LINER LTC6652AHMS8-2.048 Precision low drift low noise buffered reference Datasheet

LTC6652
Precision Low Drift Low
Noise Buffered Reference
Features
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Description
Low Drift:
A-Grade 5ppm/°C Max
B-Grade 10ppm/°C Max (MSOP8)
B-Grade 8ppm/°C Max (LS8)
High Accuracy:
A Grade ±0.05% Max
B-Grade ±0.1% Max
Low Noise: 2.1ppmP-P (0.1Hz to 10Hz)
100% Tested at –40°C, 25°C and 125°C
Sinks and Sources Current: ±5mA
Low Power Shutdown: <2µA Maximum
Thermal Hysteresis (LS8): 45ppm (–40°C to 125°C)
Long-Term Drift (LS8): 20ppm/√kHr
Low Dropout: 300mV
Available Output Voltage Options: 1.25V, 2.048V, 2.5V,
3V, 3.3V, 4.096V, 5V
8-Lead MSOP and 5mm × 5mm Surface Mount
Hermetic Packages
Applications
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Automotive Control and Monitoring
High Temperature Industrial
High Resolution Data Acquisition Systems
Instrumentation and Process Control
Precision Regulators
Medical Equipment
The LTC®6652 family of precision, low drift, low noise
references is fully specified over the temperature range
of –40°C to 125°C. High order curvature compensation
allows these references to achieve a low drift of less than
5ppm/°C with a predictable temperature characteristic and
an output voltage accuracy of ±0.05%. The performance
over temperature should appeal to automotive, high performance industrial and other high temperature applications.
The LTC6652 voltage references can be powered from
supply voltages up to 13.2V. They boast low noise, excellent load regulation, source and sink capability and
exceptional line rejection, making them a superior choice
for demanding precision applications. A shutdown mode
allows power consumption to be reduced when the reference is not needed. The optional output capacitor can be
left off when space constraints are critical.
The LTC6652 references are offered in an 8-lead MSOP
package and an 8-lead LS8 package. The LS8 is a 5mm
× 5mm surface mount hermetic package that provides
outstanding stability.
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
Typical Application
Output Voltage Temperature Drift
0.050
2.8V ≤ VIN ≤ 13.2V
CIN
0.1µF
(OPTIONAL)
VIN
SHDN
VOUT
2.5V
LTC6652-2.5 VOUT
GND
COUT
1µF
(OPTIONAL)
6652 TA01a
VOUT ACCURACY (%)
Basic Connection
0.025
0
–0.025
–0.050
–40 –20
0
20 40 60 80
TEMPERATURE (°C)
100
125
6652 TA01b
6652fe
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1
LTC6652
Absolute Maximum Ratings
(Note 1)
Input Voltage
VIN to GND........................................... –0.3V to 13.2V
SHDN to GND.............................–0.3V to (VIN + 0.3V)
Output Voltage
VOUT............................................–0.3V to (VIN + 0.3V)
Output Short-Circuit Duration....................... Indefinite
Operating Temperature Range................. –40°C to 125°C
Storage Temperature Range (Note 2)...... –65°C to 150°C
Lead Temperature Range (Soldering, 10 sec)
(Note 9)............................................................. 300°C
Pin Configuration
TOP VIEW
GND*
TOP VIEW
DNC 1
8 GND*
VIN 2
7 GND*
SHDN 3
6 VOUT
GND 4
5 GND*
MS8 PACKAGE
8-LEAD PLASTIC MSOP
DNC
1
VIN
2
SHDN
3
8
4
7
GND*
6
VOUT
5
GND*
GND
LS8 PACKAGE
8-PIN LEADLESS CHIP CARRIER (5mm × 5mm)
TJMAX = 150°C, θJA = 200°C/W
DNC: DO NOT CONNECT
*CONNECT THE PINS TO DEVICE GND (PIN 4)
TJMAX = 150°C, θJA = 120°C/W
DNC: DO NOT CONNECT
*CONNECT THE PINS TO DEVICE GND (PIN 4)
Order Information
