Maxim MAX1270BCNG, MAX1270BCAI, MAX1270AENG, MAX1270AEAI, MAX1270ACNG Datasheet

General Description

The MAX1270/MAX1271 are multirange, 12-bit data­acquisition systems (DAS) that require only a single +5V
supply for operation, yet accept signals at their analog
inputs that may span above the power-supply rail and
below ground. These systems provide eight analog
input channels that are independently software pro­grammable for a variety of ranges: ±10V, ±5V, 0 to
+10V, 0 to +5V for the MAX1270; ±V

REF

, ±V

REF

/2, 0 to

V

REF

, 0 to V

REF

/2 for the MAX1271. This range switch­ing increases the effective dynamic range to 14 bits and
provides the flexibility to interface 4–20mA, ±12V, and
±15V powered sensors directly to a single +5V system.
In addition, these converters are fault protected to
±16.5V; a fault condition on any channel will not affect
the conversion result of the selected channel. Other fea­tures include a 5MHz bandwidth track/hold, software­selectable internal/external clock, 110ksps throughput
rate, and internal 4.096V or external reference opera­tion.

The MAX1270/MAX1271 serial interface directly con­nects to SPI™/QSPI™ and MICROWIRE™ devices with­out external logic.

A hardware shutdown input (SHDN) and two software-
programmable power-down modes, standby (STBYPD)
or full power-down (FULLPD), are provided for low-cur­rent shutdown between conversions. In standby mode,
the reference buffer remains active, eliminating start-up
delays.

The MAX1270/MAX1271 are available in 24-pin narrow
DIP or space-saving 28-pin SSOP packages.

Applications

Industrial Control Systems

Data-Acquisition Systems

Robotics

Automatic Testing

Battery-Powered Instruments

Medical Instruments

Features

♦ 12-Bit Resolution, 1/2LSB Linearity

♦ +5V Single-Supply Operation

♦ SPI/QSPI and MICROWIRE-Compatible

3-Wire Interface

♦ Four Software-Selectable Input Ranges

MAX1270: 0 to +10V, 0 to +5V, ±10V, ±5V
MAX1271: 0 to V

REF

, 0 to V

REF

/2, ±V

REF

,

±V

REF

/2

♦ Eight Analog Input Channels

♦ 110ksps Sampling Rate

♦ ±16.5V Overvoltage-Tolerant Input Multiplexer

♦ Internal 4.096V or External Reference

♦ Two Power-Down Modes

♦ Internal or External Clock

♦ 24-Pin Narrow DIP or 28-Pin SSOP Packages

MAX1270/MAX1271

Multirange, +5V, 8-Channel,

Serial 12-Bit ADCs

____________________________________________________________ Maxim Integrated Products 7-169

Typical Operating Circuit

19-4782; Rev 1; 3/99

PART

MAX1270ACNG

MAX1270BCNG

MAX1270ACAI

0°C to +70°C

0°C to +70°C

0°C to +70°C

TEMP.

RANGE

PIN-PACKAGE

24 Narrow Plastic DIP

24 Narrow Plastic DIP

28 SSOP

EVALUATION KIT MANUAL

FOLLOWS DATA SHEET

Ordering Information continued at end of data sheet.

Ordering Information

Pin Configurations appear at end of data sheet.

INL

(LSB)

±1/2

±1

±1/2

MAX1270BCAI 0°C to +70°C 28 SSOP ±1

V

DD

CH0
CH1
CH2
CH3
CH4
CH5
CH6
CH7

DGND

0.01µF4.7µF

0.1µF

SHDN

MAX1270
MAX1271

+5V

ANALOG

INPUTS

CS

SCLK

DIN

DOUT

SSTRB

I/O
SCK
MOSI
MISO

REF
REFADJ

AGND

MC68HCXX

SPI and QSPI are trademarks of Motorola, Inc.

MICROWIRE is a trademark of National Semiconductor Corp.

For free samples & the latest literature: http://www.maxim-ic.com, or phone [phone].
For small orders, phone [phone].

dB

MAX1270/MAX1271

Multirange, +5V, 8-Channel,
Serial 12-Bit ADCs

7-170 ___________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VDD= +5.0V ±5%; unipolar/bipolar range; external reference mode, V

REF

= +4.096V; 4.7µF at REF; external clock, f

CLK

= 2.0MHz

(50% duty cycle), 18 clock/conversion cycle, 110ksps; T

A

= T

MIN

to T

MAX

; unless otherwise noted. Typical values are 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 AGND............................................................-0.3V to +6V

AGND to DGND.....................................................-0.3V to +0.3V

CH0–CH7 to AGND ......................................................... ±16.5V

REF, REFADJ to AGND ..............................-0.3V to (V

DD

+ 0.3V)

SSTRB, DOUT to DGND.............................-0.3V to (V

DD

+ 0.3V)

SHDN, CS, DIN, SCLK to DGND..............................-0.3V to +6V

Max Current into Any Pin ....................................................50mA

Continuous Power Dissipation (T

A

= +70°C)
24-Pin Narrow DIP (derate 13.33mW/°C above +70°C) ..1067mW

28-Pin SSOP (derate 9.52mW/°C above +70°C) ..........762mW

Operating Temperature Ranges

MAX127_C_ _ ......................................................0°C to +70°C

MAX127_E_ _....................................................-40°C to +85°C

Storage Temperature Range ............................-65°C to +150°C

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

MAX127_B

LSB

±0.1

MAX127_A

Channel-to-Channel Offset
Error Matching

Up to the 5th harmonic dB-87 -78THDTotal Harmonic Distortion

Unipolar

MAX127_A

Bipolar

MAX127_B

No missing codes over temperature

Unipolar

CONDITIONS

Bipolar

Unipolar, external reference

Bipolar, external reference

±10

LSB

±7

±0.3

Gain Error
(Note 2)

dB70SINAD

Signal-to-Noise + Distortion
Ratio

DYNAMIC SPECIFICATIONS

±7

±10

ppm/°C

±3

Gain Error Temperature
Coefficient (Note 2)

±5

DC, VIN= ±16.5V

50kHz (Note 3)

LSB

±0.5

INLIntegral Nonlinearity

bits12

ACCURACY (Note 1)

Resolution

External clock mode

External clock mode

±10

±5

±1.0

LSB±1DNLDifferential Nonlinearity

LSB

±3

Offset Error

±5

UNITSMIN TYP MAXSYMBOLPARAMETERS

Internal clock mode

-96

dB

-86

dB80SFDRSpurious-Free Dynamic Range

Channel-to-Channel Crosstalk

ns15Aperture Delay

ps<50

Aperture Jitter

ns10

MAX127_A

MAX127_B

MAX127_A

MAX127_B

Unipolar

Bipolar

MAX127_A

MAX127_B

ACCURACY (Note 1)

DYNAMIC SPECIFICATIONS (10kHz sine-wave input, ±10Vp-p (MAX1270), or ±4.096Vp-p (MAX1271), f

SAMPLE

= 110ksps)

MAX1270/MAX1271

Multirange, +5V, 8-Channel,

Serial 12-Bit ADCs

____________________________________________________________________________________ 7-171

ELECTRICAL CHARACTERISTICS (continued)

(VDD= +5.0V ±5%; unipolar/bipolar range; external reference mode, V

REF

= +4.096V; 4.7µF at REF; external clock, f

CLK

= 2.0MHz

(50% duty cycle), 18 clock/conversion cycle, 110ksps; T

A

= T

MIN

to T

MAX

; unless otherwise noted. Typical values are TA= +25°C.)

FULLPD

Normal or STBYPD

±V

REF

/2 range

MAX1271

±V

REF

range

±5V range

MAX1270

±10V range

MAX1271

0 to 5V range

MAX1270

0 to 10V range

MAX1271

RNG = 1

MAX1270

RNG = 1

MAX1271

RNG = 1

±10V or ±V

REF

range

±5V or ±V

REF/2

range

0 to 10V or 0 to V

REF

range

RNG = 1

MAX1270

0 to 5V or 0 to V

REF/2

range

1

INTERNAL REFERENCE

Input Capacitance 40 pF

16

Dynamic Resistance ∆VIN/∆I

IN

21

kΩ

REF Output Voltage V

REF

4.076 4.096 4.116 V

REF Output Tempco TC V

REF

±15

ppm/°C

-600 360

-1200 10

-600 10

Buffer Voltage Gain 1.638 V/V

REFADJ Adjustment Range ±1.5 %

REFADJ Output Voltage 2.465 2.500 2.535 V

Capacitive Bypass at REFADJ 0.01 µF

REFERENCE INPUT (Reference

Input Voltage Range 2.40 4.18 V

Load Regulation (Note 5)

Output Short Circuit Current 30 mA

10 mV

Capacitive Bypass at REF 4.7 µF

Figure 1

(Note 4)

Bipolar

Unipolar

TA= +25°C

MAX1270_C/MAX1271_C

0 to 0.5mA output current

Input Current

400

µAV

REF

= 4.18V

±30MAX1270_E/MAX1271_E

ANALOG INPUT

Track/Hold Acquisition Time t

ACQ

3 µs

Small-Signal Bandwidth

5

MHz

Input Current I

IN

-10 720

µA

-V

REF

V

REF

-10 10

0V

REF

-10 360

-10 0.1 10

2.5

1.25

Input Voltage Range V

IN

010

V

Unipolar

Bipolar
(BIP = 1),
Table 3

PARAMETERS SYMBOL MIN TYP MAX UNITS

f

CLK

= 2.0MHz

-3dB
rolloff

Unipolar
(BIP = 0),
Table 3

-1200 720

Bipolar

2.5

CONDITIONS

ANALOG INPUT

INTERNAL REFERENCE

REFERENCE INPUT (Reference buffer disabled, reference input applied to REF)

RNG = 0 05

0V

REF

/2RNG = 0

RNG = 0

RNG = 0

-5 5

-V

REF

/2 V

REF

/2

MAX1270/MAX1271

Multirange, +5V, 8-Channel,
Serial 12-Bit ADCs

7-172 ___________________________________________________________________________________

ELECTRICAL CHARACTERISTICS (continued)

(VDD= +5.0V ±5%; unipolar/bipolar range; external reference mode, V

REF

= +4.096V; 4.7µF at REF; external clock, f

CLK

= 2.0MHz

(50% duty cycle), 18 clock/conversion cycle, 110ksps; T

A

= T

MIN

to T

MAX

; unless otherwise noted. Typical values are TA= +25°C.)

C

REF

= 33µF

C

REF

= 4.7µF

FULLPD

Normal or STBYPD

Reference Buffer Settling Time

8

ms

Bandgap Reference Start-Up
Time (Note 9)

200 µs

60

DIGITAL INPUTS: DIN, SCLK,

0.4

Output Voltage Low V

OL

0.4
V

DIGITAL OUTPUTS: DOUT,

Input Capacitance C

IN

15 pF

Output Voltage High V

OH

VDD- 0.5 V

Three-State Leakage Current I

L

-10 10 µA

Input Hysteresis

Input Low Threshold Voltage V

IL

0.8 V

V

HYS

0.2 V

Input Leakage Current I

IN

-10 10 µA

I

SINK

= 16mA

I

SINK

= 5mA

(Note 4)

I

SOURCE

= 0.5mA

CS = V

DD

Power-up

Three-State Output Capacitance C

OUT

VIN= 0 to V

DD

15 pF

CS = VDD(Note 4)

Input High Threshold Voltage V

IH

2.4 V

Supply Current I

DD

18

Supply Voltage V

DD

4.75 5.25 V

POWER REQUIREMENT

REFADJ Threshold for Buffer
Disable

VDD- 0.5 V

610

Input Resistance

10 kΩ

4.18 MΩ

Conversion Time t

CONV

6

µs

35

Acquisition Phase

3

µs

External Clock Frequency
Range

f

CLK

0.1 2.0 MHz

6 7.7 11

Throughput Rate

110

ksps

Power-Supply Rejection
Ratio (Note 7)

PSRR

±0.1 ±0.5

±0.5

TIMING

External clock mode (Note 8)

Internal clock mode, Figure 9

External clock mode (Note 8)

Internal clock mode, Figure 9

Normal

External clock mode

STBYPD power down mode (Note 6)

External reference = 4.096V

Internal reference

43Internal clock mode

V

REF

= 4.18V

120 220FULLPD power down mode

SYMBOL MIN TYP MAX UNITSCONDITIONS

To 0.1mV, REF
bypass capacitor
fully discharged

Unipolar range

Bipolar range

POWER REQUIREMENT

DIGITAL INPUTS: DIN, SCLK, CS, SHDN

DIGITAL OUTPUTS: DOUT, SSTRB

mA

PARAMETERS

LSB

700 850

µA

TIMING

MAX1270/MAX1271

Multirange, +5V, 8-Channel,

Serial 12-Bit ADCs

____________________________________________________________________________________ 7-173

TIMING CHARACTERISTICS

(VDD= +4.75V to +5.25; unipolar/bipolar range; external reference mode, V

REF

= +4.096V; 4.7µF at REF; external clock, f

CLK

=

2MHz; T

A

= T

MIN

to T

MAX

, unless otherwise noted. Typical values are TA= +25°C.) (Figures 2, 5, 7, 10)

DIN to SCLK Setup

t

DS

100

DIN to SCLK Hold t

DH

0

SCLK Fall to Output Data Valid t

DO

C

LOAD

= 100pF 20 170

CS Fall to Output Enable

t

DV

C

LOAD

= 100pF 120

CS Rise to Output Disable

t

TR

C

LOAD

= 100pF 100

CS to SCLK Rise Setup

t

CSS

100

CS to SCLK Rise Hold

t

CSH

0

SCLK Pulse Width High t

CH

200

SCLK Pulse Width Low t

CL

200

SCLK Fall to SSTRB t

SSTRB

C

LOAD

= 100pF 200

CS to SSTRB Output Enable

t

SDV

C

LOAD

= 100pF

External clock mode only

200

CS to SSTRB Output Disable

t

STR

C

LOAD

= 100pF

External clock mode only

200

ns

ns

ns

ns

ns

ns

ns

ns

ns

ns

ns

ns

SSTRB Rise to SCLK Rise
(Note 4)

t

SCK

Internal clock mode only 0 ns

PARAMETERS SYMBOL CONDITIONS MIN TYP MAX UNITS

Note 1: Accuracy specifications tested at VDD= +5.0V. Performance at power-supply tolerance limit is guaranteed by Power-Supply

Rejection test.

Note 2: External reference: V

REF

= 4.096V, offset error nulled. Ideal last-code transition = FS - 3/2LSB.

Note 3: Ground “on” channel; sine wave applied to all “off” channels. V

IN

= ±5V (MAX1270), VIN= ±4V (MAX1271).

Note 4: Guaranteed by design, not production tested.
Note 5: Use static external loads during conversion for specified accuracy.
Note 6: Tested using internal reference.
Note 7: PSRR measured at full scale. Tested for the ±10V (MAX1270) and ±4.096V (MAX1271) input ranges.
Note 8: Acquisition phase and conversion time are dependent on the clock period; clock has 50% duty cycle (Figure 6).
Note 9: Not production tested. Provided for design guidance only.

MAX1270/MAX1271

Multirange, +5V, 8-Channel,
Serial 12-Bit ADCs

7-174 ___________________________________________________________________________________

Typical Operating Characteristics

(Typical Operating Circuit, VDD= +5V; external reference mode, V

REF

= +4.096V; 4.7µF at REF; external clock, f

CLK

= 2MHz;

110ksps; TA= +25°C; unless otherwise noted.)

0

5

15

10

20

25

021 34567

SUPPLY CURRENT vs. SUPPLY VOLTAGE

MAX1270/1 toc01

SUPPLY VOLTAGE (V)

SUPPLY CURRENT (mA)

5.5

5.7

6.1

5.9

6.3

6.5

-40 10-15 35 60 85

SUPPLY CURRENT vs. TEMPERATURE

MAX1270/1 toc02

TEMPERATURE (°C)

SUPPLY CURRENT (mA)

50

150

450

350

250

650

550

750

-40 10-15 35 60 85

STANDBY SUPPLY CURRENT

vs. TEMPERATURE

MAX1270/1 toc03

TEMPERATURE (°C)

STANDBY SUPPLY CURRENT (µA)

INTERNAL
REFERENCE

EXTERNAL
REFERENCE

50

70

110

90

130

150

-40 10-15 35 60 85

FULL POWER-DOWN SUPPLY CURRENT

vs. TEMPERATURE

MAX1270/1 toc04

TEMPERATURE (°C)

FULL POWER-DOWN SUPPLY CURRENT (µA)

INTERNAL
REFERENCE

EXTERNAL
REFERENCE

0.1

0.2

0.6

0.5

0.4

0.3

0.7

0.8

-40 10-15 35 60 85

CHANNEL-TO-CHANNEL GAIN-ERROR

MATCHING vs. TEMPERATURE

MAX1270/1 toc07

TEMPERATURE (°C)

CHANNEL-TO-CHANNEL GAIN-ERROR MATCHING (LSB)

BIPOLAR MODE

UNIPOLAR MODE

0.996

0.997

0.999

0.998

1.000

1.001

-40 10-15 35 60 85

NORMALIZED REFERENCE VOLTAGE

vs. TEMPERATURE

MAX1270/1 toc05

TEMPERATURE (°C)

NORMALIZED REFERENCE VOLTAGE

0

0.05

0.25

0.20

0.15

0.10

0.30

0.35

-40 10-15 35 60 85

CHANNEL-TO-CHANNEL OFFSET-ERROR

MATCHING vs. TEMPERATURE

MAX1270/1 toc06

TEMPERATURE (°C)

CHANNEL-TO-CHANNEL OFFSET-ERROR MATCHING (LSB)

BIPOLAR MODE

UNIPOLAR MODE

-0.15

-0.10

0.05

0

-0.05

0.10

0.15

0 1638819 2457 3276 4095

INTEGRAL NONLINEARITY vs.

DIGITAL CODE

MAX1270/1 toc08

DIGITAL CODE

INTEGRAL NONLINEARITY (LSB)

-120

-100

-40

-60

-80

-20

0

0 20k10k 30k 40k 50k

FTT PLOT

MAX1270/1 toc09

FREQUENCY (Hz)

AMPLITUDE (dB)

fIN = 10kHz
f

SAMPLE

= 110ksps