19-4329; Rev 2; 12/10
SPI Programmable-Gain Amplifier
with Input V
OS
Trim and Output Op Amp
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 SPI™-programmable differential gains from
0.2V/V to 157V/V, input offset-voltage compensation, and
an output 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
CC
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.
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
Features
o
SPI-Programmable Gains: 0.2V/V to 157V/V
MAX9939
Ordering Information
PART
MAX9939AUB+
TEMP RANGE
-40°C to +125°C
PIN-PACKAGE
10 µMAX
+Denotes
a lead(Pb)-free/RoHS-compliant package.
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
SCLK 1
DIN
GND
INA-
INA+
2
3
4
5
Pin Configuration
TOP VIEW
+
10 CS
9
V
CC
OUTA
INB
OUTB
MAX9939
8
7
6
µMAX
SPI is a trademark of Motorola, Inc.
µMAX is a registered trademark of Maxim Integrated Products, Inc.
Functional Diagram appears at end of data sheet.
________________________________________________________________
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim's website at www.maxim-ic.com.
SPI Programmable-Gain Amplifier
with Input V
OS
Trim and Output Op Amp
MAX9939
ABSOLUTE MAXIMUM RATINGS
V
CC
to GND ..............................................................-0.3V to +6V
INB, OUTA, OUTB, SCLK, DIN,
CS............-0.3V
to (V
CC
+ 0.3V)
INA+, INA- to GND ..................................................-16V to +16V
Output Short-Circuit Current Duration........................Continuous
Continuous Input Current into Any Terminal.....................±20mA
Continuous Power Dissipation (T
A
= +70°C)
10-Pin µMAX (derate 5.6mW/°C above +70°C) ...........707mW
Operating Temperature Range .........................-40°C to +125°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
Soldering Temperature (reflow) .......................................+260°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.
ELECTRICAL CHARACTERISTICS
(V
CC
= 5V, V
GND
= 0V, V
INA+
= V
INA-
, Gain = 10V/V, R
OUTA
= R
OUTB
= 1kΩ to V
CC
/2, T
A
= T
MIN
to T
MAX
, unless otherwise noted.
Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
PGA CHARACTERISTICS
Gain Error
Gain Temperature-Coefficient
Input Offset Voltage (Note 2)
Input Offset-Voltage Drift
Input Offset-Voltage Trim Range
Input Common-Mode Range
V
CM
Guaranteed by CMRR test (Note 3)
-1V
≤
V
CM
≤
V
CC
- 2.2V
Common-Mode Rejection Ratio
Output Short-Circuit current
Input-Voltage Noise Density
Gain-Bandwidth Product
Slew Rate
Settling Time
Distortion
Max Capacitive Load
Output Swing
CMRR
I
SC
V
N
GBW
SR
t
S
THD
C
L(MAX)
V
OH
, V
OL
Voltage output high = V
CC
- V
OUTA
,
voltage output low = V
OUTA
- V
GND
(Note 4)
T
A
= +25°C
T
A
= T
MIN
to T
MAX
70
To 1%, 2V output step
f = 1kHz, V
OUTA
= 2.5V
P-P
f = 10kHz, gain = 157V/V
Gain = 0.2V/V
Gain = 1V/V
Gain = 157V/V
-V
CC
/2
≤
V
CM
≤
V
CC
- 2.2V, T
A
= +25°C
-V
CC
/2
≤
V
CM
≤
V
CC
- 2.2V
-V
CC
/2
50
50
39
70
54
2.15
279
9
0.45
89
1
25
60
V/µs
µs
dB
nF
mV
mA
nV/√Hz
MHz
60
60
dB
GE
Tc-GE
V
OS-A
With no V
OS
trim, T
A
= +25°C
With no V
OS
trim, T
A
= T
MIN
to T
MAX
10
±17
V
CC
- 2.2
T
A
= +25°C, 0.2V
≤
V
OUTA
≤
V
CC
- 0.2V
0.05
2.2
1.5
0.38
17
9
15
%
ppm/°C
mV
µV/C
mV
V
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
OUTPUT AMPLIFIER CHARACTERISTICS
Input Bias Current
Input Offset Voltage (Note 2)
Output Short-Circuit Current
Ib
V
OS-B
I
SC
1
1.5
9
15
pA
mV
mA
2
_______________________________________________________________________________________
SPI Programmable-Gain Amplifier
with Input V
OS
Trim and Output Op Amp
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
= 5V, V
GND
= 0V, V
INA+
= V
INA-
, Gain = 10V/V, R
OUTA
= R
OUTB
= 1kΩ to V
CC
/2, T
A
= T
MIN
to T
MAX
, unless otherwise noted.
Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
Unity-Gain Bandwidth
Slew Rate
Settling Time
Input-Voltage Noise Density
Distortion
Max Capacitive Load
Output Swing
POWER SUPPLY
Supply Voltage Range
Power-Supply Rejection Ratio
Supply Current
Shutdown Supply Current
SPI CHARACTERISTICS
Input-Voltage Low
Input-Voltage High
Input Leakage Current
Input Capacitance
SPI TIMING CHARACTERISTICS
SCLK Frequency
SCLK Period
SCLK Pulse-Width High
SCLK Pulse-Width Low
CS
Fall to SCLK Rise Setup
CS
Fall to SCLK Rise Hold
DIN to SCLK Setup
DIN Hold after SCLK
SCLK Rise to
CS
Fall Delay
CS
Rise to SCLK Rise Hold
CS
Pulse-Width High
f
SCLK
t
CP
t
CH
t
CL
t
CSS
t
CSH
t
DS
t
DH
t
CS0
t
CS1
t
CSW
(Note 5)
200
80
80
80
20 + (0.5
x t
CP
)
55
0
20
80
200
5
MHz
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
V
IL
V
IH
I
IN
C
IN
5
V
CC
= 5V
V
CC
= 3.3V
2.0
1.65
±1
0.8
V
V
µA
pF
V
CC
PSRR
I
CC
I
SHDN
Guaranteed by PSRR
1kΩ between OUTA and INB, 1kΩ between
OUTB and INB, measured differentially
between OUTA and OUTB
OUTA and OUTB unloaded
Soft shutdown through SPI
2.9
60
80
3.4
13
6.7
24
5.5
V
dB
mA
µA
SYMBOL
UGBW
SR
t
S
V
N
THD
C
L(MAX)
V
OH
, V
OL
Voltage output high = V
CC
- V
OUTB
,
voltage output low = V
OUTB
- V
GND
f = 1kHz, V
OUTA
= 2.5V
P-P
, gain = -1V/V
To 1%, 2V output step
CONDITIONS
MIN
TYP
2.2
6.4
0.86
36
90
1
25
60
MAX
UNITS
MHz
V/µs
µs
nV/√Hz
dB
nF
mV
MAX9939
Note 1:
Note 2:
Note 3:
Note 4:
Note 5:
All devices are 100% production tested at T
A
= +25°C. Temperature limits are guaranteed by design.
The input offset voltage includes the effects of mismatches in the internal V
CC
/2 resistor dividers.
For gain of 0.25V/V, the input common-mode range is -1V to V
CC
- 2V.
The input current of a CMOS device is too low to be accurately measured on an ATE and is typically on the order of 1pA.
Parts are functional with f
SCLK
= 10MHz.
_______________________________________________________________________________________
3
SPI Programmable-Gain Amplifier
with Input V
OS
Trim and Output Op Amp
MAX9939
CS
t
CSS
t
CSO
SCLK
t
CL
t
CH
t
CP
t
CSH
t
CSW
t
CS1
t
DS
DIN
t
DH
Figure 1. SPI Interface Timing Diagram
Typical Operating Characteristics
(V
CC
= 5V, V
GND
= 0V, V
IN+
= V
IN-
= 0V, Gain = 10V/V, R
OUTA
= R
OUTB
= 1kΩ to V
CC
/2, T
A
= +25°C, unless otherwise noted.)
PGA GAIN vs. FREQUENCY
MAX9939 toc01
PGA GAIN vs. FREQUENCY
1V/V
≤
GAIN
≤
157V/V
R
L
= 10kΩ to V
CC
/2
GAIN =30V/V
GAIN (dB)
MAX9939 toc02
AMPLIFIER B GAIN vs. FREQUENCY
R
L
= 10kΩ to V
CC
/2
40
20
0
-20
-40
-60
-80
MAX9939 toc03
60
40
20
GAIN (dB)
0
-20
-40
-60
R
L
= 10kΩ to V
CC
/2
-80
0.01
0.1
1
FREQUENCY (MHz)
10
3
2
1
GAIN (dB)
0
-1
-2
-3
-4
60
GAIN = 160V/V
100
0.01
0.1
1
10
0.01
0.1
1
FREQUENCY (MHz)
10
100
FREQUENCY (MHz)
AMPLIFIER B GAIN vs. FREQUENCY
MAX9939 toc04
COMMON-MODE REJECTION RATIO
vs. FREQUENCY
1V/V
≤
GAIN
≤
157V/V
-10
-20
CMRR (dB)
-30
-40
-50
-60
-70
GAIN ERROR (%)
MAX9939 toc05
GAIN ERROR vs. TEMPERATURE
MAX9939 toc06
3
R
L
= 10kΩ to V
CC
/2
2
1
GAIN (dB)
0
-1
-2
-3
-4
0.01
0.1
1
0
0.20
0.15
0.10
0.05
10
-80
0.001
0
0.01
0.1
1
10
100
-40 -25 -10 5 20 35 50 65 80 95 110 125
TEMPERATURE (°C)
FREQUENCY (MHz)
FREQUENCY (MHz)
4
_______________________________________________________________________________________
SPI Programmable-Gain Amplifier
with Input V
OS
Trim and Output Op Amp
Typical Operating Characteristics (continued)
(V
CC
= 5V, V
GND
= 0V, V
IN+
= V
IN-
= 0V, Gain = 10V/V, R
OUTA
= R
OUTB
= 1kΩ to V
CC
/2, T
A
= +25°C, unless otherwise noted.)
INPUT V
OS
vs. TEMPERATURE
MAX9939 toc07
MAX9939
INPUT V
OS
TRIM RESPONSE
3.0
2.5
2.0
1.5
1.0
0.5
MAX9939 toc08
OFFSET (mV)
OUTA
10mV/div
GAIN = 1V/V
0
-40 -25 -10 5 20 35 50 65 80 95 110 125
TEMPERATURE (°C)
1ms/div
DIFFERENTIAL PSRR vs. FREQUENCY
MAX9939 toc09
TOTAL HARMONIC DISTORTION
vs. FREQUENCY
1V/V
≤
GAIN
≤
157V/V
MAX9939 toc10
0
0
-20
DISTORTION (dB)
-40
10V/V
≤
GAIN
≤
157V/V
-20
PSRR (dB)
-40
GAIN = 157V/V
-60
-80
-100
GAIN = 1V/V
-120
-60
-80
-100
0.01
0.1
1
10
100
1000 10,000
FREQUENCY (kHz)
0.01
0.1
1
FREQUENCY (kHz)
10
100
NOISE VOLTAGE DENSITY
MAX9939 toc11
NOISE VOLTAGE DENSITY
AMPLIFIER B
NOISE DENSITY (nV/√Hz)
MAX9939 toc12
10,000
PGA
10V/V
≤
GAIN
≤
157V/V
NOISE DENSITY (nV/√Hz)
1000
1000
100
100
10
10
100
1000
FREQUENCY (Hz)
10,000
100,000
10
10
100
1000
FREQUENCY (Hz)
10,000
100,000
_______________________________________________________________________________________
5
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