LTC1258 [Linear]
Micropower Low Dropout References; 微功率低压差参考型号: | LTC1258 |
厂家: | Linear |
描述: | Micropower Low Dropout References |
文件: | 总8页 (文件大小:155K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
LTC1258 Series
Micropower Low
Dropout References
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FEATURES
DESCRIPTIO
200mV Max Dropout at 10mA Output Current
The LTC®1258/LTC1258-2.5/LTC1258-3/LTC1258-4.1/
LTC1258-5 are micropower bandgap references that
combine high accuracy and low drift with very low supply
currentandsmallpackagesize.Thecombinationofultralow
quiescent current and low dropout voltage of only 200mV
max. makes them ideal for battery-powered equipment.
The output voltage is set by an external resistor divider for
the adjustable LTC1258.
■
■
4µA Typical Quiescent Current
■
■
■
■
■
■
0.15% Max Initial Accuracy (S8)
No Output Capacitor Required
Output Sources 10mA, Sinks 2mA
40ppm/°C Max Drift (S8)
Available in Small MSOP Package
Voltage Options: 2.5V, 3V, 4.1V, 5V and Adjustable
This series of references uses curvature compensation to
obtain low temperature coefficient and trimmed thin-film
resistors to achieve high output accuracy. These refer-
ences can source up to 10mA and sink up to 2mA, making
them ideal for precision regulator applications. They are
stable without an output bypass capacitor, but are also
stablewithcapacitanceupto1µF.Thisfeatureisimportant
incriticalapplicationswherePCboardspaceisapremium
and fast settling is demanded.
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APPLICATIO S
■
Battery-Powered Systems
■
Handheld Instruments
■
Precision Power Supplies
■
A/D and D/A Converters
The LTC1258 series references provide power dissipation
advantages over shunt references. In addition to supply
current, shunt references must also idle the entire load
current to operate.
The LTC1258 series is available in the 8-pin MSOP and SO
packages.
, LTC and LT are registered trademarks of Linear Technology Corporation.
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TYPICAL APPLICATION
LTC1258-2.5 Temperature Drift
2.5V Battery-Powered Reference
4
3
2
LTC1258-2.5
1
1
2
2.7V
TO 12.6V
IN
2.5V
OUT
0.1µF
0
GND
4
1258 TA01
–1
–2
–3
–4
–40 –20
0
20
40
60
80 100
TEMPERATURE (°C)
1258 TA02
1
LTC1258 Series
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ABSOLUTE MAXIMUM RATINGS
(Note 1)
Supply Voltage ........................................................ 13V
Input Voltages ...........................................–0.3V to 13V
Output Voltages .........................................–0.3V to 13V
Output Short Circuit Duration .......................... Indefinite
Operating Temperature Range (Note 2) –40°C to 100°C
Specified Temperature Range...................... 0°C to 70°C
Storage Temperature Range (Note 3) ....–65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
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PACKAGE/ORDER INFORMATION
ORDER PART
NUMBER
ORDER PART
NUMBER
TOP VIEW
TOP VIEW
OUT
IN
1
2
3
4
8
7
6
5
DNC*
DNC*
DNC*
DNC*
OUT
IN
**DNC/FB
GND
1
2
3
4
8 DNC*
7 DNC*
6 DNC*
5 DNC*
LTC1258CS8
LTC1258CMS8
LTC1258CS8-2.5
LTC1258CS8-3
LTC1258CS8-4.1
LTC1258CS8-5
LTC1258CMS8-2.5
LTC1258CMS8-3
LTC1258CMS8-4.1
LTC1258CMS8-5
**DNC/FB
GND
MS8 PACKAGE
8-LEAD PLASTIC MSOP
S8 PACKAGE
8-LEAD PLASTIC SO
MS8 PART MARKING
S8 PART MARKING
* CONNECTED INTERNALLY. DO NOT CONNECT
EXTERNAL CIRCUITRY TO THESE PINS
** DNC FOR LTC1258-2.5/LTC1258-3/LTC1258-4.1/
LTC1258-5, FB FOR LTC1258
* CONNECTED INTERNALLY. DO NOT CONNECT
EXTERNAL CIRCUITRY TO THESE PINS
** DNC FOR LTC1258-2.5/LTC1258-3/LTC1258-4.1/
LTC1258-5, FB FOR LTC1258
LTEL
LTCF
LTEU
LTEN
LTEM
1258
12582
12583
125841
12585
TJMAX = 125°C, θJA = 190°C/W
TJMAX = 125°C, θJA = 250°C/W
Consult factory for Industrial and Military grade parts.
