General Description
The MAX1236MAX1239 low-power, 12-bit, multichan-
nel analog-to-digital converters (ADCs) feature internal
track/hold (T/H), voltage reference, clock, and an
I
2
C-compatible 2-wire serial interface. These devices
operate from a single supply of 2.7V to 3.6V (MAX1237/
MAX1239) or 4.5V to 5.5V (MAX1236/MAX1238) and
require only 670µA at the maximum sampling rate of
94.4ksps. Supply current falls below 230µA for sam-
pling rates under 46ksps. AutoShutdownTM powers
down the devices between conversions, reducing sup-
ply current to less than 1µA at low throughput rates.
The MAX1236/MAX1237 have four analog input chan-
nels each, while the MAX1238/MAX1239 have 12 ana-
log input channels each. The fully differential analog
inputs are software configurable for unipolar or bipolar,
and single-ended or differential operation.
The full-scale analog input range is determined by the
internal reference or by an externally applied reference
voltage ranging from 1V to V
DD
. The MAX1237/
MAX1239 feature a 2.048V internal reference and the
MAX1236/MAX1238 feature a 4.096V internal reference.
The MAX1236/MAX1237 are available in an 8-pin µMAX
package. The MAX1238/MAX1239 are available in a 16-
pin QSOP package. The MAX1236MAX1239 are guar-
anteed over the extended temperature range
(-40°C to +85°C). For pin-compatible 10-bit parts, refer to
the MAX1136MAX1139 data sheet. For pin-compatible
8-bit parts, refer to the MAX1036MAX1039 data sheet.
Applications
Hand-Held Portable Applications
Medical Instruments
Battery-Powered Test Equipment
Solar-Powered Remote Systems
Received-Signal-Strength Indicators
System Supervision
Features
o High-Speed I
2
C-Compatible Serial Interface
400kHz Fast Mode
1.7MHz High-Speed Mode
o Single-Supply
2.7V to 3.6V (MAX1237/MAX1239)
4.5V to 5.5V (MAX1236/MAX1238)
o Internal Reference
2.048V (MAX1237/MAX1239)
4.096V (MAX1236/MAX1238)
o External Reference: 1V to V
DD
o Internal Clock
o 4-Channel Single-Ended or 2-Channel Fully
Differential (MAX1236/MAX1237)
o 12-Channel Single-Ended or 6-Channel Fully
Differential (MAX1238/MAX1239)
o Internal FIFO with Channel-Scan Mode
o Low Power
670µA at 94.4ksps
230µA at 40ksps
60µA at 10ksps
6µA at 1ksps
0.5µA in Power-Down Mode
o Software-Configurable Unipolar/Bipolar
o Small Packages
8-Pin µMAX (MAX1236/MAX1237)
16-Pin QSOP (MAX1238/MAX1239)
MAX1236MAX1239
2.7V to 3.6V and 4.5V to 5.5V, Low-Power,
4-/12-Channel, 2-Wire Serial, 12-Bit ADCs
________________________________________________________________ Maxim Integrated Products
1
Ordering Information
19-2333; Rev 2; 2/03
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.
Ordering Information continued at end of data sheet.
Pin Configurations appear at end of data sheet.
Typical Operating Circuit appears at end of data sheet.
PART
TEMP
RANGE
PIN-
PA CKA GE
I
2
C SLAVE
ADDRESS
IN L
( L SB )
MAX1236EUA
- 40
° C to + 85° C 8
µMAX
0110100
±1
MAX1236KEUA* - 40
° C to + 85° C 8
µMAX
0110000
±1
MAX1236LEUA* - 40
° C to + 85° C 8
µMAX
0110010
±1
M AX 1236M E U A* - 40
° C to + 85° C 8
µMAX
0110110
±1
MAX1237EUA
- 40
° C to + 85° C 8
µMAX
0110100
±1
MAX1237KEUA* - 40
° C to + 85° C 8
µMAX
0110000
±1
MAX1237LEUA* - 40
° C to + 85° C 8
µMAX
0110010
±1
M AX 1237M E U A* - 40
° C to + 85° C 8
µMAX
0110110
±1
AutoShutdown is a trademark of Maxim Integrated Products, Inc.
