LT1761IS5-3-PBF [Linear]
100mA, Low Noise, LDO Micropower Regulators in TSOT-23; 100mA时低噪声, LDO微功率稳压器,采用TSOT -23型号: | LT1761IS5-3-PBF |
厂家: | Linear |
描述: | 100mA, Low Noise, LDO Micropower Regulators in TSOT-23 |
文件: | 总22页 (文件大小:1154K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
LT1761 Series
100mA, Low Noise,
LDO Micropower
Regulators in TSOT-23
FEATURES
DESCRIPTION
The LT®1761 series are micropower, low noise, low
dropout regulators. With an external 0.01μF bypass
n
Low Noise: 20μV
(10Hz to 100kHz)
RMS
n
Low Quiescent Current: 20μA
Wide Input Voltage Range: 1.8V to 20V
Output Current: 100mA
Very Low Shutdown Current: <0.1μA
Low Dropout Voltage: 300mV at 100mA
Fixed Output Voltages: 1.2V, 1.5V, 1.8V, 2V, 2.5V,
2.8V, 3V, 3.3V, 5V
n
n
n
n
n
capacitor, output noise drops to 20μV
over a 10Hz to
RMS
100kHz bandwidth. Designed for use in battery-powered
systems, the low 20μA quiescent current makes them an
ideal choice. In shutdown, quiescent current drops to less
than 0.1μA. The devices are capable of operating over an
input voltage from 1.8V to 20V, and can supply 100mA of
outputcurrentwithadropoutvoltageof300mV.Quiescent
current is well controlled, not rising in dropout as it does
with many other regulators.
n
n
n
Adjustable Output from 1.22V to 20V
Stable with 1μF Output Capacitor
Stable with Aluminum, Tantalum or
Ceramic Capacitors
TheLT1761regulatorsarestablewithoutputcapacitorsas
low as 1μF. Small ceramic capacitors can be used without
the series resistance required by other regulators.
n
n
n
n
n
Reverse-Battery Protected
No Reverse Current
No Protection Diodes Needed
Internal protection circuitry includes reverse battery
protection, current limiting, thermal limiting and reverse
current protection. The device is available in fixed output
voltages of 1.2V, 1.5V, 1.8V, 2V, 2.5V, 2.8V, 3V, 3.3V and
5V, and as an adjustable device with a 1.22V reference
voltage. The LT1761 regulators are available in the 5-lead
TSOT-23 package.
Overcurrent and Overtemperature Protected
Available in Tiny 5-Lead TSOT-23 Package
APPLICATIONS
n
Cellular Phones
n
Pagers
n
Battery-Powered Systems
L, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks
of Linear Technology Corporation. All other trademarks are the property of their respective
owners.
n
Frequency Synthesizers
n
Wireless Modems
TYPICAL APPLICATION
10Hz to 100kHz Output Noise
5V Low Noise Regulator
5V AT100mA
20μV NOISE
10μF
IN
OUT
BYP
V
RMS
IN
+
V
OUT
5.4V TO
20V
1μF
0.01μF
LT1761-5
20μV
RMS
100μV/DIV
SHDN
GND
1761 TA01
1761 TA01b
1761sff
1
LT1761 Series
(Note 1)
ABSOLUTE MAXIMUM RATINGS
IN Pin Voltage ......................................................... 20V
OUT Pin Voltage...................................................... 20V
Input to Output Differential Voltage......................... 20V
ADJ Pin Voltage ...................................................... 7V
BYP Pin Voltage..................................................... 0.6V
SHDN Pin Voltage ................................................. 20V
Output Short-Circuit Duration ........................ Indefinite
Operating Junction Temperature Range
E, I Grade (Note 2)............................. –40°C to 125°C
MP Grade (Note 2)............................. –55°C to 125°C
Storage Temperature Range................... –65°C to 150°C
Lead Temperature (Soldering, 10 sec) .................. 300°C
PIN CONFIGURATION
LT1761-BYP
LT1761-SD
LT1761-X
TOP VIEW
TOP VIEW
TOP VIEW
IN 1
GND 2
BYP 3
5 OUT
4 ADJ
IN 1
GND 2
5 OUT
4 ADJ
IN 1
GND 2
5 OUT
4 BYP
SHDN 3
SHDN 3
S5 PACKAGE
5-LEAD PLASTIC TSOT-23
S5 PACKAGE
5-LEAD PLASTIC TSOT-23
S5 PACKAGE
5-LEAD PLASTIC TSOT-23
T
= 150°C, θ = 250°C/W
T
JMAX
= 150°C, θ = 250°C/W
T
= 150°C, θ = 250°C/W
JMAX JA
JMAX
JA
JA
SEE APPLICATIONS INFORMATION SECTION
SEE APPLICATIONS INFORMATION SECTION
SEE APPLICATIONS INFORMATION SECTION
ORDER INFORMATION
LEAD FREE FINISH
LT1761ES5-BYP#PBF
LT1761IS5-BYP#PBF
LT1761ES5-SD#PBF
LT1761IS5-SD#PBF
LT1761ES5-1.2#PBF
LT1761IS5-1.2#PBF
LT1761ES5-1.5#PBF
LT1761IS5-1.5#PBF
LT1761ES5-1.8#PBF
LT1761IS5-1.8#PBF
LT1761MPS5-1.8#PBF
LT1761ES5-2#PBF
LT1761IS5-2#PBF
TAPE AND REEL
PART MARKING *
LTGC
LTGC
LTGH
LTGH
LTCDS
LTCDS
LTMT
LTMT
LTJM
LTJM
LTDCH
LTJE
LTJE
LTGD
LTGD
LTLB
LTLB
LTGE
LTGE
LTGF
PACKAGE DESCRIPTION
5-Lead Plastic TSOT-23
TEMPERATURE RANGE
LT1761ES5-BYP#TRPBF
LT1761IS5-BYP#TRPBF
LT1761ES5-SD#TRPBF
LT1761IS5-SD#TRPBF
LT1761ES5-1.2#TRPBF
LT1761IS5-1.2#TRPBF
LT1761ES5-1.5#TRPBF
LT1761IS5-1.5#TRPBF
LT1761ES5-1.8#TRPBF
LT1761IS5-1.8#TRPBF
LT1761MPS5-1.8#TRPBF
LT1761ES5-2#TRPBF
LT1761IS5-2#TRPBF
LT1761ES5-2.5#TRPBF
LT1761IS5-2.5#TRPBF
LT1761ES5-2.8#TRPBF
LT1761IS5-2.8#TRPBF
LT1761ES5-3#TRPBF
LT1761IS5-3#TRPBF