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AVAILABLE OPTIO S
PACKAGE TYPE
S8
OUTPUT
VOLTAGE
(V)
TEMPERATURE
RANGE
TEMPERATURE
COEFFICIENT
MS8
ACCURACY
(%)
(
°C)
(ppm/°C)
ORDER NUMBER
PART MARKING ORDER NUMBER PART MARKING
2.5
2.5
0 to 70
0 to 70
0.15
0.21
40
60
LTC1258CS8-2.5
12582
LTC1258CMS8-2.5
LTC1258CMS8-3
LTC1258CMS8-4.1
LTC1258CMS8-5
LTC1258CMS8
LTCF
LTEU
LTEN
LTEM
LTEL
3
3
0 to 70
0 to 70
0.15
0.20
40
60
LTC1258CS8-3
LTC1258CS8-4.1
LTC1258CS8-5
LTC1258CS8
12583
125841
12585
1258
4.096
4.096
0 to 70
0 to 70
0.15
0.18
40
60
5
5
0 to 70
0 to 70
0.15
0.18
40
60
Adjustable
Adjustable
0 to 70
0 to 70
0.4
0.46
40
60
2
LTC1258 Series
ELECTRICAL CHARACTERISTICS
The ● denotes specifications which apply over the specified temperature range, otherwise specifications are T = 25°C.
A
VIN = VOUT(NOMINAL) + 0.2V, IOUT = 0mA, FB = OUT for the LTC1258 unless otherwise noted.
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
V
Input Voltage Range
Input Current
●
●
12.6
V
IN
I
FB = OUT for LTC1258
6.5
8.5
µA
µA
IN
V
Output Voltage (Note 4)
LTC1258 (S8), FB = OUT
LTC1258-2.5 (S8)
LTC1258-3 (S8)
2.3755
2.4963
2.9955
4.090
2.385
2.5
3
2.3945
2.5037
3.0045
4.102
V
V
V
V
V
V
V
V
V
V
OUT
LTC1258-4.1 (S8)
LTC1258-5 (S8)
4.096
5
4.9925
2.374
5.0075
2.396
LTC1258 (MS8), FB = OUT
LTC1258-2.5 (MS8)
LTC1258-3 (MS8)
LTC1258-4.1 (MS8)
LTC1258-5 (MS8)
2.385
2.5
3
4.096
5
2.4948
2.994
4.0885
4.991
2.5052
3.006
4.1035
5.009
e
Output Voltage Noise (Note 5)
0.1Hz ≤ f ≤ 10Hz
8
ppm
P-P
n
TC
Output Voltage Temp Coefficient (Note 6)
T
T
≤ T ≤ T
(S8)
(MS8)
●
●
15
40
60
ppm/°C
ppm/°C
MIN
MIN
J
MAX
MAX
≤ T ≤ T
J
V
V
/V
Line Regulation
V
= (V + 0.2V) to 12.6V
OUT(NOMINAL)
●
●
30
0.1
90
ppm/V
OUT IN
IN
/I
Load Regulation (Note 7)
Sourcing 0mA to 10mA
Sinking 0mA to 2mA
0.3
mV/mA
OUT OUT
1.75
4.0
6.5
mV/mA
mV/mA
●
I
Short-Circuit Output Current
Dropout Voltage (Note 8)
Output Hysteresis (Note 9)
FB Pin Input Current
V
V
Shorted to GND
20
2
40
4
mA
mA
SC
OUT
OUT
Shorted to V
IN
∆V
I
I
= 0, ∆V ≤ 0.1%
OUT
●
●
100
200
mV
mV
DO
OUT
OUT
= 10mA, ∆V
≤ 0.1%
OUT
V
∆T = –40°C to 85°C
∆T = 0°C to 70°C
200
50
ppm
ppm
HYST
I
LTC1258, OUT = FB
10
nA
FB
Note 1: Absolute Maximum Ratings are those values beyond which the life
of the device may be impaired.