*Future product--contact factory for availability.
Selector Guide
PART
INPUT
CHANNELS
INTERNAL
REFERENCE
(V)
SUPPLY
VOLTAGE (V)
MAX1236EUA
4
4.096
4.5 to 5.5
MAX1237EUA
4
2.048
2.7 to 3.6
MAX1238EEE
12
4.096
4.5 to 5.5
MAX1239EEE
12
2.048
2.7 to 3.6
MAX1236MAX1239
2.7V to 3.6V and 4.5V to 5.5V, Low-Power,
4-/12-Channel, 2-Wire Serial, 12-Bit ADCs
2
_______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(V
DD
= 2.7V to 3.6V (MAX1237/MAX1239), V
DD
= 4.5V to 5.5V (MAX1236/MAX1238), V
REF
= 2.048V (MAX1237/MAX1239), V
REF
=
4.096V (MAX1236/MAX1238), C
REF
= 0.1µF, f
SCL
= 1.7MHz, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at
T
A
= +25°C, see Tables 15 for programming notation.)
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
AIN0AIN11,
REF to GND ............-0.3V to the lower of (V
DD
+ 0.3V) and 6V
SDA, SCL to GND.....................................................-0.3V to +6V
Maximum Current Into Any Pin .........................................±50mA
Continuous Power Dissipation (T
A
= +70°C)
8-Pin µMAX (derate 4.5mW/°C above +70°C) .............362mW
16-Pin QSOP (derate 8.3mW/°C above +70°C)........666.7mW
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-60°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
DC ACCURACY (Note 1)
Resolution
12
Bits
Relative Accuracy
INL
(Note 2)
±1
LSB
Differential Nonlinearity
DNL
No missing codes over temperature
±1
LSB
Offset Error
±4
LSB
Offset-Error Temperature
Coefficient
Relative to FSR
0.3
ppm/
°C
Gain Error
(Note 3)
±4
LSB
Gain-Temperature Coefficient
Relative to FSR
0.3
ppm/
°C
Channel-to-Channel Offset
Matching
±0.1
LSB
Channel-to-Channel Gain
Matching
±0.1
LSB
DYNAMIC PERFORMANCE (f
IN(SINE-WAVE)
= 10kHz, V
IN(P-P)
= V
REF
, f
SAMPLE
= 94.4ksps)
Signal-to-Noise Plus Distortion
SINAD
70
dB
Total Harmonic Distortion
THD
Up to the 5th harmonic
-78
dB
Spurious-Free Dynamic Range
SFDR
78
dB
Full-Power Bandwidth
SINAD > 68dB
3
MHz
Full-Linear Bandwidth
-3dB point
5
MHz
CONVERSION RATE
Internal clock
7.5
Conversion Time (Note 4)
t
CONV
External clock
10.6
µs
MAX1236MAX1239
2.7V to 3.6V and 4.5V to 5.5V, Low-Power,
4-/12-Channel, 2-Wire Serial, 12-Bit ADCs
_______________________________________________________________________________________
3
ELECTRICAL CHARACTERISTICS (continued)
(V
DD
= 2.7V to 3.6V (MAX1237/MAX1239), V
DD
= 4.5V to 5.5V (MAX1236/MAX1238), V
REF
= 2.048V (MAX1237/MAX1239), V
REF
=
4.096V (MAX1236/MAX1238), C
REF
= 0.1µF, f
SCL
= 1.7MHz, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at
T
A
= +25°C, see Tables 15 for programming notation.)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Internal clock, SCAN[1:0] = 01
51
Internal clock, SCAN[1:0] = 00
CS[3:0] = 1011 (MAX1238/MAX1239)
51
Throughput Rate
f
SAMPLE
External clock
94.4
ksps
Track/Hold Acquisition Time
800
ns
Internal Clock Frequency
2.8
MHz
External clock, fast mode
60
Aperture Delay (Note 5)
t
