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LT1308BCS8#PBF

P1-P3P4-P6P7-P9P10-P12P13-P15P16-P18P19-P20
LT1308A/LT1308B
1
1308abfb
TYPICAL APPLICATION
DESCRIPTION
High Current, Micropower
Single Cell, 600kHz
DC/DC Converters
The LT
®
1308A/LT1308B are micropower, fi xed frequency
step-up DC/DC converters that operate over a 1V to 10V
input voltage range. They are improved versions of the
LT1308 and are recommended for use in new designs.
The LT1308A features automatic shifting to power sav-
ing Burst Mode operation at light loads and consumes
just 140µA at no load. The LT1308B features continuous
switching at light loads and operates at a quiescent cur-
rent of 2.5mA. Both devices consume less than 1µA in
shutdown.
Low-battery detector accuracy is signifi cantly tighter than
the LT1308. The 200mV reference is specifi ed at ±2%
at room and ±3% over temperature. The shutdown pin
enables the device when it is tied to a 1V or higher source
and does not need to be tied to V
IN
as on the LT1308. An
internal V
C
clamp results in improved transient response
and the switch voltage rating has been increased to 36V,
enabling higher output voltage applications.
The LT1308A/LT1308B are available in the 8-lead SO and
the 14-lead TSSOP packages.
Converter Effi ciency
FEATURES
APPLICATIONS
n
5V at 1A from a Single Li-Ion Cell
n
5V at 800mA in SEPIC Mode from Four NiCd Cells
n
Fixed Frequency Operation: 600kHz
n
Boost Converter Outputs up to 34V
n
Starts into Heavy Loads
n
Automatic Burst Mode™ Operation at
Light Load (LT1308A)
n
Continuous Switching at Light Loads (LT1308B)
n
Low V
CESAT
Switch: 300mV at 2A
n
Pin-for-Pin Upgrade Compatible with LT1308
n
Lower Quiescent Current in Shutdown: 1µA (Max)
n
Improved Accuracy Low-Battery Detector
Reference: 200mV ±2%
n
Available in 8-Lead SO and 14-Lead TSSOP Packages
n
GSM/CDMA Phones
n
Digital Cameras
n
LCD Bias Supplies
n
Answer-Back Pagers
n
GPS Receivers
n
Battery Backup Supplies
n
Handheld Computers
Figure 1. LT1308B Single Li-Ion Cell to 5V/1A DC/DC Converter
V
IN
SW
FB
LT1308B
L1
4.7µH
D1
LBO
LBI
47k
R2
100k
R1*
309k
5V
1A
100pF
1308A/B F01a
C1
47µF
C2
220µF
Li-Ion
CELL
V
C
GND
SHDNSHUTDOWN
C1: AVX TAJC476M010
C2: AVX TPSD227M006
D1: IR 10BQ015
+
+
L1: MURATA LQH6C4R7
*R1: 887k FOR V
OUT
= 12V
LOAD CURRENT (mA)
1
EFFICIENCY (%)
95
90
85
80
75
70
65
60
55
50
10 100 1000
1308A/B F01b
V
IN
= 4.2V
V
IN
= 1.5V
V
IN
= 2.5V
V
IN
= 3.6V
L, LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo are registered trademarks
of Linear Technology Corporation. All other trademarks are the property of their respective
owners.
LT1308A/LT1308B
2
1308abfb
ABSOLUTE MAXIMUM RATINGS
V
IN
, SHDN, LBO Voltage ........................................... 10V
SW Voltage .............................................. –0.4V to 36V
FB Voltage ......................................................... V
IN
+ 1V
V
C
Voltage ................................................................. 2V
LBI Voltage ................................................. –0.1V to 1V
Current into FB Pin ............................................... ±1mA
(Note 1)
1
2
3
4
8
7
6
5
TOP VIEW
LBO
LBI
V
IN
SW
V
C
FB
SHDN
GND
S8 PACKAGE
8-LEAD PLASTIC SO
T
JMAX
= 125°C, θ
JA
= 190°C/W
F PACKAGE
14-LEAD PLASTIC TSSOP
1
2
3
4
5
6
7
TOP VIEW
14
13
12
11
10
9
8
V
C
FB
SHDN
GND
GND
GND
GND
LBO
LBI
V
IN
V
IN
SW
SW
SW
(NOTE 6)
T
JMAX
= 125°C, θ
JA
= 80°C/W
OBSOLETE, FOR INFORMATION PURPOSES ONLY
Contact Linear Technology for Potential Replacement
PIN CONFIGURATION
ORDER INFORMATION
LEAD FREE FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE
LT1308ACS8#PBF LT1308ACS8#TRPBF 1308A 8-Lead Plastic SO 0°C to 70°C
LT1308AIS8#PBF LT1308AIS8#TRPBF 1308AI 8-Lead Plastic SO –40°C to 85°C
LT1308BCS8#PBF LT1308BCS8#TRPBF 1308B 8-Lead Plastic SO 0°C to 70°C
LT1308BIS8#PBF LT1308BIS8#TRPBF 1308BI 8-Lead Plastic SO –40°C to 85°C
LT1308ACF#PBF LT1308ACF#TRPBF LT1308ACF 14-Lead Plastic TSSOP 0°C to 70°C
LT1308BCF#PBF LT1308BCF#TRPBF LT1308BCF 14-Lead Plastic TSSOP 0°C to 70°C
LEAD BASED FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE
LT1308ACS8 LT1308ACS8#TR 1308A 8-Lead Plastic SO 0°C to 70°C
LT1308AIS8 LT1308AIS8#TR 1308AI 8-Lead Plastic SO –40°C to 85°C
LT1308BCS8 LT1308BCS8#TR 1308B 8-Lead Plastic SO 0°C to 70°C
LT1308BIS8 LT1308BIS8#TR 1308BI 8-Lead Plastic SO –40°C to 85°C
LT1308ACF LT1308ACF#TR LT1308ACF 14-Lead Plastic TSSOP 0°C to 70°C
LT1308BCF LT1308BCF#TR LT1308BCF 14-Lead Plastic TSSOP 0°C to 70°C
Consult LTC Marketing for parts specifi ed with wider operating temperature ranges.
