LINER LT1764-2.5 3a, fast transient response, low noise,ldo regulator Datasheet

LT1764 Series
3A, Fast Transient
Response, Low Noise,
LDO Regulators
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FEATURES
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DESCRIPTIO
Optimized for Fast Transient Response
Output Current: 3A
Dropout Voltage: 340mV at 3A
Low Noise: 40µVRMS (10Hz to 100kHz)
1mA Quiescent Current
Wide Input Voltage Range: 2.7V to 20V
No Protection Diodes Needed
Controlled Quiescent Current in Dropout
Fixed Output Voltages: 1.5V, 1.8V, 2.5V, 3.3V
Adjustable Output from 1.21V to 20V
< 1µA Quiescent Current in Shutdown
Stable with 10µF Output Capacitor
Reverse Battery Protection
No Reverse Current
Thermal Limiting
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APPLICATIO S
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, LTC and LT are registered trademarks of Linear Technology Corporation.
3.3V to 2.5V Logic Power Supply
Post Regulator for Switching Supplies
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The LT ®1764 is a low dropout regulator optimized for fast
transient response. The device is capable of supplying 3A
of output current with a dropout voltage of 340mV. Operating quiescent current is 1mA, dropping to < 1µA in
shutdown. Quiescent current is well controlled; it does not
rise in dropout as it does with many other regulators. In
addition to fast transient response, the LT1764 has very
low output voltage noise which makes the device ideal for
sensitive RF supply applications.
Output voltage range is from 1.21V to 20V. The LT1764
regulators are stable with output capacitors as low as 10µF.
Internal protection circuitry includes reverse battery protection, current limiting, thermal limiting and reverse current protection. The device is available in fixed output
voltages of 1.5V, 1.8V, 2.5V, 3.3V and as an adjustable
device with a 1.21V reference voltage. The LT1764 regulators are available in 5-lead TO-220 and DD packages.
TYPICAL APPLICATIO
Dropout Voltage
400
3.3VIN to 2.5VOUT Regulator
VIN > 3V
OUT
2.5V
3A
+
10µF
10µF
LT1764-2.5
SHDN SENSE
GND
DROPOUT VOLTAGE (mV)
IN
+
350
300
250
200
150
100
1764 TA01
50
0
0
0.5
1.0
1.5
2.0
LOAD CURRENT (A)
2.5
3.0
1764 TA02
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LT1764 Series
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ABSOLUTE MAXIMUM RATINGS (Note 1)
IN Pin Voltage ........................................................ ±20V
OUT Pin Voltage .................................................... ±20V
Input to Output Differential Voltage (Note 12) ....... ±20V
SENSE Pin Voltage ............................................... ±20V
ADJ Pin Voltage ...................................................... ±7V
SHDN Pin Voltage ................................................. ±20V
Output Short-Circuit Duration ......................... Indefinite
Operating Junction Temperature Range – 40°C to 125°C
Storage Temperature Range ................. – 65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
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PACKAGE/ORDER INFORMATION
FRONT VIEW
TAB IS
GND
5
SENSE/ADJ*
4
OUT
3
GND
2
IN
1
SHDN
Q PACKAGE
5-LEAD PLASTIC DD
*PIN 5 = SENSE FOR LT1764-1.8/
LT1764-2.5/LT1764-3.3
= ADJ FOR LT1764
ORDER PART
NUMBER
FRONT VIEW
5
SENSE/ADJ*
OUT
4
LT1764EQ
LT1764EQ-1.5
LT1764EQ-1.8
LT1764EQ-2.5
LT1764EQ-3.3
TJMAX = 150°C, θJA = 30°C/ W
TAB IS
GND
3
GND
2
1
ORDER PART
NUMBER
LT1764ET
LT1764ET-1.5
LT1764ET-1.8
LT1764ET-2.5
LT1764ET-3.3
IN
SHDN
T PACKAGE
5-LEAD PLASTIC TO-220
*PIN 5 = SENSE FOR LT1764-1.8/
LT1764-2.5/LT1764-3.3
= ADJ FOR LT1764
TJMAX = 150°C, θJA = 50°C/ W
Consult LTC Marketing for parts specified with wider operating temperature ranges.
ELECTRICAL CHARACTERISTICS
The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are TA = 25°C. (Note 2)
PARAMETER
CONDITIONS
Minimum Input Voltage
(Notes 3, 11)
ILOAD = 0.5A
ILOAD = 1.5A
ILOAD = 2.7A, 110°C < TJ ≤ 125°C
ILOAD = 3A, – 40°C ≤ TJ ≤ 110°C
Regulated Output Voltage
(Note 4)
ADJ Pin Voltage
(Notes 3, 4)
MIN
TYP
MAX
UNITS
1.7
1.9
2.3
2.3
2.7
2.7
V
V
V
V
LT1764-1.5 VIN = 2.21V, ILOAD = 1mA
2.7V < VIN < 20V, 1mA < ILOAD < 3A, – 40°C ≤ TJ ≤ 110°C
2.7V < VIN < 20V, 1mA < ILOAD < 2.7A, 110°C < TJ ≤ 125°C
1.477
1.447
1.447
1.500
1.500
