LINER LT1965EDD-1.8-TRPBF 1.1a, low noise, low dropout linear regulator Datasheet

LT1965 Series
1.1A, Low Noise,
Low Dropout Linear Regulator
FEATURES
DESCRIPTION
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The LT®1965 series are low noise, low dropout linear regulators. The devices supply 1.1A of output current with a
310mV typical dropout voltage. Operating quiescent current
is 500μA for the adjustable version, reducing to <1μA in
shutdown. Quiescent current is well controlled; it does not
rise in dropout as with many other regulators. The LT1965
regulators have very low output noise which makes them
ideal for sensitive RF and DSP supply applications.
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Output Current: 1.1A
Dropout Voltage: 310mV
Low Noise: 40μVRMS (10Hz to 100kHz)
500μA Quiescent Current (Adjustable Version)
Wide Input Voltage Range: 1.8V to 20V
No Protection Diodes Needed
Controlled Quiescent Current in Dropout
Adjustable Output from 1.20V to 19.5V
Fixed Output Voltages: 1.5V, 1.8V, 2.5V, 3.3V
< 1μA Quiescent Current in Shutdown
Stable with 10μF Output Capacitor
Stable with Ceramic, Tantalum or Aluminum
Electrolytic Capacitors
Reverse Battery Protection
No Reverse Current
Current Limit with Foldback Protection
Thermal Limiting
5-Lead TO-220, DD-PAK, Thermally Enhanced 8-Lead
MSOP and 8-Lead 3mm × 3mm DFN Packages
APPLICATIONS
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Output voltage ranges from 1.20V to 19.5V. The LT1965
regulators are stable with output capacitors as low as
10μF. Internal protection circuitry includes reverse battery
protection, current limiting with foldback, thermal limiting
and reverse current protection. The LT1965 series are
available in ﬁxed output voltages of 1.5V, 1.8V, 2.5V, 3.3V,
and as an adjustable device with a 1.20V reference voltage.
The package offerings include the 5-lead TO-220, 5-lead
DD-PAK as well as the thermally enhanced 8-lead MSOP
and low-proﬁle (0.75mm) 8-lead 3mm × 3mm DFN.
L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
Logic Power Supplies
Post Regulator for Switching Supplies
Low Noise Instrumentation
TYPICAL APPLICATION
Dropout Voltage
3.3V to 2.5V Regulator
IN
+
10μF*
OUT
LT1965-2.5
SHDN
2.5V
1.1A
+
10μF*
SENSE
GND
1965 TA01
*CERAMIC, TANTALUM OR
ALUMINUM ELECTROLYTIC
TJ = 25°C
350
DROPOUT VOLTAGE (mV)
VIN > 3V
TO 20V
400
300
250
200
150
100
50
0
0
0.2
0.6
0.8
0.4
OUTPUT CURRENT (A)
1
1.2
1965 TA01b
1965fa
1
LT1965 Series
ABSOLUTE MAXIMUM RATINGS
(Note 1)
IN Pin Voltage .........................................................±22V
OUT Pin Voltage ......................................................±22V
Input to Output Differential Voltage (Note 2) ......... ±22V
SENSE Pin Voltage ..................................................±22V
ADJ Pin Voltage ........................................................±9V
SHDN Pin Voltage ...................................................±22V
Output Short-Circuit Duration .......................... Indeﬁnite
Operating Junction Temperature Range (E, I Grade)
(Notes 2, 13)......................................–40°C to 125°C
Storage Temperature Range...................–65°C to 150°C
Lead Temperature (Soldering, 10 sec)
(Only for MSOP, TO-220, DD-PAK Packages) .... 300°C
PIN CONFIGURATION
TOP VIEW
OUT 1
8
IN
OUT 2
7
IN
6
SHDN
5
GND
SENSE/ADJ* 3
9
GND 4
TOP VIEW
OUT
OUT
SENSE/ADJ*
GND
1
2
3
4
8
7
6
5
9
IN
IN
SHDN
GND
MS8E PACKAGE
8-LEAD PLASTIC MSOP
DD PACKAGE
8-LEAD (3mm × 3mm) PLASTIC DFN
TJMAX = 125°C, θJA = 65°C/W, θJC = 3°C/W
EXPOSED PAD (PIN 9) IS GND, MUST BE SOLDERED TO PCB
*PIN 3 = SENSE FOR LT1965-1.5/LT1965-1.8/LT1965-2.5/LT1965-3.3
*PIN 3 = ADJ FOR LT1965
TJMAX = 125°C, θJA = 60°C/W, θJC = 10°C/W
EXPOSED PAD (PIN 9) IS GND, MUST BE SOLDERED TO PCB
*PIN 3 = SENSE FOR LT1965-1.5/LT1965-1.8/LT1965-2.5/LT1965-3.3
*PIN 3 = ADJ FOR LT1965
FRONT VIEW
TAB IS
GND
FRONT VIEW
5
SENSE/ADJ*
5
SENSE/ADJ*
4
OUT
4
OUT
3
GND
3
GND
2
IN
2
IN
1
SHDN
1
SHDN
TAB IS
GND
Q PACKAGE
5-LEAD PLASTIC DD-PAK
T PACKAGE
5-LEAD PLASTIC TO-220
TJMAX = 125°C, θJA = 30°C/W, θJC = 3°C/W
*PIN 5 = SENSE FOR LT1965-1.5/LT1965-1.8/LT1965-2.5/LT1965-3.3
*PIN 5 = ADJ FOR LT1965
TJMAX = 125°C, θJA = 50°C/W, θJC = 3°C/W
*PIN 5 = SENSE FOR LT1965-1.5/LT1965-1.8/LT1965-2.5/LT1965-3.3
*PIN 5 = ADJ FOR LT1965
ORDER INFORMATION
LEAD FREE FINISH
TAPE AND REEL
PART MARKING*
PACKAGE DESCRIPTION
TEMPERATURE RANGE
LT1965EDD#PBF
LT1965EDD#TRPBF
LCXW
8-Lead (3mm × 3mm) Plastic DFN
–40°C to 125°C
LT1965IDD#PBF
LT1965IDD#TRPBF
LCXW
8-Lead (3mm × 3mm) Plastic DFN
–40°C to 125°C
LT1965EDD-1.5#PBF
LT1965EDD-1.5#TRPBF
LDKW
8-Lead (3mm × 3mm) Plastic DFN
–40°C to 125°C
LT1965IDD-1.5#PBF
LT1965IDD-1.5#TRPBF
LDKW
8-Lead (3mm × 3mm) Plastic DFN
–40°C to 125°C
LT1965EDD-1.8#PBF
LT1965EDD-1.8#TRPBF
LDKY
8-Lead (3mm × 3mm) Plastic DFN
–40°C to 125°C
LT1965IDD-1.8#PBF
LT1965IDD-1.8#TRPBF
LDKY
8-Lead (3mm × 3mm) Plastic DFN
–40°C to 125°C
LT1965EDD-2.5#PBF
LT1965EDD-2.5#TRPBF
LDMB
8-Lead (3mm × 3mm) Plastic DFN
–40°C to 125°C
LT1965IDD-2.5#PBF
LT1965IDD-2.5#TRPBF
LDMB
8-Lead (3mm × 3mm) Plastic DFN
–40°C to 125°C
LT1965EDD-3.3#PBF
LT1965EDD-3.3#TRPBF
LDMD
8-Lead (3mm × 3mm) Plastic DFN
–40°C to 125°C
LT1965IDD-3.3#PBF
LT1965IDD-3.3#TRPBF
LDMD
8-Lead (3mm × 3mm) Plastic DFN
–40°C to 125°C
1965fa
2
LT1965 Series
ORDER INFORMATION
LEAD FREE FINISH
TAPE AND REEL
PART MARKING*
PACKAGE DESCRIPTION
TEMPERATURE RANGE
LT1965EMS8E#PBF
LT1965EMS8E#TRPBF
LTCXX
8-Lead Plastic MSOP
–40°C to 125°C
LT1965IMS8E#PBF
LT1965IMS8E#TRPBF
LTCXX
8-Lead Plastic MSOP
–40°C to 125°C
LT1965EMS8E-1.5#PBF
LT1965EMS8E-1.5#TRPBF LTDKX
8-Lead Plastic MSOP
–40°C to 125°C
LT1965IMS8E-1.5#PBF
LT1965IMS8E-1.5#TRPBF LTDKX
8-Lead Plastic MSOP
–40°C to 125°C
LT1965EMS8E-1.8#PBF