LEAD FREE FINISH
TAPE AND REEL
PART MARKING*
PACKAGE DESCRIPTION
SPECIFIED TEMPERATURE RANGE
LTC6652AHMS8-1.25#PBF
LTC6652AHMS8-1.25#TRPBF
LTCVH
8-Lead Plastic MSOP
–40°C to 125°C
LTC6652BHMS8-1.25#PBF
LTC6652BHMS8-1.25#TRPBF
LTCVH
8-Lead Plastic MSOP
–40°C to 125°C
LTC6652AHMS8-2.048#PBF
LTC6652AHMS8-2.048#TRPBF
LTCVJ
8-Lead Plastic MSOP
–40°C to 125°C
LTC6652BHMS8-2.048#PBF
LTC6652BHMS8-2.048#TRPBF
LTCVJ
8-Lead Plastic MSOP
–40°C to 125°C
LTC6652AHMS8-2.5#PBF
LTC6652AHMS8-2.5#TRPBF
LTCQV
8-Lead Plastic MSOP
–40°C to 125°C
LTC6652BHMS8-2.5#PBF
LTC6652BHMS8-2.5#TRPBF
LTCQV
8-Lead Plastic MSOP
–40°C to 125°C
LTC6652AHMS8-3#PBF
LTC6652AHMS8-3#TRPBF
LTCVK
8-Lead Plastic MSOP
–40°C to 125°C
LTC6652BHMS8-3#PBF
LTC6652BHMS8-3#TRPBF
LTCVK
8-Lead Plastic MSOP
–40°C to 125°C
LTC6652AHMS8-3.3#PBF
LTC6652AHMS8-3.3#TRPBF
LTCVM
8-Lead Plastic MSOP
–40°C to 125°C
LTC6652BHMS8-3.3#PBF
LTC6652BHMS8-3.3#TRPBF
LTCVM
8-Lead Plastic MSOP
–40°C to 125°C
LTC6652AHMS8-4.096#PBF
LTC6652AHMS8-4.096#TRPBF
LTCVN
8-Lead Plastic MSOP
–40°C to 125°C
LTC6652BHMS8-4.096#PBF
LTC6652BHMS8-4.096#TRPBF
LTCVN
8-Lead Plastic MSOP
–40°C to 125°C
LTC6652AHMS8-5#PBF
LTC6652AHMS8-5#TRPBF
LTCVP
8-Lead Plastic MSOP
–40°C to 125°C
LTC6652BHMS8-5#PBF
LTC6652BHMS8-5#TRPBF
LTCVP
8-Lead Plastic MSOP
–40°C to 125°C
6652fe
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LTC6652
order information
LEAD FREE FINISH
PART MARKING*
PACKAGE DESCRIPTION
SPECIFIED TEMPERATURE RANGE
LTC6652AHLS8-2.5#PBF †
665225
8-Lead Ceramic LCC 5mm × 5mm
–40°C to 125°C
LTC6652BHLS8-2.5#PBF †
665225
8-Lead Ceramic LCC 5mm × 5mm
–40°C to 125°C
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
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/
† This product is only offered in trays. For more information go to: http://www.linear.com/packaging/
Available Options
OUTPUT VOLTAGE
INITIAL ACCURACY
TEMPERATURE COEFFICIENT
PART NUMBER**
1.250
0.05%
0.1%
5ppm/°C
10ppm/°C
LTC6652AHMS8-1.25
LTC6652BHMS8-1.25
2.048
0.05%
0.1%
5ppm/°C
10ppm/°C
LTC6652AHMS8-2.048
LTC6652BHMS8-2.048
2.500
0.05%
0.1%
0.05%
0.1%
5ppm/°C
10ppm/°C
5ppm/°C
8ppm/°C
LTC6652AHMS8-2.5
LTC6652BHMS8-2.5
LTC6652AHLS8-2.5
LTC6652BHLS8-2.5
3.000
0.05%
0.1%
5ppm/°C
10ppm/°C
LTC6652AHMS8-3
LTC6652BHMS8-3
3.300
0.05%
0.1%
5ppm/°C
10ppm/°C
LTC6652AHMS8-3.3
LTC6652BHMS8-3.3
4.096
0.05%
0.1%
5ppm/°C
10ppm/°C
LTC6652AHMS8-4.096
LTC6652BHMS8-4.096
5.000
0.05%
0.1%
5ppm/°C
10ppm/°C
LTC6652AHMS8-5
LTC6652BHMS8-5
**See Order Information section for complete part number listing.
Electrical Characteristics
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C, VIN = VOUT + 0.5V, unless otherwise noted.
PARAMETER
CONDITIONS
Output Voltage
LTC6652A
LTC6652B
Output Voltage Temperature Coefficient
(Note 3)
LTC6652A
LTC6652BMS8
LTC6652BLS8
Line Regulation
VOUT + 0.5V ≤ VIN ≤ 13.2V, SHDN = VIN
Load Regulation (Note 4)
MIN
TYP
–0.05
–0.1
ISOURCE = 5mA, LTC6652-1.25, LTC6652-2.048,
LTC6652-2.5, LTC6652-3, LTC6652-3.3,
LTC6652-4.096, LTC6652-5
ISINK = 1mA, LTC6652-1.25, LTC6652-2.048
ISINK = 5mA, LTC6652-2.5, LTC6652-3,
LTC6652-3.3, LTC6652-4.096, LTC6652-5
l
l
UNITS
0.05
0.1
%
%
2
4
4
5
10
8
ppm/°C
ppm/°C
ppm/°C
2
50
80
ppm/V
ppm/V
20
75
200
ppm/mA
ppm/mA
80
250
600
ppm/mA
ppm/mA
50
150
450
ppm/mA
ppm/mA
l
l
l
l
MAX
6652fe
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LTC6652
Electrical Characteristics
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C, VIN = VOUT + 0.5V, unless otherwise noted.
