LT6660 - Tiny Micropower Precision Series References in 2mm x 2mm DFN

LT6660
Tiny Micropower
Precision Series References
in 2mm × 2mm DFN
DESCRIPTIO
FEATURES
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No Output Capacitor Required
Low Drift: 20ppm/°C Max
High Accuracy: 0.2% Max
Low Supply Current
20mA Output Current Guaranteed
Reverse-Battery Protection
Low IR Reflow Induced Stress: 0.02% Typ
Voltage Options: 2.5V, 3V, 3.3V, 5V and 10V
Space-Saving Alternative to the LT1460
3-Lead 2mm × 2mm × 0.75mm DFN Package
The LT®6660 is a family of micropower series references
that combine high accuracy and low drift with low power
dissipation and extremely small package size. These series references use curvature compensation to obtain
low temperature coefficient, and laser trimmed precision
thin-film resistors to achieve high output accuracy. The
LT6660 will supply up to 20mA with excellent line regulation characteristics, making it ideal for precision regulator
applications.
The LT6660 family of series references provide supply
current and power dissipation advantages over shunt
references that must idle the entire load current to operate. Additionally, the LT6660 does not require an output
compensation capacitor. This feature is important in
applications where PC board space is a premium, fast settling is demanded, or total capacitance must be kept to a
minimum, as in intrinsic safety applications. Reverse-battery protection keeps these references from conducting
reverse current.
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APPLICATIO S
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Handheld Instruments
Precision Regulators
A/D and D/A Converters
Power Supplies
Hard Disk Drives
Sensor Modules
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
TYPICAL APPLICATIO
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LT6660H VOUT Shift Due to IR Reflow
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28
Basic Connection
LT6660
VOUT + 0.9V ≤ VIN ≤ 20V
IN
C1
0.1µF
OUT
VOUT
GND
6660 TA01
DISTRIBUTION (%)
24
20
16
12
8
4
0
–0.09
–0.05 –0.01 0.01
0.05
CHANGE IN VOUT (%)
0.09
6660 TA01b
6660fa
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LT6660
AXI U RATI GS
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ABSOLUTE
(Note 1)
Input Voltage.............................................................30V
Reverse Voltage ......................................................–15V
Output Short-Circuit Duration, TA = 25°C ................5 sec
Specified Temperature Range ...................... 0°C to 70°C
Operating Temperature Range
(Note 2) ............................................... –40°C to 85°C
Storage Temperature Range (Note 3)..... –65°C to 150°C
Lead Temperature (Soldering, 10 sec) .................. 300°C
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PACKAGE/ORDER I FOR ATIO
ORDER PART NUMBER
DFN PART MARKING*
LT6660HCDC-2.5
LT6660JCDC-2.5
LT6660KCDC-2.5
LT6660HCDC-3
LT6660JCDC-3
LT6660KCDC-3
LT6660HCDC-3.3
LT6660JCDC-3.3
LT6660KCDC-3.3
LT6660HCDC-5
LT6660JCDC-5
LT6660KCDC-5
LT6660HCDC-10
LT6660JCDC-10
LT6660KCDC-10
LBXN
LBXN
LBXN
LBYV
LBYV
LBYV
LBYW
LBYW
LBYW
LBYT
LBYT
LBYT
LBYX
LBYX
LBYX
TOP VIEW
1
2
3
OUT
GND
IN
4
DC PACKAGE
3-LEAD (2mm × 2mm) PLASTIC DFN
TJMAX = 125°C, θJA = 102°C/W
EXPOSED PAD IS GND, MUST BE SOLDERED TO PCB
Order Options Tape and Reel: Add #TR
Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF
Lead Free Part Marking: http://www.linear.com/leadfree/
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
AVAILABLE OPTIONS
OUTPUT VOLTAGE
(V)
SPECIFIED TEMPERATURE
RANGE
ACCURACY
(%)
TEMPERATURE
COEFFICIENT (ppm/°C)
PART ORDER
NUMBER
2.5
2.5
2.5
0°C to 70°C
0°C to 70°C
0°C to 70°C
0.2
0.4
0.5
20
20
50
LT6660HCDC-2.5
LT6660JCDC-2.5
LT6660KCDC-2.5
3
3
3
0°C to 70°C
0°C to 70°C
0°C to 70°C
0.2
0.4
0.5
20
20
50
LT6660HCDC-3
LT6660JCDC-3
LT6660KCDC-3
3.3
3.3
3.3
0°C to 70°C
0°C to 70°C
0°C to 70°C
0.2
0.4
0.5
20
20
50
LT6660HCDC-3.3
LT6660JCDC-3.3
LT6660KCDC-3.3
6660fa
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LT6660
AVAILABLE OPTIONS
OUTPUT VOLTAGE
(V)
SPECIFIED TEMPERATURE
RANGE
ACCURACY
(%)
TEMPERATURE
COEFFICIENT (ppm/°C)
PART ORDER
NUMBER
5
5
5
0°C to 70°C
0°C to 70°C
0°C to 70°C
0.2
0.4
0.5
20
20
50
LT6660HCDC-5
LT6660JCDC-5
LT6660KCDC-5
10
10
10
0°C to 70°C
0°C to 70°C
0°C to 70°C
0.2
0.4
0.5
20
20
50
LT6660HCDC-10
LT6660JCDC-10
LT6660KCDC-10
ELECTRICAL CHARACTERISTICS
The ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VIN = VOUT + 2.5V, IOUT = 0 unless otherwise specified.