1.500
1.523
1.545
1.545
V
V
V
LT1764-1.8 VIN = 2.3V, ILOAD = 1mA
2.8V < VIN < 20V, 1mA < ILOAD < 3A, – 40°C ≤ TJ ≤ 110°C
2.8V < VIN < 20V, 1mA < ILOAD < 2.7A, 110°C < TJ ≤ 125°C
1.773
1.737
1.737
1.800
1.800
1.800
1.827
1.854
1.854
V
V
V
LT1764-2.5 VIN = 3V, ILOAD = 1mA
3.5V < VIN < 20V, 1mA < ILOAD < 3A, – 40°C ≤ TJ ≤ 110°C
3.5V < VIN < 20V, 1mA < ILOAD < 2.7A, 110°C < TJ ≤ 125°C
2.462
2.412
2.412
2.500
2.500
2.500
2.538
2.575
2.575
V
V
V
LT1764-3.3 VIN = 3.8V, ILOAD = 1mA
4.3V < VIN < 20V, 1mA < ILOAD < 3A, – 40°C ≤ TJ ≤ 110°C
4.3V < VIN < 20V, 1mA < ILOAD < 2.7A, 110°C < TJ ≤ 125°C
3.250
3.183
3.183
3.300
3.300
3.300
3.350
3.400
3.400
V
V
V
LT1764
1.192
1.168
1.168
1.210
1.210
1.210
1.228
1.246
1.246
V
V
V
VIN = 2.21V, ILOAD = 1mA
2.7V < VIN < 20V, 1mA < ILOAD < 3A, – 40°C ≤ TJ ≤ 110°C
2.7V < VIN < 20V, 1mA < ILOAD < 2.7A, 110°C < TJ ≤ 125°C
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LT1764 Series
ELECTRICAL CHARACTERISTICS
The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are TA = 25°C. (Note 2)
PARAMETER
CONDITIONS
MIN
TYP
MAX
Line Regulation
LT1764-1.5
LT1764-1.8
LT1764-2.5
LT1764-3.3
LT1764 (Note 3)
∆VIN = 2.21V to 20V, ILOAD = 1mA
∆VIN = 2.3V to 20V, ILOAD = 1mA
∆VIN = 3V to 20V, ILOAD = 1mA
∆VIN = 3.8V to 20V, ILOAD = 1mA
∆VIN = 2.21V to 20V, ILOAD = 1mA
2.5
3
4
4.5
2
10
10
10
10
10
mV
mV
mV
mV
mV
Load Regulation
LT1764-1.5
VIN = 2.7V, ∆ILOAD = 1mA to 3A
VIN = 2.7V, ∆ILOAD = 1mA to 3A, – 40°C ≤ TJ ≤ 110°C
VIN = 2.7V, ∆ILOAD = 1mA to 2.7A, 110°C < TJ ≤ 125°C
3
7
23
23
mV
mV
mV
LT1764-1.8
VIN = 2.8V, ∆ILOAD = 1mA to 3A
VIN = 2.8V, ∆ILOAD = 1mA to 3A, – 40°C ≤ TJ ≤ 110°C
VIN = 2.8V, ∆ILOAD = 1mA to 2.7A, 110°C < TJ ≤ 125°C
4
8
25
25
mV
mV
mV
LT1764-2.5
VIN = 3.5V, ∆ILOAD = 1mA to 3A
VIN = 3.5V, ∆ILOAD = 1mA to 3A, – 40°C ≤ TJ ≤ 110°C
VIN = 3.5V, ∆ILOAD = 1mA to 2.7A, 110°C < TJ ≤ 125°C
4
10
30
30
mV
mV
mV
LT1764-3.3
VIN = 4.3V, ∆ILOAD = 1mA to 3A
VIN = 4.3V, ∆ILOAD = 1mA to 3A, – 40°C ≤ TJ ≤ 110°C
VIN = 4.3V, ∆ILOAD = 1mA to 2.7A, 110°C < TJ ≤ 125°C
4
12
40
40
mV
mV
mV
LT1764 (Note 3) VIN = 2.7V, ∆ILOAD = 1mA to 3A
VIN = 2.7V, ∆ILOAD = 1mA to 3A, – 40°C ≤ TJ ≤ 110°C
VIN = 2.7V, ∆ILOAD = 1mA to 2.7A, 110°C < TJ ≤ 125°C
2
5
20
20
mV
mV
mV
0.02
0.05
0.10
V
V
0.07
0.13
0.18
V
V
0.14
0.20
0.27
V
V
0.25
0.33
0.40
V
V
0.66
V
0.34
0.45
0.66
V
V
1
1.1
3.5
11
40
120
120
1.5
1.6
5
18
75
200
200
mA
mA
mA
mA
mA
mA
mA
●
●
●
●
●
Dropout Voltage
VIN = VOUT(NOMINAL)
ILOAD = 1mA
ILOAD = 1mA
●
(Notes 5, 6, 11)
ILOAD = 100mA
ILOAD = 100mA
●
ILOAD = 500mA
ILOAD = 500mA
●
ILOAD = 1.5A
ILOAD = 1.5A
●
ILOAD = 2.7A, 110°C < TJ ≤ 125°C
ILOAD = 3A
ILOAD = 3A, – 40°C ≤ TJ ≤ 110°C
GND Pin Current
VIN = VOUT(NOMINAL) + 1V
(Notes 5, 7)
ILOAD = 0mA
ILOAD = 1mA
ILOAD = 100mA
ILOAD = 500mA
ILOAD = 1.5A
ILOAD = 2.7A, 110°C < TJ ≤ 125°C
ILOAD = 3A, – 40°C ≤ TJ ≤ 110°C
●
●
●
●
●
UNITS
µVRMS
Output Voltage Noise
COUT = 10µF, ILOAD = 3A, BW = 10Hz to 100kHz
40
ADJ Pin Bias Current
(Notes 3, 8)
3
10
µA
Shutdown Threshold
VOUT = Off to On
VOUT = On to Off
0.9
0.75
2
V
V
0.01
7
1
30
µA
µA
0.01
1
SHDN Pin Current
(Note 9)
●
●
0.25
VSHDN = 0V
VSHDN = 20V
Quiescent Current in Shutdown
VIN = 6V, VSHDN = 0V
Ripple Rejection
VIN – VOUT = 1.5V (Avg), VRIPPLE = 0.5VP-P,
fRIPPLE = 120Hz, ILOAD = 1.5A
55
63
µA
dB
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LT1764 Series
ELECTRICAL CHARACTERISTICS
The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are TA = 25°C. (Note 2)
PARAMETER
CONDITIONS
Current Limit
MIN
TYP
VIN = 7V, VOUT = 0V
Input Reverse Leakage Current
MAX
UNITS
4
A
LT1764-1.8, LT1764-2.5, LT1764-3.3
VIN = VOUT(NOMINAL) + 1V, ∆VOUT = – 0.1V, – 40°C ≤ TJ ≤ 110°C
VIN = VOUT(NOMINAL) + 1V, ∆VOUT = – 0.1V, 110°C < TJ ≤ 125°C
3.1
2.8
A
A
LT1764, LT1764-1.5
VIN = 2.7V, ∆VOUT = – 0.1V, – 40°C ≤ TJ ≤ 110°C
VIN = 2.7V, ∆VOUT = – 0.1V, 110°C < TJ ≤ 125°C
3.1
2.8
A
A
VIN = – 20V, VOUT = 0V
1
mA
1200
1200
1200
1200
600
µA
µA
µA
µA
µA
●
Reverse Output Current (Note 10) LT1764-1.5 VOUT = 1.5V, VIN < 1.5V
LT1764-1.8 VOUT = 1.8V, VIN < 1.8V
LT1764-2.5 VOUT = 2.5V, VIN < 2.5V
LT1764-3.3 VOUT = 3.3V, VIN < 3.3V
LT1764 (Note 3) VOUT = 1.21V, VIN < 1.21V
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2: The LT1764 regulators are tested and specified under pulse load
conditions such that TJ ≈ TA. The LT1764 is 100% tested at TA = 25°C.
Performance at – 40°C and 125°C is assured by design, characterization
and correlation with statistical process controls.
Note 3: The LT1764 (adjustable version) is tested and specified for these
conditions with the ADJ pin connected to the OUT pin.
Note 4. Operating conditions are limited by maximum junction temperature.
The regulated output voltage specification will not apply for all possible
combinations of input voltage and output current. When operating at
maximum input voltage, the output current range must be limited. When
operating at maximum output current, the input voltage range must be
limited.
Note 5: To satisfy requirements for minimum input voltage, the LT1764
(adjustable version) is tested and specified for these conditions with an
external resistor divider (two 4.12k resistors) for an output voltage of
2.42V. The external resistor divider will add a 300µA DC load on the output.
600
600
600
600
300
Note 6: Dropout voltage is the minimum input to output voltage differential
needed to maintain regulation at a specified output current. In dropout, the
output voltage will be equal to: VIN – VDROPOUT.
Note 7: GND pin current is tested with VIN = VOUT(NOMINAL) + 1V or
VIN = 2.7V (whichever is greater) and a current source load. The GND pin
current will decrease at higher input voltages.
Note 8: ADJ pin bias current flows into the ADJ pin.
Note 9: SHDN pin current flows into the SHDN pin.
Note 10: 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 the GND pin.
Note 11. For the LT1764, LT1764-1.5 and LT1764-1.8 dropout voltage will
be limited by the minimum input voltage specification under some output
voltage/load conditions.
Note 12. All combinations of absolute maximum input voltage and
absolute maximum output voltage cannot be achieved. The absolute
maximum differential from input to output is ±20V. For example, with
VIN = 20V, VOUT cannot be pulled below ground.
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TYPICAL PERFOR A CE CHARACTERISTICS
Typical Dropout Voltage
Guaranteed Dropout Voltage
GUARANTEED DROPOUT VOLTAGE (mV)
700
DROPOUT VOLTAGE (mV)
500
400
TJ = 125°C
300
200
TJ = 25°C
100
0
0
0.5
1.0
1.5
2.0
OUTPUT CURRENT (A)
2.5
3.0
1764 G01
4
Dropout Voltage
600
= TEST POINTS
600
500
DROPOUT VOLTAGE (mV)
600
500
TJ ≤ 125°C
400
300
TJ ≤ 25°C
200
400
IL = 3A
300
IL = 1.5A
200
IL = 0.5A
100
100
IL = 100mA
IL = 1mA
0
0
0.5
2.0
1.5
1.0
OUTPUT CURRENT (A)
2.5
3.0
1764 G02
0
–50 –25
50
25
75
0
TEMPERATURE (°C)
100
125
1764 G03
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LT1764 Series
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TYPICAL PERFOR A CE CHARACTERISTICS
LT1764-1.8 Output Voltage
LT1764-2.5 Output Voltage
2.58
1.84
1.2
1.83
2.56
1.82
2.54
1.0
LT1764
0.8
0.6
0.4
VIN = 6V
RL = ∞
IL = 0
VSHDN = VIN
0.2
0
–50 –25
50
25
75
0
TEMPERATURE (°C)
IL = 1mA
OUTPUT VOLTAGE (V)
LT1764-1.8/2.5/3.3
OUTPUT VOLTAGE (V)
1.81
1.80
1.79
1.78
100
1.76
– 50 – 25
125
75
50
25
TEMPERATURE (°C)
0
100
LT1764-3.3 Output Voltage
3.34
1.220
3.32
3.30
3.28
3.26
3.24
100
125
IL = 1mA
1.205
1.200
5
75
50
25
TEMPERATURE (°C)
0
100
0
0
9
10
1764 G10
1
2
3 4 5 6 7
INPUT VOLTAGE (V)
8
9
10
1764 G09
LT1764 Quiescent Current
1.6
TJ = 25°C
RL = ∞
VSHDN = VIN
30
25
20
15
10
TJ = 25°C
RL = 4.3k
VSHDN = VIN
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
0
8
10
125
5
3 4 5 6 7
INPUT VOLTAGE (V)
15
1756 G08
QUIESCENT CURRENT (mA)
QUIESCENT CURRENT (mA)
10
2
20
0
1.190
– 50 – 25
35
15
1
25
LT1764-3.3 Quiescent Current
20
0
30
5
40
25
125
TJ = 25°C
RL = ∞
VSHDN = VIN
35
1.210
LT1764-2.5 Quiescent Current
30
100
LT1764-1.8 Quiescent Current
1.215
40
TJ = 25°C
RL = ∞
VSHDN = VIN
75
50
25
TEMPERATURE (°C)
0
40
1756 G07
35
2.46
1756 G06
1.195
75
50
25
