MAX6226 [MAXIM]
Ultra-High-Precision, Ultra-Low-Noise, Series Voltage Reference;
| 型号： | MAX6226 |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | Ultra-High-Precision, Ultra-Low-Noise, Series Voltage Reference |
| 文件： | 总11页 (文件大小：844K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
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MAX6226
Ultra-High-Precision, Ultra-Low-Noise,
Series Voltage Reference
General Description
Benefits and Features
● 8-pin Hermetically Sealed Ceramic Package
The MAX6226 is an ultra-low-noise, high-precision, low-
dropout voltage reference. This family of voltage references
feature curvature-correction circuitry and high-stability,
laser-trimmed, thin-film resistors that result in 5ppm/°C
(max) temperature coefficients and an excellent ±0.02%
(max) initial accuracy. The proprietary low-noise reference
Reduces System Board Space
● Ultra-Low 1.45μV
Noise (0.1Hz to 10Hz, 2.5V Output)
P-P
● Ultra-Low 5ppm/°C (Max) Temperature Coefficient
● ±0.02% (Max) Initial Accuracy
architecture produces a low flicker noise of 1.45μV
and
● Wide (V
+ 200mV) to 12.6V Supply Voltage Range
P-P
OUT
wideband noise as low as 75nV/√Hz (2.5V output) without
the increased supply current usually found in low-noise
references. Improve wideband noise to 45nV/√Hz and AC
power-supply rejection by adding a 0.1μF capacitor at the
noise reduction pin. The MAX6226 series mode reference
operates from a wide 2.7V to 12.6V supply voltage range
and load-regulation specifications are guaranteed to be
less than 0.25Ω and 0.05Ω for sink and source currents up
to 10mA, respectively. These devices are available over the
automotive temperature range of -40°C to +125°C.
● Low 200mV (Max) Dropout Voltage
● 380μA Quiescent Supply Current
● 10mA Sink/Source-Current Capability
● Stable with C
= 0.1μF to 10μF
LOAD
● Low 11ppm/1000hr Long-Term Drift
● 0.05Ω (Max) Load Regulation
● 25μV/V (Max) Line Regulation
● Force and Sense Outputs for Remote Sensing
The MAX6226 typically draws 380μA of supply current
and the output voltage is 2.5V. The MAX6226 also feature
dropout voltages as low as 200mV. Unlike conventional
shunt-mode (two-terminal) references that waste supply
current and require an external resistor, the MAX6226
offers supply current that is virtually independent of
supply voltage and does not require an external resistor. The
MAX6226 is stable with 0.1μF to 10μF of load capacitance,
and is available in an 8-pin ceramic package.
Applications
● High-Resolution A/D and D/A Converters
● ATE Equipment
● High-Accuracy Reference Standard
● Precision Current Sources
● Digital Voltmeters
● High-Accuracy Industrial and Process Control
Ordering Information appears at end of data sheet.
Typical Operating Circuit
(V
+ 200mV) TO 12.6V INPUT
OUT
LONG-TERM STABILITY vs. TIME
(MAX6226ALA25+)
toc16
20
15
10
5
IN
REFERENCE
OUTPUT
OUTF
THREE TYPICAL UNITS
OUTS
MAX6226
*
NR
LOAD
*
0
GND
-5
0
200
400
600
800
1000
DURATION (HOURS)
*OPTIONAL.
19-100454; Rev 1; 4/19
MAX6226
Ultra-High-Precision, Ultra-Low-Noise,
Series Voltage Reference
Absolute Maximum Ratings
(All voltages referenced to GND)
IN...........................................................................-0.3V to +13V
OUTF, OUTS, NR..... -0.3V to the lesser of (V + 0.3V) or +6V
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
IN
Output Short Circuit to GND or IN......................................... 60s
Continuous Power Dissipation (T = +70°C)
A
8-Pin LCC (derate 17.79mW/°C above +70°C)......1423.5mW
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.
Package Information
LCC
PACKAGE CODE
L8+2
Outline Number
21-100289
90-100097
Land Pattern Number
Thermal Resistance, Four-Layer Board:
Junction to Ambient (θ
)
56.19°C/W
JA
Junction to Case (θ
)
8.11°C/W
JC
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 thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-layer board.
