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A Low Dropout Precision Voltage References

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Niveau: Supérieur, Doctorat, Bac+8
M A X 8 7 2 /M A X 8 7 4 10µA, Low-Dropout, Precision Voltage References ________________________________________________________________ Maxim Integrated Products 1 For free samples & the latest literature: or phone 1-800-998-8800. For small orders, phone 1-800-835-8769. General Description The MAX872/MAX874 precision 2.5V and 4.096V micro- power voltage references consume a maximum of only 10µA and operate from supply voltages up to 20V. The combination of ultra-low quiescent current and low 200mV dropout makes them ideal for battery-powered equipment. They source and sink up to 500µA with only 200mV input voltage headroom, which makes the 2.5V MAX872 ideal for use with a 3V supply and the 4.096V MAX874 ideal for use with a 5V supply. Initial accuracy of 0.2% at +25°C (±5mV for the MAX872, ±8mV for the MAX874) and low 40ppm/°C max drift make these references suitable for a wide range of precision applications.

  • electrical characteristics—max872c

  • stresses beyond

  • iscshort-circuit output

  • output voltage

  • range

  • max872

  • µa15iqquiescent supply


Subjects

Informations

Published by
Reads 11
Language English

19-0005; Rev 2; 6/97

10µA, Low-Dropout,
Precision Voltage References
General DescriptionFeatures
The MAX872/MAX874 precision 2.5V and 4.096V micro-
©
Output Voltage
power voltage references consume a maximum of only
2.500V ±0.2% (MAX872)
10µA and operate from supply voltages up to 20V. The
4.096V ±0.2% (MAX874)
combination of ultra-low quiescent current and low
©
Wide Operating Voltage Range
200mV dropout makes them ideal for battery-powered
equipment. They source and sink up to 500µA with only
2.7V to 20V (MAX872)
200mV input voltage headroom, which makes the 2.5V
4.3V to 20V (MAX874)
MAX872 ideal for use with a 3V supply and the 4.096V
©
10µA Max Supply Current
MAX874 ideal for use with a 5V supply.
©
40ppm/°C Max Drift Over Extended Temp. Range
Initial accuracy of 0.2% at +25°C (±5mV for the MAX872,
©
Line Regulation Over Temp.
±8mV for the MAX874) and low 40ppm/°C max drift make
these references suitable for a wide range of precision
20µV/V (MAX872)
applications.
75µV/V (MAX874)
©
Load Regulation Over Temp.
0.6mV/mA Max (MAX872)
1.0mV/mA Max (MAX874)
©
±500µA Sink/Source Current
Ordering Information
PARTTEMP. RANGEPIN-PACKAGE
MAX872
CPA0°C to +70°C8 Plastic DIP
MAX872CSA0°C to +70°C8 SO
MAX872C/D0°C to +70°CDice*
MAX872EPA-40°C to +85°C8 Plastic DIP
MAX872ESA-40°C to +85°C8 SO
MAX874
CPA0°C to +70°C8 Plastic DIP
MAX874CSA0°C to +70°C8 SO
MAX874C/D0°C to +70°CDice*
MAX874EPA-40°C to +85°C8 Plastic DIP
MAX874ESA-40°C to +85°C8 SO
*Dice are specified at +25°C only.
Pin Configuration
TOP VIEW

Hand-Held Instruments
Battery-Operated Equipment
Power Supplies

Applications

Typical Operating Circuit
35..00VV ((MMAAXX887742))
VNIVTUOMMAAXX887742
TRIM

DNG

REFERENCE WITH TRIMMED OUTPUT

I.C.18COMP
V
IN
27I.C.
MAX872
TEMP3
MAX874
6V
OUT
GND45TRIM
DIP/SO

________________________________________________________________Maxim Integrated Products1
For free samples & the latest literature: http:
/
www.maxim-ic.com, or phone 1-800-998-8800.
For sma
l
orders, phone 1-800-835-8769.

