MAXIM MAX1236, MAX1239 User Manual

General Description

The MAX1236–MAX1239 low-power, 12-bit, multichan­nel analog-to-digital converters (ADCs) feature internal
track/hold (T/H), voltage reference, clock, and an
I2C-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 sam­pling rates under 46ksps. AutoShutdown™ powers
down the devices between conversions, reducing sup­ply current to less than 1µA at low throughput rates.
The MAX1236/MAX1237 have four analog input chan­nels each, while the MAX1238/MAX1239 have 12 ana­log 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 VDD. 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 16­pin QSOP package. The MAX1236–MAX1239 are guar­anteed over the extended temperature range
(-40°C to +85°C). For pin-compatible 10-bit parts, refer to
the MAX1136–MAX1139 data sheet. For pin-compatible
8-bit parts, refer to the MAX1036–MAX1039 data sheet.

Applications

Features

♦ High-Speed I2C-Compatible Serial Interface

400kHz Fast Mode

1.7MHz High-Speed Mode

♦ Single-Supply

2.7V to 3.6V (MAX1237/MAX1239)

4.5V to 5.5V (MAX1236/MAX1238)

♦ Internal Reference

2.048V (MAX1237/MAX1239)

4.096V (MAX1236/MAX1238)

♦ External Reference: 1V to V

DD

♦ Internal Clock
♦ 4-Channel Single-Ended or 2-Channel Fully

Differential (MAX1236/MAX1237)

♦ 12-Channel Single-Ended or 6-Channel Fully

Differential (MAX1238/MAX1239)

♦ Internal FIFO with Channel-Scan Mode
♦ Low Power

670µA at 94.4ksps
230µA at 40ksps
60µA at 10ksps
6µA at 1ksps

0.5µA in Power-Down Mode

♦ Software-Configurable Unipolar/Bipolar
♦ Small Packages

8-Pin µMAX (MAX1236/MAX1237)
16-Pin QSOP (MAX1238/MAX1239)

MAX1236–MAX1239

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 4; 9/06

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.

PART

TEMP RANGE

PIN-

I2C SLAVE

ADDRESS

MAX1236EUA

8 µMAX 0110100

MAX1236KEUA

8 µMAX 0110000

MAX1236LEUA

8 µMAX 0110010

MAX1236MEUA

8 µMAX 0110110

MAX1237EUA

8 µMAX 0110100

MAX1237KEUA

8 µMAX 0110000

MAX1237LEUA

8 µMAX 0110010

MAX1237MEUA

8 µMAX 0110110

MAX1238EEE

0110101

MAX1238KEEE

0110001

MAX1238LEEE

0110011

MAX1238MEEE

0110111

Pin Configurations and Typical Operating Circuit appear at
end of data sheet.

AutoShutdown is a trademark of Maxim Integrated Products, Inc.

µMAX is a registered trademark of Maxim Integrated Products, Inc.

Ordering Information continued at end of data sheet.

PART

INPUT

INTERNAL

REFERENCE

(V)

SUPPLY

VOLTAGE

(V)

INL

(LSB)

MAX1236

4 4.096

±1

MAX1237

4 2.048

±1

MAX1238

12 4.096

±1

MAX1239

12 2.048

±1

Hand-Held Portable
Applications

Medical Instruments
Battery-Powered Test

Equipment

Solar-Powered Remote
Systems

Received-Signal-Strength
Indicators

System Supervision

Selector Guide

CHANNELS

4.5 to 5.5

2.7 to 3.6

4.5 to 5.5

2.7 to 3.6

PACKAGE

-40°C to +85°C

-40°C to +85°C

-40°C to +85°C

-40°C to +85°C

-40°C to +85°C

-40°C to +85°C

-40°C to +85°C

-40°C to +85°C

-40°C to +85°C 16 QSOP

-40°C to +85°C 16 QSOP

-40°C to +85°C 16 QSOP

-40°C to +85°C 16 QSOP

MAX1236–MAX1239

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

(VDD= 2.7V to 3.6V (MAX1237/MAX1239), VDD= 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, TA= T

MIN

to T

MAX

, unless otherwise noted. Typical values are at

T

A

= +25°C, see Tables 1–5 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.

VDDto GND..............................................................-0.3V to +6V

AIN0–AIN11,

REF to GND............-0.3V to the lower of (VDD+ 0.3V) and 6V

SDA, SCL to GND.....................................................-0.3V to +6V

Maximum Current Into Any Pin .........................................±50mA

Continuous Power Dissipation (TA= +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

CONDITIONS

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

LSB

Channel-to-Channel Gain
Matching

LSB

DYNAMIC PERFORMANCE (f

IN(SINE-WAVE)

= 10kHz, V

IN(P-P)

= V

REF

, f

SAMPLE

= 94.4ksps)

Signal-to-Noise Plus Distortion

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)

External clock

µs

SYMBOL

MIN TYP MAX

SINAD

t

CONV

10.6

±0.1

±0.1

MAX1236–MAX1239

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)

(VDD= 2.7V to 3.6V (MAX1237/MAX1239), VDD= 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, TA= T

MIN

to T

MAX

, unless otherwise noted. Typical values are at

T

A

= +25°C, see Tables 1–5 for programming notation.)

PARAMETER

CONDITIONS

UNITS

Internal clock, SCAN[1:0] = 01 51

Internal clock, SCAN[1:0] = 00
CS[3:0] = 1011 (MAX1238/MAX1239)

51

Throughput Rate

External clock

ksps

Track/Hold Acquisition Time

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 (AIN0–AIN11)

Unipolar 0

Input-Voltage Range, Single­Ended and Differential (Note 6)

Bipolar 0

V

Input Multiplexer Leakage Current

ON/OFF leakage current, V

AIN

_ = 0 or V

DD

±1µA

Input Capacitance C

IN

22 pF

INTERNAL REFERENCE (Note 7)

MAX1237/MAX1239

Reference Voltage V

REF

TA = +25°C

MAX1236/MAX1238

V

Reference-Voltage Temperature
Coefficient

25

ppm/°C

REF Short-Circuit Current 2mA
REF Source Impedance 1.5 kΩ

EXTERNAL REFERENCE

REF Input-Voltage Range V

REF

(Note 8) 1

V

REF Input Current I

REF

f

SAMPLE

= 94.4ksps 40 µA

DIGITAL INPUTS/OUTPUTS (SCL, SDA)

Input-High Voltage V

IH

V

Input-Low Voltage V

IL

V

Input Hysteresis

V

Input Current I

IN

VIN = 0 to V

DD

±10 µA

Input Capacitance C

IN

15 pF

Output Low Voltage V

OL

I

SINK

= 3mA 0.4 V

SYMBOL

f

SAMPLE

TCV

V

HYST

REF

MIN TYP MAX

94.4

800

±0.01

1.968 2.048 2.128

3.936 4.096 4.256

0.7 ✕ V

DD

0.1 ✕ V

DD

0.3 ✕ V

V

REF

±V

/2

REF

V

DD

DD

MAX1236–MAX1239

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)

(VDD= 2.7V to 3.6V (MAX1237/MAX1239), VDD= 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, TA= T

MIN

to T

MAX

, unless otherwise noted. Typical values are at

T

A

= +25°C, see Tables 1–5 for programming notation.)

PARAMETER

CONDITIONS

UNITS

POWER REQUIREMENTS

MAX1237/MAX1239 2.7 3.6

Supply Voltage V

DD

MAX1236/MAX1238 4.5 5.5

V

Internal reference

f

SAMPLE

= 94.4ksps

external clock

External reference

900

Internal reference

f

SAMPLE

= 40ksps

internal clock

External reference

Internal reference

f

SAMPLE

= 10ksps

internal clock

External reference 60

Internal reference

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)

LSB/V

TIMING CHARACTERISTICS (Figure 1)

(VDD= 2.7V to 3.6V (MAX1237/MAX1239), VDD= 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, TA= T

MIN

to T

MAX

, unless otherwise noted. Typical values are at

T

A

= +25°C, see Tables 1–5 for programming notation.)

PARAMETER

CONDITIONS

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

,

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)

,

0.6 µs

Data Hold Time (Note 10)

,

0 900 ns

Data Setup Time

,

ns

Rise Time of Both SDA and SCL
Signals, Receiving

t

R

Measured from 0.3VDD - 0.7V

DD

300 ns

Fall Time of SDA Transmitting t

F

Measured from 0.3VDD - 0.7V

DD

300 ns

Setup Time for STOP (P) Condition

,

0.6 µs

Capacitive Load for Each Bus Line

C

B

400 pF

Pulse Width of Spike Suppressed

t

SP

50 ns

SYMBOL

MIN TYP MAX

900 1150

670

530

230

380

330

±0.5 ±0.2

SYMBOL

t

HD

STA

t

SU

STA

t

HD

DAT

t

SU

DAT

t

SU

STO

MIN TYP MAX

100

20 + 0.1C

B

20 + 0.1C

B

MAX1236–MAX1239

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 (CB = 400pF, Note 11)

Serial Clock Frequency

(Note 12) 1.7

MHz

Hold Time, Repeated START
Condition (Sr)

,

ns

Low Period of the SCL Clock t

LOW

ns

High Period of the SCL Clock t

HIGH

ns

Setup Time for a Repeated START
Condition (Sr)

ns

Data Hold Time

(Note 10) 0 150 ns

Data Setup Time

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 0.3VDD - 0.7V

DD

20 160 ns

Fall Time of SCL Signal t

FCL

Measured from 0.3VDD - 0.7V

DD

20 80 ns

Rise Time of SDA Signal t

RDA

Measured from 0.3VDD - 0.7V

DD

20 160 ns

Fall Time of SDA Signal t

FDA

Measured from 0.3VDD - 0.7V

DD

20 160 ns

Setup Time for STOP (P) Condition

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)

(VDD= 2.7V to 3.6V (MAX1237/MAX1239), VDD= 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, TA= T

MIN

to T

MAX

, unless otherwise noted. Typical values are at

T

A

= +25°C, see Tables 1–5 for programming notation.)

Note 1: For DC accuracy, the MAX1136/MAX1138 are tested at V

DD

= 5V and the MAX1137/MAX1139 are tested at VDD= 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 (AIN0–AIN11) 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

VVVV

V

VV

FS FS

REF

N

(. ) (. )

(. . )

36 27

21

36 27

−

−

−

[]

×















f

SCLH

t

HD

STA

tSU,

STA

tHD,

DAT

tSU,

DAT

tSU,

STO

160

320

120

160

160

MAX1236–MAX1239

2.7V to 3.6V and 4.5V to 5.5V, Low-Power,
4-/12-Channel, 2-Wire Serial, 12-Bit ADCs

6 _______________________________________________________________________________________

Typical Operating Characteristics

(VDD= 3.3V (MAX1237/MAX1239), VDD= 5V (MAX1236/MAX1238), f

SCL

= 1.7MHz, (50% duty cycle), f

SAMPLE

= 94.4ksps, single-

ended, unipolar, TA= +25°C, unless otherwise noted.)

-0.5

-0.2

-0.4

-0.3

0.2

0.1

0.1

0

0.3

0.5

0 4000

DIFFERENTIAL NONLINEARITY

vs. DIGITAL CODE

MAX1236 toc01

DIGITAL OUTPUT CODE

DNL (LSB)

1000 1500500

2000 2500

3000 3500

0.4

-1.0

-0.4

-0.6

-0.8

-0.2

0

0.2

0.4

0.6

0.8

1.0

INTEGRAL NONLINEARITY

vs. DIGITAL CODE

MAX1236 toc02

DIGITAL OUTPUT CODE

INL (LSB)

04000

1000 1500500

2000 2500

3000 3500

-180

-160

-140

-120

-100

-80

-60

0 10k 20k 30k 40k 50k

FFT PLOT

MAX1236 toc03

FREQUENCY (Hz)

AMPLITUDE (dBc)

f

SAMPLE

= 94.4ksps

f

IN

= 10kHz

300

400

350

500

450

600

550

650

750

700

800

-40 -10 5-25 20 35 50 65 80

SUPPLY CURRENT vs. TEMPERATURE

(MAX1238/MAX1239)

MAX1236 toc04

TEMPERATURE (°C)

SUPPLY CURRENT (µA)

INTERNAL REFERENCE MAX1239/MAX1237

INTERNAL REFERENCE MAX1238/MAX1236

EXTERNAL REFERENCE MAX1238/MAX1236

EXTERNAL REFERENCE MAX1239/MAX1237

SETUP BYTE
EXT REF: 10111011
INT REF: 11011011

0

0.2

0.1

0.4

0.3

0.5

0.6

2.7 5.2

SHUTDOWN SUPPLY CURRENT

vs. SUPPLY VOLTAGE

MAX1236 toc05

INPUT VOLTAGE (V)

I

DD

(µA)

3.73.2 4.2 4.7

SDA = SCL = V

DD

0

0.10

0.05

0.20

0.15

0.30

0.25

0.35

0.45

0.40

0.50

-40 -10 5

-25

20 35 50 65 80

SHUTDOWN SUPPLY CURRENT

vs. TEMPERATURE

MAX1236 toc06

TEMPERATURE (°C)

SUPPLY CURRENT (µA)

MAX1238

MAX1239

and for the MAX1236/MAX1238 where N is the number of bits and V

REF

.

Note 10: A master device must provide a data hold time for SDA (referred to V

IL

of SCL) in order to bridge the undefined region of

SCL’s falling edge (see Figure 1).

Note 11: C

B

= total capacitance of one bus line in pF.

Note 12: f

SCL

must meet the minimum clock low time plus the rise/fall times.

VVVV

V

VV

FS FS

REF

N

(. ) (. )

(. . )

55 45

21

55 45

−

−

−

[]

×















TIMING CHARACTERISTICS (Figure 1) (continued)

(VDD= 2.7V to 3.6V (MAX1237/MAX1239), VDD= 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, TA= T

MIN

to T

MAX

, unless otherwise noted. Typical values are at

T

A

= +25°C, see Tables 1–5 for programming notation.)

MAX1236–MAX1239

2.7V to 3.6V and 4.5V to 5.5V, Low-Power,
4-/12-Channel, 2-Wire Serial, 12-Bit ADCs

_______________________________________________________________________________________ 7

200

300
250

350

400

450

500

550

600

650

700

750

800

02030406080100

AVERAGE SUPPLY CURRENT vs.

CONVERSION RATE (EXTERNAL CLOCK)

MAX1236 toc07

CONVERSION RATE (ksps)

AVERAGE I

DD

(µA)

010 50 70 90

A

B

A) INTERNAL REFERENCE ALWAYS ON
B) EXTERNAL REFERENCE

MAX1238

0.9990

0.9994

0.9992

0.9998

0.9996

1.0002

1.0000

1.0004

1.0008

1.0006

1.0010

-40 -10 5-25 20 35 50 65 80

INTERNAL REFERENCE VOLTAGE

vs. TEMPERATURE

MAX1236 toc08

TEMPERATURE (°C)

V

REF

NORMALIZED

NORMALIZED TO VALUE AT +25°C

MAX1238

MAX1239

0.99990

0.99994

0.99992

0.99998

0.99996

1.00002

1.00000

1.00004

1.00008

1.00006

1.00010

2.7 3.3 3.6 3.93.0 4.2 4.5 4.8 5.1 5.4

NORMALIZED REFERENCE VOLTAGE

vs. SUPPLY VOLTAGE

MAX1236 toc09

VDD (V)

V

REF

(V)

MAX1236/MAX1238
NORMALIZED TO
REFERENCE VALUE AT
V

DD

= 5V

MAX1237/MAX1239
NORMALIZED TO
REFERENCE VALUE AT
V

DD

= 3.3V

Typical Operating Characteristics (continued)

(VDD= 3.3V (MAX1237/MAX1239), VDD= 5V (MAX1236/MAX1238), f

SCL

= 1.7MHz, (50% duty cycle), f

SAMPLE

= 94.4ksps, single-

ended, unipolar, TA= +25°C, unless otherwise noted.)

OFFSET ERROR vs. TEMPERATURE

MAX1236 toc10

TEMPERATURE (°C)

OFFSET ERROR (LSB)

806535 50-10 5 20-25

-0.9

-0.8

-0.7

-0.6

-0.5

-0.4

-0.3

-0.2

-0.1

0

-1.0

-40

OFFSET ERROR vs. SUPPLY VOLTAGE

MAX1236 toc11

VDD (V)

OFFSET ERROR (LSB)

5.2 5.54.74.23.73.2

-1.6

-1.2

-0.8

-0.4

0

0.4

0.8

1.2

1.6

2.0

-2.0

2.7

GAIN ERROR vs. TEMPERATURE

MAX1236 toc12

TEMPERATURE (°C)

GAIN ERROR (LSB)

806535 50-10 5 20-25

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

0

-40

GAIN ERROR vs. SUPPLY VOLTAGE

MAX1236 toc13

VDD (V)

GAIN ERROR (LSB)

5.2 5.54.74.23.73.2

-1.6

-1.2

-0.8

-0.4

0

0.4

0.8

1.2

1.6

2.0

-2.0

2.7