TEMPERATURE (°C)
2.48
2.42
– 50 – 25
125
QUIESCENT CURRENT (mA)
1.225
ADJ PIN VOLTAGE (V)
OUTPUT VOLTAGE (V)
IL = 1mA
0
2.50
LT1764 ADJ Pin Voltage
1.230
3.36
3.22
– 50 – 25
2.52
1756 G05
1764 G04
3.38
IL = 1mA
2.44
1.77
QUIESCENT CURRENT (mA)
QUIESCENT CURRENT (mA)
Quiescent Current
1.4
0
1
2
3 4 5 6 7
INPUT VOLTAGE (V)
8
9
10
1764 G11
0
2
4
6 8 10 12 14 16 18 20
INPUT VOLTAGE (V)
1764 G12
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LT1764 Series
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TYPICAL PERFOR A CE CHARACTERISTICS
LT1764-1.8 GND Pin Current
LT1764-2.5 GND Pin Current
20.0
RL = 3.6Ω
IL = 500mA*
12.5
GND PIN CURRENT (mA)
RL = 6Ω
IL = 300mA*
10.0
7.5
5.0
RL = 18Ω
IL = 100mA*
2.5
30
RL = 5Ω
IL = 500mA*
25
20
RL = 25Ω
IL = 100mA*
15
RL = 8.33Ω
IL = 300mA*
10
2
3 4 5 6 7
INPUT VOLTAGE (V)
8
9
10
0
1
2
3 4 5 6 7
INPUT VOLTAGE (V)
8
1764 G13
GND PIN CURRENT (mA)
GND PIN CURRENT (mA)
9
RL = 4.33Ω
IL = 300mA*
6
RL = 12.1Ω
IL = 100mA*
3
1
2
3 4 5 6 7
INPUT VOLTAGE (V)
8
9
60
0
10
RL = 1.2Ω
IL = 1.5A*
200
0
1
2
RL = 2.57Ω
IL = 0.7A*
3 4 5 6 7
INPUT VOLTAGE (V)
8
80
RL = 2.2Ω
IL = 1.5A*
9
RL = 4.71Ω
IL = 0.7A*
40
90
RL = 0.81Ω
IL = 1.5A*
10
80
RL = 1.66Ω
IL = 1.5A*
0
1
2
RL = 3.57Ω
IL = 0.7A*
3 4 5 6 7
INPUT VOLTAGE (V)
8
9
10
1764 G18
GND Pin Current vs ILOAD
RL = 0.4Ω
IL = 3A*
60
9
RL = 0.83Ω
IL = 3A*
120
0
10
160
TJ = 25°C
VSHDN = VIN
*FOR VOUT = 1.21V
120
GND PIN CURRENT (mA)
120
8
TJ = 25°C
VSHDN = VIN
*FOR VOUT = 2.5V
160
LT1764 GND Pin Current
RL = 1.1Ω
IL = 3A*
3 4 5 6 7
INPUT VOLTAGE (V)
1764 G15
40
150
TJ = 25°C
VSHDN = VIN
*FOR VOUT = 3.3V
160
2
1764 G17
LT1764-3.3 GND Pin Current
200
1
LT1764-2.5 GND Pin Current
RL = 0.6Ω
IL = 3A*
90
1764 G16
GND PIN CURRENT (mA)
0
30
0
RL = 33Ω
IL = 100mA*
20
10
TJ = 25°C
VSHDN = VIN
*FOR VOUT = 1.8V
120
RL = 2.42Ω
IL = 500mA*
RL = 11Ω
IL = 300mA*
30
LT1764-1.8 GND Pin Current
150
TJ = 25°C
VSHDN = VIN
*FOR VOUT = 1.21V
12
RL = 6.6Ω
IL = 500mA*
40
1764 G14
LT1764 GND Pin Current
15
9
GND PIN CURRENT (mA)
1
50
0
0
0
60
10
5
0
TJ = 25°C
VSHDN = VIN
*FOR VOUT = 3.3V
70
RL = 1.73Ω
IL = 0.7A*
30
VIN = VOUT(NOM) + 1V
140
GND PIN CURRENT (mA)
GND PIN CURRENT (mA)
15.0
TJ = 25°C
VSHDN = VIN
*FOR VOUT = 2.5V
35
GND PIN CURRENT (mA)
TJ = 25°C
VSHDN = VIN
*FOR VOUT = 1.8V
17.5
0
LT1764-3.3 GND Pin Current
80
40
120
100
80
60
40
20
0
0
1
2
3 4 5 6 7
INPUT VOLTAGE (V)
8
9
10
1764 G19
0
0
1
2
3 4 5 6 7
INPUT VOLTAGE (V)
8
9
10
1764 G20
0
0
0.5
1.0
2.0
1.5
OUTPUT CURRENT (A)
2.5
3.0
1764 G21
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LT1764 Series
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TYPICAL PERFOR A CE CHARACTERISTICS
SHDN Pin Threshold
(Off-to-On)
SHDN Pin Threshold
(On-to-Off)
IL = 1mA
0.9
0.7
0.6
0.5
0.4
0.3
0.2
0.1
9
SHDN PIN INPUT CURRENT (µA)
0.8
SHDN PIN THRESHOLD (V)
SHDN PIN THRESHOLD (V)
0.9
SHDN Pin Input Current
10
1.0
IL = 3A
0.8
0.7
0.6
IL = 1mA
0.5
0.4
0.3
0.2
0.1
0
–50 –25
50
25
0
75
TEMPERATURE (°C)
100
50
25
0
75
TEMPERATURE (°C)
100
1764 G22
4
3
2
VSHDN = 20V
6
5
4
3
2
6 8 10 12 14 16 18 20
SHDN PIN VOLTAGE (V)
Current Limit
5
TJ = –50°C
3.0
CURRENT LIMIT (A)
7
4
2
6
3.5
8
0
1764 G24
ADJ Pin Bias Current
2.5
2.0
1.5
4
TJ = 125°C
3
TJ = 25°C
2
1.0
1
0.5
1
0
–50 –25
50
25
0
75
TEMPERATURE (°C)
100
0
0
– 50 – 25
125
75
50
25
TEMPERATURE (°C)
0
100
Current Limit
Reverse Output Current
VIN = 7V
VOUT = 0V
5
4
3
2
1
50
25
75
0
TEMPERATURE (°C)
100
125
1764 G28
4 6 8 10 12 14 16 18 20
INPUT/OUTPUT DIFFERENTIAL (V)
Reverse Output Current
1.0
4.5
LT1764
4.0
LT1764-1.8
3.5
3.0
LT1764-2.5
LT1764-3.3
2.5
TJ = 25°C
VIN = 0V
CURRENT FLOWS
INTO OUTPUT PIN
VOUT = VADJ (LT1764)
VOUT = VFB
(LT1764-1.8/-2.5/-3.3)
2.0
1.5
1.0
0.5
0
–50 –25
2
1764 G27
5.0
REVERSE OUTPUT CURRENT (mA)
6