LT1965EMS8E-1.8#TRPBF LTDKZ
8-Lead Plastic MSOP
–40°C to 125°C
LT1965IMS8E-1.8#PBF
LT1965IMS8E-1.8#TRPBF LTDKZ
8-Lead Plastic MSOP
–40°C to 125°C
LT1965EMS8E-2.5#PBF
LT1965EMS8E-2.5#TRPBF LTDMC
8-Lead Plastic MSOP
–40°C to 125°C
LT1965IMS8E-2.5#PBF
LT1965IMS8E-2.5#TRPBF LTDMC
8-Lead Plastic MSOP
–40°C to 125°C
LT1965EMS8E-3.3#PBF
LT1965EMS8E-3.3#TRPBF LTDMF
8-Lead Plastic MSOP
–40°C to 125°C
LT1965IMS8E-3.3#PBF
LT1965IMS8E-3.3#TRPBF LTDMF
8-Lead Plastic MSOP
–40°C to 125°C
LT1965EQ#PBF
LT1965EQ#TRPBF
LT1965Q
5-Lead Plastic DD-PAK
–40°C to 125°C
LT1965IQ#PBF
LT1965IQ#TRPBF
LT1965Q
5-Lead Plastic DD-PAK
–40°C to 125°C
LT1965EQ-1.5#PBF
LT1965EQ-1.5#TRPBF
LT1965Q-1.5
5-Lead Plastic DD-PAK
–40°C to 125°C
LT1965IQ-1.5#PBF
LT1965IQ-1.5#TRPBF
LT1965Q-1.5
5-Lead Plastic DD-PAK
–40°C to 125°C
LT1965EQ-1.8#PBF
LT1965EQ-1.8#TRPBF
LT1965Q-1.8
5-Lead Plastic DD-PAK
–40°C to 125°C
LT1965IQ-1.8#PBF
LT1965IQ-1.8#TRPBF
LT1965Q-1.8
5-Lead Plastic DD-PAK
–40°C to 125°C
LT1965EQ-2.5#PBF
LT1965EQ-2.5#TRPBF
LT1965Q-2.5
5-Lead Plastic DD-PAK
–40°C to 125°C
LT1965IQ-2.5#PBF
LT1965IQ-2.5#TRPBF
LT1965Q-2.5
5-Lead Plastic DD-PAK
–40°C to 125°C
LT1965EQ-3.3#PBF
LT1965EQ-3.3#TRPBF
LT1965Q-3.3
5-Lead Plastic DD-PAK
–40°C to 125°C
LT1965IQ-3.3#PBF
LT1965IQ-3.3#TRPBF
LT1965Q-3.3
5-Lead Plastic DD-PAK
–40°C to 125°C
LT1965ET#PBF
LT1965ET#TRPBF
LT1965T
5-Lead Plastic TO-220
–40°C to 125°C
LT1965IT#PBF
LT1965IT#TRPBF
LT1965T
5-Lead Plastic TO-220
–40°C to 125°C
LT1965ET-1.5#PBF
LT1965ET-1.5#TRPBF
LT1965T-1.5
5-Lead Plastic TO-220
–40°C to 125°C
LT1965IT-1.5#PBF
LT1965IT-1.5#TRPBF
LT1965T-1.5
5-Lead Plastic TO-220
–40°C to 125°C
LT1965ET-1.8#PBF
LT1965ET-1.8#TRPBF
LT1965T-1.8
5-Lead Plastic TO-220
–40°C to 125°C
LT1965IT-1.8#PBF
LT1965IT-1.8#TRPBF
LT1965T-1.8
5-Lead Plastic TO-220
–40°C to 125°C
LT1965ET-2.5#PBF
LT1965ET-2.5#TRPBF
LT1965T-2.5
5-Lead Plastic TO-220
–40°C to 125°C
LT1965IT-2.5#PBF
LT1965IT-2.5#TRPBF
LT1965T-2.5
5-Lead Plastic TO-220
–40°C to 125°C
LT1965ET-3.3#PBF
LT1965ET-3.3#TRPBF
LT1965T-3.3
5-Lead Plastic TO-220
–40°C to 125°C
LT1965IT-3.3#PBF
LT1965IT-3.3#TRPBF
LT1965T-3.3
5-Lead Plastic TO-220
–40°C to 125°C
Consult LTC Marketing for parts speciﬁed with wider operating temperature ranges. *Temperature grades are 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/
1965fa
3
LT1965 Series
ELECTRICAL CHARACTERISTICS
The l denotes the speciﬁcations which apply over the full operating
temperature range, otherwise speciﬁcations are at TA = 25°C. (Note 3)
PARAMETER
CONDITIONS
TYP
MAX
Minimum Input Voltage (Notes 4, 12)
ILOAD = 0.5A
ILOAD = 1.1A
l
1.65
1.8
2.3
V
V
LT1965-1.5, VIN = 2.1V, ILOAD = 1mA
LT1965-1.5, 2.5 < VIN < 20V, 1mA < ILOAD < 1.1A
l
1.477
1.455
1.5
1.5
1.523
1.545
V
V
LT1965-1.8, VIN = 2.3V, ILOAD = 1mA
LT1965-1.8, 2.8 < VIN < 20V, 1mA < ILOAD < 1.1A
l
1.773
1.746
1.8
1.8
1.827
1.854
V
V
LT1965-2.5, VIN = 3V, ILOAD = 1mA
LT1965-2.5, 3.5 < VIN < 20V, 1mA < ILOAD < 1.1A
l
2.462
2.425
2.5
2.5
2.538
2.575
V
V
LT1965-3.3, VIN = 3.8V, ILOAD = 1mA
LT1965-3.3, 4.3 < VIN < 20V, 1mA < ILOAD < 1.1A
l
3.25
3.201
3.3
3.3
3.35
3.399
V
V
ADJ Pin Voltage (Notes 4, 5)
VIN = 2.1V, ILOAD = 1mA
2.3V < VIN < 20V, 1mA < ILOAD < 1.1A
l
1.182
1.164
1.2
1.2
1.218
1.236
V
V
Line Regulation
LT1965-1.5, ΔVIN = 2.1V to 20V, ILOAD = 1mA
LT1965-1.8, ΔVIN = 2.3V to 20V, ILOAD = 1mA
LT1965-2.5, ΔVIN = 3V to 20V, ILOAD = 1mA
LT1965-3.3, ΔVIN = 3.8V to 20V, ILOAD = 1mA
LT1965,
ΔVIN = 2.1V to 20V, ILOAD = 1mA (Note 4)
l
l
l
l
l
3.5
4
4.5
5.5
3
9
10
11.5
16
8
mV
mV
mV
mV
mV
Load Regulation
LT1965-1.5, VIN = 2.5V, ΔILOAD = 1mA to 1.1A
LT1965-1.5, VIN = 2.5V, ΔILOAD = 1mA to 1.1A
l
5.25
10
20
mV
mV
LT1965-1.8, VIN = 2.8V, ΔILOAD = 1mA to 1.1A
LT1965-1.8, VIN = 2.8V, ΔILOAD = 1mA to 1.1A
l
6.25
12
24
mV
mV
LT1965-2.5, VIN = 3.5V, ΔILOAD = 1mA to 1.1A
LT1965-2.5, VIN = 3.5V, ΔILOAD = 1mA to 1.1A
l
8.75
16.5
33
mV
mV
LT1965-3.3, VIN = 4.3V, ΔILOAD = 1mA to 1.1A
LT1965-3.3, VIN = 4.3V, ΔILOAD = 1mA to 1.1A
l
11.5
22
44
mV
mV
LT1965,
LT1965,
l
4.25
8
16
mV
mV
0.055
0.08
0.14
V
V
0.12
0.175
0.28
V
V
0.21
0.25
0.36
V
V
0.31
0.36
0.49
V
V
0.5
0.6
2.2
8.2
21
1.1
1.5
5.5
20
40
mA
mA
mA
mA
mA
Regulated Output Voltage (Note 5)
Dropout Voltage
VIN = VOUT(NOMINAL)
(Notes 6, 7, 12)
VIN = 2.3V, ΔILOAD = 1mA to 1.1A (Note 4)
VIN = 2.3V, ΔILOAD = 1mA to 1.1A (Note 4)
MIN
ILOAD = 1mA
ILOAD = 1mA
l
ILOAD = 100mA
ILOAD = 100mA
l
ILOAD = 500mA
ILOAD = 500mA
l
ILOAD = 1.1A
ILOAD = 1.1A
l
GND Pin Current
VIN = VOUT(NOMINAL) + 1V
(Notes 6, 8)
ILOAD = 0mA
ILOAD = 1mA
ILOAD = 100mA
ILOAD = 500mA
ILOAD = 1.1A
l
l
l
l
l
Output Voltage Noise
COUT = 10μF, ILOAD = 1.1A, BW = 10Hz to 100kHz
40
ADJ Pin Bias Current (Notes 4, 9)
Shutdown Threshold
VOUT = Off to On
VOUT = On to Off
l
l
0.2
UNITS
μVRMS
1.3
4.5
μA
0.85
0.45
2
V
V
SHDN Pin Current (Note 10)
VSHDN = 0V
VSHDN = 20V
0.01
5.5
1
10
μA
μA
Quiescent Current in Shutdown
VIN = 6V, VSHDN = 0V
0.01
1
μA
Ripple Rejection
VIN – VOUT = 1.5V (AVG), VRIPPLE = 0.5VP-P,
fRIPPLE = 120Hz, ILOAD = 0.75A
57
75
dB
1965fa
4
LT1965 Series
ELECTRICAL CHARACTERISTICS
The l denotes the speciﬁcations which apply over the full operating
temperature range, otherwise speciﬁcations are at TA = 25°C. (Note 3)
PARAMETER
CONDITIONS
Current Limit
VIN = 7V, VOUT = 0
VIN = VOUT(NOMINAL) + 1V, ΔVOUT = -0.1V (Note 6)
MIN
Input Reverse Leakage Current
VIN = –20V, VOUT = 0
Reverse Output Current (Note 11)
LT1965-1.5, VOUT = 1.5V, VIN = 0
LT1965-1.8, VOUT = 1.8V, VIN = 0
LT1965-2.5, VOUT = 2.5V, VIN = 0
LT1965-3.3, VOUT = 3.3V, VIN = 0
LT1965 (Note 4), VOUT = 1.2V, VIN = 0
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: Absolute maximum input to output differential voltage is not
achievable with all combinations of rated IN pin and OUT pin voltages.