LT1761ES5-3.3#TRPBF
LT1761IS5-3.3#TRPBF
LT1761MPS5-3.3#TRPBF
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–55°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–55°C to 125°C
5-Lead Plastic TSOT-23
5-Lead Plastic TSOT-23
5-Lead Plastic TSOT-23
5-Lead Plastic TSOT-23
5-Lead Plastic TSOT-23
5-Lead Plastic TSOT-23
5-Lead Plastic TSOT-23
5-Lead Plastic TSOT-23
5-Lead Plastic TSOT-23
5-Lead Plastic TSOT-23
5-Lead Plastic TSOT-23
5-Lead Plastic TSOT-23
5-Lead Plastic TSOT-23
5-Lead Plastic TSOT-23
5-Lead Plastic TSOT-23
5-Lead Plastic TSOT-23
5-Lead Plastic TSOT-23
5-Lead Plastic TSOT-23
5-Lead Plastic TSOT-23
5-Lead Plastic TSOT-23
5-Lead Plastic TSOT-23
LT1761ES5-2.5#PBF
LT1761IS5-2.5#PBF
LT1761ES5-2.8#PBF
LT1761IS5-2.8#PBF
LT1761ES5-3#PBF
LT1761IS5-3#PBF
LT1761ES5-3.3#PBF
LT1761IS5-3.3#PBF
LT1761MPS5-3.3#PBF
LTGF
LTGF
1761sff
2
LT1761 Series
ORDER INFORMATION
LEAD FREE FINISH
LT1761ES5-5#PBF
LT1761IS5-5#PBF
LT1761MPS5-5#PBF
LEAD BASED FINISH
LT1761ES5-BYP
LT1761IS5-BYP
LT1761ES5-SD
LT1761IS5-SD
LT1761ES5-1.2
LT1761IS5-1.2
LT1761ES5-1.5
LT1761IS5-1.5
LT1761ES5-1.8
LT1761IS5-1.8
LT1761MPS5-1.8
LT1761ES5-2
TAPE AND REEL
PART MARKING *
LTGG
LTGG
LTGG
PART MARKING *
LTGC
LTGC
LTGH
LTGH
LTCDS
LTCDS
LTMT
LTMT
LTJM
LTJM
LTDCH
LTJE
LTJE
LTGD
LTGD
LTLB
LTLB
LTGE
LTGE
LTGF
LTGF
LTGF
PACKAGE DESCRIPTION
5-Lead Plastic TSOT-23
5-Lead Plastic TSOT-23
5-Lead Plastic TSOT-23
PACKAGE DESCRIPTION
5-Lead Plastic TSOT-23
5-Lead Plastic TSOT-23
5-Lead Plastic TSOT-23
5-Lead Plastic TSOT-23
5-Lead Plastic TSOT-23
5-Lead Plastic TSOT-23
5-Lead Plastic TSOT-23
5-Lead Plastic TSOT-23
5-Lead Plastic TSOT-23
5-Lead Plastic TSOT-23
5-Lead Plastic TSOT-23
5-Lead Plastic TSOT-23
5-Lead Plastic TSOT-23
5-Lead Plastic TSOT-23
5-Lead Plastic TSOT-23
5-Lead Plastic TSOT-23
5-Lead Plastic TSOT-23
5-Lead Plastic TSOT-23
5-Lead Plastic TSOT-23
5-Lead Plastic TSOT-23
5-Lead Plastic TSOT-23
5-Lead Plastic TSOT-23
5-Lead Plastic TSOT-23
5-Lead Plastic TSOT-23
5-Lead Plastic TSOT-23
TEMPERATURE RANGE
–40°C to 125°C
–40°C to 125°C
–55°C to 125°C
TEMPERATURE RANGE
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–55°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–55°C to 125°C
–40°C to 125°C
–40°C to 125°C
–55°C to 125°C
LT1761ES5-5#TRPBF
LT1761IS5-5#TRPBF
LT1761MPS5-5#TRPBF
TAPE AND REEL
LT1761ES5-BYP#TR
LT1761IS5-BYP#TR
LT1761ES5-SD#TR
LT1761IS5-SD#TR
LT1761ES5-1.2#TR
LT1761IS5-1.2#TR
LT1761ES5-1.5#TR
LT1761IS5-1.5#TR
LT1761ES5-1.8#TR
LT1761IS5-1.8#TR
LT1761MPS5-1.8#TR
LT1761ES5-2#TR
LT1761IS5-2#TR
LT1761ES5-2.5#TR
LT1761IS5-2.5#TR
LT1761ES5-2.8#TR
LT1761IS5-2.8#TR
LT1761ES5-3#TR
LT1761IS5-3#TR
LT1761IS5-2
LT1761ES5-2.5
LT1761IS5-2.5
LT1761ES5-2.8
LT1761IS5-2.8
LT1761ES5-3
LT1761IS5-3
LT1761ES5-3.3
LT1761IS5-3.3
LT1761MPS5-3.3
LT1761ES5-5
LT1761IS5-5
LT1761MPS5-5
LT1761ES5-3.3#TR
LT1761IS5-3.3#TR
LT1761MPS5-3.3#TR
LT1761ES5-5#TR
LT1761IS5-5#TR
LTGG
LTGG
LTGG
LT1761MPS5-5#TR
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
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/
1761sff
3
LT1761 Series
ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. (Note 2)
PARAMETER
CONDITIONS
= 100mA
MIN
TYP
MAX
UNITS
l
Minimum Input Voltage (Notes 3, 11)
Regulated Output Voltage (Note 4)
I
1.8
2.3
V
LOAD
LT1761-1.2
LT1761-1.5
LT1761-1.8
LT1761-2
LT1761-2.5
LT1761-2.8
LT1761-3
LT1761-3.3
LT1761-5
LT1761
V
= 2V, I
= 1mA
LOAD
1.185
1.170
1.150
1.2
1.2
1.2
1.215
1.230
1.240
V
V
V
IN
l
l
2.3V < V < 20V, 1mA < I
< 50mA
IN
IN
LOAD
LOAD
2.3V < V < 20V, 1mA < I
< 100mA
V
IN
= 2V, I
= 1mA
LOAD
1.478
1.457
1.436
1.5
1.5
1.5
1.522
1.538
1.555
V
V
V
l
l
2.5V < V < 20V, 1mA < I
< 50mA
< 100mA
IN
IN
LOAD
LOAD
2.5V < V < 20V, 1mA < I
V
IN
= 2.3V, I
= 1mA
LOAD
1.775
1.750
1.725
1.8
1.8
1.8
1.825
1.845
1.860
V
V
V
l
l
2.8V < V < 20V, 1mA < I
< 50mA
< 100mA
IN
IN
LOAD
LOAD
2.8V < V < 20V, 1mA < I
V
= 2.5V, I
IN
IN
= 1mA
LOAD
1.970
1.945
1.920
2
2
2
2.030
2.045
2.060
V
V
V
IN
l
l
3V < V < 20V, 1mA < I
< 50mA
< 100mA
LOAD
LOAD
3V < V < 20V, 1mA < I
V
IN
= 3V, I
= 1mA
LOAD
2.465
2.435
2.415
2.5
2.5
2.5
2.535
2.565
2.575
V
V
V
l
l
3.5V < V < 20V, 1mA < I
< 50mA
< 100mA
IN
IN
LOAD
LOAD
3.5V < V < 20V, 1mA < I
V
IN
= 3.3V, I
= 1mA
LOAD
2.762
2.732
2.706
2.8
2.8
2.8
2.838
2.868
2.884
V
V
V
l
l
3.8V < V < 20V, 1mA < I
< 50mA
< 100mA
IN
IN
LOAD
LOAD
3.8V < V < 20V, 1mA < I
V
= 3.5V, I
IN
IN
= 1mA
LOAD
2.960
2.930
2.900
3
3
3
3.040
3.070
3.090
V
V
V
IN
l
l
4V < V < 20V, 1mA < I
< 50mA
< 100mA
LOAD
LOAD
4V < V < 20V, 1mA < I
V
IN
= 3.8V, I
= 1mA
LOAD
3.250
3.230
3.190
3.3
3.3
3.3
3.350
3.370
3.400
V
V
V
l
l
4.3V < V < 20V, 1mA < I
< 50mA
< 100mA
IN
IN
LOAD
LOAD
4.3V < V < 20V, 1mA < I
V
= 5.5V, I
IN
IN
= 1mA
LOAD
4.935
4.900
4.850
