Rainbow Electronics MAX1231 User Manual

General Description

The MAX1227/MAX1229/MAX1231 are serial 12-bit analog-to-digital converters (ADCs) with an internal reference and an internal temperature sensor. These devices feature on-chip FIFO, scan mode, internal clock mode, internal averaging, and AutoShutdown™. The maximum sampling rate is 300ksps using an external clock. The MAX1231 has 16 input channels, the MAX1229 has 12 input channels, and the MAX1227 has 8 input channels. All input channels are configurable for single-ended or differential inputs in unipolar or bipolar mode. All three devices operate from a +3V supply and contain a 10MHz SPI™/QSPI™/MICROWIRE™-compatible serial port.

The MAX1231 is available in 28-pin 5mm x 5mm QFN with exposed pad and 24-pin QSOP packages. The MAX1227/MAX1229 are only available in QSOP packages. All three devices are specified over the extended

-40°C to +85°C temperature range.

________________________Applications

System Supervision

Data-Acquisition Systems

Industrial Control Systems

Patient Monitoring

Data Logging

Instrumentation

Features

♦ Internal Temperature Sensor (±1°C Accuracy) ♦ 16-Entry First-In/First-Out (FIFO) ♦ Analog Multiplexer with True Differential

Track/Hold

16-, 12-, 8-Channel Single Ended 8-, 6-, 4-Channel True Differential (Unipolar or Bipolar)

♦ Accuracy: ±1 LSB INL, ±1 LSB DNL, No Missing

Codes Over Temperature

♦ Scan Mode, Internal Averaging, and Internal Clock ♦ Low-Power Single +3V Operation

0.62mA at 300ksps

♦ Internal 2.5V Reference or External Differential

Reference

♦ 10MHz 3-Wire SPI/QSPI/MICROWIRE-Compatible

Interface

♦ Space-Saving 28-Pin 5mm x 5mm QFN Package

MAX1227/MAX1229/MAX1231

12-Bit 300ksps ADCs with FIFO,

Temp Sensor, Internal Reference

________________________________________________________________ Maxim Integrated Products 1

Pin Configurations

19-2851; Rev 1; 7/03

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.

EVALUATION KIT

AVAILABLE

Ordering Information

*Future product—contact factory for availability.

Pin Configurations continued at end of data sheet.

Ordering Information continued at end of data sheet.

AutoShutdown is a trademark of Maxim Integrated Products, Inc. SPI/QSPI are trademarks of Motorola, Inc. MICROWIRE is a trademark of National Semiconductor Corp.

PART TEMP RANGE PIN-PACKAGE

MAX1227ACEE-T* 0°C to +70°C 16 QSOP

MAX1227AEEE-T* -40°C to +85°C 16 QSOP

TOP VIEW

AIN0

AIN1

AIN2

MAX1227

AIN3

AIN4

AIN5

REF-/AIN6

CNVST/AIN7

QSOP

EOC

DOUT

DIN

SCLK

GND

REF+

AIN0

AIN1

AIN2

AIN4

AIN5

AIN6

AIN8

MAX1229

QSOP

EOC

DOUT

DIN

CSAIN3

SCLK

GND

REF+AIN7

CNVST/AIN11

REF-/AIN10AIN9

MAX1227/MAX1229/MAX1231

12-Bit 300ksps ADCs with FIFO, Temp Sensor, Internal Reference

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VDD= +2.7V to +3.6V, f

SAMPLE

= 300kHz, f

SCLK

= 4.8MHz (50% duty cycle), V

REF

= 2.5V, TA= T

MIN

to T

MAX

, unless otherwise

noted. Typical values are at T

= +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

CS, SCLK, DIN, EOC, DOUT to GND.........-0.3V to (V

+ 0.3V)

AIN0–AIN13, REF-/AIN_, CNVST/AIN_,

REF+ to GND.........................................-0.3V to (V

+ 0.3V)

Maximum Current into Any Pin............................................50mA

Continuous Power Dissipation (T

= +70°C)

