LTC1798CS8-4.1#TR [Linear]
LTC1798 Series - Micropower Low Dropout References; Package: SO; Pins: 8; Temperature Range: 0°C to 70°C;
| 型号： | LTC1798CS8-4.1#TR |
| 厂家： | 
Linear |
| 描述： | LTC1798 Series - Micropower Low Dropout References; Package: SO; Pins: 8; Temperature Range: 0°C to 70°C 光电二极管 |
| 文件： | 总8页 (文件大小：121K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
LTC1798 Series
Micropower Low
Dropout References
FEATURES
DESCRIPTION
The LTC®1798/LTC1798-2.5/LTC1798-3/LTC1798-4.1/
LTC1798-5 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 LTC1798.
n
200mV Max Dropout at 10mA Output Current
n
4μA Typical Quiescent Current
n
0.15% Max Initial Accuracy
n
No Output Capacitor Required
n
Output Sources 10mA, Sinks 2mA
n
40ppm/°C Max Drift
n
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
resistorstoachievehighoutputaccuracy.Thesereferences
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 stable
with capacitance up to 1μF. This feature is important in
critical applications where PC board space is a premium
and fast settling is demanded.
APPLICATIONS
n
Battery-Powered Systems
n
Handheld Instruments
n
Precision Power Supplies
A/D and D/A Converters
n
L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
TheLTC1798seriesreferencesprovidedpowerdissipation
advantages over shunt references. In addition to supply
current, shunt references must also idle the entire load
current to operate.
The LTC1798 series is available in the SO-8 package.
TYPICAL APPLICATION
LTC1798-2.5 Temperature Drift
2.5V Battery-Powered Reference
4
3
LTC1798-2.5
2
6
2
2.7V
TO 12.6V
IN
2.5V
OUT
1
0.1μF
GND
4
0
1798 TA01
–1
–2
–3
–4
–40 –20
0
20
40
60
80 100
TEMPERATURE (°C)
1798 TA02
1798fb
1
LTC1798 Series
ABSOLUTE MAXIMUM RATINGS
PIN CONFIGURATION
(Note 1)
TOP VIEW
Operating Temperature Range...................... 0°C to 70°C
Extended Commercial Operating
Temperature Range.................................. –40°C to 85°C
Junction Temperature ........................................... 110°C
Storage Temperature Range................... –65°C to 150°C
Lead Temperature (Soldering, 10 sec) .................. 300°C
*DNC
IN
1
2
3
4
8
7
6
5
DNC*
DNC*
OUT
**DNC/FB
GND
DNC*
S8 PACKAGE
8-LEAD PLASTIC SO
T
JMAX
= 125°C, θ = 190°C/W
JA
* CONNECTED INTERNALLY. DO NOT CONNECT EXTERNAL CIRCUITRY TO THESE PINS
** DNC FOR LTC1798-2.5/LTC1798-3/LTC1798-4.1/LTC1798-5, FB FOR LTC1798
ORDER INFORMATION
LEAD FREE FINISH
TAPE AND REEL
PART MARKING
1798
PACKAGE DESCRIPTION
8-Lead Plastic SO
8-Lead Plastic SO
8-Lead Plastic SO
8-Lead Plastic SO
8-Lead Plastic SO
SPECIFIED TEMPERATURE RANGE
0°C to 70°C
LTC1798CS8#PBF (OBSOLETE)
LTC1798CS8-2.5#PBF
LTC1798CS8-3#PBF
LTC1798CS8#TRPBF
LTC1798CS8-2.5#TRPBF
LTC1798CS8-3#TRPBF
LTC1798CS8-4.1#TRPBF
LTC1798CS8-5#TRPBF
179825
17983
0°C to 70°C
0°C to 70°C
LTC1798CS8-4.1#PBF
LTC1798CS8-5#PBF
179841
17985
0°C to 70°C
0°C to 70°C
Consult LTC Marketing for parts specified with wider operating temperature ranges.
Consult LTC Marketing for information on non-standard lead based finish parts.