10µA, Low-Dropout,
Precision Voltage References
ABSOLUTE MAXIMUM RATINGS
Supply Voltage.......................................................................24VOperating Temperature Ranges
Output Short-Circuit Duration..........Continuous to Either SupplyMAX87_C__.........................................................0°C to +70°C
C
COMP
Input...........................................................-0.3V to V
OUT
MAX87_E__......................................................-40°C to +85°C
TRIM Input...................................................-0.3V to (V+ 0.3V)
NIStorage Temperature Range.............................-65°C to +150°C
TEMP Output...............................................-0.3V to (V+ 0.3V)
NIJunction Temperature Range (T)......................-65°C to +160°C
jContinuous Power Dissipation (T= +70°C)
ALead Temperature (soldering, 10sec).............................+300°C
Plastic DIP (derate 9.09mW/°C above +70°C).............727mW
SO (derate 5.88mW/°C above +70°C)..........................471mW
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—MAX872
(V= 2.7V, I= 0mA, T= +25°C, unless otherwise noted.)
ALNIPARAMETERSYMBOLCONDITIONS
Output VoltageV
TUOOutput Voltage Noisee0.1Hz to 10Hz
nV= 4.5V to 20V
NILine RegulationV/V
NITUOV= 2.7V to 5.5V
NISourcing 0mA to 0.5mA
Load Regulation (Note 1)V/I
OUTOUT
Sinking 0mA to -0.5mA
Quiescent Supply CurrentI
QChange in Supply Current vs. VI/VV= 2.7V to 20V
INQININ
Vshort to GND
TUOShort-Circuit Output CurrentI
CSV
OUT
short to V
IN
TEMP VoltageV
PMETV
OUT
Adjustment RangeV
ADJ
V
OUT
³
V
OUT
+ 0.2V

ELECTRICAL CHARACTERISTICS—MAX874
(V
IN
= 4.3V, I
L
= 0mA, T
A
= +25°C, unless otherwise noted.)
PARAMETERSYMBOLCONDITIONS
Output VoltageV
OUT
Output Voltage Noisee
n
0.1Hz to 10Hz
Line RegulationV
OUT
/V
IN
V
IN
= 4.3V to 20V
Sourcing 0mA to 0.5mA
Load Regulation (Note 1)V
OUT
/I
OUT
Sinking 0mA to -0.5mA
Quiescent Supply CurrentI
Q
Change in Supply Current vs. V
IN
I
Q
/V
IN
V
IN
= 4.3V to 20V
V
OUT
short to GND
Short-Circuit Output CurrentI
SC
V
OUT
short to V
IN
TEMP VoltageV
TEMP
V
OUT
Adjustment RangeV
ADJ
V
OUT
³
V
OUT
+ 0.2V

MINTYPMAXUNITS
2.4952.5002.505V
60µVp-p
21480250µV/V
0.20.5mV/mA
2146.510µA
0.350.55µA/V
516Am93096Vm+75/-20+100/-25mV

MINTYPMAXUNITS
4.0884.0964.104V
90µVp-p
1575µV/V
0.150.9mV/mA
5166.510µA
0.350.55µA/V
516Am525096Vm±150±200mV

2_______________________________________________________________________________________

10µA, Low-Dropout,
Precision Voltage References
ELECTRICAL CHARACTERISTICS—MAX872C
(V
IN
= 2.7V, I
L
= 0mA, T
A
= 0°C to +70°C, unless otherwise noted.)
PARAMETERSYMBOLCONDITIONS
Output VoltageV
OUT
Output Voltage TemperatureTCV
OUT
Coefficient
V
IN
= 4.5V to 20V
Line RegulationV
OUT
/V
IN
V
IN
= 2.7V to 5.5V
Load Regulation (Note 1)V
OUT
/I
OUT
Sourcing 0mA to 0.4mA
Sinking 0mA to -0.4mA
Quiescent Supply CurrentI
Q
Change in Supply Current vs. V
IN
I
Q
/V
IN
V
IN
= 2.7V to 20V
V
OUT
Adjustment RangeV
ADJ
V
IN
³
V
OUT
+ 0.2V
TEMP Output TemperatureTCV
TEMP
Coefficient

MINTYPMAXUNITS
2.49052.5095V
2040ppm/°C
20µV/V
00301.56mV/mA
51Aµ0.7µA/V
+75/-20mV
2.3mV/°C

