Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsLinear ICsLinear IC - Op-amp Programmable gain uMAX 10

19-4329; Rev 3; 12/12

MAX9939

SPI Programmable-Gain Amplifier

with Input V

Trim and Output Op Amp

For pricing, delivery, and ordering information, please contact Maxim Direct

at 1-888-629-4642, or visit Maxim’s website at www.maximintegrated.com.

General Description

The MAX9939 is a general-purpose, differential-input

programmable-gain amplifier (PGA) that is ideal for con-

ditioning a variety of wide dynamic range signals such

as those found in motor current-sense, medical instru-

mentation, and sonar data acquisition applications. It

features programmable differential gains from 0.2V/V to

157V/V, input offset-voltage compensation, and an out-

put amplifier that can be configured either as a high-

order active filter or to provide a differential output.

The PGA is optimized for high-signal bandwidth and its

gain can be programmed to be 0.2V/V, 1V/V, 10V/V,

20V/V, 30V/V, 40V/V, 60V/V, 80V/V, 119V/V, and 157V/V.

Precision resistor matching provides extremely low gain

tempco and high CMRR. Although the MAX9939 oper-

ates from a single supply V

between 2.9V to 5.5V, it

can process signals both above and below ground due

to the use of an input level-shifting amplifier stage.

Furthermore, its inputs are protected to ±16V, allowing it

to withstand fault conditions and signal overranges.

The output amplifier is designed for high bandwidth

and low-bias currents, making it ideal for use in multi-

ple-feedback active filter topologies that offer much

higher Qs and stopband attenuation than Sallen-Key

architectures.

The MAX9939 draws 3.4mA of quiescent supply current

at 5V, and includes a software-programmable shut-

down mode that reduces its supply current to only

13µA. The MAX9939 is available in a 10-pin µMAX

package and operates over the -40°C to +125°C auto-

motive temperature range.

Applications

Sensorless Motor Control

Medical Signal Conditioning

Sonar and General Purpose Data Acquisition

Differential to Single-Ended Conversion

Differential-Input, Differential-Output Signal

Amplification

Sensor Interface and Signal Processing

Features

o SPI-Programmable Gains: 0.2V/V to 157V/V

o Extremely Low Gain Tempco

o Integrated Amplifier for R/C Programmable Active

Filter

o Input Offset-Voltage Compensation

o Input Protection to ±16V

o 13µA Software Shutdown Mode

o -40°C to +125°C Operating Temperature Range

o 10-Pin µMAX Package

Ordering Information

PART TEMP RANGE PIN-PACKAGE

MAX9939AUB+ -40°C to +125°C 10 µMAX

MAX9939AUB/V+T -40°C to +125°C 10 µMAX

/V denotes an automotive-qualified part.

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

Functional Diagram appears at end of data sheet.

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

OUTA

INBINA-

GND

DIN

SCLK

MAX9939

µMAX

TOP VIEW

OUTBINA+

Pin Configuration

Summary of content (15 pages)

