voltage reference selection basics

8/11/2019 Voltage Reference Selection Basics

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Choosing the Best Shunt or Series Reference for Your Application

Voltage references are a key building block in data conversion systems. Understanding the

specications and how they contribute to error is necessary for selecting the right referenc

for the application.Figure 1 shows the application of a voltage reference in a simple analog

to-digital converter (ADC) and digital-to-analog converter (DAC). In each case, the refere

voltage (VREF ) acts as a very precise analog meter stick against which the incoming analog

signal is compared (as in an ADC) or the outgoing analog signal is generated (as for a DA

As such, a stable system reference is required for accurate and repeatable data conversion

and as the number of bits increases, less reference error can be tolerated. Monolithic

voltage references produce an output voltage which is substantially immune to variations

ambient temperature as well as loading, input supply, and time. While many ADCs and DA

incorporate an internal reference, beyond 8 to 10 bits it is rare to nd one with sufcient

precision as high-density CMOS technologies commonly used for data converters typical

produce low-quality references. In most cases, the internal reference can be overdriven

by an external one to improve performance. Terms such as high precision and ultra-

high precision are common in reference datasheets but do little to help designers in their

selection. This article seeks to provide an explanation of common reference specications

rank their relative importance and show how a designer can use them in some simple

calculations to narrow the search.

Overview Voltage references are key components

in data conversion systems which enable

the ADC and DAC to read accurate

values and are used in various sensing

applications. While they are simple parts

which often may only have two or threepins, there are numerous parameters that

affect the performance of a reference, and

careful consideration of all the parameters

are required to select the proper one.

This paper covers the differences between

the shunt and series architectures, explains

key parameters and special features, and

shows how to properly calculate the error

for a given reference in a given operatingcondition.

Voltage ReferenceSelection Basics

Mario EdnoProduct marketing engineer

W H I T E P A P E R

Figure 1. Simplied ADC/DAC Diagrams

+

-

DECODER


2/13Voltage Reference Selection Basics June 2014

2 Texas Instruments

Figure 2 shows the two available voltage references topologies: series and shunt. A series reference prov

load current through a series transistor located between VIN and VREF (Q1), and is basically a high-precision,

low-current linear regulator. A shunt reference regulates VREF by shunting excess current to ground via a

parallel transistor (Q2). In general, series references require less power than shunt references because loa

current is provided as it is needed. The bias current of a shunt reference (IBIAS) is set by the value of RBand must be greater than or equal to the maximum load current plus the references minimum operating

current (the minimum bias current required for regulation). In applications where the maximum load

current is low (e.g. below 100 A to 200 A), the disparity in power consumption between series and sh

references shrinks. There is no inherent difference in accuracy between the two topologies and high- and

low-precision examples are available in both varieties.

The advantages and disadvantages of the two architectures are summarized inTable 1. Generally, shunt

references offer more exibility (VIN range, creation of negative or oating references) and better power

supply rejection at the expense of higher power consumption while series references typically dissipate l

power and can achieve better performance for extremely high-precision applications. The typical applica

diagram of data converters will often show a zener diode symbol representing the reference, indicating t

use of a shunt reference. This is merely a convention, and in nearly all cases a series reference could be

used as well.

Table 1. Series vs Shunt Architectures

Series Shunt

Number of Terminals 3 (VIN, VREF, GND) 2 (VREF, GND)

Current Requirements IQ + ILOAD (as needed) Min. operating current + ILOAD_MAX (continuous)

Advantages Low power dissipationShutdown/power-saving mode possible

No limit on maximum VINExcellent power supply rejectionCan be used to create negative reference voltagesCan be used to create oating references(cathode to a voltage other than GND)Inherent current sourcing and sinking

Disadvantages

Limited maximum VIN More sensitive to VIN supply (PSRR)May only be capable of sourcing current

Must idle at maximum load currentShutdown/power-saving mode not possible

Figure 2. Circuit Symbols and Simplied Schematics of Series and Shunt Architectures



Texas Instruments

As with all ICs, voltage references have standardized parameters for determining the right part for a desi

The following are key specications in order of importance that are pertinent to all suppliers.

