LTC1258 Series
Micropower Low
Dropout References
FEATURES
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DESCRIPTION
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 sup-
ply current and small package size. The combination of
ultralow quiescent current and low dropout voltage of only
200mV maximum makes them ideal for battery-powered
equipment. The output voltage is set by an external resistor
divider for the adjustable LTC1258.
This series of references uses curvature compensation to
obtain low temperature coefficient and trimmed thin-film
resistors to achieve high output accuracy. These references
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.
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.
L,
LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
200mV Max Dropout at 10mA Output Current
4μA Typical Quiescent Current
0.15% Max Initial Accuracy (S8)
No Output Capacitor Required
Output Sources 10mA, Sinks 2mA
40ppm/°C Max Drift (S8)
Voltage Options: 2.5V, 3V, 4.1V, 5V and Adjustable
Available in Small MSOP Package
APPLICATIONS
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Battery-Powered Systems
Handheld Instruments
Precision Power Supplies
A/D and D/A Converters
TYPICAL APPLICATION
4
REFERENCE VOLTAGE CHANGE (mV)
LTC1258-2.5 Temperature Drift
3
2
1
0
–1
–2
–3
–4
–40
–20
0
20
40
60
TEMPERATURE (°C)
80
100
1258sfb
2.5V Battery-Powered Reference
LTC1258-2.5
2.7V
TO 12.6V
2
0.1μF
GND
4
1258 TA01
IN
OUT
1
2.5V
1258 TA02
1
LTC1258 Series
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
PIN CONFIGURATION
TOP VIEW
TOP VIEW
OUT
IN
**DNC/FB
GND
1
2
3
4
8
7
6
5
DNC*
DNC*
DNC*
DNC*
OUT 1
IN 2
**DNC/FB 3
GND 4
8
7
6
5
DNC*
DNC*
DNC*
DNC*
MS8 PACKAGE
8-LEAD PLASTIC MSOP
T
JMAX
= 125°C,
θ
JA
= 250°C/W
*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
S8 PACKAGE
8-LEAD PLASTIC SO
T
JMAX
= 125°C,
θ
JA
= 190°C/W
*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
ORDER INFORMATION
LEAD FREE FINISH
LTC1258CMS8#PBF
(OBSOLETE)
LTC1258CMS8-2.5#PBF
LTC1258CMS8-3#PBF
LTC1258CMS8-4.1#PBF
LTC1258CMS8-5#PBF
LTC1258CS8#PBF
(OBSOLETE)
LTC1258CS8-2.5#PBF
LTC1258CS8-3#PBF
LTC1258CS8-4.1#PBF
LTC1258CS8-5#PBF
TAPE AND REEL
LTC1258CMS8#TRPBF
LTC1258CMS8-3#TRPBF
LTC1258CMS8-5#TRPBF
LTC1258CS8#TRPBF
LTC1258CS8-2.5#TRPBF
LTC1258CS8-3#TRPBF
LTC1258CS8-4.1#TRPBF
LTC1258CS8-5#TRPBF
PART MARKING
LTEL
LTEU
LTEM
1258
12582
12583
125841
12585
PACKAGE DESCRIPTION
8-Lead Plastic MSOP
8-Lead Plastic MSOP
8-Lead Plastic MSOP
8-Lead Plastic MSOP
8-Lead Plastic MSOP
8-Lead Plastic SO
8-Lead Plastic SO
8-Lead Plastic SO
8-Lead Plastic SO
8-Lead Plastic SO
TEMPERATURE RANGE
0°C to 70°C
0°C to 70°C
0°C to 70°C
0°C to 70°C
0°C to 70°C
0°C to 70°C
0°C to 70°C
0°C to 70°C
0°C to 70°C
0°C to 70°C
LTC1258CMS8-2.5#TRPBF LTCF
LTC1258CMS8-4.1#TRPBF LTEN
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/
1258sfb
2
LTC1258 Series
AVAILABLE OPTIONS
OUTPUT
VOLTAGE
(V)
2.5
2.5
3
3
4.096
4.096
5
5
Adjustable
Adjustable
TEMPERATURE
RANGE
(°C)
0 to 70
0 to 70
0 to 70
0 to 70
0 to 70
0 to 70
0 to 70
0 to 70
0 to 70
0 to 70
ACCURACY
(%)
0.15
0.21
0.15
0.20
0.15
0.18
0.15
0.18
0.4
0.46
PACKAGE TYPE
TEMPERATURE
SO-8 (S8)
MSOP-8 (MS8)
COEFFICENT
(ppm/°C)
ORDER NUMBER PART MARKING ORDER NUMBER PART MARKING
40
LTC1258CS8-2.5
12582
60
LTC1258CMS8-2.5
LTCF
40
LTC1258CS8-3
12583
60
LTC1258CMS8-3
LTEU
40
LTC1258CS8-4.1
125841
60
LTC1258CMS8-4.1
LTEN
40
LTC1258CS8-5
12585
60
LTC1258CMS8-5
LTEM
OBSOLETE
40
LTC1258CS8
1258
60
LTC1258CMS8
LTEL
ELECTRICAL CHARACTERISTICS
SYMBOL
V
IN
I
IN
V
OUT
PARAMETER
Input Voltage Range
Input Current
Output Voltage (Note 4)
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= V
OUT(NOMINAL)
+ 0.2V, I
OUT
= 0mA, FB = OUT for the LTC1258 unless
otherwise noted.