0
125
1756 G26
1764 G25
CURRENT LIMIT (A)
5
125
4.0
ADJ PIN BIAS CURRENT (µA)
SHDN PIN INPUT CURRENT (µA)
9
6
1764 G23
SHDN Pin Input Current
10
7
0
0
–50 –25
125
8
1
0
0
1
2
3 4 5 6 7 8
OUTPUT VOLTAGE (V)
9
10
1764 G29
REVERSE OUTPUT CURRENT (mA)
1.0
VIN = 0V
0.9 VOUT = 1.21V (LT1764)
= 1.8V (LT1764-1.8)
V
0.8 OUT
VOUT = 2.5V (LT1764-2.5)
0.7 VOUT = 3.3V (LT1764-3.3)
0.6
LT1764-1.8/-2.5/-3.3
0.5
0.4
0.3
LT1764
0.2
0.1
0
–50 –25
50
25
0
75
TEMPERATURE (°C)
100
125
1764 G30
1764fa
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LT1764 Series
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TYPICAL PERFOR A CE CHARACTERISTICS
Ripple Rejection
75
IL = 1.5A
VIN = VOUT(NOM) + 1V
+ 0.5VP-P RIPPLE
AT f = 120Hz
70
50
RIPPLE REJECTION (dB)
COUT = 100µF
TANTALUM +
10 × 1µF
CERAMIC
40
30
20
COUT = 10µF
IL = 1.5A
TANTALUM
10 VIN = VOUT(NOM) + 1V
+ 50mVRMS RIPPLE
0
100k
100
10
1k
10k
FREQUENCY (Hz)
65
60
55
50
–50 –25
1M
50
25
0
75
TEMPERATURE (°C)
100
1764 G31
IL = 1.5A
1.5
IL = 500mA
LT1764
–5
LT1764-1.8
–10
LT1764-2.5
–15
0.5
125
1
40
COUT = 10µF
ILOAD = 3A
LT1764-3.3
LT1764-2.5
0.1
LT1764
COUT = 10µF
LT1764-3.3
LT1764-1.8
30
LT1764-2.5
25
LT1764-1.8
20
LT1764
15
10
0.01
10
100
1k
10k
FREQUENCY (Hz)
0
0.0001
100k
0.001
0.01
0.1
LOAD CURRENT (A)
OUTPUT VOLTAGE
DEVIATION (V)
LOAD CURRENT (A)
0.2
0.1
0
VIN = 4.3V
CIN = 3.3µF TANTALUM
COUT = 10µF TANTALUM
–0.1
–0.2
0.50
0.25
0
0
2
4
6
8 10 12 14 16 18 20
TIME (µs)
1764 G38
10
LT1764-3.3 Transient Response
0.2
0.1
0
–0.1
VIN = 4.3V
CIN = 33µF
COUT = 100µF TANTALUM
+ 10 × 1µF CERAMIC
–0.2
1.00
0.75
1
1764 G36
1764 G35
LT1764-3.3 Transient Response
1764 G37
125
5
LT1764-3.3 10Hz to 100kHz
Output Noise
1ms/DIV
100
35
1764 G34
VOUT
100µV/DIV
50
25
75
0
TEMPERATURE (°C)
RMS Output Noise vs Load Current
(10Hz to 100kHz)
OUTPUT VOLTAGE
DEVIATION (V)
LT1764-3.3
–20 ∆IL = 1mA TO 3A
VIN = 2.7V (LT1764)
–25 VIN = VOUT(NOM) + 1V
(LT1764-1.8/-2.5/-3.3)
–30
75 100
0
50
25
– 50 – 25
TEMPERATURE (°C)
IL = 100mA
1.0
1764 G33
OUTPUT NOISE (µVRMS)
OUTPUT NOISE SPECTRAL DENSITY (µV/√Hz)
LOAD REGULATION (mV)
5
COUT = 10µF
IL = 3A
2.0
Output Noise Spectral Density
10
IL = 3A
1764 G32
Load Regulation
0
2.5
0
–50 –25
125
LOAD CURRENT (A)
RIPPLE REJECTION (dB)
70
60
LT1764 Minimum Input Voltage
3.0
MINIMUM INPUT VOLTAGE (V)
Ripple Rejection
80
3
2
1
0
0
2
4
6
8 10 12 14 16 18 20
TIME (µs)
1764 G39
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LT1764 Series
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PI FU CTIO S
SHDN (Pin 1): Shutdown. The SHDN pin is used to put the
LT1764 regulators into a low power shutdown state. The
output will be off when the SHDN pin is pulled low. The
SHDN pin can be driven either by 5V logic or opencollector logic with a pull-up resistor. The pull-up resistor
is required to supply the pull-up current of the opencollector gate, normally several microamperes, and the
SHDN pin current, typically 7µA. If unused, the SHDN pin
must be connected to VIN. The device will be in the low
power shutdown state if the SHDN pin is not connected.
OUT (Pin 4): Output. The output supplies power to the
load. A minimum output capacitor of 10µF is required to
prevent oscillations. Larger output capacitors will be
required for applications with large transient loads to limit
peak voltage transients. See the Applications Information
section for more information on output capacitance and
reverse output characteristics.
SENSE (Pin 5): Sense. For fixed voltage versions of the
LT1764 (LT1764-1.8/LT1764-2.5/LT1764-3.3), the SENSE
pin is the input to the error amplifier. Optimum regulation
will be obtained at the point where 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 PC traces between the regulator and the load.