PARAMETER
CONDITIONS
Minimum Operating Voltage (Note 5)
ISOURCE = 5mA, VOUT Error ≤ 0.1%
LTC6652-1.25, LTC6652-2.048
LTC6652-2.5, LTC6652-3, LTC6652-3.3,
LTC6652-4.096, LTC6652-5
MIN
l
l
Output Short-Circuit Current
Short VOUT to GND
Short VOUT to VIN
Shutdown Pin (SHDN)
Logic High Input Voltage
Logic High Input Current
l
l
Logic Low Input Voltage
Logic Low Input Current
l
l
Supply Current
TYP
MAX
V
V
2.7
VOUT + 0.3V
16
16
2
mA
mA
0.1
1
V
µA
0.1
0.8
1
V
µA
560
µA
µA
2
µA
350
No Load
UNITS
l
0.1
Shutdown Current
SHDN Tied to GND
Output Voltage Noise (Note 6)
0.1Hz ≤ f ≤ 10Hz
LTC6652-1.25
LTC6652-2.048, LTC6652-2.5, LTC6652-3
LTC6652-3.3
LTC6652-4.096
LTC6652-5
10Hz ≤ f ≤ 1kHz
2.4
2.1
2.2
2.3
2.8
3
ppmP-P
ppmP-P
ppmP-P
ppmP-P
ppmP-P
ppmRMS
Turn-On Time
0.1% Settling, CLOAD = 0
100
µs
Long-Term Drift of Output Voltage (Note 7) LTC6652MS8
LTC6652LS8
60
20
ppm/√kHr
ppm/√kHr
Hysteresis (Note 8)
80
75
45
45
25
10
ppm
ppm
ppm
ppm
ppm
ppm
l
∆T = –40°C to 125°C, LTC6652MS8
∆T = –40°C to 85°C, LTC6652MS8
∆T = 0°C to 70°C, LTC6652MS8
∆T = –40°C to 125°C, LTC6652LS8
∆T = –40°C to 85°C, LTC6652LS8
∆T = 0°C to 70°C, LTC6652LS8
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: If the parts are stored outside of the specified temperature range,
the output may shift due to hysteresis.
Note 3: Temperature coefficient is measured by dividing the maximum
change in output voltage by the specified temperature range.
Note 4: 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 5: Excludes load regulation errors.
Note 6: Peak-to-peak noise is measured with a 3-pole highpass at 0.1Hz
and 4-pole lowpass filter at 10Hz. The unit is enclosed in a still-air
environment to eliminate thermocouple effects on the leads. The test
time is 10 seconds. RMS noise is measured on a spectrum analyzer in
a shielded environment where the intrinsic noise of the instrument is
removed to determine the actual noise of the device.
Note 7: Long-term stability typically has a logarithmic characteristic and
therefore, changes after 1000 hours tend to be much smaller than before that
time. Total drift in the second thousand hours is normally less than one third
that of the first thousand hours with a continuing trend toward reduced drift
with time. Long-term stability will also be affected by differential stresses
between the IC and the board material created during board assembly.
Note 8: 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 to the hot
or cold temperature limit before successive measurements. Hysteresis
is roughly proportional to the square of the temperature change. For
instruments that are stored at well controlled temperatures (within 20 or 30
degrees of operational temperature) it’s usually not a dominant error source.
Typical hysteresis is the worst-case of 25°C to cold to 25°C or 25°C to hot to
25°C, preconditioned by one thermal cycle.
Note 9: The stated temperature is typical for soldering of the leads during
manual rework. For detailed IR reflow recommendations, refer to the
Applications section.
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LTC6652
Typical Performance Characteristics
Characteristic curves are similar for most
LTC6652s. Curves from the LTC6652-1.25, LTC6652-2.5 and the LTC6652-5 represent the extremes and typical of the voltage options.
Characteristic curves for other output voltages fall between these curves and can be estimated based on their output.
1.25V Output Voltage
Temperature Drift
1.2510
1.25V Line Regulation
1.25V Load Regulation (Sourcing)
1.2506
3 TYPICAL PARTS
0
1.2500
1.2495
125°C
1.2502
1.2500
25°C
1.2498
–40°C
1.2496
1.2490
–80
80
40
0
TEMPERATURE (°C)
–40
1.2494
160
120
OUTPUT VOLTAGE CHANGE (ppm)
1.2505
OUTPUT VOLTAGE (V)
REFERENCE VOLTAGE (V)
1.2504
0
2
8
6
10
4
INPUT VOLTAGE (V)
12
25°C
–100
125°C
–150
–200
–250
14
10
1
OUTPUT CURRENT (mA)
0.1
6652 G18
6652 G17
6652 G19
1.25V Low Frequency 0.1Hz to
10Hz Transient Noise
1.25V Load Regulation (Sinking)
1.25V Output Voltage Noise
Spectrum
400
400
350
125°C
250
200
25°C
150
100
NOISE VOLTAGE (nV/√Hz)
300
OUTPUT NOISE (1µV/DIV)
OUTPUT VOLTAGE CHANGE (ppm)
–40°C
–50
–40°C
300
200
100
50
0
0.1
1
OUTPUT CURRENT (mA)
10
0
0.01
TIME (1 SECOND/DIV)
6652 G20
0.1
1
FREQUENCY (kHz)
10
6652 G22
6652 G21
1.25 Sinking Current Without
Output Capacitor
1.25V Stability with Output
Capacitance
1.25 Sinking Current with Output
Capacitor
10µF
IOUT
0mA
VOUT
500mV/DIV
1mA
1µF
0mA
OUTPUT CAPACITOR
IOUT
1mA
VOUT
500mV/DIV
COUT = 0µF
500µs/DIV
6652 G23
COUT = 1µF
500µs/DIV
6652 G24
0.1µF
10nF
REGION OF
MARGINAL
STABILITY
1nF
100pF
NO CAP
–5
–1 0
LOAD CURRENT (mA)
5
6652 G16
6652fe
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LTC6652
Typical Performance Characteristics
Characteristic curves are similar for most
LTC6652s. Curves from the LTC6652-1.25, LTC6652-2.5 and the LTC6652-5 represent the extremes and typical of the voltage options.