With the IN pin at 22V, the OUT pin may not be pulled below 0V. The total
measured voltage from IN to OUT must not exceed ±22V.
Note 3: The LT1965 regulators are tested and speciﬁed under pulse load
conditions such that TJ ≅ TA. The LT1965E regulators are 100% tested
at TA = 25°C. Performance at –40°C and 125°C is assured by design,
characterization, and correlation with statistical process controls. The
LT1965I regulators are guaranteed over the full –40°C to 125°C operating
junction temperature range.
Note 4: The LT1965 adjustable version is tested and speciﬁed for these
conditions with the ADJ connected to the OUT pin.
Note 5: Maximum junction temperature limits operating conditions. The
regulated output voltage speciﬁcation does not apply for all possible
combinations of input voltage and output current. Limit the output current
range if operating at the maximum input voltage. Limit the input-to-output
voltage differential if operating at the maximum output current.
Note 6: To satisfy minimum input voltage requirements, the LT1965
adjustable version is tested and speciﬁed for these conditions with an
external resistor divider (bottom 4.02k, top 4.32k) for an output voltage of
l
TYP
MAX
2.4
A
A
1.2
275
275
275
275
175
UNITS
1
mA
525
525
525
525
400
μA
μA
μA
μA
μA
2.5V. The external resistor divider adds 300μA of output DC load current.
This external current is not factored into GND pin current.
Note 7: Dropout voltage is the minimum input-to-output voltage
differential needed to maintain regulation at a speciﬁed output current. In
dropout, the output voltage equals: (VIN – VDROPOUT)
Note 8: GND pin current is tested with VIN = VOUT(NOMINAL) + 1V and a
current source load. GND pin current increases slightly in dropout. For
the ﬁxed output versions, an internal resistor divider will typically add
100μA to the GND pin current. See GND pin current curves in the Typical
Performance Characteristics section.
Note 9: ADJ pin bias current ﬂows into the ADJ pin.
Note 10: SHDN pin current ﬂows into the SHDN pin.
Note 11: Reverse output current is tested with the IN pin grounded and the
OUT pin forced to the rated output voltage. This current ﬂows into the OUT
pin and out of the GND pin.
Note 12: For the LT1965, LT1965-1.5 and LT1965-1.8, the minimum
input voltage speciﬁcation limits the dropout voltage under some output
voltage/load conditions.
Note 13: This IC includes overtemperature protection that is intended
to protect the device during momentary overload conditions. Junction
temperature will exceed 125°C when overtemperature is active.
Continuous operation above the speciﬁed maximum operating junction
temperature may impair device reliability.
1965fa
5
LT1965 Series
TYPICAL PERFORMANCE CHARACTERISTICS
Typical Dropout Voltage
Guaranteed Dropout Voltage
GUARANTEED DROPOUT VOLTAGE (mV)
500
DROPOUT VOLTAGE (mV)
450
400
TJ = 125°C
350
300
250
200
TJ = 25°C
150
100
50
0
0.2
0
0.6
0.8
0.4
OUTPUT CURRENT (A)
1
= TEST POINTS
450
450
400
TJ = 125°C
350
300
TJ = 25°C
250
200
150
0.2
0.6
0.8
0.4
OUTPUT CURRENT (A)
0.6
LT1965
0.5
0.4
0.3
0.2
0.1
–25
0
25
50
75
TEMPERATURE (°C)
100
IL = 1mA
1.517
1.821
1.512
1.815
1.507
1.502
1.497
1.492
125
1.797
1.791
1.779
1.773
–50
–25
0
25
50
75
TEMPERATURE (°C)
100
125
3.340
IL = 1mA
2.500
2.492
2.484
3.310
3.300
3.290
3.280
1.206
1.198
1.194
2.468
3.260
1.186
2.460
–50
3.250
–50
0
25
50
75
TEMPERATURE (°C)
100
125
1965 G07
IL = 1mA
1.202
1.190
–25
125
1.210
3.320
3.270
2.476
100
1.214
ADJ PIN VOLTAGE (V)
OUTPUT VOLTAGE (V)
2.508
0
25
50
75
TEMPERATURE (°C)
LT1965 ADJ Pin Voltage
1.218
3.330
2.516
–25
1965 G06
LT1965-3.3 Output Voltage
2.524
OUTPUT VOLTAGE (V)
1.809
1965 G05
IL = 1mA
125
1.803
1.482
3.350
100
IL = 1mA
1.477
–50
LT1965-2.5 Output Voltage
2.532
0
25
50
75
TEMPERATURE (°C)
1.785
1965 G04
2.540
–25
LT1965-1.8 Output Voltage
1.827
1.487
0
–50
IL = 1mA
1965 G03
OUTPUT VOLTAGE (V)
LT1965-1.5/-1.8/-2.5/-3.3
IL = 100mA
0
–50
1.2
LT1965-1.5 Output Voltage
1.522
VIN = 6V
RL = ∞, IL = 0
VSHDN = VIN
0.7
200
150
1965 G02
OUTPUT VOLTAGE (V)
QUIESCENT CURRENT (mA)
0.8
1
IL = 500mA
250
50
Quiescent Current
0.9
300
50
0
IL = 1.1A
350
100
0
1.2
400
100
1965 G01
1.0
Dropout Voltage
500
DROPOUT VOLTAGE (mV)
500
–25
0
25
50
75
TEMPERATURE (°C)
100
125
1965 G08
1.182
–50
–25
0
25
50
75
TEMPERATURE (°C)
100
125
1965 G09
1965fa
6
LT1965 Series
TYPICAL PERFORMANCE CHARACTERISTICS
LT1965-1.5 Quiescent Current
LT1965-1.8 Quiescent Current
5
4
3
2
VSHDN = VIN
VSHDN = 0V
0
0
1
2
3 4 5 6 7
INPUT VOLTAGE (V)
TJ = 25°C
RL = ∞
4
3
2
1
VSHDN = VIN
VSHDN = 0V
0
8
9
0
10
1
2
3 4 5 6 7
INPUT VOLTAGE (V)
LT1965-3.3 Quiescent Current
1.0
4
VSHDN = 0V
VSHDN = VIN
8
9
0.6
VSHDN = VIN
0.5
0.4
0.3
0.2
RL = 3Ω, IL = 500mA*
5
8
2
4
6 8 10 12 14 16 18 20
INPUT VOLTAGE (V)
3
2
RL = 30Ω, IL = 50mA*
RL = 150Ω, IL = 10mA*
0
1
2
3 4 5 6 7
INPUT VOLTAGE (V)
8
9
10
1965 G15
LT1965-1.8 GND Pin Current
(Heavy Load)
3
2
RL = 36Ω, IL = 50mA*
RL = 180Ω, IL = 10mA*
1
10
0
25
TJ = 25°C
VSHDN = VIN
*FOR VOUT = 1.8V
4
9
RL = 1.5k, IL = 1mA*
VSHDN = 0V
5
GND PIN CURRENT (mA)
GND PIN CURRENT (mA)
10
3 4 5 6 7
INPUT VOLTAGE (V)
TJ = 25°C
VSHDN = VIN
*FOR VOUT = 1.5V
4
LT1965-1.8 GND Pin Current
(Light Load)
RL = 1.363Ω, IL = 1.1A*