For detailed information on package thermal considerations, refer to www.maximintegrated.com/thermal-tutorial.
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MAX6226
Ultra-High-Precision, Ultra-Low-Noise,
Series Voltage Reference
Electrical Characteristics—MAX6226_25 (V
= 2.500V)
OUT
(V = 5V, C
= 0.1μF, I
= 0, T = T
to T
, unless otherwise noted. Typical values are at T = +25°C . (Note 1))
IN LOAD
OUT
A
MIN
MAX A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
OUTPUT
Output Voltage
V
T
= +25°C
2.500
V
OUT
A
Referred to V
,
OUT
Output Voltage Accuracy
A grade
-0.02
+0.02
5
%
T
= +25°C
A
Output Voltage Temperature
Coefficient (Note 2)
T
T = -40°C to +125°C A grade
1
5
ppm/°C
CVOUT
A
T
T
= +25°C
25
45
A
ΔV
/
/
OUT
Line Regulation
2.7V ≤ V ≤ 12.6V
IN
µV/V
ΔV
IN
= -40°C to +125°C
A
Sourcing: 0 ≤ I
≤ 10mA
5
50
OUT
ΔV
ΔI
OUT
OUT
Load Regulation
µV/mA
V
Sinking: -10mA ≤ I
≤ 0
50
250
0.2
0.4
OUT
I
I
= 5mA
0.06
0.12
160
20
OUT
OUT
Dropout Voltage (Note 3)
OUT Short-Circuit Current
V
- V
ΔV
= 0.1%
IN
OUT
OUT
= 10mA
Short to GND
I
mA
SC
Short to IN
ΔV
cycle
/
/
OUT
Thermal Hysteresis (Note 4)
5
ppm
ΔV
time
ppm/
1000hr
OUT
Long-Term Stability
1000hr at T = +25°C
A
11
DYNAMIC CHARACTERISTICS
f = 0.1Hz to 10Hz
1.45
µV
P-P
Noise Voltage
e
f = 1kHz, C
= 0
75
OUT
NR
NR
nV/√Hz
f = 1kHz, C
= 0.1µF
45
1
C
= 0
NR
To V
= 0.01% of
OUT
Turn-On Settling Time
t
ms
R
final value
C
= 0.1µF
20
NR
Capacitive-Load Stability Range
INPUT
C
No sustained oscillations
0.1 to 10
µF
LOAD
Supply Voltage Range
V
Guaranteed by line-regulation test
2.7
12.6
550
725
V
IN
T
T
= +25°C
380
A
Quiescent Supply Current
I
µA
IN
= -40°C to +125°C
A
Note 1: All devices are 100% production tested at T = +25°C and are guaranteed by design for T = T
to T
, as specified.
MAX
A
A
MIN
Note 2: Temperature coefficient is measured by the “box” method, i.e., the maximum ΔV
/V
is divided by the maximum ΔT.
OUT OUT
Note 3: Dropout voltage is defined as the minimum differential voltage (V - V
) at which V decreases by 0.1% from its
IN
OUT
OUT
original value at V = 5.0V.
IN
Note 4: Thermal hysteresis is defined as the change in +25°C output voltage before and after cycling the device from T
to T
.
MIN
MAX
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MAX6226
Ultra-High-Precision, Ultra-Low-Noise,
Series Voltage Reference
Typical Operating Characteristics
(V = 5V, C
IN LOAD
= 0.1μF, I = 0, T = +25°C, unless otherwise specified.)