Note 6: Temperature coefficient is the change in output voltage divided by
the nominal output voltage divided by the specified temperature range.
Note 2: The LTC1258 is guaranteed functional over the operating
temperature range of –40°C to 100°C.
Note 3: If the part is stored outside of the specified operating temperature
Note 7: Load regulation is measured on a pulse basis from no load to the
specified load current. Output changes due to die temperature change
must be taken into account separately.
range, the output may shift due to hysteresis.
Note 8: Dropout voltage is (V – V ) when V
falls to 0.1% below its
IN
OUT
OUT
nominal value at V = V
+ 0.5V.
IN
OUT
Note 4: ESD (Electrostatic Discharge) sensitive device. Extensive use of
ESD protection devices are used internal to the LTC1258, however, high
electrostatic discharge can damage or degrade the device. Use proper ESD
handling precautions.
Note 5: Peak-to-peak noise is measured with a single pole highpass filter
at 0.1Hz and 2-pole lowpass filter at 10Hz.
Note 9: Hysteresis in output voltage is created by package stress that
differs depending on whether the IC was previously at a higher or lower
temperature. Output voltage is always measured at 25°C, but the IC is
cycled hot or cold before successive measurements. Hysteresis is not
normally a problem for operational temperature excursions where the
instrument might be stored at high or low temperature.
3
LTC1258 Series
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TYPICAL PERFORMANCE CHARACTERISTICS
LTC1258-2.5*
LTC1258 Series
LTC1258-2.5*
Dropout Voltage vs
Output Short-Circuit Current vs
Temperature
Input Current vs Temperature
Output Source Current
100
90
80
70
60
50
40
30
20
10
0
8
7
6
5
4
3
2
1
0
70
60
50
40
30
20
10
5
V
= 2.7V
T
V
= 25°C
A
OUTPUT
SHORTED
TO GND
T
A
= 25°C
IN
= V
+ 0.2V
IN
OUT(NOM)
OUTPUT
SHORTED
TO V
IN
0
0
0.1
1
10
100
–50 –25
0
25 50 75 100 125 150
TEMPERATURE (°C)
1258 G02
–50 –25
0
25 50 75 100 125 150
TEMPERATURE (°C)
1258 G03
OUTPUT SOURCE CURRENT (mA)
1258 G01
LTC1258-2.5* Output Short-Circuit
Current vs Input Voltage
LTC1258-2.5* Output Short-Circuit
Current vs Input Voltage
LTC1258 Series
Load Regulation
25
20
15
10
5
42
5
4
T = 25°C
A
T
= 25°C
A
V
= V
+ 0.2V
OUTPUT SHORTED
IN
OUT(NOM)
TO V
3
IN
SINKING
2
1
SOURCING
0
–1
–2
–3
–4
–5
T
= 25°C
A
OUTPUT SHORTED
TO GND
0
41
2
6
8
10
12
14
2
6
8
10
12
14
0
0.1
1
10
100
4
4
INPUT VOLTAGE (V)
INPUT VOLTAGE (V)
OUTPUT CURRENT (mA)
1258 G06
1258-G04
1258-G05
LTC1258-2.5
Output Voltage vs Input Voltage
LTC1258-2.5
Input Current vs Input Voltage
2.5010
2.5005
2.5000
2.4995
7
6
5
4
T
= 25°C
T
= 25°C
A
A
2
6
8
10
12
14
4
2
6
8
10
12
14
4
INPUT VOLTAGE (V)
INPUT VOLTAGE (V)
1258 G07
1258 G08
*Similar performance characteristics can be expected for all voltage options.
4
LTC1258 Series
U W
TYPICAL PERFORMANCE CHARACTERISTICS
LTC1258-2.5 PSRR vs Frequency
LTC1258-2.5 0.1Hz to 10Hz Noise
60
50
40
30
20
10
0
V
IN
= 2.7V
V
= 2.7V
IN
5µV/DIV
10
100
1k
10k
1SEC/DIV
1258 G10
FREQUENCY (Hz)
1258 G09
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U
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PIN FUNCTIONS
OUT (Pin 1): Reference Output. The output can source up
to10mAandsinkupto2mA.Itisstablewithoutputbypass
capacitor ranging from 0µF to 1µF.