16-Pin QSOP (derate 8.3mW/°C above +70°C)...........667mW

20-Pin QSOP (derate 9.1mW/°C above +70°C)...........727mW

24-Pin QSOP (derate 9.5mW/°C above +70°C)...........762mW

28-Pin QFN 5mm x 5mm

(derate 20.8mW/°C above +70°C)........................1667mW

Operating Temperature Ranges

MAX12__C__.......................................................0°C to +70°C

MAX12__E__....................................................-40°C to +85°C

Storage Temperature Range .............................-60°C to +150°C

Junction Temperature......................................................+150°C

Lead Temperature (soldering, 10s) .................................+300°C

DC ACCURACY (NOTE 1)

Resolution RES 12 Bits

Integral Nonlinearity INL ±1.0 LSB

Differential Nonlinearity DNL No missing codes over temperature ±1.0 LSB

Offset Error ±0.5 ±4.0 LSB

Gain Error (Note 2) ±0.5 ±4.0 LSB

Offset Error Temperature Coefficient

Gain Temperature Coefficient ±0.8 ppm/°C

Channel-to-Channel Offset Matching

DYNAMIC SPECIFICATIONS (10kHz sine wave input, 2.5V

Signal-to-Noise Plus Distortion SINAD 70 dB

Total Harmonic Distortion THD Up to the 5th harmonic -82 dBc

Spurious-Free Dynamic Range SFDR 80 dBc

Intermodulation Distortion IMD f

Full-Power Bandwidth -3dB point 1 MHz

Full-Linear Bandwidth S / (N + D) > 68dB 25 kHz

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

= 9.9kHz, f

in1

, 300ksps, f

P-P

= 10.2kHz 76 dBc

in2

SCLK

= 4.8MHz)

±2

±0.1 LSB

ppm/°C

FSR

MAX1227/MAX1229/MAX1231

12-Bit 300ksps ADCs with FIFO,

Temp Sensor, Internal Reference

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS (continued)

(VDD= +2.7V to +3.6V, f

SAMPLE

= 300kHz, f

SCLK

= 4.8MHz (50% duty cycle), V

REF

= 2.5V, TA= T

MIN

to T

MAX

, unless otherwise

noted. Typical values are at T

= +25°C.)

CONVERSION RATE

Power-Up Time t

Acquisition Time t

Conversion Time t

External Clock Frequency f

SCLK Duty Cycle 40 60 %

Aperture Delay 30 ns

Aperture Jitter <50 ps

ANALOG INPUT

Input Voltage Range

Input Leakage Current V

Input Capacitance During acquisition time (Note 6) 24 pF

INTERNAL TEMPERATURE SENSOR

Measurement Error (Note 7)

Tem p er atur e M easur em ent N oi se 0.4 °C

Temperature Resolution 1/8 °C

Power-Supply Rejection 0.3 °C/V

INTERNAL REFERENCE

REF Output Voltage 2.48 2.50 2.52 V

REF Temperature Coefficient TC

Output Resistance 6.5 kΩ

REF Output Noise 200 µV

REF Power-Supply Rejection PSRR -70 dB

EXTERNAL REFERENCE INPUT

REF- Input Voltage Range V

REF+ Input Voltage Range V

REF+ Input Current I

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

ACQ

CONV

SCLK

REF

REF-

REF+

External reference 0.8

Internal reference (Note 3) 65

Internally clocked 3.5

Externally clocked (Note 4) 2.7

Externally clocked conversion 0.1 4.8

Data I/O 10

Unipolar 0 V

Bipolar (Note 5) - V

= V

Grade A, TA = +25°C ±0.3

Grade A, TA = -20°C to +85°C ±0.5 ±1

Grade A, TA = T

Grade B, TA = +25°C ±0.7

Grade B, T

Grade A ±8

Grade B ±30

REF+

= 2.5V, f

= T

to T

MIN

MAX

to T

MIN

MAX

= 300ksps 40 100

SAMPLE

= 0 ±0.1 ±5

SAMPLE

/ 2 V

RE F

±0.01 ±1 µA

±0.75 ±1.5

±1.2 ±2.5

0 500 mV

1.0 VDD + 50mV V

0.6 µs

REF

/ 2

RE F

MHz

p p m /° C

µs

°C

RMS

µA

MAX1227/MAX1229/MAX1231

12-Bit 300ksps ADCs with FIFO, Temp Sensor, Internal Reference

4 _______________________________________________________________________________________