OUT A
DROPOUT VOLTAGE
vs. OUTPUT SOURCE CURRENT
LOAD REGULATION
OUTPUT VOLTAGE TEMPERATURE DRIFT
toc03
toc02
300
250
200
150
100
50
2.5005
2.5004
2.5003
2.5002
2.5001
2.5
toc1
2.5005
2.5003
2.5000
2.4998
2.4995
2.4993
2.4990
THREE TYPICAL UNITS
TA = +125°C
TA = +25°C
TA = +125°C
2.4999
2.4998
2.4997
2.4996
2.4995
TA = -40°C
TA = +25°C
TA = -40°C
0
-50
-25
0
25
50
75
100 125
0
3
6
9
12
15
-10 -8 -6 -4 -2
0
2
4
6
8
10
TEMPERATURE (°C)
SOURCE CURRENT (mA)
OUTPUT CURRENT (mA)
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
QUIESCENT SUPPLY CURRENT
vs. SUPPLY INPUT VOLTAGE
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
toc04
toc5A
toc5B
600
500
400
300
200
100
0
-20
-40
-60
-80
0
-20
TA = +125°C
CLOAD = 0µF
CLOAD = 0.1µF
-40
TA = +25°C
-60
-80
TA = -40°C
-100
-100
-120
0.001 0.01
-120
0.001 0.01
0.1
1
10
100 1000
0.1
1
10
100 1000
2.6
4.6
6.6
8.6
10.6
12.6
FREQUENCY(kHz)
FREQUENCY(kHz)
SUPPLY INPUT VOLTAGE (V)
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MAX6226
Ultra-High-Precision, Ultra-Low-Noise,
Series Voltage Reference
Typical Operating Characteristics (continued)
(V = 5V, C
= 0.1μF, I = 0, T = +25°C, unless otherwise specified.)
OUT A
IN
LOAD
LOAD TRANSIENT
(CLOAD = 0.1µF)
PEAK-PEAK VOLTAGE NOISE
(0.1Hz to 10Hz)
PEAK-PEAK VOLTAGE NOISE
(0.1Hz to 10Hz)
toc08
toc06
toc07
1.6
1.2
0.8
0.4
0
1.6
1.2
0.8
0.4
0
CNR = 0.1uF
CNR = 0
1mA
IOUT
-100µA
VOUT
AC-
COUPLED
-0.4
-0.8
-1.2
-1.6
-0.4
-0.8
-1.2
-1.6
20mV/div
0
4
8
12
16
20
24
28
32
200μs/div
0
4
8
12
16
20
24
28
32
4s/div
4s/div
LOAD TRANSIENT
(CLOAD = 0.1µF)
LOAD TRANSIENT
(CLOAD = 10µF)
LOAD TRANSIENT
(CLOAD = 10µF)
toc09
toc10
toc11
-1mA
IOUT
10mA
IOUT
1mA
IOUT
-10mA
0mA
-100µA
VOUT
VOUT
AC-
COUPLED
VOUT
AC-
COUPLED
AC-
COUPLED
100mV/div
10mV/div
20mV/div
1ms/div
1ms/div
200μs/div
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MAX6226
Ultra-High-Precision, Ultra-Low-Noise,
Series Voltage Reference
Typical Operating Characteristics (continued)
(V = 5V, C
IN LOAD
= 0.1μF, I = 0, T = +25°C, unless otherwise specified.)
OUT A
LOAD TRANSIENT
(CLOAD = 10µF)
LINE TRANSIENT
(CLOAD = 0.1µF)
TURN-ON TRANSIENT
(CLOAD = 0.1µF)
toc12
toc13
toc14
-1mA
3.2V
VIN
5.5V
VIN
IOUT
-10mA
2.7V
0V
VOUT
VOUT
VOUT
AC-
AC-
1V/div
COUPLED
COUPLED
20mV/div
50mV/div
20μs/div
20μs/div
400μs/div
TURN-ON TRANSIENT
(CLOAD = 10µF)
LONG-TERM STABILITY vs. TIME
(MAX6226ALA25+)
toc15
toc16
20
15
10
5
5.5V
VIN
THREE TYPICAL UNITS
0V
VOUT
0
1V/div
-5
40μs/div
0
200
400
600
800
1000
DURATION (HOURS)
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MAX6226
Ultra-High-Precision, Ultra-Low-Noise,
Series Voltage Reference
Pin Configuration
TOP VIEW
7
6
5
MAX6226
4
8
GND
GND
1
2
3
+
LCC
Pin Description
PIN
NAME
FUNCTION
Noise Reduction. Connect a 0.1µF capacitor to improve wideband noise. Leave unconnected if not used
(see Figure 1).
1
NR
2
4,8
3, 7
5
IN
Positive Power-Supply Input
GND
I.C.