R1+ R2
VOUT = 2.385V
;
R1 is connected from OUT
R2
to FB and R2 from FB to GND.
IN (Pin 2): Positive Supply. Bypassing with a 0.1µF
capacitor is recommended if the output loading changes.
(VOUT + 0.2V) ≤ VIN ≤ 12.6V.
GND (Pin 4): Negative Supply or Ground Connection.
DNC (Pins 5, 6, 7, 8): Do Not Connect. Connected
internally for post package trim. These pins must be left
unconnected.
DNC (Pin 3): (LTC1258-2.5/LTC1258-3/LTC1258-4.1/
LTC1258-5) Do Not Connect. Connected internally for
post package trim. This pin must be left unconnected.
FB (Pin 3): (LT1258) Resistor Divider Feedback Pin.
ConnectaresistordividerfromOUTtoGNDandthecenter
tap to FB. This pin sets the output potential.
W
BLOCK DIAGRAM
2
IN
+
–
OUT
R1
1
2.385V
FB 3 (LTC1258)
R2
GND
4
1258 BD
NOTE: R1 AND R2 ARE NOT CONNECTED FOR LTC1258
5
LTC1258 Series
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APPLICATIONS INFORMATION
tance is required, a resistor in series with the capacitor is
recommended to reduce the output ringing. Figure 2
illustrates the use of a damping resistor for capacitive
loads greater than 1µF. Figure 3 shows the resistor and
capacitor values required to achieve critical damping.
Longer Battery Life
Series references have an advantage over shunt style
references. Tooperate, shuntreferencesrequirearesistor
between the power supply and the output. This resistor
must be chosen to supply the maximum current that is
demanded by the circuit being regulated. When the circuit
beingcontrolledisnotoperatingatthismaximumcurrent,
the shunt reference must always sink this current, result-
ing in high power dissipation and short battery life.
LTC1258-5
5.2V
2
1
IN
5V
TO
OUT
C
12.6V
OUT
>1µF
GND
4
0.1µF
DAMPING RESISTOR
<1k
TheLTC1258serieslowdropoutreferencesdonotrequire
a current setting resistor and can operate with any supply
voltage from (VOUT(NOMINAL) + 0.2V) to 12.6V. When the
circuitry being regulated does not demand current, the
LTC1258 series reduces its dissipation and battery life is
extended. If the reference is not delivering load current it
dissipates only 10.8µW when operating on a 2.7V supply
for LTC1258-2.5, yet the same connection can deliver
10mA of load current when demanded.
1258 F02
Figure 2. Adding a Damping Resistor with
Output Capacitors Greater Than 1µF
10k
1k
Output Bypass Capacitor
The LTC1258 series is designed to be stable with or
without capacitive loads. With no capacitive load, the
referenceisidealforfastsettlingapplications,orwherePC
board space is at a premium.
100
10
Inapplicationswithsignificantoutputloadingchanges, an
output bypass capacitor of up to 1µF can be used to
improvetheoutputtransientresponse.Figure1showsthe
response of the reference to a 1mA to 0µA load step with
a 1µF output capacitor. If more than 1µF of output capaci-
1
10
100
1000
OUTPUT CAPACITOR VALUE (µF)
1258 F03
Figure 3. Damping Resistance vs Output Capacitor Value
1mA
IOUT
1mA
IOUT
0mA
0mA
VOUT
100mV/DIV
VOUT
100mV/DIV
10ms/DIV
0.5ms/DIV
1258 F01a
1258 F01b
Figure 1. Reference Output Load Transient Response, 1µF Output Capacitor
6
LTC1258 Series
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APPLICATIONS INFORMATION
Internal P-Channel Pass Transistor
These references consume only 4µA of quiescent current
under light and heavy loads as well as in dropout; whereas,
PNP-based references waste considerable amounts of
current when the pass transistor is saturated. In addition,
the LTC1258 series provides a lower dropout voltage
(200mV max) than PNP-based references.
The LTC1258 series features an internal P-channel
MOSFET pass transistor. This provides several advan-
tages over similar designs using a PNP bipolar pass
transistor.