Note 1: Tested at VDD= +2.7V, unipolar input mode. Note 2: Offset nulled. Note 3: Time for reference to power up and settle to within 1 LSB. Note 4: Conversion time is defined as the number of clock cycles multiplied by the clock period; clock has 50% duty cycle. Note 5: The operational input voltage range for each individual input of a differentially configured pair is from GND to V

. The

operational input voltage difference is from -V

REF

/ 2 to +V

REF

/ 2.

Note 6: See Figure 3 (Input Equivalent Circuit) and the Sampling Error vs. Source Impedance curve in the Typical Operating

Characteristics section.

Note 7: Fast automated test, excludes self-heating effects. Note 8: Supply current is specified depending on whether an internal or external reference is used for voltage conversions.

Temperature measurements always use the internal reference.

ELECTRICAL CHARACTERISTICS (continued)

(VDD= +2.7V to +3.6V, f

SAMPLE

= 300kHz, f

SCLK

= 4.8MHz (50% duty cycle), V

REF

= 2.5V, TA= T

MIN

to T

MAX

, unless otherwise

noted. Typical values are at T

= +25°C.)

DIGITAL INPUTS (SCLK, DIN, CS, CNVST)

Input Voltage Low V

Input Voltage High V

Input Hysteresis V

Input Leakage Current I

Input Capacitance C DIGITAL OUTPUTS (DOUT, EOC)

Output Voltage Low V

Output Voltage High V

Tri-State Leakage Current I

Tri-State Output Capacitance C

POWER REQUIREMENTS

Supply Voltage V

Supply Current (Note 8) I

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Power-Supply Rejection PSR VDD = 2.7V to 3.6V; full-scale input ±0.2 ±1 mV

HYST

OUT

VIN = 0 or V

SINK

SOURCE

CS = V CS = V

Internal reference

External reference

= 2mA 0.4

= 4mA 0.8

= 1.5mA VDD - 0.5 V

VDD x 0.7 V

2.7 3.6 V

During temp sense 2200 2700

Shutdown 0.2 5

During temp sense 1550 2000

Shutdown 0.2 5

= 300ksps 1550 1800

SAMPLE

= 0, REF on 1000 1200

SAMPLE

= 300ksps 880 1100

SAMPLE

200 mV

±0.01 ±1.0 µA

±0.05 ±1 µA

VDD x 0.3 V

15 pF

µA

MAX1227/MAX1229/MAX1231

12-Bit 300ksps ADCs with FIFO,

Temp Sensor, Internal Reference

_______________________________________________________________________________________ 5

TIMING CHARACTERISTICS (Figure 1)

-1.0

-0.4

-0.6

-0.8

-0.2

0.2

0.4

0.6

0.8

1.0

0 1024 2048 3072 4096

INTEGRAL NONLINEARITY

vs. OUTPUT CODE

MAX1227/29/31 toc01

OUTPUT CODE

INTEGRAL NONLINEARITY (LSB)

-1.0

-0.4

-0.6

-0.8

-0.2

0.2

0.4

0.6

0.8

1.0

0 1024 2048 3072 4096

DIFFERENTIAL NONLINEARITY

vs. OUTPUT CODE

MAX1227/29/31 toc02

OUTPUT CODE

DIFFERENTIAL NONLINEARITY (LSB)

SINAD vs. FREQUENCY

MAX1227/29/31 toc03

FREQUENCY (kHz)

AMPLITUDE (dB)

100101

100

0.1 1000

Typical Operating Characteristics

(VDD= +3V, V

REF

= +2.5V, f

SCLK

= 4.8MHz, C

LOAD

= 30pF, TA= +25°C, unless otherwise noted.)