1. Temperature Coefcient

The variation in VREF over temperature is dened by its temperature coefcient (TC, also referred to as dri

which has units of parts-per-million per degree Celsius (ppm/C). It is convenient to represent the referenvoltage temperature dependence as a polynomial for the sake of discussion:

TC1 represents the rst-order (linear) temperature dependence, TC2 the second-order, and so on. Higher

than rst-order terms are usually lumped together and described as the curvature of the drift.

The majority of monolithic references are based on a bandgap reference. A bandgap reference is creat

when a specic Proportional To Absolute Temperature (PTAT) voltage is added to the Complementary To

Absolute Temperature (CTAT) base-to-emitter voltage of a bipolar transistor yielding a voltage at roughl

bandgap energy of silicon (~1.2V) where TC1 is nearly zero. Neither the PTAT nor CTAT voltage is perfe

linear leading to non-zero higher-order TC coefcients, with TC2 usually being dominant. References

designed for drifts less than 20 ppm/C generally require special circuitry to reduce TC2 (and possibly

higher-order terms), and their datasheets will often mention some form of curvature correction. Anothe

common type of reference is based on a buried-zener diode voltage plus a bipolar base-to-emitter voltag

produce a stable reference voltage on the order of 7V. The drift performance of buried-zener references is

par with that of bandgap references, although their noise performance is superior. Buried-zener reference

usually require large quiescent currents and must have an input supply greater than 7.2V, so they cannot used in low-voltage applications (VIN = 3.3V, 5V, etc.).

The temperature coefcient can be specied over several different temperature ranges, including the

commercial temperature range (0 to 70C), the industrial temperature range (-40 to 85C), and the extend

temperature range (-40 to 125C). There are several methods of dening TC, with the box method bein

used most often. The box method calculates TC using the difference in the maximum and minimum VREF

measurements over the entire temperature range whereas other methods use the values of VREF at the

endpoints of the temperature range (TMIN, TMAX ).

Voltage ReferenceSpecications

+

+

+

+= ...TTCTTC

C25

C25

C25T

TC 1| V(T) V3

3

2

21C25REFREF

Figure 3. Different Methods for TC Calculation



4 Texas Instruments

Neither method is ideal. The weakness of the endpoints method is the failure to account for any curvatur

the drift (TC2, TC3, etc.). Calculating the

incremental TC from room temperature

to both the minimum and maximum

temperatures improves the situation asinformation on TC2 can be

garnered using three data points rather

than two. While the box method is more accurate than using endpoints, it may underestimate TC if the te

perature range of the application is smaller than the range over which the TC is specied.

2. Initial Accuracy

The initial accuracy of VREF indicates how close to the stated nominal voltage the reference voltage is

guaranteed to be at room temperature under stated bias conditions. It is typically specied as a percentag

and ranges from 0.01% to 1% (100-10,000 ppm). For example, a 2.5V reference with 0.1% initial accura

should be between 2.4975V and 2.5025V when measured at room temperature. The importance of initia

accuracy depends mainly on whether the data conversion system is calibrated. Buried-zener references h

very loose initial accuracy (5-10%) and will require some form of calibration.