PAGE 1
MAX9939 SPI Programmable-Gain Amplifier with Input VOS Trim and Output Op Amp General Description The MAX9939 is a general-purpose, differential-input programmable-gain amplifier (PGA) that is ideal for conditioning a variety of wide dynamic range signals such as those found in motor current-sense, medical instrumentation, and sonar data acquisition applications. It features programmable differential gains from 0.
PAGE 2
MAX9939 SPI Programmable-Gain Amplifier with Input VOS Trim and Output Op Amp ABSOLUTE MAXIMUM RATINGS VCC to GND ..............................................................-0.3V to +6V INB, OUTA, OUTB, SCLK, DIN, CS............-0.3V to (VCC + 0.3V) INA+, INA- to GND ..................................................-16V to +16V Output Short-Circuit Current Duration........................Continuous Continuous Input Current into Any Terminal.....................
PAGE 3
MAX9939 SPI Programmable-Gain Amplifier with Input VOS Trim and Output Op Amp ELECTRICAL CHARACTERISTICS (continued) (VCC = 5V, VGND = 0V, VINA+ = VINA-, Gain = 10V/V, ROUTA = ROUTB = 1kΩ to VCC/2, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1) PARAMETER Unity-Gain Bandwidth Slew Rate SYMBOL MAX UNITS MHz 6.4 V/µs tS VN Output Swing TYP SR Input-Voltage Noise Density Max Capacitive Load MIN 2.
PAGE 4
MAX9939 SPI Programmable-Gain Amplifier with Input VOS Trim and Output Op Amp CS tCSW tCSS tCL tCSO tCP tCH tCSH tCS1 SCLK tDS tDH DIN Figure 1. SPI Interface Timing Diagram Typical Operating Characteristics (VCC = 5V, VGND = 0V, VIN+ = VIN- = 0V, Gain = 10V/V, ROUTA = ROUTB = 1kΩ to VCC/2, TA = +25°C, unless otherwise noted.
PAGE 5
MAX9939 SPI Programmable-Gain Amplifier with Input VOS Trim and Output Op Amp Typical Operating Characteristics (continued) (VCC = 5V, VGND = 0V, VIN+ = VIN- = 0V, Gain = 10V/V, ROUTA = ROUTB = 1kΩ to VCC/2, TA = +25°C, unless otherwise noted.) INPUT VOS vs. TEMPERATURE INPUT VOS TRIM RESPONSE MAX9939 toc08 MAX9939 toc07 3.0 OFFSET (mV) 2.5 2.0 OUTA 10mV/div 1.5 1.0 0.
PAGE 6
MAX9939 SPI Programmable-Gain Amplifier with Input VOS Trim and Output Op Amp Typical Operating Characteristics (continued) (VCC = 5V, VGND = 0V, VIN+ = VIN- = 0V, Gain = 10V/V, ROUTA = ROUTB = 1kΩ to VCC/2, TA = +25°C, unless otherwise noted.) MAX9939 toc13 1000 AMPLIFIER B 800 SETTLING TIME (ns) IMPEDANCE (Ω) 10 1 0.1 VOUT = 2VP-P 900 MAX9939 toc14 1% SETTLING TIME vs. GAIN (PGA) OUTPUT IMPEDANCE vs. FREQUENCY 100 700 600 500 400 300 200 100 0.01 0.001 0 0.01 0.
PAGE 7
MAX9939 SPI Programmable-Gain Amplifier with Input VOS Trim and Output Op Amp Typical Operating Characteristics (continued) (VCC = 5V, VGND = 0V, VIN+ = VIN- = 0V, Gain = 10V/V, ROUTA = ROUTB = 1kΩ to VCC/2, TA = +25°C, unless otherwise noted.) COMMON-MODE REJECTION RESPONSE SHUTDOWN CURRENT vs. SUPPLY VOLTAGE MAX9939 toc19 INA+ 1V/div INA1V/div OUTA 2V/div SHUTDOWN CURRENT (µA) VCM = 1VP-P, 1kHz VDM = 25mVP-P, 10kHz MAX9939 toc20 20 16 12 8 4 GAIN = 157V/V 0 200µs/div 2.8 3.2 3.6 4.0 4.
PAGE 8
