
0.2
±0.01
±1
15
V
DD
≤
3.6V
V
DD
> 3.6V (MAX1241)
2.0
3.0
0.8
V
V
V
µA
pF
V
V
µA
V
V
nA
V
SHDN
= 0V
0.1
18
1.00
100
25
±0.01
10
V
DD
+
50mV
150
V
µA
kΩ
µA
µF
0mA to 0.2mA output load
4.7
±30
±30
±30
±30
0.35
µF
SYMBOL
T
A
= +25°C
CONDITIONS
MIN
2.480
TYP
2.500
MAX
2.520
30
±50
±60
±80
ppm/°C
ppm/°C
UNITS
V
mA
INTERNAL REFERENCE
(MAX1240 only)
MAX1240/MAX1241
_______________________________________________________________________________________
3
+2.7V, Low-Power,
12-Bit Serial ADCs in 8-Pin SO
MAX1240/MAX1241
ELECTRICAL CHARACTERISTICS (continued)
(V
DD
= +2.7V to +3.6V (MAX1240); V
DD
= +2.7V to +5.25V (MAX1241); 73ksps, f
SCLK
= 2.1MHz (50% duty cycle); MAX1240—4.7µF
capacitor at REF pin, MAX1241—external reference; V
REF
= 2.500V applied to REF pin; T
A
= T
MIN
to T
MAX
; unless otherwise noted.)
PARAMETERS
POWER REQUIREMENTS
Supply Voltage
V
DD
MAX1240
MAX1241
MAX1240A/B
MAX1240C
Operating
mode
Supply Current
I
DD
MAX1241C
Power-down, digital inputs
at 0V or V
DD
Supply Rejection
PSR
(Note 5)
MAX1241A/B
V
DD
= 3.6V
V
DD
= 3.6V
V
DD
= 3.6V
V
DD
= 5.25V
V
DD
= 3.6V
V
DD
= 5.25V
V
DD
= 3.6V
V
DD
= 5.25V
2.7
2.7
1.4
1.4
0.9
1.6
0.9
1.6
1.9
3.5
±0.3
3.6
5.25
2.0
3.5
1.5
2.5
2.8
3.8
10
15
µA
mV
mA
V
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
TIMING CHARACTERISTICS
(Figure 8)
(V
DD
= +2.7V to +3.6V (MAX1240); V
DD
= +2.7V to +5.25V (MAX1241); T
A
= T
MIN
to T
MAX
, unless otherwise noted.)
PARAMETERS
Acquisition Time
SCLK Fall to Output Data Valid
CS
Fall to Output Enable
CS
Rise to Output Disable
SCLK Clock Frequency
SCLK Pulse Width High
SCLK Pulse Width Low
SCLK Low to
CS
Fall Setup Time
DOUT Rise to SCLK Rise (Note 5)
CS
Pulse Width
SYMBOL
t
ACQ
t
DO
t
DV
t
TR
f
SCLK
t
CH
t
CL
t
CS0
t
STR
t
CS
Figure 1,
C
LOAD
= 50pF
Figure 1, C
LOAD
= 50pF
Figure 2, C
LOAD
= 50pF
0
200
200
50
0
240
CONDITIONS
CS
= V
DD
(Note 6)
MAX124_ _C/E
MAX124_ _M
MIN
1.5
20
20
200
240
240
240
2.1
TYP
MAX
UNITS
µs
ns
ns
ns
MHz
ns
ns
ns
ns
ns
Note 1:
Tested at V
DD
= +2.7V.
Note 2:
Relative accuracy is the deviation of the analog value at any code from its theoretical value after the full-scale range and
offset have been calibrated.
Note 3:
MAX1240—internal reference, offset nulled; MAX1241—external reference (V
REF
= +2.500V), offset nulled.
Note 4:
External load should not change during conversion for specified accuracy.
Note 5:
Guaranteed by design. Not subject to production testing.
Note 6:
Measured as [V
FS
(2.7V) - V
FS
(V
DD(MAX
)].
Note 7:
To guarantee acquisition time, t
ACQ
is the maximum time the device takes to acquire the signal, and is also the minimum
time needed for the signal to be acquired.
4
_______________________________________________________________________________________
+2.7V, Low-Power,
12-Bit Serial ADCs in 8-Pin SO
MAX1240/MAX1241
+2.7V
6k
DOUT
6k
DGND
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
= 50pF
DOUT
C
LOAD
= 50pF
DGND
Figure 1. Load Circuits for DOUT Enable Time
+2.7V
6k
DOUT
6k
DGND
a)
V
OH
to High-Z
b)
V
OL
to High-Z
C
LOAD
= 50pF
DOUT
C
LOAD
= 50pF
DGND
Figure 2. Load Circuits for DOUT Disable Time
__________________________________________Typical Operating Characteristics
(V
DD
= 3.0V, V
REF
= 2.5V, f
SCLK
= 2.1MHz, C
L
= 20pF, T
A
= +25°C, unless otherwise noted.)
OPERATING SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX1241-D
SUPPLY CURRENT vs. TEMPERATURE
MAX1241-A/NEW
OFFSET ERROR
vs. SUPPLY VOLTAGE
0.9
0.8
OFFSET ERROR (LSB)
0.7
0.6
0.5
0.4
0.3
0.2
MAX1241-03
2.0
OPERATING SUPPLY CURRENT (mA)
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
2
R
L
=
∞
CODE = 101010100000
MAX1240
1.3
MAX1240
1.0
1.2
SUPPLY CURRENT (mA)
1.1
MAX1241
1.0
MAX1241
0.9
R
LOAD
=
∞
CODE = 10101010000
-60
-20
20
60
100
140
0.1
0
2.25
2.75
3.25
3.75
4.25
4.75
5.25
SUPPLY VOLTAGE (V)
0.8
3
4
SUPPLY VOLTAGE (V)
5
6
TEMPERATURE (°C)
_______________________________________________________________________________________
5
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