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PACKAGE DESCRIPTION Dimenshions in inches (millimeters) unless otherwise noted.
MS8 Package
8-Lead Plastic MSOP
(LTC DWG # 05-08-1660)
0.118 ± 0.004*
(3.00 ± 0.102)
8
7
6
5
0.040 ± 0.006
(1.02 ± 0.15)
0.034 ± 0.004
(0.86 ± 0.102)
0.007
(0.18)
0° – 6° TYP
0.118 ± 0.004**
(3.00 ± 0.102)
SEATING
PLANE
0.193 ± 0.006
(4.90 ± 0.15)
0.012
(0.30)
REF
0.021 ± 0.006
(0.53 ± 0.015)
0.006 ± 0.004
(0.15 ± 0.102)
0.0256
(0.65)
BSC
1
2
3
4
* DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. MOLD FLASH,
PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE
MSOP (MS8) 1098
** DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS.
INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE
S8 Package
8-Lead Plastic Small Outline (Narrow 0.150)
(LTC DWG # 05-08-1610)
0.189 – 0.197*
(4.801 – 5.004)
0.010 – 0.020
(0.254 – 0.508)
7
5
8
6
× 45°
0.053 – 0.069
(1.346 – 1.752)
0.004 – 0.010
(0.101 – 0.254)
0.008 – 0.010
(0.203 – 0.254)
0°– 8° TYP
0.150 – 0.157**
(3.810 – 3.988)
0.228 – 0.244
(5.791 – 6.197)
0.016 – 0.050
(0.406 – 1.270)
0.050
(1.270)
BSC
0.014 – 0.019
(0.355 – 0.483)
TYP
*DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH
SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE
**DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD
FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE
SO8 1298
1
3
4
2
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-
tationthattheinterconnectionofitscircuitsasdescribedhereinwillnotinfringeonexistingpatentrights.
7
LTC1258 Series
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TYPICAL APPLICATIONS
Micropower Low Dropout Negative Reference
Supply Splitter
0.2V ≤ V ≤ 8.5V
CC
2
IN
LTC1258-2.5
2.5V
VIRTUAL
GROUND
1
2
1
V
CC
= 5V
IN
OUT
OUT LTC1258-3
0.1µF
0.1µF
8
0.1µF
GND
4
2
3
GND
4
–
1
1258 TA04
V
OUT
= –3V
1/2 LTC1542
+
1258 TA03
4
V
SS
= –4V
Low Power, Low Voltage Supply Reference for LTC1096L
1µF
MPU
1
2
3
4
8
7
6
5
CS/
V
CC
SHDN
SERIAL DATA LINK
(MICROWIRETM AND
SPI COMPATIBLE)
+IN
ANALOG INPUT
0V TO 3V RANGE
CLK
LTC1096L
–IN
D
OUT
SERIAL DATA LINK
GND
V
REF
1
OUT
V
IN
4
2
GND
IN
3.2V TO
12.6V
0.1µF
LTC1258-3
1258 TA05
MICROWIRE is a trademark of National Semiconductor Corp.
RELATED PARTS
PART NUMBER
DESCRIPTION
COMMENTS
LT®1389
Nanopower Precision Shunt Voltage Reference
800nA Quiescent Current, 0.05% Max, 10ppm/°C Max Drift,
1.25V and 2.5V Versions, SO-8 Package
LT1634
LT1460
LTC1440
LTC1540
Micropower Precision Shunt Voltage Reference
Micropower Series Reference
0.05% Max, 25ppm/°C Max Drift, 1.25V, 2.5V, 4.096V and 5V Outputs
0.075% Max, 10ppm/°C Max Drift, 2.5V, 5V and 10V Outputs
Micropower Comparator with Reference
Nanopower Comparator with Reference
3.7µA Max I , 1% 1.182V Reference, Adjustable Hysteresis
CC
600nA Max I , 2% 1.182V Reference, Adjustable Hysteresis
CC
1258f LT/TP 0999 4K • PRINTED IN USA
LinearTechnology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
8
●
●
LINEAR TECHNOLOGY CORPORATION 1998
(408)432-1900 FAX:(408)434-0507 www.linear-tech.com
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