Ground
Internally Connected. Do not connect anything to these pins.
Voltage Reference Sense Output
OUTS
Voltage Reference Force Output. Short OUTF to OUTS as close to the load as possible. Bypass OUTF
with a capacitor (0.1µF to 10µF) to GND.
6
OUTF
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MAX6226
Ultra-High-Precision, Ultra-Low-Noise,
Series Voltage Reference
Detailed Description
(V
OUT
+ 200mV) TO 12.6V INPUT
Wideband Noise Reduction
To improve wideband noise and transient power-supply
noise, add a 0.1μF capacitor to NR (Figure 1). A 0.1μF NR
capacitor reduces the noise from 75nV/√Hz to 45nV/√Hz.
Noise in the power-supply input can affect output noise,
but can be reduced by adding an optional bypass capaci-
tor between IN and GND, as shown in the Typical
Operating Characteristics. The 0.1Hz to 10Hz noise when
measured with a 0.1µF noise reduction capacitor (NR pin)
IN
REFERENCE
OUTPUT
OUTF
OUTS
MAX6226
*
NR
0.1µF*
is 1.45μV
.
P-P
GND
Output Bypassing
The MAX6226 requires an output capacitor between
0.1μF and 10μF. Locate the output capacitor as close
to OUTF as possible. For applications driving switching
capacitive loads or rapidly changing load currents, it is
advantageous to use a 10μF capacitor in parallel with a
0.1μF capacitor. Larger capacitor values reduce transients
on the reference output.
*OPTIONAL.
Figure 1. Noise-Reduction Capacitor
Turn-On Time
Supply Current
These devices typically turn on and settle to within 0.1% of
their final value in 200μs to 2ms depending on the device.
The turn-on time can increase up to 4ms with the device
operating at the minimum dropout voltage and the maximum
load. A noise reduction capacitor of 0.1μF increases the
turn-on time to 20ms.
The quiescent supply current of the series-mode MAX6226
family is typically 380μA and is virtually independent of the
supply voltage, with only a 2μA/V (max) variation with
supply voltage.
When the supply voltage is below the minimum specified
input voltage during turn-on, the device can draw up to
300μA beyond the nominal supply current. The input voltage
source must be capable of providing this current to ensure
reliable turn-on.
Output Force and Sense
The MAX6226 provides independent connections for the
power-circuit output (OUTF) supplying current into a load,
and for the circuit input regulating the voltage applied to
that load (OUTS). This configuration allows for the
cancellation of the voltage drop on the lines connecting the
MAX6226 and the load. When using the Kelvin connection
made possible by the independent current and voltage
connections, take the power connection to the load from
OUTF, and bring a line from OUTS to join the line from
OUTF, at the point where the voltage accuracy is needed.
Thermal Hysteresis
Thermal hysteresis is the change of output voltage at
T
= +25°C before and after the device is cycled over
A
its entire operating temperature range. The typical thermal
hysteresis value is 5ppm.
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MAX6226
Ultra-High-Precision, Ultra-Low-Noise,
Series Voltage Reference
High-Resolution DAC and Reference from
a Single Supply
Figure 3 shows a typical circuit providing the reference
for a high-resolution, 16-bit MAX541 digital-to-analog
converter.
Applications Information
Precision Current Source
Figure 2 shows a typical circuit providing a precision cur-
rent source. The OUTF output provides the bias current
for the bipolar transistor. OUTS and GND sense the volt-
age across the resistor and adjust the current sourced
by OUTF accordingly. For even higher precision, use a
MOSFET to eliminate base current errors.
Temperature Coefficient vs. Operating
Temperature Range for a 1 LSB Maximum Error
In a data converter application, the reference voltage of
the converter must stay within a certain limit to keep the
error in the data converter smaller than the resolution limit
through the operating temperature range. Figure 4 shows
the maximum allowable reference voltage temperature
coefficient to keep the conversion error to less than 1 LSB,
The voltage range of OUTF is set by the reference output
voltage (OUTS) and the V
or V
of the
BE (BJT)
GS (MOS)
output external device:
V
= V + V
BE
OUTF
REF
where:
as a function of the operating temperature range (T
-
MAX
T
) with the converter resolution as a parameter. The
MIN
V
is voltage on OUTF pin
OUTF
graph assumes the reference voltage temperature coef-
ficient as the only parameter affecting accuracy.