For more information on lead free part marking, go to:
http://www.linear.com/leadfree/
This product is only offered in trays. For more information go to:
http://www.linear.com/packaging/
Operating Temperature Range
Commercial............................................. 0°C to 70°C
Extended Commerial (Note 2) ............ –40°C to 85°C
Industrial ........................................... –40°C to 85°C
Storage Temperature Range .................. –65°C to 150°C
Lead Temperature (Soldering, 10 sec) ................. 300°C
LT1308A/LT1308B
3
1308abfb
The l denotes the specifi cations which apply over the full operating temperature
range, otherwise specifi cations are at T
A
= 25°C. Commercial Grade 0°C to 70°C. V
IN
= 1.1V, V
SHDN
= V
IN
, unless otherwise noted.
ELECTRICAL CHARACTERISTICS
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
I
Q
Quiescent Current Not Switching, LT1308A
Switching, LT1308B
V
SHDN
= 0V (LT1308A/LT1308B)
140
2.5
0.01
240
4
1
µA
mA
µA
V
FB
Feedback Voltage
l
1.20 1.22 1.24 V
I
B
FB Pin Bias Current (Note 3)
l
27 80 nA
Reference Line Regulation 1.1V ≤ V
IN
≤ 2V
2V ≤ V
IN
≤ 10V
l
0.03
0.01
0.4
0.2
%/V
%/V
Minimum Input Voltage 0.92 1 V
g
m
Error Amp Transconductance ∆I = 5µA 60 µmhos
A
V
Error Amp Voltage Gain 100 V/V
f
OSC
Switching Frequency V
IN
= 1.2V
l
500 600 700 kHz
Maximum Duty Cycle
l
82 90 %
Switch Current Limit Duty Cycle = 30% (Note 4) 2 3 4.5 A
Switch V
CESAT
I
SW
= 2A (25°C, 0°C), V
IN
= 1.5V
I
SW
= 2A (70°C), V
IN
= 1.5V
290
330
350
400
mV
mV
Burst Mode Operation Switch Current Limit
(LT1308A)
V
IN
= 2.5V, Circuit of Figure 1 400 mA
Shutdown Pin Current V
SHDN
= 1.1V
V
SHDN
= 6V
V
SHDN
= 0V
l
l
l
2
20
0.01
5
35
0.1
µA
µA
µA
LBI Threshold Voltage
l
196
194
200
200
204
206
mV
mV
LBO Output Low I
SINK
= 50µA
l
0.1 0.25 V
LBO Leakage Current V
LBI
= 250mV, V
LBO
= 5V
l
0.01 0.1 µA
LBI Input Bias Current (Note 5) V
LBI
= 150mV 33 100 nA
Low-Battery Detector Gain 3000 V/V
Switch Leakage Current V
SW
= 5V
l
0.01 10 µA
The l denotes the specifi cations which apply over the full operating temperature range, otherwise specifi cations are at T
A
= 25°C.
Industrial Grade –40°C to 85°C. V
IN
= 1.2V, V
SHDN
= V
IN
, unless otherwise noted.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
I
Q
Quiescent Current Not Switching, LT1308A
Switching, LT1308B
V
SHDN
= 0V (LT1308A/LT1308B)
l
l
l
140
2.5
0.01
240
4
1
µA
mA
µA
V
FB
Feedback Voltage
l
1.19 1.22 1.25 V
I
B
FB Pin Bias Current (Note 3)
l
27 80 nA
Reference Line Regulation 1.1V ≤ V
IN
≤ 2V
2V ≤ V
IN
≤ 10V
l
l
0.05
0.01
0.4
0.2
%/V
%/V
Minimum Input Voltage 0.92 1 V
g
m
Error Amp Transconductance ∆I = 5µA 60 µmhos
A
V
Error Amp Voltage Gain 100 V/V
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LT1308BCS8#PBF

Mfr. #:
Buy LT1308BCS8#PBF
Manufacturer:
Analog Devices / Linear Technology
Description:
Switching Voltage Regulators 1x Cell Hi C uP 600kHz Boost DC/DC Conv
Lifecycle:
New from this manufacturer.
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