AD
External clock, high-speed mode
30
ns
ANALOG INPUT (AIN0AIN11)
Unipolar
0
V
REF
Input-Voltage Range, Single-
Ended and Differential (Note 6)
Bipolar
0
±V
REF
/2
V
Input Multiplexer Leakage Current
ON/OFF leakage current, V
AIN
_ = 0 or V
DD
±0.01
±1
µA
Input Capacitance
C
IN
22
pF
INTERNAL REFERENCE (Note 7)
MAX1237/MAX1239
1.968
2.048
2.128
Reference Voltage
V
REF
T
A
= +25°C
MAX1236/MAX1238
3.936
4.096
4.256
V
Reference-Voltage Temperature
Coefficient
TCV
REF
25
ppm/
°C
REF Short-Circuit Current
2
mA
REF Source Impedance
1.5
k
EXTERNAL REFERENCE
REF Input-Voltage Range
V
REF
(Note 8)
1
V
DD
V
REF Input Current
I
REF
f
SAMPLE
= 94.4ksps
40
µA
DIGITAL INPUTS/OUTPUTS (SCL, SDA)
Input-High Voltage
V
IH
0.7
V
DD
V
Input-Low Voltage
V
IL
0.3
V
DD
V
Input Hysteresis
V
HYST
0.1
V
DD
V
Input Current
I
IN
V
IN
= 0 to V
DD
±10
µA
Input Capacitance
C
IN
15
pF
Output Low Voltage
V
OL
I
SINK
= 3mA
0.4
V
MAX1236MAX1239
2.7V to 3.6V and 4.5V to 5.5V, Low-Power,
4-/12-Channel, 2-Wire Serial, 12-Bit ADCs
4
_______________________________________________________________________________________
ELECTRICAL CHARACTERISTICS (continued)
(V
DD
= 2.7V to 3.6V (MAX1237/MAX1239), V
DD
= 4.5V to 5.5V (MAX1236/MAX1238), V
REF
= 2.048V (MAX1237/MAX1239), V
REF
=
4.096V (MAX1236/MAX1238), C
REF
= 0.1µF, f
SCL
= 1.7MHz, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at
T
A
= +25°C, see Tables 15 for programming notation.)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
POWER REQUIREMENTS
MAX1237/MAX1239
2.7
3.6
Supply Voltage
V
DD
MAX1236/MAX1238
4.5
5.5
V
Internal reference
900
1150
f
SAMPLE
= 94.4ksps
external clock
External reference
670
900
Internal reference
530
f
SAMPLE
= 40ksps
internal clock
External reference
230
Internal reference
380
f
SAMPLE
= 10ksps
internal clock
External reference
60
Internal reference
330
f
SAMPLE
=1ksps
internal clock
External reference
6
Supply Current
I
DD
Shutdown (internal REF off)
0.5
10
µA
Power-Supply Rejection Ratio
PSRR
Full-scale input (Note 9)
±0.5
±0.2
LSB/V
TIMING CHARACTERISTICS (Figure 1)
(V
DD
= 2.7V to 3.6V (MAX1237/MAX1239), V
DD
= 4.5V to 5.5V (MAX1236/MAX1238), V
REF
= 2.048V (MAX1237/MAX1239), V
REF
=
4.096V (MAX1236/MAX1238), C
REF
= 0.1µF, f
SCL
= 1.7MHz, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at
T
A
= +25°C, see Tables 15 for programming notation.)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
TIMING CHARACTERISTICS FOR FAST MODE
Serial-Clock Frequency
f
SCL
400
kHz
Bus Free Time Between a STOP (P)
and a START (S) Condition
t
BUF
1.3
µs
Hold Time for START (S) Condition
t
HD,
STA
0.6
µs
Low Period of the SCL Clock
t
LOW
1.3
µs
High Period of the SCL Clock
t
HIGH
0.6
µs
Setup Time for a Repeated START
Condition (Sr)
t
SU,
STA
0.6
µs
Data Hold Time (Note 10)
t
HD,
DAT
0
900
ns
Data Setup Time
t
SU,
DAT
100
ns
Rise Time of Both SDA and SCL
Signals, Receiving
t
R
Measured from 0.3V
DD
- 0.7V
DD