Characteristic curves for other output voltages fall between these curves and can be estimated based on their output.
2.5V Output Voltage
Temperature Drift
2.5V Load Regulation (Sourcing)
0
2.5010
3 TYPICAL PARTS
OUTPUT VOLTAGE CHANGE (ppm)
–20
2.5005
2.5005
OUTPUT VOLTAGE (V)
REFERENCE VOLTAGE (V)
2.5010
2.5V Line Regulation
2.5000
2.4995
2.4990
2.5000
125°C
25°C
2.4995
–40°C
2.4990
2.4985
2.4985
–50 –25
0
25 50
75 100 125 150
TEMPERATURE (°C)
2.4980
0
2
8
6
10
4
INPUT VOLTAGE (V)
12
6652 G01
125°C
25°C
–40°C
6652 G03
0.9
800
0.8
700
600
500
125°C
25°C
400
300
–40°C
0
0.7
0.6
0.5
125°C
0.4
0.3
0.2
100
10
25°C
0.1
0
2
10
1
OUTPUT CURRENT (mA)
0.1
2.5V Shutdown Current
vs Input Voltage
8
6
4
10
INPUT VOLTAGE (V)
12
0
14
–40°C
0
2
8
6
4
10
INPUT VOLTAGE (V)
6652 G05
6652 G04
2.5V Minimum VIN-VOUT
Differential (Sourcing)
12
14
6652 G06
2.5V Minimum VOUT-VIN
Differential (Sinking)
10
OUTPUT CURRENT (mA)
10
OUTPUT CURRENT (mA)
–180
1.0
200
1
0.1
–160
SUPPLY CURRENT (µA)
400
1
OUTPUT CURRENT (mA)
–140
900
SUPPLY CURRENT (µA)
OUTPUT VOLTAGE CHANGE (ppm)
500
0.1
–120
1000
600
0
125°C
–100
2.5V Supply Current
vs Input Voltage
700
100
25°C
–80
6652 G02
2.5V Load Regulation (Sinking)
200
–60
–200
14
–40°C
–40
25°C
1
25°C
125°C, –40°C
125°C
0.01
0.001
0.01
0.1
1
0.1
0.001
INPUT-OUTPUT VOLTAGE (V)
6652 G09
–40°C
0.01
0.1
OUTPUT-INPUT VOLTAGE (V)
1
6652 G10
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LTC6652
Typical Performance Characteristics
Characteristic curves are similar for most
LTC6652s. Curves from the LTC6652-1.25, LTC6652-2.5 and the LTC6652-5 represent the extremes and typical of the voltage options.
Characteristic curves for other output voltages fall between these curves and can be estimated based on their output.
2.5V Low Frequency 0.1Hz to
10Hz Transient Noise
2.5V Output Voltage Noise
Spectrum
600
NOISE VOLTAGE (nV/√Hz)
OUTPUT NOISE (1µV/DIV)
500
400
300
200
100
0
0.01
TIME (1 SECOND/DIV)
0.1
1
FREQUENCY (kHz)
6652 G12
6652 G11
Stability with Output Capacitance
(LTC6652-2.5, LTC6652-3,
LTC6652-3.3, LTC6652-4.096,
LTC6652-5)
Typical VOUT Distribution for
LTC6652-2.5
180
10µF
1004 UNITS
160
1µF
LTC6652A LIMITS
OUTPUT CAPACITOR
NUMBER OF UNITS
140
120
80
60
40
0.1µF
10nF
REGION OF
MARGINAL STABILITY
1nF
100pF
20
0
2.4985
10
2.5005
2.4995
OUTPUT VOLTAGE (V)
2.5015
NO CAP
6652 G15
–5
0
LOAD CURRENT (mA)
5
6652 G14
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LTC6652
Typical Performance Characteristics
Characteristic curves are similar for most
LTC6652s. Curves from the LTC6652-1.25, LTC6652-2.5 and the LTC6652-5 represent the extremes and typical of the voltage options.
Characteristic curves for other output voltages fall between these curves and can be estimated based on their output.