These 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 PC traces will add to the dropout voltage of the
regulator. The SENSE pin bias current is 600µA 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) and still
allow the device to start and operate.
IN (Pin 2): Input. Power is supplied to the device through
the IN pin. A bypass capacitor is required on this pin if the
device is more than six inches away from the main input
filter capacitor. In general, the output impedance of a
battery rises with frequency, so it is advisable to include a
bypass capacitor in battery-powered circuits. A bypass
capacitor in the range of 1µF to 10µF is sufficient. The
LT1764 regulators are designed to withstand reverse
voltages on the IN pin with respect to ground and the OUT
pin. In the case of a reverse input, which can happen if a
battery is plugged in backwards, the device will act as if
there is a diode in series with its input. There will be no
reverse current flow into the regulator and no reverse
voltage will appear at the load. The device will protect both
itself and the load.
ADJ (Pin 5): Adjust. For the adjustable LT1764, this is the
input to the error amplifier. This pin is internally clamped
to ±7V. It has a bias current of 3µA which flows into the
pin. The ADJ pin voltage is 1.21V referenced to ground and
the output voltage range is 1.21V to 20V.
GND (Pin 3): Ground.
2
IN
OUT
4
RP
LT1764
+
VIN
1
SHDN
SENSE
GND
+
5
LOAD
3
RP
1764 F01
Figure 1. Kelvin Sense Connection
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LT1764 Series
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APPLICATIO S I FOR ATIO
The LT1764 series are 3A low dropout regulators optimized for fast transient response. The devices are capable
of supplying 3A at a dropout voltage of 340mV. The low
operating quiescent current (1mA) drops to less than 1µA
in shutdown. In addition to the low quiescent current, the
LT1764 regulators incorporate several protection features
which make them ideal for use in battery-powered systems. The devices are protected against both reverse input
and reverse output voltages. In battery backup applications where the output can be held up by a backup battery
when the input is pulled to ground, the LT1764-X acts like
it has a diode in series with its output and prevents reverse
current flow. Additionally, 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
and still allow the device to start and operate.
Adjustable Operation
The adjustable version of the LT1764 has an output
voltage range of 1.21V to 20V. The output voltage is set by
the ratio of two external resistors as shown in Figure 2. The
device servos the output to maintain the voltage at the ADJ
pin at 1.21V referenced to ground. The current in R1 is
then equal to 1.21V/R1 and the current in R2 is the current
in R1 plus the ADJ pin bias current. The ADJ pin bias
current, 3µA at 25°C, flows through R2 into the ADJ pin.
The output voltage can be calculated using the formula in
Figure 2. The value of R1 should be less than 4.17k to
minimize errors in the output voltage caused by the ADJ
pin bias current. Note that in shutdown the output is turned
off and the divider current will be zero.
OUT
IN
VIN
VOUT
+
R2
LT1764
ADJ
GND
R1
1764 F02
 R2
VOUT = 1.21V  1 +  + (IADJ )(R2)
 R1
VADJ = 1.21V
IADJ = 3µA AT 25°C
OUTPUT RANGE = 1.21V TO 20V
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 1.21V.
Specifications for output voltages greater than 1.21V will
be proportional to the ratio of the desired output voltage to
1.21V: VOUT/1.21V. For example, load regulation for an
output current change of 1mA to 3A is – 3mV typical at
VOUT = 1.21V. At VOUT = 5V, load regulation is:
(5V/1.21V)(–3mV) = – 12.4mV
Output Capacitance and Transient Response
The LT1764 regulators are designed to be 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 in
the range of 50mΩ to 3Ω is recommended to prevent
oscillations. Larger values of output capacitance can decrease the peak deviations and provide improved transient
response for larger load current changes. Bypass capacitors, used to decouple individual components powered by
the LT1764-X, will increase the effective output capacitor
value.
Extra consideration must be given to the use of ceramic
capacitors. In some applications the use of ceramic capacitors with an ESR below 50mΩ can cause oscillations.
Please consult our Applications Engineering department
for help with any issues concerning the use of ceramic
output capacitors. Ceramic capacitors are manufactured
with a variety of dielectrics, each with different behavior
over temperature and applied voltage. The most common
dielectrics used are Z5U, Y5V, X5R and X7R. The Z5U and
Y5V dielectrics are good for providing high capacitances
in a small package, but exhibit strong voltage and temperature coefficients as shown in Figures 3 and 4. When
used with a 5V regulator, a 10µF Y5V capacitor can exhibit
an effective value as low as 1µF to 2µF over the operating
temperature range. The X5R and X7R dielectrics result in
more stable characteristics and are more suitable for use
as the output capacitor. The X7R type has better stability
across temperature, while the X5R is less expensive and
is available in higher values.
Voltage and temperature coefficients are not the only
sources of problems. Some ceramic capacitors have a
piezoelectric response. A piezoelectric device generates
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APPLICATIO S I FOR ATIO
20
When power is first turned on, as the input voltage rises,
the output follows the input, allowing the regulator to start
up into very heavy loads. During the 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 voltage to recover. Other regulators, such as the
LT1085, also exhibit this phenomenon, so it is not unique
to the LT1764 series.
BOTH CAPACITORS ARE 16V,
1210 CASE SIZE, 10µF
0
CHANGE IN VALUE (%)
X5R
–20
–40
–60
Y5V
–80
–100
0
2
14
8
6
4
10 12
DC BIAS VOLTAGE (V)
16
1764 F03
Figure 3. Ceramic Capacitor DC Bias Characteristics
40
CHANGE IN VALUE (%)
20
X5R
0
–20
–40
Y5V
–60
–80
The problem occurs with a heavy output load when the
input voltage is high and the output voltage is low. Common situations are immediately after the removal of a
short circuit or when the SHDN 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
BOTH CAPACITORS ARE 16V,
1210 CASE SIZE, 10µF
–100
–50 –25
50
25
75
0
TEMPERATURE (°C)
100
125
1764 F04
Figure 4. Ceramic Capacitor Temperature Characteristics
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.