3. 0.1-10 Hz Peak-to-Peak Noise

The internally-generated noise of a voltage reference causes a dynamic error that degrades the signal-to-

noise ratio (SNR) of a data converter, reducing the estimated number of bits of resolution (ENOB). Data

provide separate specications for low- and high-frequency noise. Broadband noise is typically speciedan rms value in microvolts over the 10 Hz to 10 kHz bandwidth. Broadband noise is the less troublesom

of the two as it can be reduced to some degree with a large VREF bypass capacitor. Broadband noise may

or may not be important in a given application depending on the bandwidth of the signal the designer in

interested in. Low-frequency VREF noise is specied over the 0.1 Hz to 10 Hz bandwidth as a peak-to-peak

value (in V or ppm). Filtering below 10 Hz is impractical, so the low-frequency noise contributes direc

the total reference error. Low-frequency noise is characterized using an active bandpass lter composed

a 1st-order high-pass lter at 0.1 Hz followed by an nth-order low-pass lter at 10 Hz. The order of the l

pass lter has a signicant effect on measured peak-to-peak value. Using a 2nd-order low pass at 10 Hz

reduce the peak-to-peak value by 50 to 60% compared to a 1st-order lter.

Some manufacturers use up to 8th-order lters, so a designer should read the datasheet notes

carefully when comparing references. From a design perspective, the 0.1 Hz to 10 Hz noise is mainly du

the icker (1/f ) noise of the devices and resistors in the bandgap cell, and therefore scales linearly with REF.

For example, a 5V reference will have twice the peak-to-peak noise voltage as the 2.5V option of the sam

part. Reducing the noise requires considerably higher current and larger devices in the bandgap cell, so v

=MINMAX25 CREF

TREF_MINTREF_MAX6BOX TT

1

| V

| V| V10TC

= MINMAX25 CREF

TMINREFTMAXREF6ENDPOINTS

TT

1

| V

| V| V10TC


5/13

Texas Instruments

low noise references (



should be placed as close to the load as the PCB layout will allow. References with pins for both forcing

sensing VREF provide some immunity to this problem. The impedance of the reference input is large enoug

(>10 k) on many data converters that load regulation error may not be signicant. Maximum load curr

information can be found in ADC/DAC datasheets specied as either a minimum reference pin resistanc

(RREF) or a maximum reference current (IREF). In situations where the reference is buffered with a hig

speed op amp, load regulation error can usually be ignored. The dual of load regulation for shunt referen

is the change in reverse breakdown voltage with current that species the change in VREF as a function of

the current shunted away from the load. It is calculated with the same equation as load regulation where

current is replaced with shunted current (ISHUNT). The amount of shunted current depends on both the

current and the input voltage so the change in reverse voltage with current specication also indicates

line sensitivity.

7. Line Regulation

Line regulation applies only to series voltage references and is the measure of the change in the referenc

voltage as a function of the input voltage. The importance of line regulation depends on the tolerance of

the input supply. In situations where the input voltage tolerance is within 10% or less, it may not contribu

signicantly to the total

error. The extension

of line regulation over

frequency is the Power Supply Rejection Ratio (PSRR). PSRR is rarely specied but typical curves are u

provided in the datasheet. As with line regulation, the importance of PSRR depends on specics of the in

supply. If VIN is noisy (generated with a switching regulator, sensitive to EMI, subject to large load transien

PSRR may be critical. The analogous specication for shunt references is the reverse dynamic impedanc

which indicates the sensitivity of VREF to an AC current. Noise on the supply powering a shunt reference

is converted to a noise current through RBIAS. Some shunt reference datasheets will specify the reverse

dynamic impedance at 60 Hz and 120 Hz, and nearly all will provide a plot of reverse dynamic impedan

versus frequency.

8. Special Features

In applications where power consumption is crucial, a series reference is usually the right choice. The

quiescent current of most series references ranges from 25 A to 200 A, although several are available

with IQ



mode is not possible in shunt references. Additionally, series references can have dropout voltages less th

200 mV, allowing them to be used at lower input voltages. Shunt references can also be used at low

voltages, but the bias current may vary widely with changes in VIN due to the small RBIAS resistor required

References do not require many external passive components but proper selection can improve

performance. A bypass capacitor on VREF substantially improves PSRR (or reverse dynamic impedance in tcase of a shunt reference) at higher frequencies. It will also improve the load transient response, and redu

high-frequency noise. Generally speaking, the best performance is achieved with the largest bypass capa

allowed. The range of allowable bypass capacitors depends on the stability of the reference, which shoul

detailed along with ESR restrictions in the component selection section of the datasheet. When using a la

bypass capacitor (>1 F) it may be advantageous to bypass it with a smaller value, lower-ESR capacitor

reduce the effects of the ESR and ESL. The reverse dynamic impedance of a shunt reference varies inver

with the amount of current shunted. If noise immunity is more important than power consumption in a g

application, a smaller RBIAS may be used to increase ISHUNT.