5
5
5
5.065
5.100
5.120
V
V
V
IN
l
l
6V < V < 20V, 1mA < I
< 50mA
< 100mA
LOAD
LOAD
6V < V < 20V, 1mA < I
ADJ Pin Voltage (Note 3, 4)
Line Regulation
V
IN
= 2V, I
= 1mA
LOAD
1.205
1.190
1.170
1.220
1.220
1.220
1.235
1.250
1.260
V
V
V
l
l
2.3V < V < 20V, 1mA < I
< 50mA
< 100mA
IN
IN
LOAD
LOAD
2.3V < V < 20V, 1mA < I
l
l
l
l
l
l
l
l
l
l
LT1761-1.2
LT1761-1.5
LT1761-1.8
LT1761-2
LT1761-2.5
LT1761-2.8
LT1761-3
LT1761-3.3
LT1761-5
LT1761 (Note 3)
1
1
1
1
1
1
1
1
1
1
10
10
10
10
10
10
10
10
10
10
mV
mV
mV
mV
mV
mV
mV
mV
mV
mV
ΔV = 2V to 20V, I
= 1mA
= 1mA
IN
IN
IN
IN
IN
IN
IN
IN
LOAD
LOAD
LOAD
LOAD
ΔV = 2V to 20V, I
ΔV = 2.3V to 20V, I
= 1mA
= 1mA
ΔV = 2.5V to 20V, I
ΔV = 3V to 20V, I
= 1mA
LOAD
ΔV = 3.3V to 20V, I
= 1mA
= 1mA
= 1mA
= 1mA
LOAD
LOAD
LOAD
LOAD
ΔV = 3.5V to 20V, I
ΔV = 3.8V to 20V, I
ΔV = 5.5V to 20V, I
IN
IN
ΔV = 2V to 20V, I
= 1mA
LOAD
1761sff
4
LT1761 Series
ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. (Note 2)
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Load Regulation
LT1761-1.2
1
6
mV
mV
mV
mV
V
IN
V
IN
V
IN
V
IN
= 2.3V, ΔI
= 2.3V, ΔI
= 2.3V, ΔI
= 2.3V, ΔI
= 1mA to 50mA
= 1mA to 50mA
= 1mA to 100mA
= 1mA to 100mA
LOAD
LOAD
LOAD
LOAD
l
l
12
12
50
1
LT1761-1.5
LT1761-1.8
LT1761-2
10
14
20
35
30
55
mV
mV
mV
mV
V
V
V
V
= 2.5V, ΔI
= 2.5V, ΔI
= 2.5V, ΔI
= 2.5V, ΔI
= 1mA to 50mA
= 1mA to 50mA
= 1mA to 100mA
= 1mA to 100mA
IN
IN
IN
IN
LOAD
LOAD
LOAD
LOAD
l
l
10
15
20
35
30
60
mV
mV
mV
mV
V
IN
V
IN
V
IN
V
IN
= 2.8V, ΔI
= 2.8V, ΔI
= 2.8V, ΔI
= 2.8V, ΔI
= 1mA to 50mA
= 1mA to 50mA
= 1mA to 100mA
= 1mA to 100mA
LOAD
LOAD
LOAD
LOAD
l
l
10
15
20
35
35
65
mV
mV
mV
mV
V
IN
V
IN
V
IN
V
IN
= 3V, ΔI
= 3V, ΔI
= 3V, ΔI
= 3V, ΔI
= 1mA to 50mA
= 1mA to 50mA
= 1mA to 100mA
= 1mA to 100mA
LOAD
LOAD
LOAD
LOAD
l
l
LT1761-2.5
LT1761-2.8
LT1761-3
10
20
20
35
40
80
mV
mV
mV
mV
V
V
V
V
= 3.5V, ΔI
= 3.5V, ΔI
= 3.5V, ΔI
= 3.5V, ΔI
= 1mA to 50mA
= 1mA to 50mA
= 1mA to 100mA
= 1mA to 100mA
IN
IN
IN
IN
LOAD
LOAD
LOAD
LOAD
l
l
10
20
20
38
40
86
mV
mV
mV
mV
V
IN
V
IN
V
IN
V
IN
= 3.8V, ΔI
= 3.8V, ΔI
= 3.8V, ΔI
= 3.8V, ΔI
= 1mA to 50mA
= 1mA to 50mA
= 1mA to 100mA
= 1mA to 100mA
LOAD
LOAD
LOAD
LOAD
l
l
10
20
20
40
40
90
mV
mV
mV
mV
V
IN
V
IN
V
IN
V
IN
= 4V, ΔI
= 4V, ΔI
= 4V, ΔI
= 4V, ΔI
= 1mA to 50mA
= 1mA to 50mA
= 1mA to 100mA
= 1mA to 100mA
LOAD
LOAD
LOAD
LOAD
l
l
LT1761-3.3
LT1761-5
10
20
20
40
mV
mV
mV
mV
V
V
V
V
= 4.3V, ΔI
= 4.3V, ΔI
= 4.3V, ΔI
= 4.3V, ΔI
= 1mA to 50mA
= 1mA to 50mA
= 1mA to 100mA
= 1mA to 100mA
IN
IN
IN
IN
LOAD
LOAD
LOAD
LOAD
l
l
40
100
15
25
30
60
mV
mV
mV
mV
V
V
V
V
= 6V, ΔI
= 6V, ΔI
= 6V, ΔI
= 6V, ΔI
= 1mA to 50mA
= 1mA to 50mA
= 1mA to 100mA
= 1mA to 100mA
IN
IN
IN
IN
LOAD
LOAD
LOAD
LOAD
l
l
65
150
LT1761 (Note 3)
1
1
6
mV
mV
mV
mV
V
IN
V
IN
V
IN
V
IN
= 2.3V, ΔI
= 2.3V, ΔI
= 2.3V, ΔI
= 2.3V, ΔI
= 1mA to 50mA
= 1mA to 50mA
= 1mA to 100mA
= 1mA to 100mA
LOAD
LOAD
LOAD
LOAD
l
l
12
12
50
Dropout Voltage
I
I
= 1mA
= 1mA
0.10
0.17
0.24
0.30
0.15
0.19
V
V
LOAD
LOAD
l
l
l
V
= V
OUT(NOMINAL)
IN
(Notes 5, 6, 11)
I
I
= 10mA
= 10mA
0.22
0.29
V
V
LOAD
LOAD
I
I
= 50mA
= 50mA
0.28
0.38
V
V
LOAD
LOAD
I
I
= 100mA
= 100mA
0.35
0.45
V
V
LOAD
LOAD
1761sff
5
LT1761 Series
ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. (Note 2)
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
l
l
l
l
l
GND Pin Current
I
I
I
I
I
= 0mA
20
55
45
100
400
2
μA
μA
LOAD
LOAD
LOAD
LOAD
LOAD
V
= V
= 1mA
IN
OUT(NOMINAL)
(Notes 5, 7)
= 10mA
= 50mA
= 100mA
230
1
μA
mA
mA
2.2
4
Output Voltage Noise
ADJ Pin Bias Current
Shutdown Threshold
C
= 10μF, C
= 0.01μF, I
= 100mA, BW = 10Hz to 100kHz
20
30
μV
RMS
OUT
BYP
LOAD
(Notes 3, 8)
100
2
nA
l
l
V
V
= Off to On
= On to Off
0.8
0.65
V
V
OUT
OUT
0.25
l
l
SHDN Pin Current
(Note 9)
V
SHDN
V
SHDN
= 0V
= 20V
0
1
0.5
3
μA
μA
Quiescent Current in Shutdown
Ripple Rejection (Note 3)
V
V
= 6V, V
= 0V
0.01
65
0.1
μA
dB
IN
SHDN
– V
= 1.5V (Avg), V
= 0.5V , f
P-P RIPPLE
= 120Hz,
= –5%
55
IN
OUT
RIPPLE
I
= 50mA
LOAD
Current Limit
V
IN
V
IN
= 7V, V
= 0V
200
mA
mA
OUT
OUT(NOMINAL)
l
l
= V
+ 1V or 2.3V (Note 12), ΔV
110
OUT
Input Reverse Leakage Current
V
IN
= –20V, V
= 0V
OUT
1
mA
Reverse Output Current
(Note 10)
LT1761-1.2
LT1761-1.5
LT1761-1.8
LT1761-2
LT1761-2.5
LT1761-2.8
LT1761-3
LT1761-3.3
LT1761-5
LT1761 (Note 3)
V
= 1.2V, V < 1.2V
10
10
10
10
10
10
10
10
10
5
20
20
20
20
20
20
20
20
20
10
μA
μA
μA
μA
μA
μA
μA
μA
μA
μA
OUT
OUT
OUT
OUT
OUT
OUT
OUT
OUT
OUT
OUT
IN
V
V
V
V
V
V
V
V
V
= 1.5V, V < 1.5V
IN
= 1.8V, V < 1.8V
IN
= 2V, V < 2V
IN
= 2.5V, V < 2.5V
IN
= 2.8V, V < 2.8V
IN
= 3V, V < 3V
IN
= 3.3V, V < 3.3V
IN
= 5V, V < 5V
IN
= 1.22V, V < 1.22V
IN
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 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: V – V
.