Overload Recovery
Like many IC power regulators, the LT1764-X has safe
operating area protection. The safe area protection decreases the 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 protection is designed to provide some output current
at all values of input-to-output voltage up to the device
breakdown.
The LT1764 regulators have been designed to provide low
output voltage noise over the 10Hz to 100kHz bandwidth
while operating at full load. Output voltage noise is typically 50nV√Hz over this frequency bandwidth for the
LT1764 (adjustable version). For higher output voltages
(generated by using a resistor divider), the output voltage
noise will be gained up accordingly. This results in RMS
noise over the 10Hz to 100kHz bandwidth of 15µVRMS for
the LT1764 increasing to 37µVRMS for the LT1764-3.3.
Higher values of output voltage noise may be measured
when care is not exercised with regards to circuit layout
and testing. Crosstalk from nearby traces can induce
unwanted noise onto the output of the LT1764-X. Power
supply ripple rejection must also be considered; the LT1764
regulators do not have unlimited power supply rejection
and will pass a small portion of the input noise through to
the output.
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APPLICATIONS INFORMATION
Thermal Considerations
Calculating Junction Temperature
The power handling capability of the device is limited by
the maximum rated junction temperature (125°C). The
power dissipated by the device is made up of two components:
Example: Given an output voltage of 3.3V, an input voltage
range of 4V to 6V, an output current range of 0mA to
500mA and a maximum ambient temperature of 50°C,
what will the maximum junction temperature be?
1. Output current multiplied by the input/output voltage
differential: (IOUT)(VIN – VOUT), and
The power dissipated by the device will be equal to:
2. GND pin current multiplied by the input voltage:
(IGND)(VIN).
where,
The GND pin current can be found using the GND Pin
Current curves in the Typical Performance Characteristics. Power dissipation will be equal to the sum of the two
components listed above.
The LT1764 series regulators have internal thermal limiting designed to protect the device during overload conditions. For continuous normal conditions, the maximum
junction temperature rating of 125°C must not be
exceeded. It is important to give careful consideration to
all sources of thermal resistance from junction to ambient.
Additional heat sources mounted nearby must also be
considered.
For surface mount devices, heat sinking is accomplished
by using the heat spreading capabilities of the PC board
and its copper traces. Surface mount heatsinks and plated
through-holes can also be used to spread the heat generated by power devices.
The following table lists 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. Q Package, 5-Lead DD
COPPER AREA
TOPSIDE*
BACKSIDE
BOARD AREA
THERMAL RESISTANCE
(JUNCTION-TO-AMBIENT)
2500mm2
2500mm2
2500mm2
23°C/W
1000mm2
2500mm2
2500mm2
25°C/W
2
2
33°C/W
125mm
2
2500mm
2500mm
*Device is mounted on topside.
T Package, 5-Lead TO-220
Thermal Resistance (Junction-to-Case) = 2.5°C/W
IOUT(MAX)(VIN(MAX) – VOUT) + IGND(VIN(MAX))
IOUT(MAX) = 500mA
VIN(MAX) = 6V
IGND at (IOUT = 500mA, VIN = 6V) = 10mA
So,
P = 500mA(6V – 3.3V) + 10mA(6V) = 1.41W
Using a DD package, the thermal resistance will be in the
range of 23°C/W to 33°C/W depending on the copper
area. So the junction temperature rise above ambient will
be approximately equal to:
1.41W(28°C/W) = 39.5°C
The maximum junction temperature will then be equal to
the maximum junction temperature rise above ambient
plus the maximum ambient temperature or:
TJMAX = 50°C + 39.5°C = 89.5°C
Protection Features
The LT1764 regulators incorporate several protection
features which make 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 are protected
against reverse input voltages, reverse output voltages
and reverse voltages from output to input.
Current limit protection and thermal overload protection
are intended to protect the device against current overload
conditions at the output of the device. For normal operation, the junction temperature should not exceed 125°C.
The input of the device will withstand reverse voltages of
20V. Current flow into the device will be limited to less than
1mA and no negative voltage will appear at the output. The
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APPLICATIONS INFORMATION
The output of the LT1764-X can be pulled below ground
without damaging the device. If the input is left open circuit
or grounded, the output can be pulled below ground by
20V. For fixed voltage versions, the output will act like a
large resistor, typically 5k or higher, limiting current flow
to typically less than 600µA. For adjustable versions, the
output will act like an open circuit; no current will flow out
of the pin. If the input is powered by a voltage source, the
output will source the short-circuit current of the device
and will protect itself by thermal limiting. In this case,
grounding the SHDN pin will turn off the device and stop
the output from sourcing the short-circuit current.
The ADJ pin of the adjustable device can be pulled above
or below ground by as much as 7V without damaging the
device. If the input is left open circuit or grounded, the ADJ
pin will act like an open circuit when pulled below ground
and like a large resistor (typically 5k) in series with a diode
when pulled above ground.
In situations where the ADJ pin is connected to a resistor
divider that would pull the ADJ pin above its 7V 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 1.21V 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 7V. The 13V difference between OUT and ADJ
pins divided by the 5mA maximum current into the ADJ pin
yields a minimum top resistor value of 2.6k.
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 will follow
the curve shown in Figure 5.
When the IN pin of the LT1764-X is forced below the OUT
pin or the OUT pin is pulled above the IN pin, input current
will typically drop to less than 2µA. This can happen if the
input of the device is connected to a discharged (low
voltage) battery and the output is held up by either a
backup battery or a second regulator circuit. The state of
the SHDN pin will have no effect on the reverse output
current when the output is pulled above the input.
5.0
REVERSE OUTPUT CURRENT (mA)
device will protect both itself and the load. This provides
protection against batteries which can be plugged in
backward.