Some series references have a TRIM / NOISE REDUCTION (NR) pin to further enhance performanc

using a series of resistors shown inFigure 4 , the TRIM/NR pin can be used to adjust output voltage by up

15 mV. The pin can also be used to create a low pass lter to decrease overall noise measured on VOUT by

using a capacitor as shown inFigure 5 . Note that increasing the capacitor size will continue to improve no

performance, but also increases startup time.

9. Other Considerations

Voltage references are becoming increasingly popular in the automotive space and as reliability becomes

more critical, the need for AEC-Q100 qualied parts increases as well. The AEC-Q100 qualication wascreated by the Automotive Electronics Council and requires specic quality and testing procedures to en

a devices performance. On top of the general qualication, there are also grades from 0-4 which indicate

temperature range of the qualied device. At the time of this article, the most common is grade 1 where t

operating temperature range of the device spans from -40 to 125C. It should be noted that many manu-

facturers offer voltage references in the extended temperature range of -40 to 125C and mention that the

device is suitable for automotive applications but this does not mean that the device is AEC-Q100 grad

1-qualied. Therefore, designers for automotive applications should be cautious of devices that state

DNC

TEMP VOUT

VIN

GND

DNC

NC

TRIM/NR

REF50xx

+V SUPPLY

10 k

1 k

470 k

DNC

TEMP VOUT

VIN

GND

DNC

NC

TRIM/NR

REF50xx

C11F

+VSUPPLY

Figure 4: V OUT Adjustment Using the TRIM/NR Pin Figure 5: Noise Reduction Using the TRIM/NR Pin

Texas Instruments



suitability for automotive applications unless it is specically specied in the datasheet as AEC-Q100

qualied.

Due to the popularity of voltage references, many manufacturers have produced identical products a

sometimes even release them as the same part number as the original manufacturer for part recognition.

While the main performance characteristics are identical, there are times when there are subtle differencwhich could be of concern to a designer depending on their application. For example, the LM4040 offer

from Texas Instruments has a wideband noise value of 35 VRMS for a 2.5V output. The same part from

another supplier has a wideband noise value of 350 VRMS which is 10x the value even though the

initial accuracy and temperature coefcient are the same. Other differences that are prevalently found ar

operating temperature range and current consumption. A designer should be careful when considering

secondary or alternate parts with the same part number and should do a thorough comparison of the

performance to ensure that the key parameters are indeed the same.

Selecting the rightVoltage Reference

8 Texas Instruments

!"#$%&'%$'%()

T e m p c o ( p p m

/ o C )

LM4030

Initial Accuracy

REF1112

LM4050 / 51TL4050 / 51

LM4040/41

0.05% 0.1% 0.2% 0.5% 1.0% 2.0%

150

100

75

50

30

10

1.5%

TLV431

LMV431

LM1 / 2 / 385

LM431/ TL431

Shunt References

AECQ-100

Device Tempco (ppm/C) Initial Accuracy (%) Noise (V PP) VOUT (V) Iq (A) Package

LM4030 10 to 30 0.05 to 0.15 105 2.5, 4.096 120SOT23-3SOT23-5

REF1112 30 to 50 0.2 25 1.25 1.2 SOT23-3

LM1/2/385 30 to 150 1.0 to 2.0 50 Adj, 2.5 50SOT23-3TO-92SOIC-8

LM4050/51 50 0.1 to 0.5 48 Adj, 1.225, 2.0, 2.5, 4.096,

5.0, 8.2, 1039 SOT23-3

TL431 50 0.5 to 2.0 Adj, 2.5 4SOIC-8TO-92SC-70

LM4040/41 100 0.1 to 0.5 35 Adj, 1.225, 2.0, 2.5, 3.0,

4.096, 5.0, 8.2, 1065

SOT23-3SC-70TO-92



Voltage reference selection begins with satisfying the application operating conditions, specically: nom