IN
DROPOUT
Note 7: GND pin current is tested with V = V
or V = 2.3V
IN
IN
OUT(NOMINAL)
Note 2: The LT1761 regulators are tested and specified under pulse load
(whichever is greater) and a current source load. This means the device
is tested while operating in its dropout region or at the minimum input
voltage specification. This is the worst-case GND pin current. The GND pin
current will decrease slightly 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.
conditions such that T ≈ T . The LT1761E is 100% production tested
J
A
at T = 25°C. Performance at –40°C and 125°C is assured by design,
A
characterization and correlation with statistical process controls. The
LT1761I is guaranteed over the full –40°C to 125°C operating junction
temperature range. The LT1761MP is 100% tested and guaranteed over
the –55°C to 125°C operating junction temperature range.
Note 3: The LT1761 (adjustable versions) are 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 LT1761
(adjustable version) is tested and specified for these conditions with an
external resistor divider (two 250k resistors) for an output voltage of
2.44V. The external resistor divider will add a 5μA DC load on the output.
Note 11: For the LT1761, LT1761-1.2, LT1761-1.5, LT1761-1.8 and
LT1761-2 dropout voltage will be limited by the minimum input voltage
specification under some output voltage/load conditions. See the curve of
Minimum Input Voltage in the Typical Performance Characteristics.
Note 12: To satisfy requirements for minimum input voltage, current limit
is tested at V = V
+ 1V or V = 2.3V, whichever is greater.
IN
OUT(NOMINAL)
IN
1761sff
6
LT1761 Series
TYPICAL PERFORMANCE CHARACTERISTICS
Typical Dropout Voltage
Guaranteed Dropout Voltage
Dropout Voltage
500
450
400
350
300
250
200
150
100
50
500
450
400
350
300
250
200
150
100
50
500
450
400
350
300
250
200
150
100
50
= TEST POINTS
T
≤ 125°C
J
T
= 125°C
J
I
L
= 100mA
T
≤ 25°C
J
I
= 50mA
= 10mA
L
T
= 25°C
J
I
L
I
= 1mA
L
0
0
0
40
50
TEMPERATURE (°C)
125
40
50 60 70 80 90 100
OUTPUT CURRENT (mA)
0
10 20 30
50 60 70 80 90 100
–50 –25
0
25
75 100
0
10 20 30
OUTPUT CURRENT (mA)
1761 G01
1761 G01.1
1761 G00
LT1761-1.2
Output Voltage
LT1761-1.5
Quiescent Current
Output Voltage
1.220
1.215
1.210
1.205
1.200
1.195
1.190
1.185
1.180
1.528
1.521
1.514
1.507
1.500
1.493
1.486
1.479
1.472
40
35
30
25
20
15
10
5
V
= 6V
I
= 1mA
I
= 1mA
IN
L
L
L
R
= ∞ (250k FOR LT1761-BYP, -SD)
I
= 0 (5μA FOR LT1761-BYP, -SD)
L
V
= V
IN
SHDN
V
= 0V
50
SHDN
0
–25
0
25
50
75
125
–25
0
25
50
75
125
–50
100
–50
100
–25
0
25
75
125
–50
100
TEMPERATURE (°C)
TEMPERATURE (°C)
TEMPERATURE (°C)
1761 G05
1761 G51
1761 G03
LT1761-1.8
Output Voltage
LT1761-2
Output Voltage
LT1761-2.5
Output Voltage
1.84
1.83
1.82
1.81
1.80
1.79
1.78
1.77
1.76
2.04
2.03
2.02
2.01
2.00
1.99
1.98
1.97
1.96
2.54
2.53
2.52
2.51
2.50
2.49
2.48
2.47
2.46
I
= 1mA
I
= 1mA
I
= 1mA
L
L
L
–25
0
25
50
75
125
–25
0
25
50
75
125
–25
0
25
50
75
125
–50
100
–50
100
–50
100
TEMPERATURE (°C)
TEMPERATURE (°C)
TEMPERATURE (°C)
1761 G06
1761 G07
1761 G08
1761sff
7
LT1761 Series
TYPICAL PERFORMANCE CHARACTERISTICS
LT1761-2.8
Output Voltage
LT1761-3
Output Voltage
LT1761-3.3
Output Voltage
2.84
2.83
2.82
2.81
2.80
2.79
2.78
2.77
2.76
3.060
3.045
3.030
3.015
3.000
2.985
2.970
2.955
2.940
3.360
3.345
3.330
3.315
3.300
3.285
3.270
3.255
3.240
I
= 1mA
I
= 1mA
I = 1mA
L
L
L
–25
0
25
50
75
125
–50
100
–25
0
25
50
75
125
–25
0
25
50
75
125
–50
100
–50
100
TEMPERATURE (°C)
TEMPERATURE (°C)
TEMPERATURE (°C)
1761 G52
1761 G09
1761 G11
LT1761-5
Output Voltage
LT1761-BYP, LT1761-SD
ADJ Pin Voltage
LT1761-1.2
Quiescent Current
250
225
200
175
150
125
100
75
5.08
5.06
5.04
5.02
5.00
4.98
4.96
4.94
4.92
1.240
1.235
1.230
1.225
1.220
1.215
1.210
1.205
1.200
I
= 1mA
T
= 25°C
= ∞
I
= 1mA
L
J
L
L
R
50
V
V
= V
IN
SHDN
25
= 0V
8
SHDN
0
–25
0
25
50
75
125
–50
100
–25
0
25
50
75
125
–50
100
0
1
2
3
4
5
6
7
9
10
TEMPERATURE (°C)
TEMPERATURE (°C)
INPUT VOLTAGE (V)
1761 G12
1761 G10
1761 G10b
LT1761-1.5
Quiescent Current
LT1761-1.8
Quiescent Current
LT1761-2
Quiescent Current
200
175
150
125
100
75
200
175
150
125
100
75
200
175
150
125
100
75
T
= 25°C
= ∞
T
= 25°C
= ∞
T
= 25°C
R = ∞
L
J
L
J
L
J
R
R
50
50
50
V
V
= V
V
V
= V
V
V
= V
IN
SHDN
IN
SHDN
IN
SHDN
25
25
25
= 0V
8
= 0V
8
= 0V
8
SHDN
SHDN
SHDN
0
0
0
0
1
2
3
4
5
6
7
9
10
0
1
2
3
4
5
6
7
9
10
0
1
2
3
4
5
6
7
9
10
INPUT VOLTAGE (V)
INPUT VOLTAGE (V)
INPUT VOLTAGE (V)
1761 G53
1761 G18
1761 G19
1761sff
8
LT1761 Series
TYPICAL PERFORMANCE CHARACTERISTICS
LT1761-2.5
Quiescent Current
LT1761-2.8
Quiescent Current
LT1761-3
Quiescent Current
200
175
150
125
100
75
200
175
150
125
100
75
200
175
150
125
100
75
T
= 25°C
= ∞
T
= 25°C
= ∞
T
= 25°C
= ∞
J
L
J
L
J
L
R
R
R
50
50
50
V
= V
IN
V
= V
IN
V
= V
IN
SHDN
SHDN
SHDN
25
