Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsData collecting ICsData acquisition IC - AD converter (ADC) Internal SOIC 8 N

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General Description

The MAX1084/MAX1085 10-bit analog-to-digital convert-

ers (ADCs) combine a high-bandwidth track/hold, a serial

interface with high conversion speed, an internal +2.5V

reference, and low power consumption. The MAX1084

operates from a single +4.5V to +5.5V supply; the

MAX1085 operates from a single +2.7V to +3.6V supply.

The 3-wire serial interface connects directly to

SPI™/QSPI™/MICROWIRE™ devices without external

logic. The devices use an external serial-interface clock to

perform successive-approximation analog-to-digital con-

versions.

Low power combined with ease of use and small pack-

age size make these converters ideal for remote-sensor

and data-acquisition applications, or for other circuits with

demanding power consumption and space requirements.

The MAX1084/MAX1085 are available in 8-pin SO

packages.

These devices are pin-compatible, higher-speed versions

of the MAX1242/MAX1243; for more information, refer to

the respective data sheets.

Applications

Portable Data Logging

Data Acquisition

Medical Instruments

Battery-Powered Instruments

Pen Digitizers

Process Control

Features

♦ Single-Supply Operation

+4.5V to +5.5V (MAX1084)

+2.7V to +3.6V (MAX1085)

♦ 10-Bit Resolution

♦ 400ksps Sampling Rate (MAX1084)

♦ Internal Track/Hold

♦ Internal +2.5V Reference

♦ Low Power: 2.5mA (400ksps)

♦ SPI/QSPI/MICROWIRE 3-Wire Serial Interface

♦ Pin-Compatible, High-Speed Upgrade to

MAX1242/MAX1243

♦ 8-Pin SO Package

MAX1084/MAX1085

400ksps/300ksps, Single-Supply, Low-Power,

Serial 10-Bit ADCs with Internal Reference

________________________________________________________________ Maxim Integrated Products 1

19-1686; Rev 1; 12/10

PART

MAX1084ACSA+

MAX1084BCSA+

MAX1084AESA+ -40°C to +85°C

0°C to +70°C

TEMP

RANGE

PIN-

PACKAGE

8 SO

Pin Configuration

Ordering Information

INL

(LSB)

±1/2

±1

±1/2

MAX1084BESA+

MAX1085ACSA+

MAX1085BCSA+ 0°C to +70°C

0°C to +70°C

-40°C to +85°C 8 SO

8 SO

±1

±1/2

±1

MAX1085AESA+

MAX1085BESA+ -40°C to +85°C

-40°C to +85°C 8 SO

8 SO

±1/2

±1

AIN

T/H

DOUT

OUTPUT

SHIFT

CONTROL

LOGIC

2.5V

REFERENCE

INT

CLOCK

10-BIT

SAR

REF

SHDN

SCLK

MAX1084

MAX1085

GND

Functional Diagram

SPI and QSPI are trademarks of Motorola, Inc.

MICROWIRE is a trademark of National Semiconductor Corp.

TOP VIEW

SCLK

DOUT

GND

REF

SHDN

AIN

MAX1084

MAX1085

+Denotes a lead(Pb)-free/RoHS-compliant package.

Summary of content (16 pages)

PAGE 1
9-1686; Rev 1; 12/10 400ksps/300ksps, Single-Supply, Low-Power, Serial 10-Bit ADCs with Internal Reference The MAX1084/MAX1085 10-bit analog-to-digital converters (ADCs) combine a high-bandwidth track/hold, a serial interface with high conversion speed, an internal +2.5V reference, and low power consumption. The MAX1084 operates from a single +4.5V to +5.5V supply; the MAX1085 operates from a single +2.7V to +3.6V supply.
PAGE 2
MAX1084/MAX1085 400ksps/300ksps, Single-Supply, Low-Power, Serial 10-Bit ADCs with Internal Reference ABSOLUTE MAXIMUM RATINGS VDD to GND .............................................................-0.3V to +6V AIN to GND................................................-0.3V to (VDD + 0.3V) REF to GND ...............................................-0.3V to (VDD + 0.3V) Digital Inputs to GND...............................................-0.3V to +6V DOUT to GND............................................-0.
PAGE 3
400ksps/300ksps, Single-Supply, Low-Power, Serial 10-Bit ADCs with Internal Reference (VDD = +4.5V to +5.5V, fSCLK = 6.4MHz, 50% duty cycle, 16 clocks/conversion cycle (400ksps), 4.7µF capacitor at REF, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS 2.48 2.50 2.52 V INTERNAL REFERENCE REF Output Voltage VREF TA = +25°C REF Short-Circuit Current REF Output Tempco TC VREF Load Regulation (Note 5) 0 to 1.
PAGE 4
MAX1084/MAX1085 400ksps/300ksps, Single-Supply, Low-Power, Serial 10-Bit ADCs with Internal Reference ELECTRICAL CHARACTERISTICS—MAX1085 (continued) (VDD = +2.7V to +3.6V, fSCLK = 4.8MHz, 50% duty cycle, 16 clocks/conversion cycle (300ksps), 4.7µF capacitor at REF, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS DYNAMIC SPECIFICATIONS (75kHz sinewave, 2.5VP-P, fSAMPLE = 300ksps, fSCLK = 4.
PAGE 5
400ksps/300ksps, Single-Supply, Low-Power, Serial 10-Bit ADCs with Internal Reference (Figures 1, 2, 8, 9; VDD = +4.5V to +5.5V, TA = TMIN to TMAX, unless otherwise noted.
PAGE 6
Typical Operating Characteristics (MAX1084: VDD = +5.0V, fSCLK = 6.4MHz; MAX1055: VDD = +3.0V, fSCLK = 4.8MHz; CLOAD = 20pF, 4.7µF capacitor at REF, TA = +25°C, unless otherwise noted.) 0.10 0.05 0.02 DNL (LSB) INL (LSB) 0.04 OFFSET ERROR (LSB) 0.06 0 -0.02 0 -0.05 -0.04 -0.06 0.50 MAX1084/5toc02 0.08 OFFSET ERROR vs. SUPPLY VOLTAGE 0.15 MAX1084/5toc01 0.10 DIFFERENTIAL NONLINEARITY vs. DIGITAL OUTPUT CODE MAX1084/5 toc03 INTEGRAL NONLINEARLITY vs. DIGITAL OUTPUT CODE 0.25 0 -0.
PAGE 7
400ksps/300ksps, Single-Supply, Low-Power, Serial 10-Bit ADCs with Internal Reference INTERNAL REFERENCE VOLTAGE vs. SUPPLY VOLTAGE INTERNAL REFERENCE VOLTAGE vs. TEMPERATURE 2.506 2.508 2.506 2.504 2.502 2.502 VREF (V) 2.504 2.500 2.500 2.498 2.498 2.496 2.496 2.494 2.494 2.492 2.492 2.490 MAX1084/5 toc08 2.508 2.490 2.5 3.0 3.5 4.0 4.5 5.0 5.5 -40 -20 0 SUPPLY VOLTAGE (V) MAX1084/5 toc09 CONVERTING, SCLK = 6.4MHz 2.50 2.25 CONVERTING, SCLK = 4.8MHz 2.00 1.
PAGE 8
MAX1084/MAX1085 400ksps/300ksps, Single-Supply, Low-Power, Serial 10-Bit ADCs with Internal Reference VDD 6kΩ DOUT DOUT 6kΩ CLOAD = 20pF CLOAD = 20pF DGND DGND a) HIGH-Z TO VOH AND VOL TO VOH b) HIGH-Z TO VOL AND VOH TO VOL Figure 1. Load Circuits for DOUT Enable Time VDD 6kΩ DOUT DOUT 6kΩ CLOAD = 20pF CLOAD = 20pF DGND a) VOH TO HIGH-Z DGND b) VOLTO HIGH-Z Figure 2.
PAGE 9
400ksps/300ksps, Single-Supply, Low-Power, Serial 10-Bit ADCs with Internal Reference +3V to +5V 0.1µF 10µF 1 2 ANALOG INPUT 0 TO VREF 3 SHUTDOWN INPUT 4 tACQ = 7(RS + RIN) ✕ 12pF where R IN = 800Ω, R S = the input signal’s source impedance, and t ACQ is never less than 468ns (MAX1284) or 625ns (MAX1085). Source impedance below 4kΩ does not significantly affect the ADC’s AC performance.
PAGE 10
MAX1084/MAX1085 400ksps/300ksps, Single-Supply, Low-Power, Serial 10-Bit ADCs with Internal Reference To start a conversion, pull CS low. At CS’s falling edge, the T/H enters its hold mode and a conversion is initiated. Data can then be shifted out serially with the external clock. needed to shift out these bits. Extra clock pulses occurring after the conversion result has been clocked out, and prior to a rising edge of CS, produce trailing zeros at DOUT and have no effect on converter operation.
PAGE 11
400ksps/300ksps, Single-Supply, Low-Power, Serial 10-Bit ADCs with Internal Reference MAX1084/MAX1085 SUPPLY CURRENT vs. CONVERSION RATE 10,000 1.50 SUPPLY CURRENT (µA) 1000 REFERENCE POWER-UP DELAY (ms) VDD = 3.0V DOUT = FS RL = ∞ CL = 10pF 100 10 1 1.00 0.75 0.50 0.25 0.1 0.1 1 10 100 1k 10k CREF = 4.7µF 1.25 0 0.0001 100k 0.001 0.01 0.1 1 10 TIME IN SHUTDOWN (s) CONVERSION RATE (SAMPLES) Figure 6. Supply Current vs. Conversion Rate Figure 7. Reference Power-Up vs.
PAGE 12
MAX1084/MAX1085 400ksps/300ksps, Single-Supply, Low-Power, Serial 10-Bit ADCs with Internal Reference OUTPUT CODE 11…111 FULL-SCALE TRANSITION I/O CS SCK 11…110 SCLK MISO DOUT +3V OR +5V 11…101 MAX1084 MAX1085 FS = VREF 1LSB = VREF 1024 SS a) SPI 00…011 CS 00…010 SCK CS SCLK MISO 00…001 DOUT +3V OR +5V 00…000 0 1 2 3 INPUT VOLTAGE (LSB) Figure 10. Unipolar Transfer Function, Full Scale (FS) = VREF, Zero Scale (ZS) = GND 3) Pull CS high at or after the 13th rising clock edge.
PAGE 13
400ksps/300ksps, Single-Supply, Low-Power, Serial 10-Bit ADCs with Internal Reference once offset and gain errors have been nullified. The static linearity parameters for the MAX1084/MAX1085 are measured using the endpoints method. Differential Nonlinearity Differential nonlinearity (DNL) is the difference between an actual step width and the ideal value of 1LSB. A DNL error specification of 1LSB or less guarantees no missing codes and a monotonic transfer function.
PAGE 14
400ksps/300ksps, Single-Supply, Low-Power, Serial 10-Bit ADCs with Internal Reference MAX1084/MAX1085 Effective Number of Bits SUPPLIES VDD VDD GND Effective number of bits (ENOB) indicates the global accuracy of an ADC at a specific input frequency and sampling rate. An ideal ADC’s error consists of quantization noise only. With an input range equal to the fullscale range of the ADC, calculate the effective number of bits as follows: ENOB = (SINAD - 1.76)/6.
PAGE 15
400ksps/300ksps, Single-Supply, Low-Power, Serial 10-Bit ADCs with Internal Reference PACKAGE TYPE PACKAGE CODE OUTLINE NO. LAND PATTERN NO. 8 SO S8+5 21-0041 90-0096 ______________________________________________________________________________________ 15 MAX1084/MAX1085 Package Information For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the package code indicates RoHS status only.
PAGE 16
MAX1084/MAX1085 400ksps/300ksps, Single-Supply, Low-Power, Serial 10-Bit ADCs with Internal Reference Revision History REVISION NUMBER REVISION DATE 0 5/00 Initial release 1 12/10 Add lead-free, update Absolute Maximum Ratings, update Figure 10, style updates DESCRIPTION PAGES CHANGED — 1–5, 7–12, 14, 15, 16 Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied.