19-3337; Rev 2; 3/05
100k
Ω
Precision-Matched Resistor-Divider in
SOT23
MAX5490
General Description
The MAX5490 precision resistor-divider consists of two
accurately matched resistors with access to the ends
and center of the divider. This device offers excellent
resistance matching of 0.035% (A grade), 0.05% (B
grade), and 0.1% (C grade). The MAX5490 provides an
extremely low resistance-ratio temperature drift of
1ppm/°C (typ) over -55°C to +125°C, and has an end-to-
end resistance of 100kΩ. Resistance ratios from 1:1 to
100:1 are available. Five standard ratios are available
(see Table 1), and custom ratios are also available upon
request. The MAX5490 is ideal for precision gain-setting
applications where tight resistance matching and low
temperature drift are necessary.
The MAX5490 is available in a space-saving 3-pin
SOT23 package, and is guaranteed over the military
-55°C to +125°C temperature range.
♦
Resistance Ratios from 1:1 to 100:1
♦
Custom Ratios Available Upon Request
♦
Tight Initial Ratio Accuracy
0.035% (MAX5490A)
0.05% (MAX5490B)
0.1% (MAX5490C)
♦
Low 1ppm/°C (typ) Resistor-Ratio-Drift
♦
Up to 80V Operating Voltage Across Sum of R1
and R2
♦
Tiny 3-Pin SOT23 Package
Features
Applications
Industrial Process Control
Instrumentation
Precision Gain Setting
Medical Equipment
Automatic Test Equipment
Base Stations
PART
Ordering Information*
TEMP
RANGE
RATIO
PIN-
ACCURACY
PACKAGE
(%)
0.035
0.05
0.1
MAX5490
_
A
_ _ _ _ _
-T -55°C to +125°C 3 SOT23-3
MAX5490
_
B
_ _ _ _ _
-T -55°C to +125°C 3 SOT23-3
MAX5490
_
C
_ _ _ _ _
-T -55°C to +125°C 3 SOT23-3
*See
the How to Order section for more details.
Block Diagram
TOP VIEW
P1
Pin Configuration
MAX5490
R
1
P3
R
2
P2
2
P1
1
MAX5490
3
P3
P2
SOT23
________________________________________________________________
Maxim Integrated Products
1
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.
100k
Ω
Precision-Matched Resistor-Divider in
SOT23
MAX5490
ABSOLUTE MAXIMUM RATINGS
Voltage Between P1 and P2.................................................100V
Maximum Current into Any Pin ......................................±1.00mA
Continuous Power Dissipation (T
A
= +70°C)
3-Pin SOT23 (derate 7.1mW/°C above +70°C).........571.4mW
3-Pin SOT23 (θ
J-A
) .....................................................141°C/W
Operating Temperature Range .........................-55°C to +125°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°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.
DC ELECTRICAL CHARACTERISTICS
(T
A
= -55°C to +125°C, unless otherwise noted. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
Initial Resistor Ratio Error (Note 2)
Resistance-Ratio Temperature
Coefficient (Note 3)
Absolute Temperature Coefficient
of Resistance
Voltage Coefficient of Resistance
End-to-End Resistance (R
1
+ R
2
)
Continuous Working Voltage
Between P1 and P2
Continuous Current
P1, P2, P3 Capacitance
Maximum Power Rating
Resistance Ratio Long-Term
Stability
-3dB Bandwidth
Thermal Noise
Current Noise
In accordance with MIL-STD-2020
method 30B
f
3dB
2000 hours at +70°C
1:1 ratio (Note 6)
V
P1-P2
I
R1
, I
R2
2
67.2
±0.03
3
45
-25
TCR
VCR
SYMBOL
CONDITIONS
MAX5490_A, T
A
= +25°C
MAX5490_B, T
A
= +25°C
MAX5490_C, T
A
= +25°C
1:1
≤
ratio
≤
10:1
10:1
≤
ratio
≤
25:1
(Note 4)
(Note 5)
T
A
= +25°C
95
-80
1
2
35
0.1
100
105
+80
840
MIN
TYP
MAX
±0.035
±0.05
±0.1
2
4
ppm/°C
ppm/°C
ppm/V
kΩ
V
µA
pF
mW
%
MHz
µV
RMS
dB
%
UNITS
Note 1:
The MAX5490 is 100% production tested at T
A
= +25°C. Specifications over -55°C to +125°C are guaranteed by design
and characterization.
Note 2:
Testing conditions: T
A
= +25°C, V
P1-P2
= 10V and 80V.
⎛
R
⎞
∆⎜
1
⎟
Note 3:
Resistance-ratio temperature coefficient is defined as
⎝
R
2
⎠
and is guaranteed by design, not production tested.
R
1
× ∆
T
For ratios from 25:1 to 100:1, contact factory.
R
2
Note 4:
Absolute TCR is defined as
(
R
1
+
∆
(
R
1
+
R
2
)
R
2
)
× ∆
T
and is tested at 10V and 80V.
2
_______________________________________________________________________________________
100k
Ω
Precision-Matched Resistor-Divider in
SOT23
DC ELECTRICAL CHARACTERISTICS (continued)
(T
A
= -55°C to +125°C, unless otherwise noted. Typical values are at T
A
= +25°C.) (Note 1)
MAX5490
Note 5:
Resistance-ratio voltage coefficient is defined as
⎛
R
⎞
∆⎜
1
⎟
⎝
R
2
⎠
R
1
× ∆
V
R
2
and is guaranteed by design, not production tested.
Note 6:
Calculate bandwidth by using
1
R
×
R
,
where C = C
P3
and
R
=
1 2
.
2πRC
R
1
+
R
2
Typical Operating Characteristics
(V
P1-P2
= 10V, T
A
= +25°C, unless otherwise noted.)
NORMALIZED RESISTANCE-RATIO DRIFT
vs. TEMPERATURE
MAX5490 toc01
NORMALIZED RESISTANCE-RATIO DRIFT
vs. TEMPERATURE
MAX5490 toc02
NORMALIZED RESISTANCE-RATIO DRIFT
vs. TEMPERATURE
150
100
RATIO DRIFT (ppm)
50
0
-50
-100
-150
-200
-55
-25
5
35
65
95
125
V
P1-P2
= 10V
RATIO 25:1
MAX5490 toc03
50
40
30
RATIO DRIFT (ppm)
20
10
0
-10
-20
-30
-55
-25
5
35
65
95
V
P1-P2
= 10V
RATIO 1:1
160
120
RATIO DRIFT (ppm)
80
40
0
-40
-80
-120
V
P1-P2
= 10V
RATIO 10:1
200
125
-55
-25
5
35
65
95
125
TEMPERATURE (°C)
TEMPERATURE (°C)
TEMPERATURE (°C)
RESISTANCE-RATIO ACCURACY
vs. VOLTAGE
MAX5490 toc04
FREQUENCY RESPONSE
3
0
RESPONSE (dB)
-3
-6
-9
-12
-15
-18
0.1
1
10
FREQUENCY (kHz)
100
1000
1:1 RATIO
C
L
= 10pF
MAX5490 toc05
0.04
RATIO 25:1
0.03
RATIO ACCURACY (%)
0.02
0.01
0
-0.01
-0.02
-0.03
-0.04
0
10
20
30
40
50
60
70
6
80
VOLTAGE (V)
_______________________________________________________________________________________
3
100k
Ω
Precision-Matched Resistor-Divider in
SOT23
MAX5490
Typical Operating Characteristics (continued)
(V
P1-P2
= 10V, T
A
= +25°C, unless otherwise noted.)
TOTAL HARMONIC DISTORTION
PLUS NOISE RESPONSE
MAX5490 toc06
SPECTRAL NOISE DENSITY
1000
RATIO 1:1
SIGNAL CONNECTED TO P2
P1 GROUNDED
V
P1-P2
= 10V
100
V
P1-P2
= 2V
THD+N (%)
100
10
1
0.1
0.01
0.001
10
1
10
100
1k
FREQUENCY (Hz)
0.0001
10
1:1 RATIO
20Hz TO 20kHz BANDPASS
NOISE (nV/√Hz)
100
1k
FREQUENCY (Hz)
10k
100k
Pin Description
PIN
1
2
3
NAME
P1
P2
P3
R
1
Connection Terminal
R
2
Connection Terminal
Set-Point Connection Terminal
FUNCTION
Detailed Description
As shown in the
Block Diagram,
the MAX5490 consists
of two precision, low-ratio-drift resistors with an end-to-
end resistance of 100kΩ (R
1
+ R
2
). P3 is the set point
of the divider. The maximum working voltage of the
MAX5490 is 80V. This device offers a wide range of
resistance ratios (R
1
/R
2
) from 1:1 to 100:1 and is ideal
for precision operational amplifier gain/attenuation con-
trol. A maximum initial ratio accuracy of 0.035% and a
low 1ppm/°C ratio drift enhance system accuracy.
The worst-case self-heating occurs when the operating
voltage attains its maximum value. Approximate the
result of power dissipation under this condition as:
P
DISS
=
(
V
MAX
)
2
R
=
(
80V
)
2
100k
Ω
MAX5490 toc07
=
64mW
Applications Information
Self-Heating and Error
Applying a voltage across terminals P1 and P2 causes
the device to heat up due to power dissipation. In high-
voltage applications, consider the error in resistance-
ratio temperature coefficient caused by self-heating.
The thermal resistance from junction to ambient,
θ
J-A
,
for a 3-pin SOT23 package is 141°C/W. Calculate the
resulting temperature rise as:
∆T
= 64mW x 141°C/W = 9.02°C
If the ratio temperature coefficient is 1ppm/°C (typ), the
total error introduced by self-heating is:
9.02°C x 1ppm/°C = 9.02ppm
4
_______________________________________________________________________________________
100k
Ω
Precision-Matched Resistor-Divider in
SOT23
Typical Applications
A
=
V
OUT
R
= −
1
V
IN
R
2
IN
OUT
OUT
A
=
V
OUT
R
=
1
+
1
V
IN
R
2
MAX5490
P3
P3
P2
IN
R
2
R
1
MAX5490
P1
P2
R
2
R
1
MAX5490
P1
Figure 1. Inverting Amplifier Configuration
Figure 2. Noninverting Amplifier Configuration
IN
IN
P1
A
=
V
OUT
R
2
=
V
IN
R
1
+
R
2
A
=
MAX5490
R
1
P3
V
OUT
R
2
=
V
IN
R
1
+
R
2
P1
MAX5490
R
1
P3
OUT
R
2
P2
P2
R
2
OUT
Figure 3. Buffered Attenuator
Figure 4. Attenuator with Buffer
_______________________________________________________________________________________
5
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