ELECTRICAL CHARACTERISTICS—MAX874C
(V
IN
= 4.3V, I
L
= 0mA, T
A
= 0°C to +70°C, unless otherwise noted.)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS
Output VoltageV
OUT
4.08054.1115V
Output Voltage TemperatureTCV
OUT
2040ppm/°C
Coefficient
Line RegulationV
OUT
/V
IN
V
IN
= 4.3V to 20V75µV/V
Load Regulation (Note 1)V
OUT
/I
OUT
Sourcing 0mA to 0.4mA1.0mV/mA
Sinking 0mA to -0.4mA25
Quiescent Supply CurrentI
Q
15µA
Change in Supply Current vs. V
IN
I
Q
/V
IN
V
IN
= 4.3V to 20V0.7µA/V
V
OUT
Adjustment RangeV
ADJ
V
IN
³
V
OUT
+ 0.2V±150mV
TEMP Output TemperatureTCV
TEMP
2.3mV/°C
Coefficient
Note 1:
If the load current exceeds 300µA, connect a minimum of 1000pF from V
OUT
to GND. Note that if a capacitor larger than
1000pF is used, a compensation capacitor of C
OUT
/100 must be connected from V
OUT
to COMP.

_______________________________________________________________________________________3

10µA, Low-Dropout,
Precision Voltage References
ELECTRICAL CHARACTERISTICS—MAX872E
(V
IN
= 2.7V, I
L
= 0mA, T
A
= -40°C to +85°C, unless otherwise noted.)
PARAMETERSYMBOLCONDITIONS
Output VoltageV
OUT
Output Voltage TemperatureTCV
OUT
Coefficient
V
IN
= 4.5V to 20V
Line RegulationV
OUT
/V
IN
V
IN
= 2.7V to 5.5V
Load Regulation V
OUT
/I
OUT
Sourcing 0mA to 0.30mA
Sinking 0mA to -0.30mA
Quiescent Supply CurrentI
Q
Change in Supply Current vs. V
IN
I
Q
/V
IN
V
IN
= 2.7V to 20V
V
OUT
Adjustment RangeV
ADJ
V
IN
³
V
OUT
+ 0.2V
TEMP Output TemperatureTCV
TEMP
Coefficient

ELECTRICAL CHARACTERISTICS—MAX874E
(V
IN
= 4.3V, I
L
= 0mA, T
A
= -40°C to +85°C, unless otherwise noted.)
PARAMETERSYMBOLCONDITIONS
Output VoltageV
OUT
OCuotepffuitc iVeonlttage TemperatureTCV
OUT
Line RegulationV
OUT
/V
IN
V
IN
= 4.3V to 20V
Load Regulation V
OUT
/I
OUT
Sourcing 0mA to 0.30mA
Sinking 0mA to -0.30mA
Quiescent Supply CurrentI
Q
Change in Supply Current vs. V
IN
I
Q
/V
IN
V
IN
= 4.3V to 20V
V
OUT
Adjustment RangeV
ADJ
V
IN
³
V
OUT
+ 0.2V
TCEoeMffPi ciOeunttput TemperatureTCV
TEMP

MINTYP
884.202

+75/-20
3.2

MINTYP
770.402051±3.2

4_______________________________________________________________________________________