PARAMETER
Output Voltage Tolerance
Output Voltage Temperature Coefficient (Note 4)
Line Regulation
CONDITIONS
LT6660HCDC
LT6660JCDC
LT6660KCDC
LT6660HCDC
LT6660JCDC
LT6660KCDC
VOUT + 0.9V ≤ VIN ≤ VOUT + 2.5V
VOUT + 2.5V ≤ VIN ≤ 20V
Load Regulation Sourcing (Note 5)
IOUT = 100µA
IOUT = 10mA
IOUT = 20mA
Thermal Regulation (Note 6)
Dropout Voltage (Note 7)
ΔP = 200mW
VIN – VOUT, ΔVOUT ≤ 0.2%, IOUT = 0
VIN – VOUT, ΔVOUT ≤ 0.2%, IOUT = 10mA
Output Current
Reverse Leakage
Short VOUT to GND
VIN = –15V
Output Voltage Noise (Note 8)
0.1Hz ≤ f ≤ 10Hz
10Hz ≤ f ≤ 1kHz
Long-Term Stability of Output Voltage (Note 9)
Hysteresis (Note 10)
Supply Current
ΔT = 0°C to 70°C
ΔT = –40°C to 85°C
MIN
–0.2
–0.4
–0.5
MAX
0.2
0.4
0.5
20
20
50
UNITS
%
%
%
ppm/°C
ppm/°C
ppm/°C
●
800
1000
100
130
3000
4000
200
300
70
100
10
0.9
ppm/V
ppm/V
ppm/V
ppm/V
ppm/mA
ppm/mA
ppm/mA
ppm/mA
ppm/mA
ppm/mA
ppm/mW
V
●
1.3
1.4
●
●
●
TYP
10
10
25
150
●
50
●
1000
●
50
●
20
●
2.5
●
40
0.5
●
●
4
4
100
50
250
LT6660-2.5
115
●
LT6660-3
145
●
LT6660-3.3
145
●
LT6660-5
160
●
LT6660-10
215
●
10
V
V
mA
µA
ppm (P-P)
ppm (RMS)
ppm/√kHr
ppm
ppm
145
175
180
220
180
220
200
240
270
350
µA
µA
µA
µA
µA
µA
µA
µA
µA
µA
6660fa
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LT6660
ELECTRICAL CHARACTERISTICS
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 LT6660 is guaranteed functional over the operating
temperature range of –40°C to 85°C.
Note 3: If the parts are stored outside of the specified temperature range,
the output may shift due to hysteresis.
Note 4: Temperature coefficient is measured by dividing the change in
output voltage by the specified temperature range. Incremental slope is
also measured at 25°C.
Note 5: 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 6: Thermal regulation is caused by die temperature gradients created
by load current or input voltage changes. This effect must be added to
normal line or load regulation. This parameter is not 100% tested.
Note 7: Excludes load regulation errors.
Note 8: Peak-to-peak noise is measured with a single pole highpass filter
at 0.1Hz and 2-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 sec. RMS noise is measured with a single pole highpass filter at
10Hz and a 2-pole lowpass filter at 1kHz. The resulting output is full wave
rectified and then integrated for a fixed period, making the final reading an
average as opposed to RMS. A correction factor of 1.1 is used to convert
from average to RMS and a second correction of 0.88 is used to correct
for the nonideal bandpass of the filters.