CONDITIONS
l
MIN
TYP
4
MAX
12.6
6.5
8.5
2.3945
2.5037
3.0045
4.102
5.0075
2.396
2.5052
3.006
4.1035
5.009
40
60
120
0.3
4.0
6.5
UNITS
V
μA
μA
V
V
V
V
V
V
V
V
V
V
ppm
P-P
ppm/°C
ppm/°C
ppm/V
mV/mA
mV/mA
mV/mA
mA
mA
mV
mV
ppm
ppm
nA
FB = OUT for LTC1258
LTC1258 (S8), FB = OUT
LTC1258-2.5 (S8)
LTC1258-3 (S8)
LTC1258-4.1 (S8)
LTC1258-5 (S8)
LTC1258 (MS8), FB = OUT
LTC1258-2.5 (MS8)
LTC1258-3 (MS8)
LTC1258-4.1 (MS8)
LTC1258-5 (MS8)
0.1Hz ≤ f ≤ 10Hz
T
MIN
≤ T
J
≤ T
MAX
(S8)
T
MIN
≤ T
J
≤ T
MAX
(MS8)
V
IN
= (V
OUT(NOMINAL)
+ 0.2V) to 12.6V
Sourcing 0mA to 10mA
Sinking 0mA to 2mA
l
2.3755
2.4963
2.9955
4.090
4.9925
2.374
2.4948
2.994
4.0885
4.991
l
l
l
l
l
e
n
TC
V
OUT
/V
IN
V
OUT
/I
OUT
Output Voltage Noise (Note 5)
Output Voltage Temp Coefficient (Note 6)
Line Regulation
Load Regulation (Note 7)
2.385
2.5
3
4.096
5
2.385
2.5
3
4.096
5
8
15
30
0.1
1.75
I
SC
ΔV
DO
V
HYST
I
FB
Short-Circuit Output Current
Dropout Voltage (Note 8)
Output Hysteresis (Note 9)
FB Pin Input Current
V
OUT
Shorted to GND
V
OUT
Shorted to V
IN
I
OUT
= 0,
ΔV
OUT
≤ 0.1%
I
OUT
= 10mA,
ΔV
OUT
≤ 0.1%
ΔT
= –40°C to 85°C
ΔT
= 0°C to 70°C
LTC1258, OUT = FB
l
l
20
2
40
4
100
200
200
50
10
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 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
range, the output may shift due to hysteresis.
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3
LTC1258 Series
ELECTRICAL CHARACTERISTICS
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 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
IN
– V
OUT
) when V
OUT
falls to 0.1% below its
nominal value at V
IN
= V
OUT
+ 0.5V.
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.