MAXUNITS
2.512V
40ppm/°C
20µV/V
00301.56mV/mA
51Aµ0.7µA/V
VmC°/Vm

MAXUNITS
4.115V
40ppm/°C
75µV/V
1.0mV/mA
5251Aµ0.7µA/V
VmC°/Vm

10µA, Low-Dropout,
Precision Voltage References
Typical Operating Characteristics
(V
IN
= 3V (MAX872), V
IN
= 5V (MAX874), no load, T
A
= +25°C, unless otherwise noted.)
DROPOUT VOLTAGESUPPLY CURRENTMAX872
vs. SOURCE CURRENTvs. INPUT VOLTAGESUPPLY CURRENT vs. TEMPERATURE
2502020
NO LOAD
00215MAX874V
IN
= 20V
51150T
A
= +85°CV
IN
= 10V
T
A
= +25°C10
V
IN
= 5V
001015MAX872
50T
A
= -40°C
V
IN
= 3V
50010015020025002468101214161820-50-250255075100
SOURCE CURRENT (
m
A)INPUT VOLTAGE (V)TEMPERATURE (°C)
MAX874MAX872MAX874
SUPPLY CURRENT vs. TEMPERATUREOUTPUT VOLTAGE vs. INPUT VOLTAGEOUTPUT VOLTAGE vs. INPUT VOLTAGE
252.5054.100
20V
IN
= 20V2.5034.098
690.415V
IN
= 10V2.500
V
IN
= 5V4.094
102.4984.092
52.4954.090
-50-2502550751002468101214161820468101214161820
TEMPERATURE (°C)INPUT VOLTAGE (V)INPUT VOLTAGE (V)
MAX872
MAX872MAX874OUTPUT VOLTAGE
LOAD REGULATION vs. TEMPERATURELOAD REGULATION vs. TEMPERATUREvs. SOURCE CURRENT
452.502
432.501
32SINKING 0
m
A TO -500
m
ASINKING 0
m
A TO -500
m
A2.500
2112.499
SOURCING 0
m
A TO 500
m
ASOURCING 0
m
A TO 500
m
A
002.498
-50-250255075100-50-2502550751000.010.1110
TEMPERATURE (°C)TEMPERATURE (°C)SOURCE CURRENT (mA)
_______________________________________________________________________________________5

10µA, Low-Dropout,
Precision Voltage References
Typical Operating Characteristics (continued)
(V
IN
= 3V (MAX872), V
IN
= 5V (MAX874), no load, T
A
= +25°C, unless otherwise noted.)
MAX874
OUTPUT VOLTAGEMAX872MAX874
vs. SOURCE CURRENTOUTPUT VOLTAGE vs. TEMPERATUREOUTPUT VOLTAGE vs. TEMPERATURE
4.0982.5064.100
4.0972.5044.098
2.5024.096
690.42.5004.094
4.0952.4984.092
4.0942.4964.090
0.010.1110-50-250255075100-50-250255075100
SOURCE CURRENT (mA)TEMPERATURE (°C)TEMPERATURE (°C)
POWER-SUPPLY REJECTION RATIOTEMP OUTPUT
vs. FREQUENCYvs. TEMPERATURENOISE vs. FREQUENCY
-201.02.0
VN
I
O
N
=L O+A3VD TO +5V (MAX872)NO LOAD
V
IN
= +5V TO +7V (MAX874)0.9
5.1-40NO INPUT FILTERMAX874
0.8MAX872
0.17.0-60 INPUT FILTER
CIRCUIT IN FIGURE 20.5
0.6 NOISE IS FROM
0.01Hz TO FREQUENCY
INDICATED
-800.50
1101001k10k-50-2502550751001101001k10k
FREQUENCY (Hz)TEMPERATURE (°C)FREQUENCY (Hz)
MAX872 MAX874
1Hz TO 100Hz NOISE1Hz TO 100Hz NOISE
6_______________________________________________________________________________________