VREF, VIN range, current drive, power consumption, and package size. Beyond that, a reference is chosen ba

on the accuracy requirements of a given data converter application. The most convenient unit for

understanding how the reference error affects accuracy is in terms of the least signicant bit (LSB) of the

data converter. The LSB in units of parts-per-million is simply one million divided by two raised to the nu

of bits power.Table 2 provides the LSB values for

common resolutions.

ADCs / DACs have their own sources of error including

integral nonlinearity (INL), differential nonlinearity (DNL), and gain

and off set error. If we consider the case of the more common

unipolar data converter, voltage reference error is functionally

equivalent to a gain error. INL and DNL gauge the nonlinearity of

a data converter, on which the reference voltage has no effect.

The gain and off set errors can be understood conceptually

Bits LSB (ppm)

8 3906

10 977

12 244

14 61

16 15

Table 2. LSB Values in PPM forCommon Data Converter Resolution

Texas Instruments

Initial Accuracy

100

75

50

20

10

40

30

LM4128

REF30xx

LM4120 /21 /25

0.05% 0.1% 0.2% 0.5% 1.0% 2.0%

REF33xx REF32xx

REF31xxREF02

LM4132

REF50xxREF20xx REF102

LM4140

REF29xx

AECQ-100

T e m p c o ( p p m

/ o C )

Series References

Device Tempco (ppm/C) Initial Accuracy (%) Noise (V PP) VOUT(V) Iq (A) Package

REF50xx 3 to 8 0.05 to 0.1 6 to 302.0, 2.5, 3.0, 4.096, 4.5,

5.0, 101000

MSOP-8SO-8

LM4132 10 to 20 0.05 to 0.5 170 to 3501.8, 2.0, 2.5, 3.0, 3.3,

4.09560 (3)* SOT23-5

REF33xx 30 0.15 35 to 921.25, 1.8, 2.048, 2.5,

3.0, 3.38.5

SOT23-3SC-70UQFN-8

REF30xx 50 to 75 0.2 14 to 451.2, 2.0, 2.5, 3.0, 3.3,

4.09550 SOT23-3

LM4120/21 50 0.2 to 0.5 20 Adj, 1.2, 1.8, 2.0, 2.5, 3.0,

3.3, 4.095, 5.0275 (2)* SOT23-5

LM4128 75 to 100 0.1 to 1.0 170 to 3501.8, 2.0, 2.5, 3.0, 3.3,

4.095100 (7)* SOT23-5

* Shutdown current noted in parens

Bitof Number:NOB 21

10LSB(ppm)

NOB6

=



by recognizing that ADCs / DACs have two reference voltages: VREF and GND in the case of a unipolar data

converter, and VREF and -VREF for bipolar data converters. The offset error is the deviation in the output (in

bits for an ADC and voltage for a DAC) from the ideal minus full-scale (MFS) value when a MFS input

applied. The MFS reference voltage is GND so VREF error has no effect. The gain error is the deviation

the ideal positive full-scale (PFS) output for a PFS input, minus the offset error. The PFS reference voltagis VREF, so any shift in the reference voltage equates to a gain error. As such, the reference error can cause

loss of dynamic range for input signals near PFS, which is also where it has the most pronounced effect

accuracy. The effect of reference error on a mid-scale (MS) input signal is half that for a PFS input, and i

negligible for inputs near MFS. For example, a worst-case reference error of 8 LSB would result in a los

3 bits of accuracy for a PFS input, 2 bits of lost accuracy at mid-scale, and no loss of accuracy at MFS. I

designer has no idea what kind of reference error they can live with, matching the worst-case reference e

to the maximum gain error is a reasonable starting point. In systems where error contributors are statistic

independent, and consequently add together as a root mean squared sum, balancing the error contributio

represents the optimal case. Otherwise, the error will tend to be dominated by one variable and the accur

of the other variable(s) is essentially wasted.