For more information on lead free part marking, go to: http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/
AVAILABLE OPTIONS
PACKAGE STYLE
SO-8 (S8)
TEMPERATURE
RANGE
TEMPERATURE
COEFFICIENT
(PPM/ºC)
OUTPUT VOLTAGE
(V)
ACCURACY
(%)
(ºC)
ORDER NUMBER
LTC1798CS8-2.5
LTC1798CS8-3
LTC1798CS8-4.1
LTC1798CS8-5
LTC1798CS8
PART MARKING
179825
17983
2.5
0 to 70
0 to 70
0 to 70
0 to 70
0 to 70
0.15
0.15
0.15
0.15
0.4
40
40
40
40
40
3
4.096
5
179841
17985
Adjustable
1798
1798fb
2
LTC1798 Series
ELECTRICAL CHARACTERISTICS The l denotes specifications which apply over the full specified temperature
range, otherwise specifications are at TA = 25°C. VIN = VOUT(NOMINAL) + 0.2V, IOUT = 0mA unless otherwise noted. FB = OUT for the LTC1798.
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
l
l
V
Input Voltage Range
Input Current
V
IN
I
IN
FB = OUT for LTC1798
4
6.5
8.5
μA
μA
V
OUT
Output Voltage (Note 4)
LTC1798, FB = OUT
LTC1798 ADJ
2.3755
–0.4
2.4963
2.9955
4.090
4.9925
–0.15
2.385
2.3945
0.4
2.5037
3.0045
4.102
5.0075
0.15
V
%
V
LTC1798-2.5
2.5
3
4.096
5
LTC1798-3
V
LTC1798-4.1
V
LTC1798-5
V
LTC1798 All Fixed Options
%
e
Output Voltage Noise (Note 5)
Output Voltage Temp Coefficient (Note 6)
Line Regulation
0.1Hz ≤ f ≤ 10Hz
8
15
ppmP-P
ppm/°C
ppm/V
n
l
l
l
TC
T
MIN
≤ T ≤ T
40
120
0.3
J
MAX
V
V
/V
V
IN
= (V
+ 0.2V) to 12.6V
30
OUT IN
OUT(NOMINAL)
/I
Load Regulation (Note 7)
Sourcing 0mA to 10mA
Sinking 0mA to 2mA
0.1
1.75
mV/mA
OUT OUT
4
6.5
mV/mA
mV/mA
l
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
l
l
100
200
mV
mV
ΔV
I
I
= 0, ΔV
≤ 0.1%
OUT
DO
OUT
OUT
OUT
= 10mA, ΔV
≤ 0.1%
V
200
50
ppm
ppm
ΔT = –40°C to 85°C
ΔT = 0°C to 70°C
HYST
I
FB
LTC1798, OUT = FB
10
nA
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2: The LTC1798 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
range, the output may shift due to hysteresis.
Note 4: ESD (Electostatic Discharge) sensitive device. Extensive use of
ESD protection devices are used internal to the LTC1798, however, high
electrostatic discharge can damage or degrade the device. Use proper ESD
handling precautions.
Note 6: Temperature coefficient is the change in output voltage divided by
the nominal output voltage divided by the specified temperature range.
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.
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 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.
Note 5: Peak-to-peak noise is measured with a single pole highpass filter
at 0.1Hz and 2-pole lowpass filter at 10Hz.