Note 9: 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 10: 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 70°C or 0°C 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) hysteresis is not a problem.
TYPICAL PERFOR A CE CHARACTERISTICS
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Characteristic curves are similar for all voltage
options of the LT6660. Curves from the LT6660-2.5 and the LT6660-10 represent the extremes of the voltage options. Characteristic
curves for other output voltages fall between these curves, and can be estimated based on their voltage output.
2.5V Minimum Input-Output
Voltage Differential
2.5V Load Regulation, Sourcing
25°C
– 55°C
1
0
0.5
1.0
1.5
2.0
INPUT-OUTPUT VOLTAGE (V)
2.5
6660 G01
– 0.5
– 1.0
– 1.5
OUTPUT VOLTAGE CHANGE (mV)
125°C
10
0.1
2.5V Load Regulation, Sinking
120
0
OUTPUT VOLTAGE CHANGE (mV)
OUTPUT CURRENT (mA)
100
– 55°C
– 2.0
25°C
– 2.5
– 3.0
125°C
– 3.5
– 4.0
0.1
1
10
OUTPUT CURRENT (mA)
100
6660 G02
100
80
60
25°C
40
125°C
– 55°C
20
0
0
1
2
3
4
OUTPUT CURRENT (mA)
5
6660 G03
6660fa
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LT6660
TYPICAL PERFOR A CE CHARACTERISTICS
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Characteristic curves are similar for all voltage
options of the LT6660. Curves from the LT6660-2.5 and the LT6660-10 represent the extremes of the voltage options. Characteristic
curves for other output voltages fall between these curves, and can be estimated based on their voltage output.
2.5V Output Voltage
Temperature Drift
THREE TYPICAL PARTS
2.502
2.501
2.500
2.499
2.501
25°C
200
SUPPLY CURRENT (µA)
OUTPUT VOLTAGE (V)
2.5V Line Regulation
2.502
250
125°C
– 55°C
150
100
50
2.498
2.497
–50 –25
50
25
75
0
TEMPERATURE (°C)
100
0
125
– 55°C
2.499
2.498
125°C
2.497
2.496
5
0
10
2.494
15
20
0
2
4
INPUT VOLTAGE (V)
6 8 10 12 14 16 18 20
INPUT VOLTAGE (V)
6660 G06
6660 G05
2.5V Power Supply Rejection
Ratio vs Frequency
2.5V Output Impedance
vs Frequency
2.5V Transient Response
1000
80
CL = 0µF
OUTPUT IMPEDANCE (Ω)
60
50
40
30
20
20
LOAD CURRENT (mA)
70
CL = 0.1µF
100
10
CL = 1µF
10
1
0.1
1
200µs/DIV
10
6660 G09
CLOAD = 0µF
10
100
FREQUENCY (kHz)
1000
0.1
0.01
0.1
1
10
FREQUENCY (kHz)
100
6660 G07
1000
6660 G08
2.5V Output Voltage
Noise Spectrum
2.5V Output Noise 0.1Hz to 10Hz
1000
OUTPUT NOISE (20µV/DIV)
1
NOISE VOLTAGE (nV/√Hz)
POWER SUPPLY REJECTION RATIO (dB)
25°C
2.500
2.495
6660 G04
0
0.1
OUTPUT VOLTAGE (V)
2.503
2.5V Supply Current
vs Input Voltage
100
10
100
1k
10k
FREQUENCY (Hz)
100k
6660 G10
TIME (2 SEC/DIV)
6660 G11
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LT6660
TYPICAL PERFOR A CE CHARACTERISTICS
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Characteristic curves are similar for all voltage
options of the LT6660. Curves from the LT6660-2.5 and the LT6660-10 represent the extremes of the voltage options. Characteristic
curves for other output voltages fall between these curves, and can be estimated based on their voltage output.