2
1965 G14
TJ = 25°C
VSHDN = VIN
*FOR VOUT = 1.5V
15
1
1
0
10
LT1965-1.5 GND Pin Current
(Heavy Load)
20
VSHDN = VIN
1965 G12
5
1965 G13
25
VSHDN = 0V
LT1965-1.5 GND Pin Current
(Light Load)
0.7
0
3 4 5 6 7
INPUT VOLTAGE (V)
2
0
0.8
0.1
0
2
4
10
GND PIN CURRENT (mA)
6
1
9
TJ = 25°C
RL = 4.02k
0.9
QUIESCENT CURRENT (mA)
QUIESCENT CURRENT (mA)
8
0
6
LT1965 Quiescent Current
TJ = 25°C
RL = ∞
2
8
1965 G11
1965 G10
10
TJ = 25°C
RL = ∞
0
8
GND PIN CURRENT (mA)
1
LT1965-2.5 Quiescent Current
10
QUIESCENT CURRENT (mA)
TJ = 25°C
RL = ∞
QUIESCENT CURRENT (mA)
QUIESCENT CURRENT (mA)
5
TJ = 25°C
VSHDN = VIN
*FOR VOUT = 1.8V
20
RL = 1.636Ω, IL = 1.1A*
15
10
RL = 3.6Ω, IL = 500mA*
5
RL = 18Ω, IL = 100mA*
RL = 1.8k, IL = 1mA*
RL = 15Ω, IL = 100mA*
0
0
1
2
3 4 5 6 7
INPUT VOLTAGE (V)
8
0
9
10
1965 G16
0
0
1
2
3 4 5 6 7
INPUT VOLTAGE (V)
8
9
10
1965 G17
0
1
2
3 4 5 6 7
INPUT VOLTAGE (V)
8
9
10
1965 G18
1965fa
7
LT1965 Series
TYPICAL PERFORMANCE CHARACTERISTICS
25
12
GND PIN CURRENT (mA)
TJ = 25°C
VSHDN = VIN
*FOR VOUT = 2.5V
10
8
6
4
RL = 250Ω, IL = 10mA*
RL = 2.5k, IL = 1mA*
20
RL = 2.272Ω, IL = 1.1A*
15
10
RL = 5Ω, IL = 500mA*
1
2
3 4 5 6 7
INPUT VOLTAGE (V)
8
9
1
2
3 4 5 6 7
INPUT VOLTAGE (V)
8
LT1965-3.3 GND Pin Current
(Heavy Load)
2.0
15
RL = 6.6Ω, IL = 500mA*
TJ = 25°C
VSHDN = VIN
*FOR VOUT = 1.2V
1.8
GND PIN CURRENT (mA)
RL = 3Ω, IL = 1.1A*
10
5
9
10
0
2
3 4 5 6 7
INPUT VOLTAGE (V)
8
9
1.6
RL = 24Ω, IL = 50mA*
1.4
1.2
1.0
0.8
RL = 120Ω, IL = 10mA*
0.6
RL = 1.2k, IL = 1mA*
2
3 4 5 6 7
INPUT VOLTAGE (V)
8
10
20
RL = 1.091Ω, IL = 1.1A*
15
10
RL = 2.4Ω, IL = 500mA*
5
RL = 12Ω, IL = 100mA*
0
0
10
9
TJ = 25°C
VSHDN = VIN
*FOR VOUT = 1.2V
0.2
1
2
3 4 5 6 7
INPUT VOLTAGE (V)
8
9
0
10
1
2
3 4 5 6 7
INPUT VOLTAGE (V)
8
9
10
1965 G24
1965 G23
SHDN Pin Threshold
GND Pin Current vs ILOAD
1.0
VIN = VOUT(NOMINAL) + 1V
22.5
0.9
20.0
0.8
SHDN PIN THRESHOLD (V)
GND PIN CURRENT (mA)
1
25
1965 G22
25.0
0
LT1965 GND Pin Current
(Heavy Load)
0
1
RL = 66Ω, IL = 50mA*
1965 G21
0.4
RL = 33Ω, IL = 100mA*
0
RL = 3.3k, IL = 1mA*
LT1965 GND Pin Current
(Light Load)
TJ = 25°C
VSHDN = VIN
*FOR VOUT = 3.3V
20
RL = 330Ω, IL = 10mA*
4
1965 G20
1965 G19
25
6
0
0
10
8
2
0
0
TJ = 25°C
VSHDN = VIN
*FOR VOUT = 3.3V
10
RL = 25Ω, IL = 100mA*
0
GND PIN CURRENT (mA)
12
TJ = 25°C
VSHDN = VIN
*FOR VOUT = 2.5V
5
RL = 50Ω, IL = 50mA*
2
LT1965-3.3 GND Pin Current
(Light Load)
GND PIN CURRENT (mA)
GND PIN CURRENT (mA)
LT1965-2.5 GND Pin Current
(Heavy Load)
GND PIN CURRENT (mA)
LT1965-2.5 GND Pin Current
(Light Load)
17.5
15.0
12.5
10.0
7.50
5.00
OFF TO ON
0.7
0.6
ON TO OFF
0.5
0.4
0.3
0.2
0.1
2.50
0
0
0.2
0.6
0.8
0.4
LOAD CURRENT (A)
1.0
1.2
1965 G09
0
–50
–25
0
25
50
75
TEMPERATURE (°C)
100
125
1965 G26
1965fa
8
LT1965 Series
TYPICAL PERFORMANCE CHARACTERISTICS
SHDN Pin Input Current
SHDN Pin Input Current
6.0
5.9
4
3
2
1
ADJ Pin Bias Current
4.5
VSHDN = 20V
4.0
5.8
ADJ PIN BIAS CURRENT (μA)
5
SHDN PIN INPUT CURRENT (μA)
SHDN PIN INPUT CURRENT (μA)
6
5.7
5.6
5.5
5.4
5.3
5.2
2
4
5.0
–50
6 8 10 12 14 16 18 20
SHDN PIN VOLTAGE (V)
–25
0
25
50
75
TEMPERATURE (°C)
100
1965 G11
CURRENT LIMIT (A)
TJ = 25°C
1.0
0.5
VIN = 7V
VOUT = 0V
2.0
1.5
1.0
0.5
0.0
2
4 6 8 10 12 14 16 18
INPUT/OUTPUT DIFFERENTIAL (V)
20
0
–50
–25
0
25
50
75
TEMPERATURE (°C)
0.40
0.35
0.30
0.20
LT1965
0.10
0.05
0.00
–50
–25
0
25
50
75
TEMPERATURE (°C)
TJ = 25°C
VIN = 0V
VOUT = VADJ (LT1965)
VOUT = VSENSE
(LT1965-1.5/-1.8/-2.5/-3.3)
CURRENT FLOWS INTO
OUTPUT PIN
5
4
3
100
125
LT1965
LT1965-1.5
2
LT1965-1.8
1
LT1965-3.3
0
1
2
LT1965-2.5
3
4
5
6
7
OUTPUT VOLTAGE (V)
8
9
1965 G32
80
LT1965-1.5/-1.8/-2.5/-3.3
0.15
6
90
VIN = 0V
VOUT = 1.2V (LT1965)
VOUT = 1.5V (LT1965-1.5)
VOUT = 1.8V (LT1965-1.8)
VOUT = 2.5V (LT1965-2.5)
VOUT = 3.3V (LT1965-3.3)
0.25
125
Ripple Rejection vs Frequency
Reverse Output Current
0.45
100
1965 G13
1965 G15
1965 G30
0.50
0
25
50
75
TEMPERATURE (°C)
0
RIPPLE REJECTION (dB)
0
REVERSE OUTPUT CURRENT (mA)
CURRENT LIMIT (A)
TJ = –50°C
–25
Reverse Output Current
2.5
2.0
TJ = 125°C
1.0
Current Limit vs Temperature
3.0
ΔVOUT = 100mV
1.5
2.0
1.5
1965 G12
Current Limit vs VIN – VOUT
2.5
2.5
0
–50
125
REVERSE OUTPUT CURRENT (mA)
0
3.0
0.5
5.1
0
3.5
100
125
1965 G33
70
60
50
40
30
20 IL = 0.75A
COUT = 10μF CERAMIC
10 VIN = VOUT(NOMINAL)
+ 1V + 50mVRMS RIPPLE
0
10
100
1k
10k
FREQUENCY (Hz)
100k
1M
1965 G34
1965fa
9
LT1965 Series
TYPICAL PERFORMANCE CHARACTERISTICS
Ripple Rejection vs Temperature
LT1965 Minimum Input Voltage
100
Load Regulation
0
2.5
90
80
70
IL = 0.75A
VIN = VOUT(NOMINAL) + 1V + 0.5P-P
RIPPLE AT f = 120Hz
60
–50
–25
0
25
50
75
TEMPERATURE (°C)
100
2.0
IL = 1.1A
1.5
IL = 500mA
1.0
0.5
–25
0
25
50
75
TEMPERATURE (°C)
100
1965 G35
OUTPUT NOISE VOLTAGE (μVRMS)
OUTPUT NOISE SPECTRAL DENSITY (μV Hz)
LT1965-3.3
0.10
LT1965
LT1965-1.8
LT1965-1.5
VIN = VOUT(NOMINAL) + 1V
(LT1965-1.5/-1.8/-2.5/-3.3)
VIN = 2.3V (LT1965)
ΔIL = 1mA TO 1.1A
–30
–50
–25
0
25
50
75
TEMPERATURE (°C)
100
125
1965 G37
LT1965-1.8 10Hz to 100kHz
Output Noise
100
1k
10k
COUT = 10μF
70 IL = 1.1A
60
LT1965-3.3
50
LT1965-2.5
LT1965-1.8
30
20
LT1965
400μs/DIV
LT1965-1.5
10
0
0.0001
100k
0.001
1
0.01
0.1
LOAD CURRENT (A)
SHDN AND OUTPUT VOLTAGE (V)
OUTPUT VOLTAGE
DEVIATION (mV)
4.0
VOUT = 3.3V
50
0
–50
LOAD CURRENT (A)
–100
VIN = 4.3V
CIN = 10μF CERAMIC
COUT = 10μF CERAMIC
1.0
0.5
0.0
0
10
20
10
LT1965-2.5 SHDN Transient
Response
LT1965-3.3 Transient Response
1.5
1965 G40
1965 G39
1965 G38
100
VOUT
100μV/DIV
40
FREQUENCY (Hz)
30 40 50
TIME (μs)
60
70
80
1965 G41
10
LT1965-3.3
80
COUT = 10μF
IL = 1.1A
10
LT1965-2.5
–20
RMS Output Noise vs Load
Current (10Hz to 100kHz)
LT1965-2.5
0.01
LT1965-1.8
–15
1965 G36
Output Noise Spectral Density
1.00
125
LT1965
–10
–25
0
–50
125
IL = 100mA
LOAD REGULATION (mV)
MINIMUM INPUT VOLTAGE (V)
RIPPLE REJECTION (dB)
LT1965-1.5
–5
3.5
SHDN
3.0
2.5
2.0
1.5
OUTPUT
1.0
0.5
0.0
0
10 20 30 40 50 60 70 80 90 100
TIME (μs)
1965 G42
VIN = 3.3V
COUT = 10μF CERAMIC
RL = 2.5k, IL = 1mA FOR VOUT = 2.5V
1965fa
LT1965 Series
PIN FUNCTIONS
(DFN/MSOP/DD-PAK/TO-220)
OUT (Pins 1, 2 / 1, 2 / 4 / 4): Output. This pin supplies
power to the load. Use a minimum output capacitor of
10μF to prevent oscillations. Large load transient applications require larger output capacitors to limit peak voltage transients. See the Applications Information section
for more information on output capacitance and reverse
output characteristics.
ADJ (Pin 3 / 3 / 5 / 5): Adjust. This pin is the input to the
error ampliﬁer. It has a typical bias current of 1.3μA that
ﬂows into the pin. The ADJ pin voltage is 1.20V referenced
to ground.
SENSE (Pin 3 / 3 / 5 / 5): Sense. For ﬁxed voltage versions of the LT1965 (LT1965-1.5/LT1965-1.8/ LT1965-2.5/
LT1965-3.3), the SENSE pin is the input to the error ampliﬁer. Optimum regulation is obtained when the SENSE pin
is connected to the OUT pin of the regulator. In critical applications, small voltage drops are caused by the resistance
(RP) of PCB traces between the regulator and the load.
These drops may be eliminated by connecting the SENSE
pin to the output at the load as shown in Figure 1 (Kelvin
Sense Connection). Note that the voltage drop across
the external PCB traces will add to the dropout voltage
of the regulator. The SENSE pin bias current is 100μA at
the nominal rated output voltage. The SENSE pin can be
pulled below ground (as in a dual supply system where
the regulator load is returned to a negative supply) while
still allowing the device to start and operate.
SHDN (Pin 6 / 6 / 1 / 1): Shutdown. Pulling the SHDN
pin low puts the LT1965 into a low power state and turns
the output off. Drive the SHDN pin with either logic or an
open collector/drain with a pull-up resistor. The resistor
supplies the pull-up current to the open collector/drain
logic, normally several microamperes and the SHDN pin
current, typically less than 5.5μA. If unused, connect the
SHDN pin to VIN. The SHDN pin cannot be driven below
GND unless it is tied to the IN pin. If the SHDN pin is
driven below GND while IN is powered, the output will
turn on. SHDN pin logic cannot be referenced to a negative supply rail.
IN
OUT
LT1965
+
VIN
RP
SHDN SENSE
LOAD
+
GND
RP
1965 F01
Figure 1. Kelvin Sense Connection
GND (Pins 4, 5 / 4, 5 / 3 / 3): Ground. For the adjustable
LT1965, connect the bottom of the resistor divider, setting
output voltage, directly to GND for optimum regulation.
IN (Pins 7, 8 / 7, 8 / 2 / 2): Input. This pin supplies power
to the device. The LT1965 requires a bypass capacitor at IN
if located more than six inches from the main input ﬁlter
capacitor. Include a bypass capacitor in battery-powered
circuits as a battery’s output impedance generally rises with
frequency. A bypass capacitor in the range of 1μF to 10μF
sufﬁces. The LT1965’s design withstands reverse voltages
on the IN pin with respect to ground and the OUT pin. In
the case of a reversed input, which occurs if a battery is
plugged in backwards, the LT1965 behaves as if a diode
is in series with its input. No reverse current ﬂows into
the LT1965 and no reverse voltage appears at the load.
The device protects itself and the load.
Exposed Pad (Pin 9 / 9, DFN and MSOP Packages Only):
Ground. Tie this pin directly to Pins 4 and 5 and the PCB
ground. This pin provides enhanced thermal performance
with its connection to the PCB ground. See the Applications Information section for thermal considerations and
calculating junction temperature.
1965fa
11
LT1965 Series
APPLICATIONS INFORMATION
The LT1965 series are 1.1A low dropout regulators with
shutdown. The devices are capable of supplying 1.1A at
a typical dropout voltage of 310mV. The low operating
quiescent current (500μA for the adjustable version, 600μA
for the ﬁxed voltage versions) drops to less than 1μA in
shutdown. In addition to the low quiescent current, the
LT1965 regulators incorporate several protection features
that makes them ideal for use in battery-powered systems.
The devices protect themselves against both reverse input
and reverse output voltages. In battery backup applications,
if a backup battery holds up the output when the input is
pulled to ground, the LT1965 performs like it has a diode
in series with its output, preventing reverse current ﬂow.
Also, in dual supply applications where the regulator load
is returned to a negative supply, the output can be pulled
below ground by as much as 20V. The LT1965 still starts
and operates normally in this situation.