TYPICAL PERFORMANCE CHARACTERISTICS
LTC1258-2.5* Dropout Voltage vs
Output Source Current
100
90
DROPOUT VOLTAGE (mV)
80
70
60
50
40
30
20
10
0
0
1
10
0.1
OUTPUT SOURCE CURRENT (mA)
100
1258 G01
LTC1258-2.5* Input Current vs
Temperature
8
OUTPUT SHORT-CIRCUIT CURRENT (mA)
70
V
IN
= 2.7V
7
INPUT CURRENT (μA)
6
5
4
3
2
1
0
–50 –25
0
25 50 75 100 125 150
TEMPERATURE (°C)
1258 G02
LTC1258 Series Output Short-
Circuit Current vs Temperature
60
50
40
30
20
10
5
0
–50 –25
0
OUTPUT
SHORTED
TO V
IN
25 50 75 100 125 150
TEMPERATURE (°C)
1258 G03
T
A
= 25 C
T
A
= 25°C
V
IN
= V
OUT(NOM)
+ 0.2V
OUTPUT
SHORTED
TO GND
LTC1258-2.5* Output Short-
Circuit vs Input Voltage
25
OUTPUT SHORT-CIRCUIT CURRENT (mA)
T
A
= 25°C
OUTPUT SHORTED
TO V
IN
OUTPUT SHORT-CIRCUIT CURRENT (mA)
42
LTC1258-2.5* Output Short-
Circuit Current vs Input Voltage
5
4
V
OUT
FROM NO LOAD (mV)
3
2
1
0
–1
–2
–3
–4
12
14
1258-G05
LTC1258 Series Load Regulation
T
A
= 25°C
V
IN
= V
OUT(NOM)
+ 0.2V
SINKING
20
15
SOURCING
10
5
T
A
= 25°C
OUTPUT SHORTED
TO GND
41
2
4
6
8
10
INPUT VOLTAGE (V)
0
2
4
6
8
10
INPUT VOLTAGE (V)
12
14
1258-G04
–5
0
1
10
0.1
OUTPUT CURRENT (mA)
100
1258 G06
*Similar performance characteristics can be expected for all voltage options.
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4
LTC1258 Series
TYPICAL PERFORMANCE CHARACTERISTICS
LTC1258-2.5 Output Voltage vs
Input Voltage
2.5010
T
A
= 25°C
7
POWER SUPPLY REJECTION RATIO (dB)
T
A
= 25°C
LTC1258-2.5 Input Current vs
Input Voltage
60
LTC1258-2.5 PSRR vs Frequency
V
IN
= 2.7V
50
40
30
20
10
0
OUTPUT VOLTAGE (V)
2.5005
INPUT CURRENT (μA)
2
6
8
10
INPUT VOLTAGE (V)
12
14
1258 G07
6
2.5000
5
2.4995
4
4
2
4
6
8
10
INPUT VOLTAGE (V)
12
14
1258 G08
10
100
1k
FREQUENCY (Hz)
10k
1258 G09
LTC1258-2.5 0.1Hz to 10Hz Noise
1400
V
IN
= 2.7V
1200
INPUT CURRENT (μA)
1000
LTC1258-5 Input Current vs Input
Voltage in Dropout
250
T
A
= –55°C
T
A
= 25°C
INPUT CURRENT (μA)
T
A
= 125°C
800
600
400
200
0
0
0
1
2
3 4 5 6 7
INPUT VOLTAGE (V)
8
9
10
200
LTC1258-2.5 Input Current vs
Input Voltage in Dropout
T
A
= 125°C
150
T
A
= 25°C
5μV/DIV
100
T
A
= –55°C
50
1SEC/DIV
1258 G10
0
0.5
1
1.5 2 2.5 3 3.5
INPUT VOLTAGE (V)
4
4.5
5
1258 G11
1258 G12
PIN FUNCTIONS
OUT (Pin 1):
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
.
IN (Pin 2):
Positive Supply. Bypassing with a 0.1μF ca-
pacitor is recommended if the output loading changes.
(V
OUT
+ 0.2V) ≤ V
IN
≤ 12.6V.
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. Con-
nect a resistor divider from OUT to GND and the center
tap to FB. This pin sets the output potential.
⎛
R1
+
R2
⎞
;
R1 is connected from OUT to
V
OUT
=
2.385V
⎜
⎝
R2
⎟
⎠
FB and R2 from FB to GND.
GND (Pin 4):
Negative Supply or Ground Connection.
DNC (Pins 5, 6, 7, 8):
Do Not Connect. Connected in-
ternally for post package trim. These pins must be left
unconnected.
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