1798fb
3
LTC1798 Series
TYPICAL PERFORMANCE CHARACTERISTICS
LTC1798-2.5* Dropout Voltage
vs Output Source Current
LTC1798-2.5*
LTC1798 Series Output Short-Circuit
Current vs Temperature
Input Current vs Temperature
8
7
6
5
4
3
2
1
0
70
60
50
40
30
20
10
5
100
90
80
70
60
50
40
30
20
10
0
V
IN
= 2.7V
T
= 25°C
= V
OUTPUT
SHORTED
TO GND
A
IN
T
= 25°C
A
V
+ 0.2V
OUT(NOM)
OUTPUT
SHORTED
TO V
IN
0
50 75
25
TEMPERATURE (°C)
50 75
TEMPERATURE (°C)
–50 –25
0
100 125 150
–50 –25
0
25
100 125 150
0
0.1
1
10
100
OUTPUT SOURCE CURRENT (mA)
1798 G01
1798 G02
1798 G03
LTC1798-2.5* Output Short-Circuit
Current vs Input Voltage
LTC1798-2.5* Output Short-Circuit
Current vs Input Voltage
LTC1798 Series
Load Regulation
25
20
15
10
5
42
5
4
T = 25°C
A
T
= 25°C
A
V
IN
= V
+ 0.2V
OUT(NOM)
OUTPUT SHORTED
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)
1798 G06
1798 G04
1798 G05
LTC1798-2.5*
Output Voltage vs Input Voltage
LTC1798-2.5*
Input Current vs Input Voltage
LTC1798-2.5
PSRR vs Frequency
2.5010
2.5005
2.5000
2.4995
7
6
5
4
60
50
40
30
20
10
0
V
IN
= 2.7V
T
= 25°C
T = 25°C
A
A
2
6
8
10
12
14
2
6
8
10
12
14
10
100
1k
10k
4
4
FREQUENCY (Hz)
INPUT VOLTAGE (V)
INPUT VOLTAGE (V)
1798 G09
1798 G07
1798 G08
1798fb
4
LTC1798 Series
TYPICAL PERFORMANCE CHARACTERISTICS
LTC1798-2.5
0.1Hz to 10Hz Noise
LTC1798-5 Input Current
vs Input Voltage in Dropout
LTC1798-2.5 Input Current
vs Input Voltage in Dropout
1400
1200
1000
800
600
400
200
0
250
200
150
100
50
V
IN
= 2.7V
T
= –55°C
A
T
T
= 25°C
A
A
T
T
= 25°C
A
A
T
= 125°C
A
= 125°C
5μV/DIV
= –55°C
0
1SEC/DIV
0
1
2
3
4
5
6
7
8
9
10
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
1798 G10
INPUT VOLTAGE (V)
INPUT VOLTAGE (V)
1798 G11
1798 G12
PIN FUNCTIONS
DNC (Pins 1, 5, 7, 8): Do Not Connect. Connected
internally for post package trim. These pins must be left
unconnected.
R1+ R2
⎛
⎜
⎝
⎞
⎟
⎠
VOUT = 2.385V
;
R1 is connected from OUT
R2
to FB and R2 from FB to GND. Selecting R2 ≥ 10k will
make I < 250μA.
IN(Pin2):PositiveSupply. Bypassingwitha0.1μFcapaci-
OUT
tor is recommended if the output loading changes. (V
OUT
GND (Pin 4): Negative Supply or Ground Connection.
+ 0.2V) ≤ V ≤ 12.6V.
IN
OUT (Pin 6): Reference Output. The output can source
up to 10mA and sink up to 2mA. It is stable with output
bypass capacitor ranging from 0μF to 1μF.
DNC (Pin 3): (LTC1798-2.5/LTC1798-3/LTC1798-4.1/
LTC1798-5)DoNotConnect.Connectedinternallyforpost
package trim. This pin must be left unconnected.
FB (Pin 3): (LTC1798) Resistor Divider Feedback Pin.
ConnectaresistordividerfromOUTtoGNDandthecenter
tap to FB. This pin sets the output potential.
1798fb
5
LTC1798 Series
BLOCK DIAGRAM
2
IN
+
–
OUT
R1
6
2.385V
FB 3 (LTC1798)
R2
GND
4
1798 BD
NOTE: R1 AND R2 ARE NOT CONNECTED FOR LTC1798
APPLICATIONS INFORMATION
Longer Battery Life
dissipates only 10.8μW when operating on a 2.7V supply
for LTC1798-2.5, yet the same connection can deliver
10mA of load current when demanded.
Series references have an advantage over shunt style
references. To operate, shunt references require a resistor
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,
theshuntreferencemustalwayssinkthiscurrent,resulting
in high power dissipation and short battery life.