Adjustable Operation
The LT1965 adjustable version has an output voltage range
of 1.20V to 19.5V. Figure 2 illustrates that the ratio of two
external resistors sets the output voltage. The device servos the output to maintain the ADJ pin voltage at 1.20V
referenced to ground. R1’s current equals 1.20V/R1. R2’s
current equals R1’s current plus the ADJ pin bias current.
The ADJ pin bias current, 1.3μA at 25°C, ﬂows through
R2 into the ADJ pin. Use the formula in Figure 2 to calculate output voltage. Linear Technology recommends that
R1’s value be less than 12.1k to minimize output voltage
errors due to the ADJ pin bias current. In shutdown, the
output turns off and the divider current is zero. For curves
depicting ADJ Pin Voltage vs Temperature and ADJ Pin
Bias Current vs Temperature, see the Typical Performance
Characteristics section.
IN
VIN
OUT
R2
LT1965
ADJ
R1
GND
1965 F02
+
VOUT
R2 VOUT = 1.20V 1+ +IADJ • R2
R1
VADJ = 1.20V
IADJ = 1.3µA AT 25ºC
OUTPUT RANGE = 1.20V TO 19.5V
Figure 2. Adjustable Operation
The adjustable device is tested and speciﬁed with the ADJ
pin tied to the OUT pin for an output voltage of 1.20V.
Speciﬁcations for output voltages greater than 1.20V are
proportional to the ratio of the desired output voltage to
1.20V: VOUT/1.20V. For example, load regulation for an
output current change of 1mA to 1.1A is typically –4.25mV
at VOUT = 1.20V. At VOUT = 5V, load regulation is:
5V
• –4.25mV = –17.71mV
1.20V
Output Capacitance
The LT1965’s design is stable with a wide range of output capacitors. The ESR of the output capacitor affects
stability, most notably with small capacitors. A minimum
output capacitor of 10μF with an ESR of 3Ω or less is
recommended to prevent oscillations. The LT1965 is a
low quiescent current device and output load transient
response is a function of output capacitance. Larger values
of output capacitance decrease the peak deviations and
provide improved transient response for larger current
changes.
Ceramic capacitors require extra consideration. Manufacturers make ceramic capacitors with a variety of dielectrics,
each with different behavior across temperature and applied
voltage. The most common dielectrics used are speciﬁed
with EIA temperature characteristic codes of Z5U, Y5V,
X5R and X7R. The Z5U and Y5V dielectrics provide high
C-V products in a small package at low cost, but exhibit
strong voltage and temperature coefﬁcients as shown in
Figures 3 and 4. When used with a 5V regulator, a 16V
10μF Y5V capacitor can exhibit an effective value as low
as 1μF to 2μF for the DC bias applied and over the operating temperature range. The X5R and X7R dielectrics yield
much more stable characteristics and are more suitable
for use as the output capacitor. The X7R type works over
a wider temperature range and has better temperature
stability whereas X5R is less expensive and is available in
higher values. Care still must be exercised when using X5R
and X7R capacitors; the X5R and X7R codes only specify
operating temperature range and maximum capacitance
change over temperature. Capacitance change due to DC
bias with X5R and X7R capacitors is better than Y5V and
Z5U capacitors, but can still be signiﬁcant enough to drop
1965fa
12
LT1965 Series
APPLICATIONS INFORMATION
capacitor values below appropriate levels. Capacitor DC
bias characteristics tend to improve as component case
size increases, but expected capacitance at operating
voltages should be veriﬁed.
Voltage and temperature coefﬁcients are not the only
sources of problems. Some ceramic capacitors have a
piezoelectric response. A piezoelectric device generates
voltage across its terminals due to mechanical stress,
similar to the way a piezoelectric accelerometer or microphone works. For a ceramic capacitor, the stress can be
induced by vibrations in the system or thermal transients.
The resulting voltages produced can cause appreciable
amounts of noise. A ceramic capacitor produced the trace
in Figure 5 in response to light tapping from a pencil.
Similar vibration induced behavior can masquerade as
increased output voltage noise.
Overload Recovery
Like many IC power regulators, the LT1965 has safe operating area protection. The safe area protection decreases
current limit as input-to-output voltage increases and keeps
the power transistor inside a safe operating region for all
values of input-to-output voltage. The protective design
provides some output current at all values of input-tooutput voltage up to the device breakdown.
When power is ﬁrst applied, as input voltage rises, the
output follows the input, allowing the regulator to start up
into very heavy loads. During start-up, as the input voltage
is rising, the input-to-output voltage differential is small,
allowing the regulator to supply large output currents.
With a high input voltage, a problem can occur wherein
removal of an output short will not allow the output to
40
20
BOTH CAPACITORS ARE 16V,
1210 CASE SIZE, 10μF
20
CHANGE IN VALUE (%)
CHANGE IN VALUE (%)
0
X5R
–20
–40
–60
Y5V
–80
–100
–20
–40
2
4
8
6
10 12
DC BIAS VOLTAGE (V)
14
Y5V
–60
–80
0
X5R
0
BOTH CAPACITORS ARE 16V,
1210 CASE SIZE, 10μF
–100
–50 –25
16
1965 F03
Figure 3. Ceramic Capacitor DC Bias Characteristics
50
25
75
0
TEMPERATURE (°C)
100
125
1965 F04
Figure 4. Ceramic Capacitor Temperature Characteristics
1mV/DIV
VOUT = 1.3V
COUT = 10μF
ILOAD = 0
1ms/DIV
1965 F05
Figure 5. Noise Resulting from Tapping on a Ceramic Capacitor
1965fa
13
LT1965 Series
APPLICATIONS INFORMATION
recover. Other regulators, such as the LT1083/LT1084/
LT1085 family, also exhibit this phenomenon, so it is not
unique to the LT1965.
The problem occurs with a heavy output load when the
input voltage is high and the output voltage is low. Common situations occur immediately after the removal of a
short-circuit or if the shutdown pin is pulled high after the
input voltage has already been turned on. The load line for
such a load may intersect the output current curve at two
points. If this happens, there are two stable output operating
points for the regulator. With this double intersection, the
input power supply may need to be cycled down to zero
and brought up again to make the output recover.
Output Voltage Noise
The LT1965 regulators are designed to provide low output
voltage noise over the 10Hz to 100kHz bandwidth while
operating at full load. Output voltage noise is approximately
80nV/√Hz over this frequency bandwidth for the LT1965
adjustable version. For higher output voltages (generated
by using a resistor divider), the output voltage noise gains
up accordingly.
Higher values of output voltage noise may be measured
if care is not exercised with regard to circuit layout and
testing. Crosstalk from nearby traces can induce unwanted
noise onto the LT1965’s output. Power supply ripple rejection must also be considered; the LT1965 regulators do
not have unlimited power supply rejection and will pass a
small portion of the input noise through to the output.
Thermal Considerations
The LT1965’s maximum rated junction temperature of
125°C limits its power handling capability. Two components comprise the power dissipated by the device:
1. Output current multiplied by the input/output voltage
differential: IOUT • (VIN – VOUT), and
2. GND pin current multiplied by the input voltage:
IGND • VIN
GND pin current is determined using the GND Pin Current
curves in the Typical Performance Characteristics section.
Power dissipation equals the sum of the two components
listed.
The LT1965 regulators have internal thermal limiting that
protect the device during overload conditions. For continuous normal conditions, do not exceed the maximum
junction temperature rating of 125°C. Carefully consider
all sources of thermal resistance from junction to ambient including other heat sources mounted in proximity to
the LT1965.
The underside of the LT1965 DFN package has exposed
metal (4mm2) from the lead frame to the die attachment.
The underside of the LT1965 MSOP package also has
exposed metal (3.7mm2). Both packages allow heat to
directly transfer from the die junction to the printed circuit
board metal to control maximum operating junction temperature. The dual-in-line pin arrangement allows metal
to extend beyond the ends of the package on the topside
(component side) of a PCB. Connect this metal to GND
on the PCB. The multiple IN and OUT pins of the LT1965
also assist in spreading heat to the PCB.
For surface mount devices, heat sinking is accomplished
by using the heat spreading capabilities of the PC board
and its copper traces. Copper board stiffeners and plated
through-holes can also be used to spread the heat generated by power devices.
1965fa
14
LT1965 Series
APPLICATIONS INFORMATION
The following tables list thermal resistance for several
different board sizes and copper areas. All measurements
were taken in still air on 1/16" FR-4 board with one ounce
copper.