V
V
is base-emitter drop across BJT
BE
is the actual voltage reference output this part is
REF
In reality, the absolute static accuracy of a data converter
is dependent on the combination of many parameters
such as integral nonlinearity, differential nonlinearity, offset
error, gain error, as well as voltage reference changes.
supposed to provide.
It translates to supply voltage requirement for voltage
reference:
V
≥ V
DROP
(dropout voltage) + V
+ V
BEmax REF
IN
where:
V
is dropout voltage of voltage reference
3V SUPPLY
DROP
V
IN
MAX6226
GND
DD
I
SOURCE
IN
REF
OUT
OUTF
OUTS
ANALOG
OUTPUT
MAXꢀꢁꢂ
ꢃAꢄ
OUTF
OUTS
MAX6226
GND
R
GND
V
/ R = I
SOURCE
OUT(NOMINAL)
Figure 3. 14-Bit High-Resolution DAC and Positive Reference
from a Single 3V Supply
Figure 2. Precision Current Source
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MAX6226
Ultra-High-Precision, Ultra-Low-Noise,
Series Voltage Reference
10,000
1000
100
8 BIT
TEMPERATURE
COEFFICIENT
(ppm/°C)
10
1
10 BIT
12 BIT
14 BIT
16 BIT
0.1
18 BIT
20 BIT
0.01
100
1
10
OPERATING TEMPERATURE RANGE (T - T ) (°C)
MAX MIN
Figure 4. Temperature Coefficient vs. Operating Temperature Range for a 1 LSB Maximum Error
The ceramic package also enables the MAX6226 to
exhibit improved thermal hysteresis. Thermal hysteresis
is the change in the reference’s output voltage at +25°C
as a result of being cycled over its full operating temperature
range. The MAX6226 has a typical hysteresis value of
5ppm.
MAX6226 in Ceramic LCC Package
The MAX6226’s ceramic LCC package is a hermetic
package that gives substantially better performance than
plastic, packages, while maintaining a small, surface-
mount form factor. Conventional plastic packages are
affected by humidity, stressing the die and cause the
voltage reference’s output to vary as humidity changes.
The MAX6226’s ceramic package eliminates this effect.
In addition, the package reduces stress on the die that
changes with time, thereby dramatically improving long-
term drift. The MAX6226 exhibits excellent output voltage
long-term drift performance (11ppm, typ), as illustrated
in the Long-Term Stability vs. Time plot in the Typical
Operating Characteristics.
Note that although the MAX6226’s ceramic package
prevents the output voltage from being affected by
mechanical stresses due to humid environments, the
PC board may be affected by humidity, and may in turn
cause mechanical stress to the MAX6226 mounted on it.
Take extra care with PC board layout. Power and ground
planes should be avoided under the voltage reference IC
for best stability. Closely follow the layout guidelines in the
Output Bypassing and Output Force and Sense.
Chip Information
PROCESS: BiCMOS
Ordering Information
OUTPUT
VOLTAGE
(V)
MAXIMUM TEMPCO
(-40°C to +125°C)
(ppm/°C)
PIN-
PACKAGE
MAXIMUM INITIAL
ACCURACY (%)
PART
TEMP RANGE
MAX6226ALA25+T
-40°C to +125°C
8LCC
2.500
0.02
5
+Denotes a lead(Pb)-free/RoHS-compliant package.
T = Tape and reel.
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MAX6226
Ultra-High-Precision, Ultra-Low-Noise,
Series Voltage Reference
Revision History
REVISION
NUMBER
REVISION
DATE
DESCRIPTION
PAGES CHANGED
0
1
12/18
Initial release
—
4/19
Correct LTD typical number
1, 3, 10
For pricing, delivery, and ordering information, please visit Maxim Integrated’s online storefront at https://www.maximintegrated.com/en/storefront/storefront.html.
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. Maxim Integrated reserves the right to change the circuitry and specifications without notice at any time. The parametric values (min and max limits)
shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance.
©
Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc.
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