20 + 0.1C
B
300
ns
Fall Time of SDA Transmitting
t
F
Measured from 0.3V
DD
- 0.7V
DD
20 + 0.1C
B
300
ns
Setup Time for STOP (P) Condition
t
SU,
STO
0.6
µs
Capacitive Load for Each Bus Line
C
B
400
pF
Pulse Width of Spike Suppressed
t
SP
50
ns
MAX1236MAX1239
2.7V to 3.6V and 4.5V to 5.5V, Low-Power,
4-/12-Channel, 2-Wire Serial, 12-Bit ADCs
_______________________________________________________________________________________
5
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
TIMING CHARACTERISTICS FOR HIGH-SPEED MODE (C
B
= 400pF, Note 11)
Serial Clock Frequency
f
SCLH
(Note 12)
1.7
MHz
Hold Time, Repeated START
Condition (Sr)
t
HD,
STA
160
ns
Low Period of the SCL Clock
t
LOW
320
ns
High Period of the SCL Clock
t
HIGH
120
ns
Setup Time for a Repeated START
Condition (Sr)
t
SU
,
STA
160
ns
Data Hold Time
t
HD
,
DAT
(Note 10)
0
150
ns
Data Setup Time
t
SU
,
DAT
10
ns
Rise Time of SCL Signal
(Current Source Enabled)
t
RCL
20
80
ns
Rise Time of SCL Signal after
Acknowledge Bit
t
RCL1
Measured from 0.3V
DD
- 0.7V
DD
20
160
ns
Fall Time of SCL Signal
t
FCL
Measured from 0.3V
DD
- 0.7V
DD
20
80
ns
Rise Time of SDA Signal
t
RDA
Measured from 0.3V
DD
- 0.7V
DD
20
160
ns
Fall Time of SDA Signal
t
FDA
Measured from 0.3V
DD
- 0.7V
DD
20
160
ns
Setup Time for STOP (P) Condition
t
SU
,
STO
160
ns
Capacitive Load for Each Bus Line
C
B
400
pF
Pulse Width of Spike Suppressed
t
SP
(Notes 10 and 12)
0
10
ns
TIMING CHARACTERISTICS (Figure 1) (continued)
(V
DD
= 2.7V to 3.6V (MAX1237/MAX1239), V
DD
= 4.5V to 5.5V (MAX1236/MAX1238), V
REF
= 2.048V (MAX1237/MAX1239), V
REF
=
4.096V (MAX1236/MAX1238), C
REF
= 0.1µF, f
SCL
= 1.7MHz, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at
T
A
= +25°C, see Tables 15 for programming notation.)
Note 1: For DC accuracy, the MAX1136/MAX1138 are tested at V
DD
= 5V and the MAX1137/MAX1139 are tested at V
DD
= 3V. All
devices are configured for unipolar, single-ended inputs.
Note 2: Relative accuracy is the deviation of the analog value at any code from its theoretical value after the full-scale range and
offsets have been calibrated.
Note 3: Offset nulled.
Note 4: Conversion time is defined as the number of clock cycles needed for conversion multiplied by the clock period. Conversion
time does not include acquisition time. SCL is the conversion clock in the external clock mode.
Note 5: A filter on the SDA and SCL inputs suppresses noise spikes and delays the sampling instant.
Note 6: The absolute input-voltage range for the analog inputs (AIN0AIN11) is from GND to V
DD
.
Note 7: When the internal reference is configured to be available at AIN_/REF (SEL[2:1] = 11) decouple AIN_/REF to GND with a
0.01µF capacitor.
Note 8: ADC performance is limited by the converter's noise floor, typically 300µV
P-P
.
Note 9: Measured as for the MAX1237/MAX1239
V
V
V
V
V
V
V
FS
FS
REF
N
( .
)
( .
)
( .
.
)
3 6
2 7
2
1
3 6
2 7
-
-
-
[
]
×
PDF 
ZIP