MAX9939 SPI Programmable-Gain Amplifier with Input VOS Trim and Output Op Amp CS SCLK DIN D0 D1 D2 D3 D6 D5 D6 D7 Figure 2. SPI Interface Timing Diagram (CPOL = CPHA = 0) CMRR, gain accuracy, and very low temperature drift due to precise resistor matching. The output of this amplifier is level shifted to VCC/2. This amplifier is followed by a programmable-gain inverting amplifier (amplifier A) with programmable RF and RI resistors whose gain varies between 0.2V/V and 157V/V.
PAGE 9
MAX9939 SPI Programmable-Gain Amplifier with Input VOS Trim and Output Op Amp SHDN: Set SHDN to 0 for normal operation. Set SHDN to 1 to place the device in a low-power 13µA shutdown mode. In shutdown mode, the outputs OUTA and OUTB are high impedance, however, the SPI decode circuitry is still active. Each instruction requires a write to the SHDN bit. MEAS: The MAX9939 provides a means for measuring its own input offset voltage.
PAGE 10
MAX9939 SPI Programmable-Gain Amplifier with Input VOS Trim and Output Op Amp Table 4. Input Offset-Voltage Trim INPUT OFFSET VOLTAGE (V4 = 0 TRIMS POSITIVE, V4 = 1 TRIMS NEGATIVE) V3:V0 VOS (mV) 0000 0 0001 1.3 0010 2.5 0011 3.8 0100 4.9 0101 6.1 0110 7.3 0111 8.4 1000 10.6 1001 11.7 1010 12.7 1011 13.7 1100 14.7 1101 15.7 1110 16.7 1111 17.
PAGE 11
MAX9939 SPI Programmable-Gain Amplifier with Input VOS Trim and Output Op Amp VCC 1µF 0.1µF VCC MAX9939 VCC 20kΩ 20kΩ VCC/2 VCC/2 20kΩ 20kΩ 10kΩ INA+ OUTA A RI LVL 10kΩ 66.5kΩ RF INA- ASIC INB 121kΩ VCC 10kΩ 220pF GAIN INPUT OFFSETVOLTAGE TRIM DIN 66.5kΩ 1.21kΩ 20kΩ B SHUTDOWN SPI REGISTERS SCLK 4.7nF ADC OUTB 100nF 20kΩ VCC/2 CS GND CS DOUT SCLK Figure 3. Using the MAX9939 Output Amplifier as an Anti-Aliasing Filter (Corner Frequency = 1.
PAGE 12
MAX9939 SPI Programmable-Gain Amplifier with Input VOS Trim and Output Op Amp VCC 1µF 0.1µF VCC MAX9939 VCC 20kΩ 20kΩ VCC/2 VCC/2 20kΩ 20kΩ 10kΩ INA+ OUTA A RI LVL 10kΩ 10kΩ RF INA- ASIC INB VCC 10kΩ 10kΩ GAIN INPUT OFFSETVOLTAGE TRIM 20kΩ B SHUTDOWN ADC OUTB VCC/2 SPI REGISTERS SCLK DIN 20kΩ CS GND CS DOUT SCLK Figure 4.
PAGE 13
MAX9939 SPI Programmable-Gain Amplifier with Input VOS Trim and Output Op Amp Functional Diagram VCC VCC MAX9939 VCC 20kΩ 20kΩ VCC/2 VCC/2 20kΩ 20kΩ 10kΩ INA+ OUTA A RI LVL 10kΩ RF INA- INB VCC 10kΩ GAIN INPUT OFFSETVOLTAGE TRIM 20kΩ B OUTB SHUTDOWN VCC/2 SPI REGISTERS SCLK DIN 20kΩ CS GND Maxim Integrated 13
PAGE 14
MAX9939 SPI Programmable-Gain Amplifier with Input VOS Trim and Output Op Amp Package Information For the latest package outline information and land patterns (footprints), go to www.maximintegrated.com/packages. Note that a “+”, “#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status. PACKAGE TYPE PACKAGE CODE OUTLINE NO. LAND PATTERN NO.
PAGE 15
MAX9939 SPI Programmable-Gain Amplifier with Input VOS Trim and Output Op Amp Revision History REVISION NUMBER REVISION DATE 0 11/08 Initial release — 1 2/09 Corrected gain value in Table 3 9 2 12/10 Modified Figure 2 8 3 12/12 Added the MAX9939AUB/V+T 1 DESCRIPTION PAGES CHANGED Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent licenses are implied.