Note 9: This time is defined as the number of clock cycles needed for conversion multiplied by the clock period. If the internal refer-

ence needs to be powered up, the total time is additive. The internal reference is always used for temperature measurements.

SCLK Clock Period t

SCLK Duty Cycle t

SCLK Fall to DOUT Transition t

CS Rise to DOUT Disable t CS Fall to DOUT Enable t

DIN to SCLK Rise Setup t

SCLK Rise to DIN Hold t CS to SCLK Rise Setup t SCLK Rise to CS Hold t

CNVST Pulse Width

CS or CNVST Rise to EOC

Low (Note 9)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

DOT

DOD

DOE

CSS

CSH

CSW

Externally clocked conversion 208

Data I/O 100

40 60 %

= 30pF 40 ns

LOAD

= 30pF 40 ns

LOAD

= 30pF 40 ns

LOAD

40 ns

0ns

40 ns

0ns

CKSEL = 00, CKSEL = 01 (temp sense) 40 ns

CKSEL = 01 (voltage conversion) 1.4 µs

T S

Temp sense 55

Voltage conversion 7

µs

Reference power-up 65

2.4970

2.4974

2.4982

2.4978

2.4986

2.4990

2.7 3.0 3.3 3.6

INTERNAL REFERENCE VOLTAGE

vs. SUPPLY VOLTAGE

MAX1227/29/31 toc10

SUPPLY VOLTAGE (V)

INTERNAL REFERENCE VOLTAGE (V)

MAX1227/MAX1229/MAX1231

12-Bit 300ksps ADCs with FIFO, Temp Sensor, Internal Reference

6 _______________________________________________________________________________________

Typical Operating Characteristics (continued)

(VDD= +3V, V

REF

= +2.5V, f

SCLK

= 4.8MHz, C

LOAD

= 30pF, TA= +25°C, unless otherwise noted.)

120

SFDR vs. FREQUENCY

SUPPLY CURRENT vs. SAMPLING RATE

700

SUPPLY CURRENT vs. SUPPLY VOLTAGE

700

100

AMPLITUDE (dB)

0.1 1000 FREQUENCY (kHz)

100101

MAX1227/29/31 toc04

SUPPLY CURRENT (µA)

600

500

400

300

200

1 1000

SAMPLING RATE (ksps)

10010

SHUTDOWN SUPPLY CURRENT

vs. SUPPLY VOLTAGE

0.5

0.4

0.3

0.2

0.1

SHUTDOWN SUPPLY CURRENT (µA)

MAX1227/29/31 toc07

650

MAX1227/29/31 toc05

600

SUPPLY CURRENT (µA)

550

500

2.7 3.6

SUPPLY CURRENT vs. TEMPERATURE

625

fS = 300ksps

620

615

SUPPLY CURRENT (µA)

610

MAX1227/29/31 toc06

3.33.0

SUPPLY VOLTAGE (V)

MAX1227/29/31 toc08

SHUTDOWN SUPPLY CURRENT (µA)

2.7 3.0 3.3 3.6 SUPPLY VOLTAGE (V)

SHUTDOWN SUPPLY CURRENT

vs. TEMPERATURE

0.5

0.4

0.3

0.2

0.1

-40 10-15 35 60 85

TEMPERATURE (°C)

MAX1227/29/31 toc09

605

-40 10-15 35 60 85 TEMPERATURE (°C)

MAX1227/MAX1229/MAX1231

12-Bit 300ksps ADCs with FIFO,

Temp Sensor, Internal Reference

_______________________________________________________________________________________ 7

Typical Operating Characteristics (continued)

(VDD= +3V, V

REF

= +2.5V, f

SCLK

= 4.8MHz, C

LOAD

= 30pF, TA= +25°C, unless otherwise noted.)