Table 1. Measured Thermal Resistance for DFN Package
Copper Area
Topside*
Backside
2500mm2
2500mm2
2
1000mm
2500mm2
2
225mm
2500mm2
100mm2
2500mm2
2
50mm
2500mm2
*Device is mounted on topside
Board Area
Thermal Resistance
(Junction-to-Ambient)
2500mm2
2500mm2
2500mm2
2500mm2
2500mm2
60°C/W
62°C/W
65°C/W
68°C/W
70°C/W
2500mm2
2500mm2
2
1000mm
2500mm2
2
225mm
2500mm2
100mm2
2500mm2
2
50mm
2500mm2
*Device is mounted on topside
Example: Given an output voltage of 2.5V, an input voltage
range of 3.3V ± 5%, an output current range of 0mA to
500mA and a maximum ambient temperature of 85°C,
what will the maximum junction temperature be?
The power dissipated by the device equals:
IOUT(MAX) • (VIN(MAX) – VOUT) + IGND • VIN(MAX)
where:
IOUT(MAX) = 500mA
VIN(MAX) = 3.465V
Table 2. Measured Thermal Resistance for MSOP Package
Copper Area
Topside*
Backside
Calculating Junction Temperature
Board Area
Thermal Resistance
(Junction-to-Ambient)
2500mm2
2500mm2
2500mm2
2500mm2
2500mm2
55°C/W
57°C/W
60°C/W
65°C/W
68°C/W
IGND at (IOUT = 500mA, VIN = 3.465V) = 8.2mA
So,
P = 500mA(3.465V – 2.5V) + 8.2mA(3.465V) = 0.511W
Using a DFN package, the thermal resistance will be in
the range of 60°C/W to 70°C/W depending on the copper area. So the junction temperature rise above ambient
approximately equals:
0.511W • 65°C/W = 33.22°C
Table 3. Measured Thermal Resistance for DD-PAK Package
Copper Area
Topside*
Backside
2500mm2
2500mm2
1000mm2
2500mm2
125mm2
2500mm2
*Device is mounted on topside
Board Area
Thermal Resistance
(Junction-to-Ambient)
2500mm2
2500mm2
2500mm2
25°C/W
30°C/W
35°C/W
The maximum junction temperature equals the maximum
ambient temperature plus the maximum junction temperature rise above ambient or:
TJMAX = 85°C + 33.22°C = 118.22°C
Measured Thermal Resistance for TO-220 Package
Thermal Resistance (Junction-to-Case) = 3°C/W
1965fa
15
LT1965 Series
APPLICATIONS INFORMATION
Protection Features
The LT1965 regulators incorporate several protection
features that makes them ideal for use in battery-powered
circuits. In addition to the normal protection features
associated with monolithic regulators, such as current
limiting and thermal limiting, the devices also protect
against reverse input voltages, reverse output voltages
and reverse output-to-input voltages.
Current limit protection and thermal overload protection
protect the device against current overload conditions
at its output. For normal operation, do not exceed the
maximum rated junction temperature of 125°C.
The input of the device withstands reverse voltages of 22V.
The LT1965 limits current ﬂow to less than 1mA (typically
less than 300μA) and no negative voltage appears at the
output. The device protects both itself and the load against
batteries that are plugged in backwards.
The LT1965 incurs no damage if its output is pulled below ground. If the input is left open circuit or grounded,
the output can be pulled below ground by 22V. For ﬁxed
voltage versions, the output will act like a large resistor,
typically 5k or higher, limiting current ﬂow to typically
less than 300μA. For the adjustable version, the output
acts like an open circuit and no current ﬂows from the
output. However, current ﬂows in (but is limited by) the
resistor divider that sets the output voltage. If the input
is powered by a voltage source, the output sources current equal to its current limit capability and the LT1965
protects itself by thermal limiting. In this case, grounding
the SHDN pin turns off the device and stops the output
from sourcing current.
The LT1965 adjustable version incurs no damage if the
ADJ pin is pulled above or below ground by 9V. If the input
is left open circuit or grounded, the ADJ pin performs
like an open circuit when pulled below ground and like a
large resistor (typically 5k up to 3V on the ADJ pin and
then 1.5k up to 9V) in series with a diode when pulled
above ground.
In situations where the ADJ pin connects to a resistor
divider that would pull the ADJ pin above its 9V clamp voltage if the output is pulled high, the ADJ pin input current
must be limited to less than 5mA. For example, a resistor
divider is used to provide a regulated 1.5V output from the
1.20V reference when the output is forced to 20V. The top
resistor of the resistor divider must be chosen to limit the
current into the ADJ pin to less than 5mA when the ADJ
pin is at 9V. The 11V difference between the OUT and ADJ
pins divided by the 5mA maximum current into the ADJ
pin yields a minimum top resistor value of 2.2k.
In circuits where a backup battery is required, several
different input/output conditions can occur. The output
voltage may be held up while the input is either pulled
to ground, pulled to some intermediate voltage, or is left
open circuit. Current ﬂow back into the output follows the
curve shown in Figure 6.
If the LT1965’s IN pin is forced below the OUT pin or the
OUT pin is pulled above the IN pin, input current typically
drops to less than 2μA. This occurs if the LT1965 input is
connected to a discharged (low voltage) battery and either
a backup battery or a second regulator holds up the output.
The state of the SHDN pin has no effect on the reverse
output current if the output is pulled above the input.
REVERSE OUTPUT CURRENT (mA)
6
TJ = 25°C
VIN = 0V
5 VOUT = VADJ (LT1965)
VOUT = VSENSE
(LT195-1.5/-1.8/-2.5/-3.3)
4 CURRENT FLOWS INTO
OUTPUT PIN
3
LT1965
LT1965-1.5
LT1965-1.8
2
1
LT1965-2.5
LT1965-3.3
0
0
1
2
3
4
5
6
7
OUTPUT VOLTAGE (V)
9
8
1965 F06
Figure 6. Reverse Output Current
1965fa
16
LT1965 Series
TYPICAL APPLICATIONS
Paralleling of Regulators for Higher Output Current
R1
0.01Ω
+
VIN > 3.7V
IN
OUT
+
LT1965-3.3
C1
100μF
SHDN
SENSE
3.3V
2.2A
C2
22μF
GND
R2
0.01Ω
IN
OUT
R6
6.65k
1%
LT1965
SHDN
SHDN
ADJ
R7
4.02k
1%
GND
R3
2.2k
R4
2.2k
3
2
+
1/2
LT1366
–
R5
10k
8
4
1
C3
0.01μF
1965 TA03
1965fa
17
LT1965 Series
PACKAGE DESCRIPTION
DD Package
8-Lead Plastic DFN (3mm × 3mm)
(Reference LTC DWG # 05-08-1698)
R = 0.115
TYP
5
0.38 ± 0.10
8
0.675 ±0.05
3.5 ±0.05
1.65 ±0.05
2.15 ±0.05 (2 SIDES)
3.00 ±0.10
(4 SIDES)
PACKAGE
OUTLINE
1.65 ± 0.10
(2 SIDES)
PIN 1
TOP MARK
(NOTE 6)