In calculating the total error in VREF it is helpful to separate the specications where a maximum value

is guaranteed (TC, initial accuracy, load regulation, line regulation) and those where only a typical value

provided (0.1 Hz to 10 Hz noise, thermal hysteresis, and long-term stability). Other than initial accuracy,

guaranteed specications are all linear coefcients and their contribution to the total error can be calcula

based on the operating ranges of the reference (temperature range, load current, and input voltage).

In calibrated systems, initial accuracy can be dropped from the equation. The above calculation repres

the worst case, and most of the time a reference will perform better than the guaranteed maximums (esp

cially when it comes to line and load regulation where the maximum may be more a function of the testi

system due to the very low signal-to-noise ratio of the measurement). It is worth noting that the statistica

methods through which the guaranteed maximum specications are calculated vary by manufacturer, so

comparing datasheets may not tell the full story. If the designer wants to estimate the average reference

10 Texas Instruments

1160 ppm50 ppm60 ppm550 ppm500 ppm)(0.05%|ERROR

50 ppm4.5V)(5.5V(50 ppm/V)|ERROR

60 ppm0 mA)(0.5 mA )(120 ppm/mA |ERROR

550 ppmC)0C(55C)(10 ppm/ |ERROR

Example using LM4132A 2.5V with 2.5V output

|ERROR|ERROR|ERROR |ERROR|ERROR

) V(VLINE_REG|ERROR

)I(ILOAD_REG|ERROR )T(TTC|ERROR

GUARANTEED

LINE

LOAD

oooTEMP

LINELOADTEMPCURACYINITIAL_ACGUARANTEED

IN_MININ_MAXLINE

LOAD_MINLOAD_MAXLOAD

MINMAXTEMP

=+++==

==

==

==

+++=

=

=

=



Texas Instruments

1631 ppm 96 ppm 150 ppm225 ppm 1160 ppm |ERROR

96 ppm2.5V

240 10|ERROR

150 ppm(50 ppm)3|ERROR

225 ppm(75 ppm)3 |ERROR

|ERROR|ERROR|ERROR|ERROR|ERROR VREF

Peak toPeak 10 Hz0.110|ERROR

Stability)Term-Long(Typ.3|ERROR

)HysteresisThermal(Typ.3 |ERROR

TOT

PP6NOISELF_

LITYTERM_STABILONG

S_HYSTERESITHERMAL

LF_NOISELITYTERM_STABILONGS_HYSTERESITHERMALGUARANTEEDTOT

6NOISELF_

LITYTERM_STABILONG

S_HYSTERESITHERMAL

=+++=

=

=

=

=

+++=

=

V

Example using LM4132A 2.5V with 2.5V output

error, they can take the rms sum of the individual error sources rather than just adding them up. For

simplicity, one can convert from peak to peak to rms value by using the equation peak-to-peak = 6.6x rm

This is because 99.99% of the error will fall within 6.6 standard deviations of the total error distribution.

most cases, the TC error will be dominant, so TC error by itself gives a good indication of average

reference performance. Datasheets only provide typical values for thermal hysteresis and long-term stabi

but both are likely to vary a great deal unit to unit. The typical specication is not very helpful in estimat

worst-case error without knowing the standard deviation of the distribution. Many times this information

can be obtained by calling the manufacturer. Otherwise, a conservative, albeit crude, approach would be

multiply the typical specication by three or four to get a ballpark estimate of the worst-case shift. This i

assuming that the standard deviation of the distribution is on the order of the mean value and designing fa two or three standard deviation worst case. The loss of resolution due to noise is harder to predict and c

only really be known by testing a reference in the application.

Low-frequency noise should be very consistent on a unit-to-unit basis and no sand-bagging of the ty

value is required. Over a 10-second window, one can expect the VREF to shift by an amount equal to the

0.1 Hz to 10 Hz peak-to-peak specication.

Once the worst-case reference error in parts-per-million is estimated, it can be converted into LSB for

different data converter resolutions using the values inTable 2 . The worst-case accuracy loss at positive ful

scale and mid-scale can then be calculated taking the log base-2 of the number of LSB of error.

( )

(14 bit)bits 3.7 bit) (12 bits 1.7(10 bit)bit0 (MS) AccuracyLostCaseWorst

(14 bit)bits 4.7bit) (12bits 2.7(10 bit)bit80 (PFS) AccuracyLostCaseWorst

(LSB)|ERRORlog AccuracyLostCaseWorst

(14 bit)LSB 26.7 (12 bit)LSB 6.7(10 bit)1.7 LSB

LSBppm

ppm1631(LSB)|ERROR

TOTAL2

TOTAL

===

===

=

===

=

.


12/13

SLPY00 2014 Texas Instruments Incorporated

WEBENCH is a registered trademark and the platform bar is a trademarksof Texas Instruments Incorporated. All other trademarks are the property oftheir respective owners.

12 Texas Instruments

If the average rather than the worst case is considered, the rms sum of reference error contributors can be

taken (replacing the maximums for the typicals).

Using the voltage reference specications to perform the above analysis, a designer should be able to pre

the typical and worst-case accuracy loss due to reference error in their data conversion system. Repeatin

this exercise for several different references should provide the designer with more insight into what

reference specications are most critical in their application. These often include operating temperature

range for temperature drift, initial accuracy if calibration is not possible, and low frequency noise which

cannot be ltered. Knowing which parameter is the dominant error factor helps to narrow down the refer

options signicantly and makes choosing the right reference easier.

1. Voltage Reference Selection BasicsPower Designer, issue #123by David Megaw2. For online resources for reference designs, technical documents, and selector wheel,

visit the Voltage Reference landing pageti.com/vref3. Try the interactive selection tool to help instantly choose the proper reference for an ADC from

the broad TI portfolio, see the WEBENCH Series Voltage Reference Selector Tool atti.com/webenchvref

About the author Mario Endo is a product marketing engineer for TIs Power Products group where he is responsible for

creating product awareness and identifying solutions for customer applications. Mario received his

Master of Science from Santa Clara University.

Resources

( )

(14 bit)bits2.6bit)(12bits0.6(10 bit)bit(MS) AccuracyLostTypical

(14 bit)bits3.6bit)(12bits1.6(10 bit)bit(PFS) AccuracyLostTypical

(LSB)|ERRORlog AccuracyLostTypical

(14 bit)LSB 12.5(12 bit)LSB 3(10 bit)0.8 LSB

LSBppm

ppm760(LSB)|ERROR

760 ppm 96) (50) (75)(60)(50)(500)(550) |ERROR

:)(Example

TOTAL2

RMS

2222222RMS

======

=

===

=

=++++++=

0

0

1.

(

5V LM4132A_2.

Conclusion


13/13

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Logic logic.ti.com Security www.ti.com/security

Power Mgmt power.ti.com Space, Avionics and Defense www.ti.com/space-avionics-defenseMicrocontrollers microcontroller.ti.com Video and Imaging www.ti.com/video

RFID www.ti-rfid.com

OMAP Applications Processors www.ti.com/omap TI E2E Community e2e.ti.com

Wireless Connectivity www.ti.com/wirelessconnectivity

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