10V Minimum Input-Output
Voltage Differential
10V Load Regulation, Sourcing
25°C
– 55°C
30
25
20
15
10
5
– 55°C
0
–5
0
0.5
1.0
1.5
2.0
INPUT-OUTPUT VOLTAGE (V)
125°C
–10
0.1
2.5
1
10
OUTPUT CURRENT (mA)
10V Output Voltage
Temperature Drift
10.004
100
–55°C
50
SUPPLY CURRENT (µA)
9.998
9.996
9.994
9.992
9.990
9.988
9.986
100
125
6660 G15
3
4
2
OUTPUT CURRENT (mA)
6660 G14
10.005
25°C
250
125°C
200
– 55°C
150
100
0
5
10V Line Regulation
25°C
10.000
– 55°C
9.995
125°C
9.990
9.985
50
9.984
1
0
10.010
300
10.000
OUTPUT VOLTAGE (V)
25°C
0
100
350
10.002
50
25
0
75
TEMPERATURE (°C)
150
10V Supply Current
vs Input Voltage
THREE TYPICAL PARTS
9.982
– 50 – 25
125°C
6660 G13
6660 G12
10.006
200
25°C
OUTPUT VOLTAGE (V)
1
250
OUTPUT VOLTAGE CHANGE (mV)
125°C
10
0.1
10V Load Regulation, Sinking
35
OUTPUT VOLTAGE CHANGE (mV)
OUTPUT CURRENT (mA)
100
0
2
4
6 8 10 12 14 16 18 20
INPUT VOLTAGE (V)
6660 G16
9.980
6
8
14
12
16
10
INPUT VOLTAGE (V)
18
20
6660 G17
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LT6660
TYPICAL PERFOR A CE CHARACTERISTICS
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Characteristic curves are similar for all voltage
options of the LT6660. Curves from the LT6660-2.5 and the LT6660-10 represent the extremes of the voltage options. Characteristic
curves for other output voltages fall between these curves, and can be estimated based on their voltage output.
10V Power Supply Rejection
Ratio vs Frequency
10V Output Impedance
vs Frequency
10V Transient Response
1000
90
20
OUTPUT IMPEDANCE (Ω)
80
70
60
50
40
30
20
100
LOAD CURRENT (mA)
CL = 0µF
CL = 0.1µF
10
CL = 1µF
1
1
200µs/DIV
1
10
100
FREQUENCY (kHz)
1000
6660 G20
CLOAD = 0µF
0.1
0.01
0.1
1
10
FREQUENCY (kHz)
100
6660 G18
1000
6660 G19
10V Output Voltage
Noise Spectrum
10V Output Noise 0.1Hz to 10Hz
10
OUTPUT NOISE (20µV/DIV)
0
0.1
10
0.1
10
NOISE VOLTAGE (µV/√Hz)
POWER SUPPLY REJECTION RATIO (dB)
100
1
0.1
0.01
0.1
1
10
FREQUENCY (kHz)
100
6660 G21
TIME (2 SEC/DIV)
6660 G22
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LT6660
APPLICATIO S I FOR ATIO
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Longer Battery Life
Series references have a large advantage over older shunt
style references. Shunt references require a resistor
from the power supply to operate. This resistor must be
chosen to supply the maximum current that can ever be
demanded by the circuit being regulated. When the circuit
being controlled is not operating at this maximum current,
the shunt reference must always sink this current, resulting
in high dissipation and short battery life.
The LT6660 series references do not require a current
setting resistor and can operate with any supply voltage
from VOUT + 0.9V to 20V. When the circuitry being regulated does not demand current, the LT6660s reduce their
dissipation and battery life is extended. If the references
are not delivering load current, they dissipate only several
mW, yet the same connection can deliver 20mA of load
current when demanded.
Capacitive Loads
The LT6660 family of references are designed to be stable
with a large range of capacitive loads. With no capacitive
load, these references are ideal for fast settling or applications where PC board space is a premium. The test circuit
shown in Figure 1 is used to measure the response time
and stability of various load currents and load capacitors.
This circuit is set for the 2.5V option. For other voltage
options, the input voltage must be scaled up and the
output voltage generator offset voltage must be adjusted.
The 1V step from 2.5V to 1.5V produces a current step of
10mA or 1mA for RL = 100Ω or RL = 1k. Figure 2 shows
the response of the reference to these 1mA and 10mA
load steps with no load capacitance, and Figure 3 shows
a 1mA and 10mA load step with a 0.1µF output capacitor. Figure 4 shows the response to a 1mA load step with
CL = 1µF and 4.7µF.