(DD) DFN 1203
0.25 ± 0.05
0.75 ±0.05
0.200 REF
0.50 BSC
4
0.25 ± 0.05
2.38 ±0.05
(2 SIDES)
1
0.50 BSC
2.38 ±0.10
(2 SIDES)
0.00 – 0.05
BOTTOM VIEW—EXPOSED PAD
RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS
NOTE:
1. DRAWING TO BE MADE A JEDEC PACKAGE OUTLINE M0-229 VARIATION OF (WEED-1)
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 TOP AND BOTTOM OF PACKAGE
MS8E Package
8-Lead Plastic MSOP
(Reference LTC DWG # 05-08-1662)
BOTTOM VIEW OF
EXPOSED PAD OPTION
0.889 ± 0.127
(.035 ± .005)
2.794 ± 0.102
(.110 ± .004)
1
2.06 ± 0.102
(.081 ± .004)
3.00 ± 0.102
(.118 ± .004)
(NOTE 3)
8
7 6 5
1.83 ± 0.102
(.072 ± .004)
5.23
(.206)
MIN
2.083 ± 0.102 3.20 – 3.45
(.082 ± .004) (.126 – .136)
0.65
(.0256)
BSC
0.42 ± 0.038
(.0165 ± .0015)
TYP
0.254
(.010)
8
1
1.10
(.043)
MAX
DETAIL “A”
DETAIL “A”
0° – 6° TYP
3.00 ± 0.102
(.118 ± .004)
(NOTE 4)
4.90 ± 0.152
(.193 ± .006)
RECOMMENDED SOLDER PAD LAYOUT
0.52
(.0205)
REF
2 3
4
0.86
(.034)
REF
0.18
(.007)
SEATING
PLANE
GAUGE
PLANE
0.53 ± 0.152
(.021 ± .006)
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
0.22 – 0.38
(.009 – .015)
TYP
0.65
(.0256)
BSC
0.127 ± 0.076
(.005 ± .003)
MSOP (MS8E) 0603
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
1965fa
18
LT1965 Series
PACKAGE DESCRIPTION
Q Package
5-Lead Plastic DD Pak
(Reference LTC DWG # 05-08-1461)
.256
(6.502)
.390 – .415
(9.906 – 10.541)
.060
(1.524)
.165 – .180
(4.191 – 4.572)
.045 – .055
(1.143 – 1.397)
15° TYP
.060
(1.524)
.060
(1.524)
TYP .330 – .370
(8.382 – 9.398)
.183
(4.648)
+.008
.004 –.004
+0.203
0.102 –0.102
.059
(1.499)
TYP
(
)
.095 – .115
(2.413 – 2.921)
.075
(1.905)
.300
(7.620)
+.012
.143 –.020
+0.305
3.632 –0.508
(
BOTTOM VIEW OF DD PAK
HATCHED AREA IS SOLDER PLATED
COPPER HEAT SINK
.067
(1.702)
.028 – .038 BSC
(0.711 – 0.965)
TYP
)
Q(DD5) 0502
.420
.276
.080
.420
.050 ± .012
(1.270 ± 0.305)
.013 – .023
(0.330 – 0.584)
.325
.350
.205
.565
.565
.320
.090
.090
NOTE:
1. DIMENSIONS IN INCH/
(MILLIMETER)
2. DRAWING NOT TO SCALE
.042
.067
.042
.067
RECOMMENDED SOLDER PAD LAYOUT
FOR THICKER SOLDER PASTE APPLICATIONS
RECOMMENDED SOLDER PAD LAYOUT
T Package
5-Lead Plastic TO-220 (Standard)
(Reference LTC DWG # 05-08-1420)
.390 – .415
(9.906 – 10.541)
.165 – .180
(4.191 – 4.572)
.147 – .155
(3.734 – 3.937)
DIA
.045 – .055
(1.143 – 1.397)
.230 – .270
(5.842 – 6.858)
.460 – .500
(11.684 – 12.700)
.570 – .620
(14.478 – 15.748)
.330 – .370
(8.382 – 9.398)
.700 – .728
(17.78 – 18.491)
.620
(15.75)
TYP
.095 – .115
(2.413 – 2.921)
SEATING PLANE
.260 – .320
(6.60 – 8.13)
.152 – .202
(3.861 – 5.131)
.155 – .195*
(3.937 – 4.953)
.013 – .023
(0.330 – 0.584)
.067
BSC
(1.70)
.028 – .038
(0.711 – 0.965)
.135 – .165
(3.429 – 4.191)
* MEASURED AT THE SEATING PLANE
T5 (TO-220) 0801
1965fa
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.
19
LT1965 Series
TYPICAL APPLICATION
Adjustable Current Source
R5, 0.01Ω
IN
+
VIN > 2.7V
R1
1k
C1
10μF
R4
2.2k
R3
2k
R6
2.2k
2
3
NOTE: ADJUST R1 FOR
0A TO 1.1A CONSTANT-CURRENT
LOAD
+
SHDN
ADJ
GND
LT1004-1.2
R2
80.6k
LT1965
OUT
C2
3.3μF
R7
470Ω
8
1
1/2
LT1366
+
R8
100k
C3
1μF
–
C4
10μF
1965 TA04
4
RELATED PARTS
PART NUMBER DESCRIPTION
COMMENTS
LT1129
700mA, Micropower, LDO
VIN: 4.2V to 30V, VOUT(MIN) = 3.8V, VDO = 0.40V, IQ = 50μA, ISD = 16μA;
DD, SOT-223, S8, TO220-5 and TSSOP20 Packages
LT1761
100mA, Low Noise Micropower, LDO
VIN: 1.8V to 20V, VOUT(MIN) = 1.22V, VDO = 0.30V, IQ = 20μA, ISD = < 1μA,
Low Noise < 20μVRMS , Stable with 1μF Ceramic Capacitors, ThinSOT™ Package
LT1762
150mA, Low Noise Micropower, LDO
VIN: 1.8V to 20V, VOUT(MIN) = 1.22V, VDO = 0.30V, IQ = 25μA, ISD = < 1μA,
Low Noise < 20μVRMS , MS8 Package
LT1763
500mA, Low Noise Micropower, LDO
VIN: 1.8V to 20V, VOUT(MIN) = 1.22V, VDO = 0.30V, IQ = 30μA, ISD = < 1μA,
Low Noise < 20μVRMS , S8 Package
LT1764/
LT1764A
3A, Low Noise, Fast Transient Response,
LDO
VIN: 2.7V to 20V, VOUT(MIN) = 1.21V, VDO = 0.34V, IQ = 1mA, ISD = < 1μA, Low Noise
< 40μVRMS , “A” Version Stable with Ceramic Capacitors, DD and TO220-5 Packages
LTC1844
150mA, Very Low Drop-Out LDO
VIN: 1.6V to 6.5V, VOUT(MIN) = 1.25V, VDO = 0.08V, IQ = 35μA, ISD = < 1μA,
Low Noise < 60μVRMS , ThinSOT™ Package
LT1962
300mA, Low Noise Micropower, LDO
VIN: 1.8V to 20V, VOUT(MIN) = 1.22V, VDO = 0.27V, IQ = 30μA, ISD = < 1μA,
Low Noise < 20μVRMS , MS8 Package
LT1963/
LT1963A
1.5A, Low Noise, Fast Transient Response, VIN: 2.1V to 20V, VOUT(MIN) = 1.21V, VDO = 0.34V, IQ = 1mA, ISD = < 1μA,
Low Noise < 40μVRMS , “A” Version Stable with Ceramic Capacitors;
LDO
DD, TO220-5, SOT-223 and S8 Packages
LT3020
100mA, Low Voltage VDO , VIN(MIN) = 0.9V,
LDO
VIN: 0.9V to 10V, VOUT(MIN) = 0.20V, VDO = 0.15V, IQ = 120μA, ISD = 3μA, DFN and
MS8 Packages
LT3021
500mA, Low Voltage VDO , VIN(MIN) = 0.9V,
LDO
VIN: 0.9V to 10V, VOUT(MIN) = 0.20V, VDO = 0.16V, IQ = 120μA, ISD = 3μA, DFN and
S8 Packages
LT3023
Dual, 2x 100mA, Low Noise Micropower,
LDO
VIN: 1.8V to 20V, VOUT(MIN) = 1.22V, VDO = 0.30V, IQ = 40μA, ISD = < 1μA, DFN and
MS10 Packages
LT3024
Dual, 100mA/500mA, Low Noise
Micropower, LDO
VIN: 1.8V to 20V, VOUT(MIN) = 1.22V, VDO = 0.30V, IQ = 60μA, ISD = < 1μA, DFN and
TSSOP Packages
LT3027
Dual, 2x 100mA, Low Noise Micropower,
LDO with Independent Inputs
VIN: 1.8V to 20V, VOUT(MIN) = 1.22V, VDO = 0.30V, IQ = 25μA, ISD = < 1μA,
Low Noise < 20μVRMS , DFN and MS10 Packages
LT3028
Dual, 100mA/500mA, Low Noise
Micropower, LDO with Independent Inputs
VIN: 1.8V to 20V, VOUT(MIN) = 1.22V, VDO = 0.30V, IQ = 30μA, ISD = < 1μA,
Low Noise < 20μVRMS , DFN and TSSOP Packages
LT3080/
LT3080-1
1.1A Parallelable, Low Noise, Low Dropout 300mV Dropout Voltage (2-Supply Operation), Low Noise: 40μVRMS, VIN: 1.2V to 36V, VOUT:
0V to 35.7V, Current-Based Reference with 1-Resistor VOUT Set; Directly Parallelable (No Op
Linear Regulator
Amp Required), Stable with Ceramic Caps, TO-220, SOT-223, MSOP and 3mm × 3mm DFN
Packages; LT3080-1 Version Has Integrated Internal Ballast Resistor
ThinSOT is a trademark of Linear Technology Corporation
1965fa
20 Linear Technology Corporation
LT 0408 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 2007

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