4.5
TJ = 25°C
VIN = OV
CURRENT FLOWS INTO
OUTPUT PIN
VOUT = VADJ (LT1764)
VOUT = VFB (LT1764-1.8,
LT1764-2.5, LT1764-3.3)
LT1764
4.0
3.5
LT1764-1.8
3.0
2.5
2.0
LT1764-2.5
1.5
1.0
LT1764-3.3
0.5
0
1764 F05
0
1
2
3 4 5 6 7 8
OUTPUT VOLTAGE (V)
9
10
Figure 5. Reverse Output Current
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TYPICAL APPLICATIO S
SCR Preregulator Provides Efficiency Over Line Variations
L1
500µH
NTE5437
LT1764-3.3
L2
90V AC
TO 140V AC
+
1N4148
10V AC
AT 115VIN
IN
SHDN
10000µF
OUT
FB
+
22µF
GND
1k
VOUT
3.3V
3A
34k*
10V AC
AT 115VIN
12.1k*
NTE5437
1N4002
1N4002
V+
“SYNC”
1N4002
TO
ALL “V +”
POINTS
2.4k
+
+
22µF
200k
1N4148
C1A
1/2 LT1018
750Ω
0.1µF
–
V+
0.033µF
V+
+
750Ω
C1B
1/2 LT1018
+
1N4148
A1
LT1006
–
L1: COILTRONICS CTX500-2-52
L2: STANCOR P-8560
*1% FILM RESISTOR
10k
10k
V+
–
10k
1µF
V+
LT1004
1.2V
1764 TA03
Adjustable Current Source
R5
0.01Ω
+
VIN > 2.7V
C1
10µF
LT1004-1.2
IN
OUT
LT1764-1.8
SHDN
FB
R1
1k
R2
40.2k
R4
2.2k
R6
2.2k
LOAD
R8
100k
GND
R3
2k
C3
1µF
R7
470Ω
ADJUST R1 FOR 0A TO 3A
CONSTANT CURRENT
2
–
8
1/2 LT1366
3
C2
3.3µF
1
+
4
1764 TA04
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PACKAGE DESCRIPTION
Q Package
5-Lead Plastic DD Pak
(LTC DWG # 05-08-1461)
0.256
(6.502)
0.060
(1.524)
0.060
(1.524)
TYP
0.390 – 0.415
(9.906 – 10.541)
0.165 – 0.180
(4.191 – 4.572)
0.045 – 0.055
(1.143 – 1.397)
15° TYP
0.060
(1.524)
0.183
(4.648)
0.059
(1.499)
TYP
0.330 – 0.370
(8.382 – 9.398)
(
+0.008
0.004 –0.004
+0.203
0.102 –0.102
)
0.095 – 0.115
(2.413 – 2.921)
0.075
(1.905)
0.300
(7.620)
(
+0.012
0.143 –0.020
+0.305
3.632 –0.508
BOTTOM VIEW OF DD PAK
HATCHED AREA IS SOLDER PLATED
COPPER HEAT SINK
)
0.067
(1.70)
0.028 – 0.038 BSC
(0.711 – 0.965)
0.013 – 0.023
(0.330 – 0.584)
0.050 ± 0.012
(1.270 ± 0.305)
Q(DD5) 1098
T Package
5-Lead Plastic TO-220 (Standard)
(LTC DWG # 05-08-1421)
0.390 – 0.415
(9.906 – 10.541)
0.165 – 0.180
(4.191 – 4.572)
0.147 – 0.155
(3.734 – 3.937)
DIA
0.045 – 0.055
(1.143 – 1.397)
0.230 – 0.270
(5.842 – 6.858)
0.460 – 0.500
(11.684 – 12.700)
0.570 – 0.620
(14.478 – 15.748)
0.330 – 0.370
(8.382 – 9.398)
0.620
(15.75)
TYP
0.700 – 0.728
(17.78 – 18.491)
SEATING PLANE
0.152 – 0.202
0.260 – 0.320 (3.861 – 5.131)
(6.60 – 8.13)
0.095 – 0.115
(2.413 – 2.921)
0.155 – 0.195*
(3.937 – 4.953)
0.013 – 0.023
(0.330 – 0.584)
BSC
0.067
(1.70)
0.028 – 0.038
(0.711 – 0.965)
0.135 – 0.165
(3.429 – 4.191)
* MEASURED AT THE SEATING PLANE
T5 (TO-220) 0399
1764fa
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.
15
LT1764 Series
U
TYPICAL APPLICATIO
Paralleling of Regulators for Higher Output Current
R1
0.01Ω
+
IN
OUT
LT1764-3.3
SHDN
FB
C1
100µF
VIN > 3.7V
+
3.3V
6A
C2
22µF
GND
R2
0.01Ω
IN
SHDN
OUT
LT1764
SHDN
ADJ
R7
4.12k
GND
R3
2.2k
R4
2.2k
3
+
8
–
4
R5
1k
1
1/2 LT1366
2
R6
6.65k
C3
0.01µF
1764 TA05
RELATED PARTS
PART NUMBER
DESCRIPTION
COMMENTS
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Includes 2.5V Reference and Comparator
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50µA Quiescent Current
LT1175
500mA Negative Low Dropout Micropower Regulator
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LT1529
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500mV Dropout Voltage
LT1573
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Drives External PNP
LT1575
UltraFast Transient Response Low Dropout Regulator
Drives External N-Channel MOSFET
LT1735
Synchronous Step-Down Converter
High Efficiency, OPTI-LOOPTM Compensation
LT1761 Series
100mA, Low Noise, Low Dropout Micropower Regulators in SOT-23
20µA Quiescent Current, 20µVRMS Noise, SOT-23 Package
LT1762 Series
150mA, Low Noise, LDO Micropower Regulators
25µA Quiescent Current, 20µVRMS Noise, MSOP Package
LT1763 Series
500mA, Low Noise, LDO Micropower Regulators
30µA Quiescent Current, 20µVRMS Noise, SO-8 Package
LT1962
300mA, Low Noise, LDO Micropower Regulator
20µVRMS Noise, MSOP Package
LT1963
1.5A, Low Noise, Fast Transient Response LDO
40µVRMS Noise, SOT-223 Package
UltraFast and OPTI-LOOP are trademarks of Linear Technology Corporation.
1764fa
16
Linear Technology Corporation
LT/TP 0602 1.5K 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 2000
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