5V Output Voltage
Temperature Drift
5.002
3 TYPICAL PARTS
5.000
4.998
800
5.001
SUPPLY CURRENT (µA)
5.003
1000
900
OUTPUT VOLTAGE (V)
REFERENCE VOLTAGE (V)
5.005
5V Supply Current
vs Input Voltage
5V Line Regulation
25°C
5.000
125°C
4.999
700
600
500
125°C
400
25°C
300
–40°C
200
–40°C
100
4.995
–50 –25
0
25 50
75 100 125 150
TEMPERATURE (°C)
4.998
0
8
6
10
4
INPUT VOLTAGE (V)
2
5V Shutdown Current
vs Input Voltage
0
0
2
8
6
4
10
INPUT VOLTAGE (V)
14
12
6652 G27
5V Minimum VIN to VOUT
Differential (Sourcing)
5V Low Frequency 0.1Hz to 10Hz
Transient Noise
10
1.0
0.9
0.7
0.6
0.5
0.4
0.3
–40°C
0.2
OUTPUT NOISE (5µV/DIV)
OUTPUT CURRENT (mA)
125°C
0.8
SUPPLY CURRENT (µA)
14
6652 G26
6652 G25
1
25°C
0.1
–40°C
0.1
0
12
125°C
25°C
0
2
8
6
4
10
INPUT VOLTAGE (V)
12
14
0.01
0.001
0.01
0.1
1
TIME (1 SECOND/DIV)
INPUT-OUTPUT VOLTAGE (V)
6652 G30
6652 G29
6652 G31
5V Start-Up Response Without
Output Capacitor
5V Output Voltage Noise Spectrum
5V Start-Up Response with Output
Capacitor
NOISE VOLTAGE (nV/√Hz)
1000
800
VIN
2V/DIV
VIN
2V/DIV
VOUT
2V/DIV
VOUT
2V/DIV
600
400
200
COUT = 0µF
0
0.01
0.1
1
FREQUENCY (kHz)
100µs/DIV
6652 G33
COUT = 1µF
100µs/DIV
6652 G34
10
6652 G32
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LTC6652
Typical Performance Characteristics
Characteristic curves are similar for most
LTC6652s. Curves from the LTC6652-1.25, LTC6652-2.5 and the LTC6652-5 represent the extremes and typical of the voltage options.
Characteristic curves for other output voltages fall between these curves and can be estimated based on their output.
Power Supply Rejection Ratio
vs Frequency
100
–30
COUT = 1µF
–40
–50
–60
COUT = 10µF
–70
–80
VTH(UP)
2.0
10
VTRIP (V)
–20
2.5
COUT = 0µF
COUT = 0µF
OUTPUT IMPEDANCE (Ω)
POWER SUPPLY REJECTION RATIO (dB)
0
–10
SHDN Input Voltage Thresholds
vs VIN
Output Impedance vs Frequency
COUT = 1µF
COUT = 10µF
1
1.5
VTH(DN)
1.0
0.5
–90
–100
0.01
0.1
1
10
FREQUENCY (kHz)
100
1000
0.1
0.01
0.1
1
10
FREQUENCY (kHz)
100
0
2
6
8
VIN (V)
6652 G08
6652 G07
4
10
12
14
6652 G13
Pin Functions
DNC (Pin 1): Do Not Connect.
GND (Pin 4): Device Ground.
VIN (Pin 2): Power Supply. The minimum supply input is
VOUT + 300mV or 2.7V; whichever is higher. The maximum
supply is 13.2V. Bypassing VIN with a 0.1µF capacitor to
GND will improve PSRR.
VOUT (Pin 6): Output Voltage. An output capacitor is not
required. For some applications, a capacitor between 0.1µF
to 10µF can be beneficial. See the graphs in the Typical
Performance Characteristics section for further details.
SHDN (Pin 3): Shutdown Input. This active low input
powers down the device to <2µA. For normal operation
tie this pin to VIN.
GND (Pins 5,7,8): Internal Function. Ground these pins.
6652fe
For more information www.linear.com/6652
9
LTC6652
Block Diagram
2
3
VIN
+
SHDN
VOUT
BANDGAP
6
–
4
GND
6652 BD
Applications Information
Bypass and Load Capacitors
The LTC6652 voltage references do not require an input
capacitor, but a 0.1µF capacitor located close to the part
improves power supply rejection.
The LTC6652 voltage references are stable with or without
a capacitive load. For applications where an output capacitor is beneficial, a value of 0.1µF to 10µF is recommended
depending on load conditions. The Typical Performance
Characteristics section includes a plot illustrating a region
of marginal stability. Either no or low value capacitors for
any load current are acceptable. For loads that sink current
or light loads that source current, a 0.1µF to 10µF capacitor
has stable operation. For heavier loads that source current
a 0.5µF to 10µF capacitor range is recommended.
VIN
3V
CIN
0.1µF
2, 3
LTC6652-2.5
4, 5, 7, 8
The transient response for a 0.5V step on VIN with and
without an output capacitor is shown in Figures 2 and 3,
respectively.
The LTC6652 references with an output of 2.5V and above
are guaranteed to source and sink 5mA. The 1.25V and
2.048V versions are guaranteed to source 5mA and sink
1mA. The test circuit for transient load step response is
shown in Figure 1. Figures 4 and 5 show a 5mA source
and sink load step response without a load capacitor,
respectively.
Start-Up
The start-up characteristic of the LTC6652 is shown in
Figures 8 and 9. Note that the turn-on time is affected by
the value of the output capacitor.
6
100Ω
COUT
1µF
VGEN
0.5V
6652 F01
Figure 1. Transient Load Test Circuit
6652fe
10
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LTC6652
Applications Information
VIN
3.5V
IOUT
3V
VOUT
500mV/DIV
5mA
0mA
VOUT
200mV/DIV
COUT = 0µF
500µs/DIV
COUT = 0µF
6652 F02
Figure 2. Transient Response Without Output Capacitor
VIN
250µs/DIV
6652 F05
Figure 5. LTC6652-2.5 Sinking
Current Without Output Capacitor
0mA
IOUT
–5mA
3.5V
3V
VOUT
500mV/DIV
VOUT
200mV/DIV
COUT = 1µF
500µs/DIV
6652 F03
COUT = 1µF
6652 F06
Figure 6. LTC6652-2.5 Sourcing Current
with Output Capacitor
Figure 3. Transient Response with 1µF Output Capacitor
0mA
IOUT
–5mA
250µs/DIV
IOUT
5mA
0mA
VOUT
50mV/DIV
VOUT
200mV/DIV
COUT = 0µF
250µs/DIV
Figure 4. LTC6652-2.5 Sourcing
Current Without Output Capacitor
6652 F04
COUT = 1µF
250µs/DIV
6652 F07
Figure 7. LTC6652-2.5 Sinking
Current with Output Capacitor
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11
LTC6652
Applications Information
2.8V ≤ VIN ≤ 13.2V
VIN
2V/DIV
C1
1µF
R1
20k
VIN
LTC6652-2.5
SHDN
TO µC
VOUT
1V/DIV
COUT = 0µF
100µs/DIV
VOUT
VOUT
GND
2N7002
6652 F10
C2
1µF
Figure 10. Open-Drain Shutdown Circuit
6652 F08
Figure 8. Start-Up Response without Output Capacitor
SHDN
1V/DIV
VIN
2V/DIV
VOUT
1V/DIV
VOUT
1V/DIV
ILOAD = 5mA
COUT = 1µF
100µs/DIV
6652 F09
1ms/DIV
6652 F11
Figure 11. Shutdown Response with 5mA Load
Figure 9. Start-Up Response with 1µF Output Capacitor
In Figure 8, ripple momentarily appears just after the
leading edge of powering on. This brief one time event is
caused by calibration circuitry during initialization. When
an output capacitor is used, the ripple is virtually undetectable as shown in Figure 9.
Shutdown Mode
Shutdown mode is enabled by tying SHDN low which
places the part in a low power state (i.e., <2µA). In shutdown mode, the output pin takes the value 20k • (rated
output voltage). For example, an LTC6652-2.5 will have
an output impedance of 20k • 2.5 = 50kΩ. For normal
operation, SHDN should be greater than or equal to 2.0V.
For use with a microcontroller, use a pull-up resistor to
VIN and an open-drain output driver as shown in Figure
10. The LTC6652’s response into and out of shutdown
mode is shown in Figure 11.
The trip thresholds on SHDN have some dependence on the
voltage applied to VIN as shown in the Typical Performance
Characteristics section. Be careful to avoid leaving SHDN
at a voltage between the thresholds as this will likely cause
an increase in supply current due to shoot-through current.
6652fe
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LTC6652
Applications Information
80
80
40
40
LTC6652-2.5 LS8 PACKAGE
4 TYPICAL PARTS
60 TA = 30°C
ppm
ppm
LTC6652-2.5 MS8 PACKAGE
3 TYPICAL PARTS
60 TA = 35°C
20
20
0
0
–20
–20
–40
0
300
900
600
HOURS
1200
–40
1500
6652 F12a
Figure 12a. MS8 Long-Term Drift
35
9
8
30
600
400
HOURS
800
1000
6652 F12b
25°C TO 125°C TO 25°C 25°C TO –40°C TO 25°C
7
25
NUMBER OF UNITS
NUMBER OF UNITS
200
Figure 12b. LS8 Long-Term Drift
25°C TO 125°C TO 25°C 25°C TO –40°C TO 25°C
20
15
10
6
5
4
3
2
5
0
–250
0
1
50
–150
–50
DISTRIBUTION (ppm)
0
–110 –80 –50 –20 0 20 50
DISTRIBUTION (ppm)
150
80
110
6652 F13b
6652 F13a
Figure 13a. MS8 Hysteresis Plot –40°C to 125°C
Figure 13b. LS8 Hysteresis Plot –40°C to 125°C
Long-Term Drift
Hysteresis
Long-term drift cannot be extrapolated from accelerated
high temperature testing. This erroneous technique gives
drift numbers that are wildly optimistic. The only way
long-term drift can be determined is to measure it over
the time interval of interest. The LTC6652 long-term drift
data was collected on more than 100 parts that were soldered into PC boards similar to a “real world” application.
The boards were then placed into a constant temperature
oven with TA = 35°C, their outputs were scanned regularly
and measured with an 8.5 digit DVM. Long-term drift is
shown below in Figure 12.
The hysteresis data shown in Figure 13 represents the
worst-case data collected on parts from –40°C to 125°C.
The output is capable of dissipating relatively high power,
i.e., for the LTC6652-2.5, PD = 10.7V • 5.5mA = 58.85mW.
The thermal resistance of the MS8 package is 200°C/W
and this dissipation causes a 11.8°C internal rise. This
could increase the junction temperature above 125°C and
may cause the output to shift due to thermal hysteresis.
6652fe
For more information www.linear.com/6652
13
LTC6652
Applications Information
PC Board Layout
The mechanical stress of soldering a surface mount voltage reference to a PC board can cause the output voltage
to shift and temperature coefficient to change. These two
changes are not correlated. For example, the voltage may
shift, but the temperature coefficient may not.
To reduce the effects of stress-related shifts, mount the
reference near the short edge of the PC board or in a
corner. In addition, slots can be cut into the board on two
sides of the device.
The capacitors should be mounted close to the package.
The GND and VOUT traces should be as short as possible
to minimize I • R drops. Excessive trace resistance directly
impacts load regulation.
IR Reflow Shift
The different expansion and contraction rates of the materials that make up the lead-free LTC6652 package cause the
output voltage to shift after undergoing IR reflow. Lead-free
reflow profiles reach over 250°C, considerably more than
their leaded counterparts. The lead-free IR reflow profile
used to experimentally measure output voltage shift in the
LTC6652-2.5 is shown in Figure 14. Similar results can be
300
380s
TP = 260°C
TL = 217°C
TS(MAX) = 200°C
225
TS = 190°C
RAMP
DOWN
tL
130s
RAMP TO
150°C
75
40s
120s
0
0
2
4
6
MINUTES
8
Power Dissipation
Power dissipation in the LTC6652 is dependent on VIN,
load current, and package. The LTC6652 package has
a thermal resistance, or θJA, of 200°C/W. A curve that
illustrates allowed power dissipation vs temperature for
this package is shown in Figure 16.
The power dissipation of the LTC6652-2.5V as a function
of input voltage is shown in Figure 17. The top curve
shows power dissipation with a 5mA load and the bottom
curve shows power dissipation with no load.
When operated within its specified limits of VIN = 13.2V
and sourcing 5mA, the LTC6652-2.5 consumes just under
60mW at room temperature. At 125°C the quiescent cur­
rent will be slightly higher and the power consumption
increases to just over 60mW. The power-derating curve
in Figure 16 shows the LTC6652-2.5 can safely dissipate
125mW at 125°C about half the maximum power con­
sumption of the package.
Humidity Sensitivity
tP
30s
T = 150°C
150
expected using a convection reflow oven. In our experiment,
the serialized parts were run through the reflow process
twice. The results indicate that the standard deviation of
the output voltage increases with a slight positive mean
shift of 0.003% as shown in Figure 15. While there can
be up to 0.016% of output voltage shift, the overall drift
of the LTC6652 after IR reflow does not vary significantly.
10
6652 F14
Plastic mould compounds absorb water. With changes
in relative humidity, plastic packaging materials change
the amount of pressure they apply to the die inside,
which can cause slight changes in the output of a voltage reference, usually on the order of 100ppm. The LS8
package is hermetic, so it is not affected by humidity, and
is therefore more stable in environments where humidity
may be a concern.
Figure 14. Lead-Free Reflow Profile
6652fe
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LTC6652
Applications Information
10
7
NUMBER OF UNITS
NUMBER OF UNITS
8
6
4
2
0
1X
3X
6
5
4
3
2
1
0
0.06
–0.1
–0.06 –0.02 0 0.02
0.1
OUTPUT VOLTAGE SHIFT DUE TO IR REFLOW (%)
0.002
0.010
0.018
–0.014 –0.006
OUTPUT VOLTAGE SHIFT DUE TO IR REFLOW (%)
6652 F15b
6652 F15a
Figure 15b. LS8 Output Voltage Shift Due to IR Reflow
0.7
0.06
0.6
0.05
0.5
TA = 25°C
0.04
POWER (W)
DISSIPATION (W)
Figure 15a. MS8 Output Voltage Shift Due to IR Reflow
0.4
0.3
5mA LOAD
0.03
0.02
0.2
0.1
0.01
0
0
0
20
40
60
80 100
TEMPERATURE (°C)
120
140
6652 F16
Figure 16. Maximum Recommended Dissipation for LTC6652
NO LOAD
2
4
6
8
VIN (V)
10
12
14
6652 F17
Figure 17. Typical Power Dissipation of the LTC6652
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For more information www.linear.com/6652
15
LTC6652
Typical Applications
Extended Supply Range Reference
Extended Supply Range Reference
4V TO 30V
R1
330k
R1
VIN
BZX84C18
LTC6652-2.5 VOUT
SHDN
C1
0.1µF
6V TO 160V
R2
4.7k
ON SEMI
MMBT5551
VOUT
VIN
GND
C2
OPTIONAL
6652 TA02
GND
6652 TA03
VCC ≥ 1.75V
V+ ≥ (VOUT + 1.8V)
C1
1µF
2, 3
R1
220Ω
VIN
LTC6652-2.5
2N2905
SHDN
LTC6652-2.5 VOUT
500Ω
VEE ≤ –3V
C2
OPTIONAL
Boosted Output Current
Negative Rail Circuit
4, 5, 7, 8
VOUT
LTC6652-2.5 VOUT
BZX84C18
C1
0.1µF
C1
0.1µF
6
SHDN
VOUT
–2.5V
1µF
VOUT
C2
1µF
GND
6652 TA04
6652 TA06
6652fe
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LTC6652
Package Description
Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings.
MS8 Package
8-Lead Plastic MSOP
(Reference LTC DWG # 05-08-1660 Rev F)
3.00 ± 0.102
(.118 ± .004)
(NOTE 3)
0.889 ± 0.127
(.035 ± .005)
5.23
(.206)
MIN
0.254
(.010)
7 6 5
0.52
(.0205)
REF
3.00 ± 0.102
(.118 ± .004)
(NOTE 4)
4.90 ± 0.152
(.193 ± .006)
DETAIL “A”
0° – 6° TYP
GAUGE PLANE
3.20 – 3.45
(.126 – .136)
0.53 ± 0.152
(.021 ± .006)
DETAIL “A”
0.42 ± 0.038
(.0165 ± .0015)
TYP
8
0.65
(.0256)
BSC
RECOMMENDED SOLDER PAD LAYOUT
1
1.10
(.043)
MAX
2 3
4
0.86
(.034)
REF
0.18
(.007)
SEATING
PLANE
NOTE:
1. DIMENSIONS IN MILLIMETER/(INCH)
2. DRAWING NOT TO SCALE
3. DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS.
MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.152mm (.006") PER SIDE
4. DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS.
INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.152mm (.006") PER SIDE
5. LEAD COPLANARITY (BOTTOM OF LEADS AFTER FORMING) SHALL BE 0.102mm (.004") MAX
0.22 – 0.38
(.009 – .015)
TYP
0.65
(.0256)
BSC
0.1016 ± 0.0508
(.004 ± .002)
MSOP (MS8) 0307 REV F
6652fe
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17
LTC6652
Package Description
Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings.
LS8Package
Package
LS8
8-Leadless
8-Pin
LeadlessChip
ChipCarrier
Carrier(5mm
(5mm× ×5mm)
5mm)
(ReferenceLTC
LTCDWG
DWG##05-08-1852
05-08-1852 Rev Ø)
(Reference
8
2.50 ±0.15
PACKAGE OUTLINE
7
1
6
2
2.54 ±0.15
5
3
1.50 ±0.15
4
0.70 ±0.05
5.00 SQ ±0.15
5.80 SQ ±0.15
APPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED
5.00 SQ ±0.15
1.45 ±0.10
0.95 ±0.10
4.20 SQ ±0.10
8
1
PIN 1
TOP MARK
(SEE NOTE 5)
R0.20 REF
8
2.00 REF
7
2
6
3
5
1
7
4.20 ±0.10
R0.20 REF
6
2
2.54 ±0.15
5
3
1.00 TYP
4
LS8 0609 REV Ø
4
0.70 TYP
NOTE:
1. ALL DIMENSIONS ARE IN MILLIMETERS
2. DRAWING NOT TO SCALE
3. DIMENSIONS PACKAGE DO NOT INCLUDE PLATING BURRS
PLATING BURRS, IF PRESENT, SHALL NOT EXCEED 0.30mm ON ANY SIDE
4. PLATING—ELECTO NICKEL MIN 1.25UM, ELECTRO GOLD MIN 0.30UM
5. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE
TOP AND BOTTOM OF PACKAGE
0.10 TYP
0.64 TYP
6652fe
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LTC6652
Revision History
(Revision history begins at Rev C)
REV
DATE
DESCRIPTION
C
11/09
Change to Typical Performance Characteristics.
PAGE NUMBER
D
8/12
Change to Typical Application.
Addition of 5mm × 5mm Hermetic LS8 Package.
Update to Electrical Characteristics to Include LS8 Package.
Addition of Long Term Drift, Hysteresis, IR Drift Plots for LS8 Package.
E
1/13
6
14
1, 2, 3, 12, 18
4
13, 15
Addition of Humidity Sensitivity Information.
14
Correction to pin labeling of LS8 Package
2
6652fe
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 representaForofmore
information
www.linear.com/6652
tion that the interconnection
its circuits
as described
herein will not infringe on existing patent rights.
19
LTC6652
Typical Application
Improved Reference Supply Rejection in a Data Converter Application
LTC1657
DATA
VCC
16
D/A
GND
VDAC
REF
VIN
R1
50k
VOUT
LTC6652
REF
SHDN
C1
0.1µF
C2
10µF
GND
COUT
1µF
V1
V2
V3
V4
LTC1605
A/D
16
DOUT
GND
6652 TA05
Related Parts
PART NUMBER
DESCRIPTION
COMMENTS
LT1460
Micropower Series References
0.075% Max, 10ppm/°C Max, 20mA Output Current
LT1461
Micropower Series Low Dropout
0.04% Max, 3ppm/°C Max, 50mA Output Current
LT1790
Micropower Precision Series References
0.05% Max, 10ppm/°C Max, 60µA Supply, SOT23 Package
LT6650
Micropower Reference with Buffer Amplifier
0.5% Max, 5.6µA Supply, SOT23 Package
LT6660
Tiny Micropower Series Reference
0.2% Max, 20ppm/°C Max, 20mA Output Current, 2mm × 2mm DFN
LT6654
Precision Wide Supply High Output Drive Low Noise Reference
0.05% Max, 10ppm/°C Max, 10mA Output Current,
1.6ppmP-P Noise in SOT23 and LS8 Packages
6652fe
20 Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
For more information www.linear.com/6652
(408) 432-1900 ● FAX: (408) 434-0507
●
www.linear.com/6652
LT 0113 REV E • PRINTED IN USA
 LINEAR TECHNOLOGY CORPORATION 2007
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