-1.00

-0.50

0.50

0.25

-0.25

-0.75

1.00

0.75

TEMPERATURE SENSOR ERROR

vs. TEMPERATURE

MAX1227/29/31 toc16

TEMPERATURE (°C)

TEMPERATURE SENSOR ERROR (°C)

-40 -15 35 85

6010

GRADE A

GRADE B

-5

-3

-4

-1

-2

0426810

SAMPLING ERROR

vs. SOURCE IMPEDANCE

MAX1227/29/31 toc17

SOURCE IMPEDANCE (kΩ)

SAMPLING ERROR (LSB)

INTERNAL REFERENCE VOLTAGE

vs. TEMPERATURE

2.510

2.506

2.502

2.498

2.494

INTERNAL REFERENCE VOLTAGE (V)

2.490

-40 10-15 35 60 85 TEMPERATURE (°C)

2.0

1.5

GAIN ERROR vs. SUPPLY VOLTAGE

MAX1227/29/31 toc11

-0.1

OFFSET ERROR (LSB)

-0.2

-0.3

OFFSET ERROR

vs. SUPPLY VOLTAGE

0.3

0.2

0.1

2.7 3.0 3.3 3.6 SUPPLY VOLTAGE (V)

MAX1227/29/31 toc12

GAIN ERROR vs. TEMPERATURE

2.0

MAX1227/29/31 toc14

1.5

OFFSET ERROR

vs. TEMPERATURE

0.4

0.3

0.2

0.1

OFFSET ERROR (LSB)

-0.1

-0.2

-0.3

-40 10-15 35 60 85 TEMPERATURE (°C)

MAX1227/29/31 toc15

MAX1227/29/31 toc13

1.0

GAIN ERROR (LSB)

0.5

2.7 3.6 SUPPLY VOLTAGE (V)

1.0

GAIN ERROR (LSB)

0.5

3.33.0

-40 -15 35 85 TEMPERATURE (°C)

6010

MAX1227/MAX1229/MAX1231

12-Bit 300ksps ADCs with FIFO, Temp Sensor, Internal Reference

8 _______________________________________________________________________________________

Pin Description

MAX1231

QFN

2–12, 26,

27, 28,

——1–10 — AIN0–9 Analog Inputs

———1–6AIN0–5 Analog Inputs

13 15 ——REF-/AIN14

——11 — REF-/AIN10

——— 7 REF-/AIN6

14 16 ——

——12 —

——— 8

15 17 13 9 REF+ Positive Reference Input. Bypass to GND with a 0.1µF capacitor.

16 18 14 10 GND Ground

18 19 15 11 V

20 20 16 12 SCLK

MAX1231

QSOP

1–14 ——AIN0–13 Analog Inputs

MAX1229 MAX1227 NAME FUNCTION

Negative Input for External Differential Reference/Analog Input 14. See Table 3 for details on programming the setup register.

Negative Input for External Differential Reference/Analog Input 10. See Table 3 for details on programming the setup register.

Negative Input for External Differential Reference/Analog Input 6. See Table 3 for details on programming the setup register.

CNVST/

AIN15

CNVST/

AIN11

CNVST/

AIN7

Active-Low Conversion Start Input/Analog Input 15. See Table 3 for details on programming the setup register.

Active-Low Conversion Start Input/Analog Input 11. See Table 3 for details on programming the setup register.

Active-Low Conversion Start Input/Analog Input 7. See Table 3 for details on programming the setup register.

Power Input. Bypass to GND with a 0.1µF capacitor.

Serial Clock Input. Clocks data in and out of the serial interface. (Duty cycle must be 40% to 60%.) See Table 3 for details on programming the clock mode.

21 21 17 13 CS

22 22 18 14 DIN

23 23 19 15 DOUT

24 24 20 16 EOC End of Conversion Output. Data is valid after EOC pulls low.

1, 17, 19,

———N.C. No Connection. Not internally connected.

Active-Low Chip Select Input. When CS is low, the serial interface is enabled. When CS is high, DOUT is high impedance.

Serial Data Input. DIN data is latched into the serial interface on the rising edge of SCLK.

Serial Data Output. Data is clocked out on the falling edge of SCLK. High impedance when CS is connected to V

+ 16 hidden pages

Rainbow Electronics MAX1231 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual