Datasheet

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General Description

The MAX4194 is a variable-gain precision instrumenta-

tion amplifier that combines Rail-to-Rail

single-supply

operation, outstanding precision specifications, and a

high gain bandwidth. This amplifier is also offered in

three fixed-gain versions: the MAX4195 (G = +1V/V), the

MAX4196 (G = +10V/V), and the MAX4197 (G =

+100V/V). The fixed-gain instrumentation amplifiers fea-

ture a shutdown function that reduces the quiescent

current to 8µA. A traditional three operational amplifier

configuration is used to achieve maximum DC precision.

The MAX4194–MAX4197 have rail-to-rail outputs and

inputs that can swing to 200mV below the negative rail

and to within 1.1V of the positive rail. All parts draw only

93µA and operate from a single +2.7V to +7.5V supply

or from dual ±1.35V to ±3.75V supplies. These amplifiers

are offered in 8-pin SO packages and are specified for

the extended temperature range (-40°C to +85°C).

See the MAX4198/MAX4199 data sheet for single-supply,

precision differential amplifiers.

Applications

Medical Equipment

Thermocouple Amplifier

4–20mA Loop Transmitters

Data-Acquisition Systems

Battery-Powered/Portable Equipment

Transducer Interface

Bridge Amplifier

Features

♦ +2.7V Single-Supply Operation

♦ Low Power Consumption

93µA Supply Current

8µA Shutdown Current

(MAX4195/MAX4196/MAX4197)

♦ High Common-Mode Rejection: 115dB (G = +10V/V)

♦ Input Common-Mode Range Extends 200mV

Below GND

♦ Low 50µV Input Offset Voltage (G ≥ +100V/V)

♦ Low ±0.01% Gain Error (G = +1V/V)

♦ 250kHz -3dB Bandwidth (G = +1V/V, MAX4194)

♦ Rail-to-Rail Outputs

MAX4194–MAX4197

Micropower, Single-Supply, Rail-to-Rail,

Precision Instrumentation Amplifiers

________________________________________________________________ Maxim Integrated Products 1

OUT

REFV

RG+

IN-

IN+

RG-

TOP VIEW

MAX4194

OUT

FBV

SHDN

IN-

IN+

REF

MAX4195

MAX4196

MAX4197

19-1468; Rev 1; 6/03

PART

MAX4194ESA

MAX4195ESA

MAX4196ESA

-40°C to +85°C

TEMP RANGE PIN-PACKAGE

8 SO

Pin Configurations

Ordering Information

MAX4197ESA

-40°C to +85°C 8 SO

PART

MAX4194

MAX4195

MAX4196 Yes

Yes

SHUTDOWN GAIN (V/V)

Variable

+10

MAX4197 Yes +100

Selector Guide

Rail-to-Rail is a registered trademark of Nippon Motorola, Ltd.

CMRR (dB)

95 (G = +1V/V)

115

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.

Summary of content (13 pages)

PAGE 1
9-1468; Rev 1; 6/03 Micropower, Single-Supply, Rail-to-Rail, Precision Instrumentation Amplifiers The MAX4194–MAX4197 have rail-to-rail outputs and inputs that can swing to 200mV below the negative rail and to within 1.1V of the positive rail. All parts draw only 93µA and operate from a single +2.7V to +7.5V supply or from dual ±1.35V to ±3.75V supplies. These amplifiers are offered in 8-pin SO packages and are specified for the extended temperature range (-40°C to +85°C).
PAGE 2
MAX4194–MAX4197 Micropower, Single-Supply, Rail-to-Rail, Precision Instrumentation Amplifiers ABSOLUTE MAXIMUM RATINGS Supply Voltage (VCC to VEE)..................................................+8V All Other Pins .................................. (VCC + 0.3V) to (VEE - 0.3V) Current into Any Pin..........................................................±30mA Output Short-Circuit Duration (to VCC or VEE)........... Continuous Continuous Power Dissipation (TA = +70°C) 8-Pin SO (derate 5.
PAGE 3
Micropower, Single-Supply, Rail-to-Rail, Precision Instrumentation Amplifiers (VCC = +5V, VEE = 0V, RL = 25kΩ tied to VCC/2, VREF = VCC/2, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER SYMBOL CONDITIONS VCM = VEE + 0.2V to VCC - 1.1V, TA = +25°C, ∆RS = 1kΩ DC Common-Mode Rejection CMRDC VCM = VEE + 0.2V to VCC - 1.
PAGE 4
MAX4194–MAX4197 Micropower, Single-Supply, Rail-to-Rail, Precision Instrumentation Amplifiers ELECTRICAL CHARACTERISTICS (continued) (VCC = +5V, VEE = 0V, RL = 25kΩ tied to VCC/2, VREF = VCC/2, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER Short-Circuit Current (Note 2) SYMBOL CONDITIONS MIN ISC Gain Equation Gain Error ±0.01 ±0.1 G = +10V ±0.03 ±0.3 G = +100V/V ±0.05 ±0.5 G = +1000V/V, MAX4194 ±0.5 G = +1V ±0.01 ±0.1 ±0.03 ±0.3 ±0.05 ±0.
PAGE 5
Micropower, Single-Supply, Rail-to-Rail, Precision Instrumentation Amplifiers (VCC = +5V, VEE = 0V, RL = 25kΩ tied to VCC/2, VREF = VCC/2, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER SYMBOL CONDITIONS Time to Shutdown tSHDN G = +1V/V, 0.1%, VOUT = +3V Enable Time From Shutdown tENABLE G = +1V/V, 0.1%, VOUT = +3.5V Power-Up Delay MIN TYP ms MAX4195/MAX4196/ MAX4197 only 0.5 ms 1 ms 0.5 ms VSHDN = VCC - 2.5V to VCC - 1.5V, G = +100V/V, 0.
PAGE 6
Typical Operating Characteristics (continued) (VCC = +5V, VEE = 0, RL = 25kΩ tied to VCC/2, TA = +25°C, unless otherwise noted.
PAGE 7
Micropower, Single-Supply, Rail-to-Rail, Precision Instrumentation Amplifiers MAX4195/MAX4196 TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY VOLTAGE-NOISE DENSITY vs. FREQUENCY G = +1V/V MAX4194 toc13 1.000 MAX4194 toc12 0.100 THD + NOISE (%) 100 G = +10V/V 10 0.010 MAX4196 G = +10V/V 0.001 G = +1V/V MAX4195 G = +100V/V G = +1000V/V 1 1 10 100 1k 10k 0 100k 1 10 1k 10k SUPPLY CURRENT vs. TEMPERATURE SUPPLY CURRENT vs.
PAGE 8
Typical Operating Characteristics (continued) (VCC = +5V, VEE = 0, RL = 25kΩ tied to VCC/2, TA = +25°C, unless otherwise noted.) INPUT OFFSET CURRENT vs. TEMPERATURE MAX4197 -50 -100 MAX4195 -150 MAX4194TOC19 MAX4196 0 INPUT OFFSET VOLTAGE vs.
PAGE 9
Micropower, Single-Supply, Rail-to-Rail, Precision Instrumentation Amplifiers Input Stage The MAX4194–MAX4197 family of low-power instrumentation amplifiers implements a three-amplifier topology (Figure 1). The input stage is composed of two operational amplifiers that together provide a fixed-gain differential and a unity common-mode gain.
PAGE 10
Table 1. MAX4194 External Gain Resistor Selection This disables the instrumentation amplifier and puts its output in a high-impedance state. Pulling SHDN high enables the instrumentation amplifier. CLOSEST RG (1%) CLOSEST RG (5%) (Ω) (Ω) Applications Information GAIN (V/V) +1 ∞* ∞* +2 49.9k 51k +5 12.4k 12k +10 5.62k 5.6k +20 2.61k 2.7k +50 1.02k 1.0k +100 511 510 +200 249 240 +500 100 100 +1,000 49.9 51 +2,000 24.9 24 +5,000 10 10 +10,000 4.99 5.
PAGE 11
Micropower, Single-Supply, Rail-to-Rail, Precision Instrumentation Amplifiers IN+ RISO VOUT INRL VEE RG = ∞ (MAX4194) (INTERNAL, MAX4195) VREF CL VREF SHDN (5V/div) Figure 6a. Using a Resistor to Isolate a Capacitive Load from the Instrumentation Amplifier (G = +1V/V) 50µs/div Figure 5b. MAX4196 Shutdown Mode INPUT (50mV/div) MAX4197 OUT AC-COUPLED (VDIFF = 20mV, G = +100V/V) (500mV/div) OUTPUT (50mV/div) SHDN (5V/div) 50µs/div 50µs/div Figure 5c.
PAGE 12
MAX4194–MAX4197 Micropower, Single-Supply, Rail-to-Rail, Precision Instrumentation Amplifiers Power-Supply Bypassing and Layout identical two-element strain gauges) to the inputs of the MAX4194. The bridge contains four resistors, two of which increase and two of which decrease by the same ratio. Good layout technique optimizes performance by decreasing the amount of stray capacitance at the instrumentation amplifier’s gain-setting pins.
PAGE 13
Micropower, Single-Supply, Rail-to-Rail, Precision Instrumentation Amplifiers N E H INCHES MILLIMETERS MAX MIN 0.069 0.053 0.010 0.004 0.014 0.019 0.007 0.010 0.050 BSC 0.150 0.157 0.228 0.244 0.016 0.050 MAX MIN 1.35 1.75 0.10 0.25 0.35 0.49 0.19 0.25 1.27 BSC 3.80 4.00 5.80 6.20 0.40 SOICN .EPS DIM A A1 B C e E H L 1.27 VARIATIONS: 1 INCHES TOP VIEW DIM D D D MIN 0.189 0.337 0.386 MAX 0.197 0.344 0.394 MILLIMETERS MIN 4.80 8.55 9.80 MAX 5.00 8.75 10.