25
25
V
= 0V
8
V
= 0V
8
V
= 0V
8
SHDN
SHDN
SHDN
0
0
0
0
1
2
3
4
5
6
7
9
10
0
1
2
3
4
5
6
7
9
10
0
1
2
3
4
5
6
7
9
10
INPUT VOLTAGE (V)
INPUT VOLTAGE (V)
INPUT VOLTAGE (V)
1761 G13
1761 G54
1761 G14
LT1761-3.3
Quiescent Current
LT1761-5
Quiescent Current
LT1761-BYP, LT1761-SD
Quiescent Current
200
175
150
125
100
75
200
175
150
125
100
75
30
25
20
15
10
5
T
= 25°C
= ∞
T
= 25°C
= 250k
L
T
= 25°C
= ∞
J
L
J
J
L
R
R
R
I
= 5μA
L
V
= V
IN
SHDN
50
50
V
V
= V
V
= V
IN
SHDN
IN
SHDN
25
25
V
= 0V
8
= 0V
8
V
= 0V
SHDN
SHDN
SHDN
0
0
0
0
1
2
3
4
5
6
7
9
10
0
1
2
3
4
5
6
7
9
10
0
2
4
6
8
10 12 14 16 18 20
INPUT VOLTAGE (V)
INPUT VOLTAGE (V)
INPUT VOLTAGE (V)
1761 G15
1761 G16
1761 G17
LT1761-1.2
GND Pin Current
LT1761-1.5
GND Pin Current
LT1761-1.8
GND Pin Current
2.50
2.25
2.00
1.75
1.50
1.25
1.00
0.75
0.50
0.25
0
2.50
2.25
2.00
1.75
1.50
1.25
1.00
0.75
0.50
0.25
0
2.50
2.25
2.00
1.75
1.50
1.25
1.00
0.75
0.50
0.25
0
T
= 25°C
T
= 25°C
T
= 25°C
J
J
J
*FOR V
= 1.8V
*FOR V
= 1.2V
*FOR V
= 1.5V
OUT
OUT
OUT
R
L
= 12Ω
R
L
= 15Ω
R
L
= 18Ω
L
L
L
I
= 100mA*
I
= 100mA*
I
= 100mA*
R
L
= 24Ω
L
R
I
= 36Ω
L
L
R
L
= 30Ω
L
I
= 50mA*
= 50mA*
I
= 50mA*
R
L
= 1.2k
L
R
L
= 1.5k
R = 1.8k
L
I = 1mA*
L
L
R
I
= 120Ω
R
I
= 150Ω
R
I
= 180Ω
L
L
L
L
L
L
I
= 1mA*
I
= 1mA*
= 10mA*
= 10mA*
= 10mA*
4
0
1
2
3
5
6
7
8
9
10
4
4
0
1
2
3
5
6
7
8
9
10
0
1
2
3
5
6
7
8
9
10
INPUT VOLTAGE (V)
INPUT VOLTAGE (V)
INPUT VOLTAGE (V)
1761 G17b
1761 G55
1761 G02
1761sff
9
LT1761 Series
TYPICAL PERFORMANCE CHARACTERISTICS
LT1761-2
GND Pin Current
LT1761-2.5
GND Pin Current
LT1761-2.8
GND Pin Current
2.50
2.25
2.00
1.75
1.50
1.25
1.00
0.75
0.50
0.25
0
2.50
2.25
2.00
1.75
1.50
1.25
1.00
0.75
0.50
0.25
0
2.50
2.25
2.00
1.75
1.50
1.25
1.00
0.75
0.50
0.25
0
T
= 25°C
T
= 25°C
T
= 25°C
J
J
J
*FOR V
= 2.8V
*FOR V
= 2.5V
*FOR V
= 2V
OUT
OUT
OUT
R
L
= 25Ω
L
R
L
= 28Ω
L
I
= 100mA
I
= 100mA
R
L
= 20Ω
L
I
= 100mA*
R
I
= 50Ω
R = 56Ω
L
I = 50mA*
L
R
= 40Ω
= 50mA*
L
L
= 50mA*
I
L
L
R
L
= 2k
R
L
= 2.5k
R = 2.8k
L
I = 1mA*
L
L
L
R
= 200Ω
= 10mA*
R
I
= 250Ω
R = 280Ω
L
I = 10mA*
L
L
L
I
= 1mA*
I
= 1mA*
I
= 10mA*
L
L
4
4
4
0
1
2
3
5
6
7
8
9
10
0
1
2
3
5
6
7
8
9
10
0
1
2
3
5
6
7
8
9
10
INPUT VOLTAGE (V)
INPUT VOLTAGE (V)
INPUT VOLTAGE (V)
1761 G04
1761 G20
1761 G56
LT1761-3
GND Pin Current
LT1761-3.3
GND Pin Current
LT1761-5
GND Pin Current
2.50
2.25
2.00
1.75
1.50
1.25
1.00
0.75
0.50
0.25
0
2.50
2.25
2.00
1.75
1.50
1.25
1.00
0.75
0.50
0.25
0
2.50
2.25
2.00
1.75
1.50
1.25
1.00
0.75
0.50
0.25
0
T
= 25°C
T
= 25°C
T = 25°C
J
J
J
*FOR V
= 3.3V
*FOR V
= 3V
*FOR V
= 5V
OUT
OUT
OUT
R
L
= 50Ω
L
I
= 100mA
R
L
= 30Ω
L
R
L
= 33Ω
L
I
= 100mA*
I
= 100mA*
R
L
= 100Ω
L
R
I
= 66Ω
L
R
L
= 60Ω
I
= 50mA*
L
= 50mA*
L
I
= 50mA*
R
I
= 5k
= 1mA*
L
L
R
L
= 3k
= 1mA*
R = 3.3k
L
I = 1mA*
L
L
R
= 500Ω
= 10mA*
R
= 300Ω
= 10mA*
R
I
= 330Ω
L
L
L
I
I
L
I
= 10mA*
L
L
4
4
4
0
1
2
3
5
6
7
8
9
10
0
1
2
3
5
6
7
8
9
10
0
1
2
3
5
6
7
8
9
10
INPUT VOLTAGE (V)
INPUT VOLTAGE (V)
INPUT VOLTAGE (V)
1761 G21
1761 G22
1761 G23
LT1761-BYP, LT1761-SD
GND Pin Current
SHDN Pin Threshold
GND Pin Current vs ILOAD
(On to Off)
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
2.50
2.25
2.00
1.75
1.50
1.25
1.00
0.75
0.50
0.25
0
2.50
2.25
2.00
1.75
1.50
1.25
1.00
0.75
0.50
0.25
0
I
= 1mA
V
= V
+ 1V
OUT(NOMINAL)
T
= 25°C
L
IN
J
*FOR V
= 1.22V
OUT
R
L
= 12.2Ω
L
I
= 100mA*
R
L
= 24.4Ω
L
I
= 50mA*
R
L
= 1.22k
L
R
L
= 122Ω
L
I
= 1mA*
I
= 10mA*
4
0
1
2
3
5
6
7
8
9
10
40
50 60 70 80 90 100
50
75 100 125
0
10 20 30
–50
0
25
–25
TEMPERATURE (°C)
INPUT VOLTAGE (V)
OUTPUT CURRENT (mA)
1761 G24
1761 G25
1761 G26
1761sff
10
LT1761 Series
TYPICAL PERFORMANCE CHARACTERISTICS
SHDN Pin Threshold
(Off to On)
SHDN Pin Input Current
SHDN Pin Input Current
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
V
= 20V
SHDN
I
= 100mA
L
I
= 1mA
L
50
TEMPERATURE (°C)
75 100 125
4
50
125
–50
0
25
0
1
2
3
5
6
7
8
9
10
–50
0
25
75
–25
–25
100
TEMPERATURE (°C)
SHDN PIN VOLTAGE (V)
1761 G27
1761 G28
1761 G29
ADJ Pin Bias Current
Current Limit
Current Limit
100
90
80
70
60
50
40
30
20
10
0
350
300
250
200
150
100
50
350
300
250
200
150
100
50
V
V
= 7V
V
T
= 0V
IN
OUT
OUT
J
= 0V
= 25°C
0
0
–50
0
25
50
75 100 125
0
2
3
4
5
6
7
–50
0
25
50
75 100 125
–25
1
–25
TEMPERATURE (oC)
INPUT VOLTAGE (V)
TEMPERATURE (°C)
1761 G30
1761 G31
1761 G32
Reverse Output Current
Reverse Output Current
Input Ripple Rejection
25.0
22.5
80
70
60
50
40
30
20
10
0
100
V
V
V
= 0V
IN
I = 100mA
L
T = 25°C
LT1761-BYP
LT1761-SD
J
= 1.22V (LT1761-BYP, -SD)
= 1.2V (LT1761-1.2)
= 1.5V (LT1761-1.5)
= 1.8V (LT1761-1.8)
= 2V (LT1761-2)
= 2.5V (LT1761-2.5)
= 2.8V (LT1761-2.8)
= 3V (LT1761-3)
OUT
OUT
V
= V
+
90 V = 0V
IN
OUT(NOMINAL)
IN
LT1761-BYP
LT1761-5
1V + 50mV
RIPPLE
CURRENT FLOWS
RMS
V
20.0 OUT
80
70
60
50
40
30
20
10
0
C
= 0
INTO OUTPUT PIN
BYP
V
OUT
LT1761-1.2
V
= V
V
OUT
V
OUT
V
OUT
V
OUT
V
OUT
V
OUT
17.5
15.0
12.5
10.0
7.5
OUT
ADJ
(LT1761-BYP, -SD)
LT1761-1.5
C
= 10μF
LT1761-1.8
LT1761-2
LT1761-2.5
OUT
= 3.3V (LT1761-3.3)
= 5V (LT1761-5)
LT1761-2.8
LT1761-3
LT1761-BYP,-SD
5.0
C
= 1μF
OUT
LT1761-1.2,-1.5,-1.8,-2,
-2.5,-2.8,-3,-3.3,-5
LT1761-3.3
2.5
LT1761-5
0
10
100
1k
10k
100k
1M
–50
0
25
50
75 100 125
–25
4
0
1
2
3
5
6
7
8
9
10
FREQUENCY (Hz)
TEMPERATURE (°C)
OUTPUT VOLTAGE (V)
1761 G35
1761 G34
1761 G33
1761sff
11
LT1761 Series
TYPICAL PERFORMANCE CHARACTERISTICS
LT1761-5
Input Ripple Rejection
LT1761-BYP, LT1761-SD
Minimum Input Voltage
Input Ripple Rejection
80
70
60
50
40
30
20
10
0
80
70
60
50
40
30
20
10
0
2.5
2.0
1.5
1.0
0.5
0
C
= 0.01μF
BYP
C
= 1000pF
BYP
I
= 100mA
L
I
= 50mA
L
C
= 100pF
BYP
I
= 100mA
= V
V
= V
+
OUT (NOMINAL)
L
IN
IN
V
+
OUT(NOMINAL)
1V + 0.5V RIPPLE
P-P
1V + 50mV
RIPPLE
AT f = 120Hz
RMS
C
= 10μF
I
= 50mA
OUT
L
–25
0
25
50
75
125
–50
100
10
100
1k
10k
100k
1M
–50
0
25
50
75 100 125
–25
FREQUENCY (Hz)
TEMPERATURE (°C)
TEMPERATURE (°C)
1761 G36
1761 G37
1761 G38
Load Regulation
ΔIL = 1mA to 50mA
Load Regulation
ΔIL = 1mA to 100mA
0
0
–10
–20
–30
–40
–50
–60
–70
–80
–90
–100
LT1761-BYP, -SD, -1.2
LT1761-1.5
LT1761-BYP, -SD, -1.2
LT1761-1.5
LT1761-1.8
LT1761-2
–5
–10
–15
–20
–25
–30
–35
–40
LT1761-1.8
LT1761-2
LT1761-2.5
LT1761-2.8
LT1761-3
LT1761-2.5
LT1761-2.8
LT1761-3
LT1761-3.3
LT1761-3.3
LT1761-5
LT1761-5
–25
0
25
50
75
125
–25
0
25
50
75
125
–50
100
–50
100
TEMPERATURE (°C)
TEMPERATURE (°C)
1761 G39
1761 G40
RMS Output Noise vs
Bypass Capacitor
Output Noise Spectral Density
Output Noise Spectral Density
10
1
10
1
140
120
100
80
C
L
= 10μF
OUT
LT1761-5
LT1761-3.3
LT1761-3
LT1761-2.8
LT1761-2.5
LT1761-3.3
I
= 100mA
LT1761-2.8,-3
f = 10Hz TO 100kHz
LT1761-2.5
LT1761-5
LT1761-5
C
= 1000pF
BYP
C
BYP
= 100pF
LT1761-BYP,
-SD, 1.2
LT1761-BYP
60
LT1761-1.5
0.1
0.01
LT1761-1.8
LT1761-2
0.1
0.01
C
= 0.01μF
BYP
40
LT1761-1.8, -2
100
C
C
I
= 10μF
= 0
OUT
BYP
L
20
LT1761-1.5
C
OUT
I
= 10μF
= 100mA
LT1761-BYP, -1.2
= 100mA
L
0
10
100
1k
FREQUENCY (Hz)
10k
100k
10
100
1k
FREQUENCY (Hz)
10k
100k
10
1k
10k
C
(pF)
BYP
1761 G43
1761 G41
1761 G42
1761sff
12
LT1761 Series
TYPICAL PERFORMANCE CHARACTERISTICS
LT1761-5
10Hz to 100kHz Output Noise
CBYP = 0pF
LT1761-5
10Hz to 100kHz Output Noise
CBYP = 100pF
RMS Output Noise vs
Load Current (10Hz to 100kHz)
160
140
120
100
80
C
= 10μF
OUT
C
= 0
BYP
BYP
C
= 0.01μF
LT1761-5
V
V
OUT
OUT
100μV/DIV
100μV/DIV
LT1761-BYP
LT1761-5
60
40
1761 G46
1761 G45
C
I
= 10μF
1ms/DIV
C
I
= 10μF
1ms/DIV
OUT
L
OUT
L
20
= 100mA
= 100mA
LT1761-BYP
10
0
0.01
0.1
1
100
LOAD CURRENT (mA)
1761 G44
LT1761-5
10Hz to 100kHz Output Noise
CBYP = 1000pF
LT1761-5
10Hz to 100kHz Output Noise
CBYP = 0.01μF
V
OUT
V
OUT
100μV/DIV
100μV/DIV
1761 G46
1761 G48
C
L
= 10μF
1ms/DIV
OUT
C
= 10μF
1ms/DIV
OUT
I
= 100mA
I = 100mA
L
LT1761-5 Transient Response
CBYP = 0pF
LT1761-5 Transient Response
CBYP = 0.01μF
V
C
C
= 6V
V
C
C
= 6V
IN
IN
IN
IN
0.2
0.1
0.04
0.02
0
= 10μF
= 10μF
= 10μF
= 10μF
OUT
OUT
0
–0.1
–0.2
–0.02
–0.04
100
50
0
100
50
0
800
TIME (μs)
80
0
400
1200
1600
2000
0
20 40 60
100 120 140 160 180 200
TIME (μs)
1761 G49
1761 G50
1761sff
13
LT1761 Series
PIN FUNCTIONS
IN (Pin 1): 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 LT1761 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.
BYP (Pins 3/4, Fixed/-BYP Devices): Bypass. The BYP
pin is used to bypass the reference of the LT1761 regula-
tors to achieve low noise performance from the regulator.
The BYP pin is clamped internally to 0.6V (one V ) from
BE
ground. A small capacitor from the output to this pin will
bypass the reference to lower the output voltage noise.
A maximum value of 0.01μF can be used for reducing
output voltage noise to a typical 20μV
over a 10Hz
RMS
to 100kHz bandwidth. If not used, this pin must be left
unconnected.
ADJ (Pin 4, Adjustable Devices Only): Adjust Pin. For the
adjustable LT1761, this is the input to the error amplifier.
This pin is internally clamped to 7V. It has a bias current
of 30nA which flows into the pin (see curve of ADJ Pin
Bias Current vs Temperature in the Typical Performance
Characteristics section). The ADJ pin voltage is 1.22V
referenced to ground and the output voltage range is
1.22V to 20V.
GND (Pin 2): Ground.
SHDN (Pin 3, Fixed/-SD Devices): Shutdown. The SHDN
pin is used to put the LT1761 regulators into a low power
shutdown state. The output will be off when the SHDN pin
ispulledlow.TheSHDNpincanbedriveneitherby5Vlogic
or open-collector logic with a pull-up resistor. The pull-up
resistor is required to supply the pull-up current of the
open-collector gate, normally several microamperes, and
the SHDN pin current, typically 1μA. If unused, the SHDN
OUT(Pin5):Output.Theoutputsuppliespowertotheload.
A minimum output capacitor of 1μF is required to prevent
oscillations. Larger output capacitors will be required for
applications with large transient loads to limit peak volt-
age transients. See the Applications Information section
for more information on output capacitance and reverse
output characteristics.
pin must be connected to V . The device will not function
IN
if the SHDN pin is not connected. For the LT1761-BYP, the
SHDN pin is internally connected to V .
IN
1761sff
14
LT1761 Series
APPLICATIONS INFORMATION
The LT1761 series are 100mA low dropout regulators with
micropowerquiescentcurrentandshutdown.Thedevices
are capable of supplying 100mA at a dropout voltage of
ADJ pin bias current. Note that in shutdown the output is
turned off and the divider current will be zero. Curves of
ADJ Pin Voltage vs Temperature and ADJ Pin Bias Cur-
rent vs Temperature appear in the Typical Performance
Characteristics.
300mV. Output voltage noise can be lowered to 20μV
RMS
over a 10Hz to 100kHz bandwidth with the addition of a
0.01μF reference bypass capacitor. Additionally, the refer-
ence bypass capacitor will improve transient response of
the regulator, lowering the settling time for transient load
conditions. The low operating quiescent current (20μA)
drops to less than 1μA in shutdown. In addition to the
low quiescent current, the LT1761 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 LT1761-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.
The adjustable device is tested and specified with the ADJ
pin tied to the OUT pin for an output voltage of 1.22V.
Specifications for output voltages greater than 1.22V will
be proportional to the ratio of the desired output voltage
to 1.22V: V /1.22V. For example, load regulation for an
OUT
output current change of 1mA to 100mA is –1mV typical
at V
= 1.22V. At V
= 12V, load regulation is:
OUT
OUT
(12V/1.22V)(–1mV) = –9.8mV
Bypass Capacitance and Low Noise Performance
The LT1761 regulators may be used with the addition of a
bypass capacitor from OUT to the BYP pin to lower output
voltage noise. A good quality low leakage capacitor is rec-
ommended. Thiscapacitorwillbypassthereferenceofthe
regulator, providing a low frequency noise pole. The noise
poleprovidedbythisbypasscapacitorwilllowertheoutput
voltage noise to as low as 20μV
with the addition of a
RMS
Adjustable Operation
0.01μF bypass capacitor. Using a bypass capacitor has the
added benefit of improving transient response. With no
bypass capacitor and a 10μF output capacitor, a 10mA to
100mA load step will settle to within 1% of its final value
in less than 100μs. With the addition of a 0.01μF bypass
capacitor, the output will stay within 1% for a 10mA to
100mA load step (see LT1761-5 Transient Response in
Typical Performance Characteristics section). However,
regulator start-up time is proportional to the size of the
bypass capacitor, slowing to 15ms with a 0.01μF bypass
capacitor and 10μF output capacitor.
TheadjustableversionoftheLT1761hasanoutputvoltage
range of 1.22V to 20V. The output voltage is set by the
ratio of two external resistors as shown in Figure 1. The
device servos the output to maintain the ADJ pin voltage
at 1.22V referenced to ground. The current in R1 is then
equal to 1.22V/R1 and the current in R2 is the current in
R1 plus the ADJ pin bias current. The ADJ pin bias cur-
rent, 30nA at 25°C, flows through R2 into the ADJ pin.
The output voltage can be calculated using the formula in
Figure 1. The value of R1 should be no greater than 250k
to minimize errors in the output voltage caused by the
IN
OUT
ADJ
V
OUT
¥
´
µ
R2
R1
+
V
ꢀ 1ꢄ22V 1ꢁ
ꢁ I
ꢂ
R2
V
ꢃꢂ
ꢃ
IN
OUT
ADJ
¦
§
¶
R2
R1
LT1761
GND
V
ꢀ 1ꢄ22V
ADJ
I
ꢀ 30nA AT 25oC
ADJ
OUTPUT RANGE = 1.22V TO 20V
1761 F01
Figure 1. Adjustable Operation
1761sff
15
LT1761 Series
APPLICATIONS INFORMATION
Output Capacitance and Transient Response
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 voltage applied and over the operating tempera-
ture 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 avail-
able 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
capacitancechangeovertemperature.Capacitancechange
due to DC bias with X5R and X7R capacitors is better than
Y5VandZ5Ucapacitors,butcanstillbesignificantenough
to drop capacitor values below appropriate levels. Capaci-
tor DC bias characteristics tend to improve as component
casesizeincreases, butexpectedcapacitanceatoperating
voltage should be verified.
The LT1761 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 capaci-
tors. A minimum output capacitor of 1μF with an ESR of
3Ω or less is recommended to prevent oscillations. The
LT1761-X is a micropower device and output transient
response will be a function of output capacitance. Larger
values of output capacitance decrease the peak deviations
and provide improved transient response for larger load
current changes. Bypass capacitors, used to decouple
individual components powered by the LT1761-X, will
increase the effective output capacitor value. With larger
capacitors used to bypass the reference (for low noise
operation), larger values of output capacitors are needed.
For 100pF of bypass capacitance, 2.2μF of output capaci-
tor is recommended. With a 330pF bypass capacitor or
larger, a 3.3μF output capacitor is recommended. The
shaded region of Figure 2 defines the region over which
the LT1761 regulators are stable. The minimum ESR
needed is defined by the amount of bypass capacitance
used, while the maximum ESR is 3Ω.
20
BOTH CAPACITORS ARE 16V,
1210 CASE SIZE, 10μF
0
X5R
–20
Extra consideration must be given to the use of ceramic
capacitors. Ceramic capacitors are manufactured with a
variety of dielectrics, each with different behavior across
temperature and applied voltage. The most common
dielectrics used are specified with EIA temperature char-
acteristic codes of Z5U, Y5V, X5R and X7R. The Z5U and
Y5V dielectrics are good for providing high capacitances
in a small package, but they tend to have strong voltage
–40
–60
Y5V
–80
–100
0
8
12 14
2
4
6
10
16
DC BIAS VOLTAGE (V)
1761 F03
Figure 3. Ceramic Capacitor DC Bias Characteristics
4.0
3.5
40
20
3.0
STABLE REGION
2.5
X5R
0
–20
2.0
–40
C
= 0
1.5
1.0
0.5
0
BYP
C
Y5V
= 100pF
BYP
–60
C
= 330pF
BYP
C
> 3300pF
BYP
–80
BOTH CAPACITORS ARE 16V,
1210 CASE SIZE, 10μF
–100
1
3
6 9 10
7 8
2
4
5
50
TEMPERATURE (°C)
100 125
–50 –25
0
25
75
OUTPUT CAPACITANCE (μF)
1761 F02
1761 F04
Figure 4. Ceramic Capacitor Temperature Characteristics
Figure 2. Stability
1761sff
16
LT1761 Series
APPLICATIONS INFORMATION
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 micro-
phone 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, especially when a ceramic capacitor is
used for noise bypassing. A ceramic capacitor produced
Figure 5’s trace in response to light tapping from a pencil.
Similar vibration induced behavior can masquerade as
increased output voltage noise.
The ground pin current can be found by examining the
GND Pin Current curves in the Typical Performance Char-
acteristics section. Power dissipation will be equal to the
sum of the two components listed above.
TheLT1761seriesregulatorshaveinternalthermallimiting
designedtoprotectthedeviceduringoverloadconditions.
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. Copper board stiffeners and plated
through-holes can also be used to spread the heat gener-
ated 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 3/32" FR-4 board with one ounce
copper.