Output Bypass Capacitor
TheLTC1798seriesisdesignedtobestablewithorwithout
capacitive loads. With no capacitive load, the reference
is ideal for fast settling applications, or where PC board
space is at a premium.
Inapplicationswithsignificantoutputloadingchanges, an
outputbypasscapacitorofupto1μFcanbeusedtoimprove
theoutputtransientresponse.Figure1showstheresponse
ofthereferencetoa1mAto0μAloadstepwitha1μFoutput
capacitor.Ifmorethan1μFofoutputcapacitanceisrequired,
a resistor in series with the capacitor is recommended
The LTC1798 series low dropout references do not require
a current setting resistor and can operate with any supply
voltage from (V
) + 0.2V) to 12.6V. When the
OUT(NOMINAL
circuitry being regulated does not demand current, the
LTC1798 series reduces its dissipation and battery life is
extended. If the reference is not delivering load current it
1mA
1mA
I
I
OUT
OUT
0mA
0mA
V
V
OUT
100mV/DIV
OUT
100mV/DIV
1798 F01a
1798 F01b
10ms/DIV
0.5ms/DIV
Figure 1. Reference Output Load Transient Response, 1μF Output Capacitor
1798fb
6
LTC1798 Series
APPLICATIONS INFORMATION
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.
These references consume only 4μA of quiescent current
underlightandheavyloadsaswellasindropout;whereas,
PNP-basedreferenceswasteconsiderableamountsofcur-
rent when the pass transistor is saturated. In addition, the
LTC1798 series provides a lower dropout voltage (200mV
max) than PNP-based references.
Internal P-Channel Pass Transistor
TheLTC1798seriesfeaturesaninternalP-channelMOSFET
pass transistor. This provides several advantages over
similar designs using a PNP bipolar pass transistor.
10k
1k
LTC1798-5
5.2V
2
6
IN
5V
TO
OUT
C
12.6V
OUT
>1μF
100
10
GND
4
0.1μF
DAMPING RESISTOR
<1k
1798 F02
1
10
100
1000
Figure 2. Adding a Damping Resistor with
Output Capacitors Greater Than 1μF
OUTPUT CAPACITOR VALUE (μF)
1798 F03
Figure 3. Damping Resistance vs Output Capacitor Value
Dimensions in inches (millimeters) unless otherwise noted.
PACKAGE DESCRIPTION
S8 Package
8-Lead Plastic SO (Narrow 0.150)
(Reference LTC DWG # 05-08-1610)
0.189 – 0.197*
(4.801 – 5.004)
7
5
8
6
0.150 – 0.157**
(3.810 – 3.988)
0.228 – 0.244
(5.791 – 6.197)
1
2
3
4
0.010 – 0.020
(0.254 – 0.508)
× 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
0.016 – 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
1798fb
7
LTC1798 Series
TYPICAL APPLICATION
Micropower Low Dropout Negative Reference
Supply Splitter
0.2V ≤ V ≤ 8.5V
CC
2
LTC1798-2.5
2.5V
VIRTUAL
GROUND
IN
2
6
V
= 5V
IN
OUT
CC
6
0.1μF
0.1μF
OUT LTC1798-3
GND
4
1798 TA04
8
0.1μF
GND
4
2
3
–
1
V
OUT
= –3V
1/2 LTC1542
1798 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
6
OUT
V
IN
4
2
GND
IN
3.2V TO
12.6V
0.1μF
LTC1798-3
1798 TA05
MICROWIRE is a trademark of National Semiconductor Corporation.
RELATED PARTS
PART NUMBER
DESCRIPTION
COMMENTS
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1.25V and 2.5V Versions, SO-8 Package
LT1634
LT1460
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LT1790
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
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Micropower Precision Series Voltage Reference
SOT-23, LDO Precision Micropower Reference
1798fb
LT 0309 REV B • PRINTED IN USA
LinearTechnology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
8
●
●
© LINEAR TECHNOLOGY CORPORATION 2008
(408) 432-1900 FAX: (408) 434-0507 www.linear.com
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