VIN = 2.5V
CIN
0.1µF
LT6660-2.5
VGEN
CL
2.5V
1.5V
VOUT
1mA
VOUT
10mA
1µs/DIV
6660 F02
Figure 2. CL = 0µF
2.5V
VGEN
1.5V
VOUT
1mA
VOUT
10mA
100µs/DIV
6660 F03
Figure 3. CL = 0.1µF
2.5V
VGEN
1.5V
VOUT
1µF
VOUT
4.7µF
100µs/DIV
6660 F04
Figure 4. IOUT = 1mA
RL
VOUT
VGEN
2.5V
1.5V
6660 F01
Figure 1. Response Time Test Circuit
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LT6660
APPLICATIO S I FOR ATIO
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Table 1. Maximum Output Capacitance
VOLTAGE
OPTION
IOUT = 100µA
IOUT = 1mA
IOUT = 10mA
IOUT = 20mA
2.5V
>10µF
>10µF
2µF
0.68µF
3V
>10µF
>10µF
2µF
0.68µF
3.3V
>10µF
>10µF
1µF
0.68µF
5V
>10µF
>10µF
1µF
0.68µF
10V
>10µF
1µF
0.15µF
0.1µF
Long-Term Drift
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 LT6660 long-term
drift data was taken on over 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 = 30°C, their outputs were scanned regularly and
measured with an 8.5 digit DVM. Figure 5 shows typical
long-term drift of the LT6660s.
Hysteresis
Hysteresis data shown in Figure 6 and Figure 7 represents
the worst-case data taken on parts from 0°C to 70°C and
from –40°C to 85°C. The output is capable of dissipating relatively high power, i.e., for the LT6660-2.5, PD =
17.5V • 20mA = 350mW. The thermal resistance of the
DFN package is 102°C/W and this dissipation causes a
36°C internal rise. This elevated temperature may cause
the output to shift due to thermal hysteresis. For highest
performance in precision applications, do not let the
LT6660’s junction temperature exceed 85°C.
Input Capacitance
It is recommended that a 0.1µF or larger capacitor be
added to the input pin of the LT6660. This can help with
stability when large load currents are demanded.
18
16
WORST-CASE HYSTERESIS
ON 40 UNITS
14
NUMBER OF UNITS
W
Table 1 gives the maximum output capacitance for various load currents and output voltages to avoid instability.
Load capacitors with low ESR (effective series resistance)
cause more ringing than capacitors with higher ESR such
as polarized aluminum or tantalum capacitors.
12
10
8
70°C TO 25°C
0°C TO 25°C
6
4
2
0
150
–240 –200 –160 –120 – 80 –40 0
40
HYSTERESIS (ppm)
80
120 160 200 240
6660 F06
Figure 6. 0°C to 70°C Hysteresis
100
9
8
0
7
– 50
–100
–150
0 100 200 300 400 500 600 700 800 900 1000
HOURS
6660 F05
Figure 5. Typical Long-Term Drift
NUMBER OF UNITS
ppm
50
6
WORST-CASE HYSTERESIS
ON 34 UNITS
85°C TO 25°C
–40°C TO 25°C
5
4
3
2
1
0
–600 –500 –400 –300 –200 –100 0 100 200 300 400 500 600
HYSTERESIS (ppm)
6660 F07
Figure 7. – 40°C to 85°C Hysteresis
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LT6660
APPLICATIO S I FOR ATIO
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Output Accuracy
Like all references, either series or shunt, the error budget
of the LT6660s is made up of primarily three components:
initial accuracy, temperature coefficient and load regulation.
Line regulation is neglected because it typically contributes
only 150ppm/V. The LT6660s typically shift 0.02% when
soldered into a PCB, so this is also neglected. The output
errors are calculated as follows for a 100µA load and 0°C
to 70°C temperature range:
Total worst-case output error is:
0.2% + 0.04% + 0.14% = 0.380%
Table 2 gives the worst-case accuracy for LT6660HC,
LT6660JC and LT6660KC from 0°C to 70°C, and shows
that if the LT6660HC is used as a reference instead of a
regulator, it is capable of 8 bits of absolute accuracy over
temperature without a system calibration.
Table 2. Worst-Case Output Accuracy over Temperature
IOUT
LT6660HCDC
LT6660JCDC
LT6660KCDC
Initial Accuracy = 0.2%
0µA
0.340%
0.540%
0.850%
100µA
0.380%
0.580%
0.890%
For IOUT = 100µA
10mA
0.640%
0.840%
1.15%
20mA
0.540%
0.740%
1.05%
LT6660HCDC
ΔVOUT = (4000ppm/mA)(0.1mA) = 0.04%
For Temperature 0°C to 70°C the maximum ΔT = 70°C
ΔVOUT = (20ppm/°C)(70°C) = 0.14%
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LT6660
PACKAGE DESCRIPTIO
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DC Package
3-Lead Plastic DFN (2mm × 2mm)
(Reference LTC DWG # 05-08-1717 Rev Ø)
1.35 ±0.05
(2 SIDES)
1.00 ±0.05
1.30 ±0.05 (2 SIDES)
2.00 ±0.05
PACKAGE
OUTLINE
0.25 ± 0.05
0.50 BSC
RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS
1.35 ± 0.05
(2 SIDES)
2.00 ±0.10
(4 SIDES)
PIN 1 BAR
TOP MARK
(SEE NOTE 6)
1.00 ± 0.05
(2 SIDES)
0.40 ±0.05
0.200 REF
0.75 ±0.05
R = 0.05
TYP
0.70 ±0.05
PIN 1 NOTCH
R = 0.20 OR
0.25 × 45°
CHAMFER
3
R = 0.115 TYP
1
0.25 ± 0.05
0.50 BSC
BOTTOM VIEW—EXPOSED PAD
(DC3) DFN 1205 REV Ø
0.00 – 0.05
NOTE:
1. DRAWING TO BE MADE A JEDEC PACKAGE OUTLINE M0-229 VARIATION OF (W-TBD)
2. DRAWING NOT TO SCALE
3. ALL DIMENSIONS ARE IN MILLIMETERS
4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE
MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE
5. EXPOSED PAD SHALL BE SOLDER PLATED
6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE
TOP AND BOTTOM OF PACKAGE
6660fa
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 representation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
11
LT6660
TYPICAL APPLICATIO
U
Handling Higher Load Currents
V+
+
40mA
3
47µF
IN
R1*
LT6660
OUT
1
10mA
VOUT
GND
2
RL
TYPICAL LOAD
CURRENT = 50mA
*SELECT R1 TO DELIVER 80% OF TYPICAL LOAD CURRENT.
LT6660 WILL THEN SOURCE AS NECESSARY TO MAINTAIN
PROPER OUTPUT. DO NOT REMOVE LOAD AS OUTPUT WILL
BE DRIVEN UNREGULATED HIGH. LINE REGULATION IS
DEGRADED IN THIS APPLICATION
Boosted Output Current with No Current Limit
V + ≥ (VOUT + 1.8V)
+
R1
220Ω
R1 =
V + – VOUT
40mA
6660 TA02
Boosted Output Current with Current Limit
V+ ≥ VOUT + 2.8V
D1*
LED
47µF
+
R1
220Ω
8.2Ω
2N2905
3
2N2905
3
IN
47µF
IN
LT6660
OUT
1
GND
+
2
2µF
SOLID
TANT
LT6660
VOUT
100mA
OUT
1
GND
2
6660 TA03
+
2µF
SOLID
TANT
VOUT
100mA
* GLOWS IN CURRENT LIMIT,
DO NOT OMIT
6660 TA04
RELATED PARTS
PART NUMBER
DESCRIPTION
COMMENTS
LT1019
Precision Bandgap Reference
0.05% Max, 5ppm/°C Max
LT1027
Precision 5V Reference
0.02%, 2ppm/°C Max
LT1236
Precision Low Noise Reference
0.05% Max, 5ppm/°C Max, SO Package
LT1460
Micropower Series References
0.075% Max, 10ppm/°C Max, 20mA Output Current
LT1461
Micropower Precision Low Dropout
0.04% Max, 3ppm/°C Max, 50mA Output Current
LT1634
Micropower Precision Shunt Reference 1.25V, 2.5V Output
0.05%, 25ppm/°C Max
LT1790
Micropower Precision Series References
0.05% Max, 10ppm/°C Max, 60µA Supply, SOT23 Package
LTC 1798
Micropower Low Dropout Reference, Fixed or Adjustable
0.15% Max, 40ppm/°C, 6.5µA Max Supply Current
®
6660fa
12 Linear Technology Corporation
LT 0406 REV A PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507
●
www.linear.com
 LINEAR TECHNOLOGY CORPORATION 2006