3VV
IN
V
OUT
MAX872
TRIM
DNG

TRIM RANGE: -35mV/+80mV

M1M5.1

Figure 1a. Adjusting V
OUT
with the TRIM Input on the MAX872

10µA, Low-Dropout,
Precision Voltage References
Pin Description
PINNAMEFUNCTION
1, 7I.C.Internal Connection. Make no connection
to this pin
2V
IN
Input Voltage
Temperature-Proportional Output
3TEMPpVrooltpaogrtei.o nGael nteor jautnecst iaonn oteutmppute rvaotlutraeg.e
4GNDGround
Output Voltage Trim. Connect to the
5TRIMcenter of a voltage divider for output
trimming. Otherwise make no
connection.
6V
OUT
Reference Output
Compensation Input. Connect
C/100 capacitor from Vto
8COMPC
L
O
O
M
A
P
D
to provide capacitive l
O
o
U
a
T
d
compensation.
Applications Information
Trimming the Output Voltage
The MAX872/MAX874’s output voltage is trimmed for
0.2% tolerance at +25°C. If additional V
OUT
trimming is
desired, connect a potentiometer to TRIM, as shown in
Figures 1a and 1b. Adjusting V
OUT
away from its facto-
ry-trimmed voltage typically changes the output voltage
tempco by 7ppm/°C per 100mV.
Reducing Input Ripple with an Input Filter
The Power-Supply Rejection Ratio vs. Frequency graph
in the Typical Operating Characteristicsshows ripple
rejection between 10Hz and 2kHz. As input RC filter
with a pole less than 10Hz, as shown in Figure 2, fur-
ther attenuates input ripple with this band. The voltage
drop across the input resistor (due to supply and load
current) slightly increases the dropout voltage. The
increase is given by [(I
LOAD
+ I
SUPPLY
)
·
R].
Choosing the Output and
Compensation Capacitors
Connecting a capacitor between Void and GND
reduces load transients. If the load exceeds 300µA,
connect a minimum of 1000pF from V
OUT
to GND. The
type of capacitor is not critical. If the total load capaci-
tance from V
OUT
to GND (C
LOAD
= output capacitor +
other capacitive load) is larger than 1000pF, connect a
compensation capacitor with a value of C
LOAD
/100
between COMP and V
OUT
.
_______________________________________________________________________________________7

5VV
IN
V
OUT
MAX874
MIRTDNG

M2M1M4

TRIM RANGE: -200mV/+300mV
Figure 1b. Adjusting V
OUT
with the TRIM Input on the MAX874

1Pr0eµcAi,s iLoonw V-Dolrtoapgoeu tR,eferences

REF OUT
V+313700kk ((MMAAXX887724))
150
W
V
IN
+5V
35..00VV ((MMAAXX887742))V
IN
COMPV
OUT
1/2OVER TEMP
27kMAX922
100
m
F
MAX872
0.047
m
F
MAX872
TEMP OUT OF RANGE
MAX874
V
OUT
MAX874
TEMP+5V
4.7
m
F1/21/4 74HC86
MAX922UNDER TEMP
GNDGND
k45-40°C TO +85°C OPERATING RANGE
Figure 2. Input Filter Reduces Input RippleFigure 3. Operating Temperature Range Window Comparator
TEMP Output
___________________Chip Topography
The TEMP output provides a voltage proportional to the
MAX872/MAX874 junction temperature. Since the
MAX872/MAX874
power dissipation of the MAX872/MAX874 is <100µW
typ, the junction temperature is within 0.5°C of the
*N.C.COMP
ambient temperature. Although it goes unused in most
applications, the ambient temperature information
given by the TEMP output may be used to control LCD
contrast, or to provide ADC gain compensation or ther-
mal out-of-range indication. TEMP must be buffered or
connected to a high-impedance input.
Operating Temperature
V
IN
Window Comparator
In Figure 3, a window comparator monitors the TEMP
TEMP
output and indicates if the temperature is out of the
nominal operating range. For the resistor values shown,
the circuit will indicate an out-of-range condition if the
ambient temperature should rise above +85°C or dip
below -40°C.
Start-Up
When the input voltage is below the factory-selected
GND
output voltage, the MAX872/MAX874 can draw exces-
sive supply current (hundreds of microamps). If the
source resistance is too high, the voltage drop across
(1.08.2097m2"m)
the source resistance can prevent the input voltage to
the device from reaching the minimum dropout voltage.
*MAKE NO CONNECTIONS TO THESE PADS
Therefore, when using the MAX872/MAX874 in low-
dropout applications, ensure that the power supply hasTRANSISTOR COUNT: 89
a low source resistance.SUBSTRATE CONNECTED TO GND.
iMmapxliiemd . cMananxiomt raessseurmvee s rtehsep roignhsit btioli tcy hfaonr gues teh eo fc iarcnuyi trcyir caunidtr ys poetchiefirc tahtiaonn sc iwrictuhiotruyt neonttiirceel ya t eamnby otidmiee.d in a Maxim product. No circuit patent licenses are
8
_____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
©1997 Maxim Integrated Products Printed USAis a registered trademark of Maxim Integrated Products.

.C.N*OUT0.110"
(2.794mm)

MIRT