LTC1258 Series
Micropower Low
Dropout References
FEATURES
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DESCRIPTIO
200mV Max Dropout at 10mA Output Current
4
µ
A 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
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
current and small package size. The combination of ultralow
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.
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
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.
APPLICATIO S
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Battery-Powered Systems
Handheld Instruments
Precision Power Supplies
A/D and D/A Converters
, LTC and LT are registered trademarks of Linear Technology Corporation.
The LTC1258 series is available in the 8-pin MSOP and SO
packages.
TYPICAL APPLICATION
LTC1258-2.5 Temperature Drift
2.5V Battery-Powered Reference
REFERENCE VOLTAGE CHANGE (mV)
4
3
2
1
0
–1
–2
–3
–4
–40
–20
0
20
40
60
TEMPERATURE (°C)
80
100
LTC1258-2.5
2.7V
TO 12.6V
2
0.1µF
GND
1258 TA01
IN
OUT
1
2.5V
4
U
1258 TA02
U
U
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
PACKAGE/ORDER INFORMATION
TOP VIEW
OUT
IN
**DNC/FB
GND
1
2
3
4
8
7
6
5
DNC*
DNC*
DNC*
DNC*
ORDER PART
NUMBER
LTC1258CMS8
LTC1258CMS8-2.5
LTC1258CMS8-3
LTC1258CMS8-4.1
LTC1258CMS8-5
MS8 PART MARKING
LTEL
LTCF
LTEU
LTEN
LTEM
OUT 1
IN 2
**DNC/FB 3
GND 4
MS8 PACKAGE
8-LEAD PLASTIC MSOP
* 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
T
JMAX
= 125°C,
θ
JA
= 250°C/W
Consult factory for Industrial and Military grade parts.
AVAILABLE OPTIO S
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
TEMPERATURE
COEFFICIENT
(ppm/
°
C)
40
60
40
60
40
60
40
60
40
60
PACKAGE TYPE
S8
ORDER NUMBER
LTC1258CS8-2.5
LTC1258CS8-3
LTC1258CS8-4.1
LTC1258CS8-5
LTC1258CS8
PART MARKING
12582
LTC1258CMS8-2.5
12583
LTC1258CMS8-3
125841
LTC1258CMS8-4.1
12585
LTC1258CMS8-5
1258
LTC1258CMS8
LTEL
LTEM
LTEN
LTEU
LTCF
MS8
ORDER NUMBER PART MARKING
2
U
U
W
W W
U
U
W
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
TOP VIEW
8
7
6
5
DNC*
DNC*
DNC*
DNC*
ORDER PART
NUMBER
LTC1258CS8
LTC1258CS8-2.5
LTC1258CS8-3
LTC1258CS8-4.1
LTC1258CS8-5
S8 PART MARKING
S8 PACKAGE
8-LEAD PLASTIC SO
* 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
T
JMAX
= 125°C,
θ
JA
= 190°C/W
1258
12582
12583
125841
12585
LTC1258 Series
ELECTRICAL CHARACTERISTICS
The
q
denotes specifications which apply over the specified temperature range, otherwise specifications are TA = 25°C.
V
IN
= V
OUT(NOMINAL)
+ 0.2V, I
OUT
= 0mA, FB = OUT for the LTC1258 unless otherwise noted.
SYMBOL
V
IN
I
IN
V
OUT
PARAMETER
Input Voltage Range
Input Current
Output Voltage (Note 4)
CONDITIONS
q
MIN
TYP
FB = OUT for LTC1258
q
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)
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
V
OUT
Shorted to GND
V
OUT
Shorted to V
IN
I
OUT
= 0,
∆V
OUT
≤
0.1%
I
OUT
= 10mA,
∆V
OUT
≤
0.1%
∆T
= –40°C to 85°C
∆T
= 0°C to 70°C
LTC1258, OUT = FB
2.3755
2.4963
2.9955
4.090
4.9925
2.374
2.4948
2.994
4.0885
4.991
q
q
q
q
q
2.385
2.5
3
4.096
5
2.385
2.5
3
4.096
5
8
15
30
0.1
1.75
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
90
0.3
4.0
6.5
I
SC
∆V
DO
V
HYST
I
FB
Short-Circuit Output Current
Dropout Voltage (Note 8)
Output Hysteresis (Note 9)
FB Pin Input Current
20
2
q
q
40
4
100
200
200
50
10
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
Note 1:
Absolute Maximum Ratings are those values beyond which the life
of the device may be impaired.
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.
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.
3
LTC1258 Series
TYPICAL PERFORMANCE CHARACTERISTICS
LTC1258-2.5*
Dropout Voltage vs
Output Source Current
100
90
DROPOUT VOLTAGE (mV)
OUTPUT SHORT-CIRCUIT CURRENT (mA)
T
A
= 25°C
80
70
60
50
40
30
20
10
0
0
1
10
0.1
OUTPUT SOURCE CURRENT (mA)
100
1258 G01
INPUT CURRENT (µA)
LTC1258-2.5* Output Short-Circuit
Current vs Input Voltage
25
OUTPUT SHORT-CIRCUIT CURRENT (mA)
OUTPUT SHORT-CIRCUIT CURRENT (mA)
T
A
= 25°C
OUTPUT SHORTED
TO V
IN
42
∆V
OUT
FROM NO LOAD (mV)
20
15
10
5
0
2
4
6
8
10
INPUT VOLTAGE (V)
12
14
1258-G04
LTC1258-2.5
Output Voltage vs Input Voltage
2.5010
T
A
= 25°C
7
OUTPUT VOLTAGE (V)
2.5005
INPUT CURRENT (µA)
2.5000
2.4995
2
4
6
8
10
INPUT VOLTAGE (V)
*Similar performance characteristics can be expected for all voltage options.
4
U W
LTC1258-2.5*
Input Current vs Temperature
8
V
IN
= 2.7V
7
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
70
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
V
IN
= V
OUT(NOM)
+ 0.2V
OUTPUT
SHORTED
TO GND
LTC1258-2.5* Output Short-Circuit
Current vs Input Voltage
5
4
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
SOURCING
T
A
= 25°C
OUTPUT SHORTED
TO GND
41
2
4
6
8
10
INPUT VOLTAGE (V)
–5
0
1
10
0.1
OUTPUT CURRENT (mA)
100
1258 G06
LTC1258-2.5
Input Current vs Input Voltage
T
A
= 25°C
6
5
12
14
1258 G07
4
2
4
6
8
10
INPUT VOLTAGE (V)
12
14
1258 G08
LTC1258 Series
TYPICAL PERFORMANCE CHARACTERISTICS
LTC1258-2.5 PSRR vs Frequency
60
POWER SUPPLY REJECTION RATIO (dB)
V
IN
= 2.7V
50
40
30
20
10
0
5µV/DIV
10
1k
100
FREQUENCY (Hz)
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
capacitor 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.
Connect a resistor divider from OUT to GND and the center
tap to FB. This pin sets the output potential.
R1
+
R2
V
OUT
=
2.385V
;
R1 is connected from OUT
R2
to 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
internally for post package trim. These pins must be left
unconnected.
BLOCK DIAGRAM
U W
LTC1258-2.5 0.1Hz to 10Hz Noise
V
IN
= 2.7V
10k
1258 G09
1SEC/DIV
1258 G10
W
U
U
U
2
IN
+
OUT 1
2.385V
–
R1
FB 3 (LTC1258)
R2
GND
4
1258 BD
NOTE: R1 AND R2 ARE NOT CONNECTED FOR LTC1258
5
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