V
OUT
500μV/DIV
Table 1. Measured Thermal Resistance
1761 F05
LT1761-5
100ms/DIV
COPPER AREA
THERMAL RESISTANCE
C
C
LOAD
= 10μF
OUT
BYP
= 0.01μF
= 100mA
TOPSIDE*
BACKSIDE BOARD AREA (JUNCTION-TO-AMBIENT)
I
2
2
2
2
2
2
2
2
2
2
2
2500mm
2500mm
2500mm
2500mm
2500mm
2500mm
2500mm
2500mm
2500mm
2500mm
2500mm
125°C/W
125°C/W
130°C/W
135°C/W
150°C/W
2
1000mm
Figure 5. Noise Resulting from Tapping on a Ceramic Capacitor
2
225mm
Thermal Considerations
2
100mm
2
50mm
The power handling capability of the device will be limited
by the maximum rated junction temperature (125°C). The
power dissipated by the device will be made up of two
components:
*Device is mounted on topside.
Calculating Junction Temperature
Example: Given an output voltage of 3.3V, an input voltage
range of 4V to 6V, an output current range of 0mA to 50mA
1. Output current multiplied by the input/output voltage
differential: (I )(V – V ), and
OUT
IN
OUT
2. GND pin current multiplied by the input voltage:
(I )(V ).
GND
IN
1761sff
17
LT1761 Series
APPLICATIONS INFORMATION
and a maximum ambient temperature of 50°C, what will
the maximum junction temperature be?
Current limit protection and thermal overload protection
areintendedtoprotectthedeviceagainstcurrentoverload
conditionsattheoutputofthedevice.Fornormaloperation,
the junction temperature should not exceed 125°C.
The power dissipated by the device will be equal to:
I
(V
– V ) + I (V
)
OUT(MAX) IN(MAX)
OUT
GND IN(MAX)
The input of the device will withstand reverse voltages
of 20V. Current flow into the device will be limited to less
than 1mA (typically less than 100μA) and no negative
voltage will appear at the output. The device will protect
both itself and the load. This provides protection against
batteries which can be plugged in backward.
where,
I
= 50mA
= 6V
OUT IN
OUT(MAX)
V
IN(MAX)
I
at (I
= 50mA, V = 6V) = 1mA
GND
So,
The output of the LT1761-X can be pulled below ground
withoutdamagingthedevice.Iftheinputisleftopencircuit
or grounded, the output can be pulled below ground by
20V. For fixed voltage versions, the output will act like a
largeresistor,typically500korhigher,limitingcurrentflow
to typically less than 100μA. 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.
P = 50mA(6V – 3.3V) + 1mA(6V) = 0.14W
The thermal resistance will be in the range of 125°C/W to
150°C/W depending on the copper area. So the junction
temperature rise above ambient will be approximately
equal to:
0.14W(150°C/W) = 21.2°C
The maximum junction temperature will then be equal to
the maximum junction temperature rise above ambient
plus the maximum ambient temperature or:
T
= 50°C + 21.2°C = 71.2°C
JMAX
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 100k) in series
with a diode when pulled above ground.
Protection Features
The LT1761 regulators incorporate several protection
features which make them ideal for use in battery-pow-
ered 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.
1761sff
18
LT1761 Series
APPLICATIONS INFORMATION
In situations where the ADJ pin is connected to a resistor
dividerthatwouldpulltheADJpinaboveits7Vclampvolt-
age 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
1.22V 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 output and ADJ
pin divided by the 5mA maximum current into the ADJ pin
yields a minimum top resistor value of 2.6k.
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 6.
When the IN pin of the LT1761-X is forced below the OUT
pin or the OUT pin is pulled above the IN pin, input cur-
rent 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.
In circuits where a backup battery is required, several
different input/output conditions can occur. The output
100
T = 25°C
LT1761-BYP
LT1761-SD
J
90 V = 0V
IN
CURRENT FLOWS
80
70
60
50
40
30
20
10
0
INTO OUTPUT PIN
= V
(LT1761-BYP, -SD)
LT1761-1.5
LT1761-1.2
V
OUT
ADJ
LT1761-1.8
LT1761-2
LT1761-2.5
LT1761-2.8
LT1761-3
LT1761-3.3
LT1761-5
4
0
1
2
3
5
6
7
8
9
10
OUTPUT VOLTAGE (V)
1761 F06
Figure 6. Reverse Output Current
1761sff
19
LT1761 Series
PACKAGE DESCRIPTION
S5 Package
5-Lead Plastic TSOT-23
(Reference LTC DWG # 05-08-1635)
0.62
MAX
0.95
REF
2.90 BSC
(NOTE 4)
1.22 REF
1.50 – 1.75
(NOTE 4)
2.80 BSC
1.4 MIN
3.85 MAX 2.62 REF
PIN ONE
RECOMMENDED SOLDER PAD LAYOUT
PER IPC CALCULATOR
0.30 – 0.45 TYP
5 PLCS (NOTE 3)
0.95 BSC
0.80 – 0.90
0.20 BSC
DATUM ‘A’
0.01 – 0.10
1.00 MAX
0.30 – 0.50 REF
1.90 BSC
0.09 – 0.20
(NOTE 3)
NOTE:
S5 TSOT-23 0302 REV B
1. DIMENSIONS ARE IN MILLIMETERS
2. DRAWING NOT TO SCALE
3. DIMENSIONS ARE INCLUSIVE OF PLATING
4. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR
5. MOLD FLASH SHALL NOT EXCEED 0.254mm
6. JEDEC PACKAGE REFERENCE IS MO-193
1761sff
20
LT1761 Series
REVISION HISTORY (Revision history begins at Rev F)
REV
DATE
DESCRIPTION
PAGE NUMBER
F
5/10
Added MP-grade
2, 3
22
Added Typical Application
1761sff
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 representa-
tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.
21
LT1761 Series
TYPICAL APPLICATION
Noise Bypassing Provides Soft-Start
Startup Time
100
10
1
5V
AT 100mA
IN
OUT
BYP
V
IN
LT1761-5
10μF
1μF
C
BYP
5.4V TO 20V
OFF ON
SHDN
GND
1761 TA02a
0.1
10
100
1000
10000
C
(pF)
BYP
1761 TA02b
RELATED PARTS
PART NUMBER
DESCRIPTION
COMMENTS
Includes 2.5V Reference and Comparator
LT1120
125mA Low Dropout Regulator with 20μA I
Q
LT1121
150mA Micropower Low Dropout Regulator
700mA Micropower Low Dropout Regulator
30μA I , SOT-223 Package
Q
LT1129
50μA Quiescent Current
LT1175
500mA Negative Low Dropout Micropower Regulator
300mA Low Dropout Micropower Regulator with Shutdown
3A Low Dropout Regulator with 50μA I
45μA I , 0.26V Dropout Voltage, SOT-223 Package
Q
LT1521
15μA I , Reverse-Battery Protection
Q
LT1529
500mV Dropout Voltage
Q
LT1762 Series
LT1763 Series
LTC1928
LT1962 Series
LT1963
150mA, Low Noise, LDO Micropower Regulator
500mA, Low Noise, LDO Micropower Regulator
Doubler Charge Pump with Low Noise Linear Regulator
300mA, Low Noise, LDO Micropower Regulator
1.5A, Low Noise, Fast Transient Response LDO
3A, Low Noise, Fast Transient Response LDO
25μA Quiescent Current, 20μV
30μA Quiescent Current, 20μV
Noise
Noise
RMS
RMS
Low Output Noise: 60μV
(100kHz BW)
RMS
30μA Quiescent Current, 20μV
Noise
RMS
40μV
40μV
, SOT-223 Package
RMS
LT1764
, 340mV Dropout Voltage
RMS
LTC3404
High Efficiency Synchronous Step-Down Switching Regulator Burst Mode® Operation, Monolithic, 100% Duty Cycle
1761sff
LT 0510 REV F • PRINTED IN USA
LinearTechnology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
22
●
●
© LINEAR TECHNOLOGY CORPORATION 2005
(408) 432-1900 FAX: (408) 434-0507 www.linear.com
相关型号:
LT1761IS5-3.3#TRM
LT1761 - 100mA, Low Noise, LDO Micropower Regulators in TSOT-23; Package: SOT; Pins: 5; Temperature Range: -40°C to 85°C
Linear
©2020 ICPDF网 联系我们和版权申明