IC DC/DC CONV SINGLE CELL 8-SOIC

LT1308BCS8#TRPBF

Manufacturer Part NumberLT1308BCS8#TRPBF
DescriptionIC DC/DC CONV SINGLE CELL 8-SOIC
ManufacturerLinear Technology
TypeStep-Up (Boost)
LT1308BCS8#TRPBF datasheet
 

Specifications of LT1308BCS8#TRPBF

Internal Switch(s)YesSynchronous RectifierNo
Number Of Outputs1Voltage - Output5V
Current - Output1AFrequency - Switching600kHz
Voltage - Input1 ~ 10 VOperating Temperature0°C ~ 70°C
Mounting TypeSurface MountPackage / Case8-SOIC (3.9mm Width)
Lead Free Status / RoHS StatusLead free / RoHS CompliantPower - Output-
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FEATURES
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
Switch: 300mV at 2A
CESAT
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
APPLICATIONS
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
TYPICAL APPLICATION
L1
4.7μH
V
SW
+
IN
C1
LBO
LBI
47μF
LT1308B
Li-Ion
SHUTDOWN
SHDN
CELL
V
GND
C
47k
100pF
C1: AVX TAJC476M010
L1: MURATA LQH6C4R7
C2: AVX TPSD227M006
*R1: 887k FOR V
OUT
D1: IR 10BQ015
Figure 1. LT1308B Single Li-Ion Cell to 5V/1A DC/DC Converter
High Current, Micropower
DESCRIPTION
®
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
internal V
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.
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.
D1
5V
1A
R1*
309k
+
C2
FB
220μF
R2
100k
= 12V
1308A/B F01a
LT1308A/LT1308B
Single Cell, 600kHz
DC/DC Converters
as on the LT1308. An
IN
clamp results in improved transient response
C
Converter Effi ciency
95
V
= 3.6V
V
= 4.2V
IN
IN
90
85
80
V
= 2.5V
IN
V
= 1.5V
IN
75
70
65
60
55
50
1
10
100
1000
LOAD CURRENT (mA)
1308A/B F01b
1308abfb
1

LT1308BCS8#TRPBF Summary of contents

  • Page 1

    ... The LT1308A/LT1308B are available in the 8-lead SO and the 14-lead TSSOP packages. 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. ...

  • Page 2

    ... S8 PACKAGE 8-LEAD PLASTIC SO = 125°C, θ 190°C/W JMAX JA ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL LT1308ACS8#PBF LT1308ACS8#TRPBF LT1308AIS8#PBF LT1308AIS8#TRPBF LT1308BCS8#PBF LT1308BCS8#TRPBF LT1308BIS8#PBF LT1308BIS8#TRPBF LT1308ACF#PBF LT1308ACF#TRPBF LT1308BCF#PBF LT1308BCF#TRPBF LEAD BASED FINISH TAPE AND REEL LT1308ACS8 LT1308ACS8#TR LT1308AIS8 LT1308AIS8#TR LT1308BCS8 LT1308BCS8#TR ...

  • Page 3

    ELECTRICAL CHARACTERISTICS range, otherwise specifi cations are 25°C. Commercial Grade 0°C to 70° SYMBOL PARAMETER I Quiescent Current Q V Feedback Voltage Pin Bias Current B Reference Line Regulation Minimum Input Voltage ...

  • Page 4

    LT1308A/LT1308B ELECTRICAL CHARACTERISTICS range, otherwise specifi cations are 25°C. Industrial Grade –40°C to 85° SYMBOL PARAMETER f Switching Frequency OSC Maximum Duty Cycle Switch Current Limit Switch V CESAT Burst Mode Operation Switch Current Limit ...

  • Page 5

    TYPICAL PERFORMANCE CHARACTERISTICS LT1308B 12V Output Effi ciency 3. 100 LOAD CURRENT (mA) 1308A/B G04 SHDN Pin Bias Current vs Voltage 50 ...

  • Page 6

    LT1308A/LT1308B PIN FUNCTIONS (SO/TSSOP) V (Pin 1/Pin 1): Compensation Pin for Error Amplifi er. C Connect a series RC from this pin to ground. Typical values are 47kΩ and 100pF. Minimize trace area (Pin 2/Pin 2): Feedback ...

  • Page 7

    BLOCK DIAGRAMS 40k V OUT R1 (EXTERNAL (EXTERNAL) Figure 2a. LT1308A/LT1308B Block Diagram (SO-8 Package 40k 40k V OUT R1 (EXTERNAL ...

  • Page 8

    LT1308A/LT1308B APPLICATIONS INFORMATION OPERATION The LT1308A combines a current mode, fi xed frequency PWM architecture with Burst Mode micropower opera- tion to maintain high effi ciency at light loads. Operation can be best understood by referring to the block diagram ...

  • Page 9

    APPLICATIONS INFORMATION Waveforms for a LT1308B 5V to 12V boost converter using a 10μF ceramic output capacitor are pictured in Figures 4 and 5. In Figure 4, the converter is operating in continuous mode, delivering a load current of approximately ...

  • Page 10

    LT1308A/LT1308B APPLICATIONS INFORMATION LBI LBO GROUND PLANE SHUTDOWN 3 12 LT1308A 4 11 LT1308B 10 5 MULTIPLE VIAs GND V OUT Figure 7. Recommended Component Placement for ...

  • Page 11

    APPLICATIONS INFORMATION SHDN PIN The LT1308A/LT1308B SHDN pin is improved over the LT1308. The pin does not require tying to V the device, but needs only a logic level signal. The voltage on the SHDN pin can vary from 1V ...

  • Page 12

    LT1308A/LT1308B APPLICATIONS INFORMATION V OUT 1V/DIV I L1 2A/DIV V SHDN 5V/DIV 500μs/DIV Figure 14. 5V Boost Converter of Figure 1. Start-Up from 3V Input into 5Ω Load V OUT 2V/DIV I SW 2A/DIV V SHDN 5V/DIV 500μs/DIV Figure 15. ...

  • Page 13

    APPLICATIONS INFORMATION 12V V OUT 5V/DIV 1A/DIV V SHDN 10V/DIV 50μs/DIV Figure 17. Start-Up Waveforms of Figure 16’s Circuit without Soft-Start Components 12V V OUT 1A/DIV V SHDN 10V/DIV 5ms/DIV Figure 18. Start-Up Waveforms ...

  • Page 14

    LT1308A/LT1308B APPLICATIONS INFORMATION Ceramic Capacitors Multilayer ceramic capacitors have become popular, due to their small size, low cost, and near-zero ESR. Ceramic capacitors can be used successfully in LT1308A/LT1308B designs provided loop stability is considered. A tantalum capacitor has some ...

  • Page 15

    APPLICATIONS INFORMATION V OUT 500mV/DIV I L1 1A/DIV 500mA LOAD CURRENT 50mA 200μs/DIV Figure 23. Load Step Response with 10μF X5R Ceramic Output Capacitor and C GSM AND CDMA PHONES The LT1308A/LT1308B are suitable for converting a single Li-Ion cell ...

  • Page 16

    LT1308A/LT1308B TYPICAL APPLICATIONS C1:TAIYO-YUDEN JMK212BJ475MG C2, C3:TAIYO-YUDEN LMK325BJ106MN C4, C5, C6:TAIYO-YUDEN EMK212BJ105MG D1: MBRM120 D2,D3,D4: BAT54S L1: TOKO 817FY-4R7M AV 500mV/DIV 500mV/DIV 500mV/DIV 800mA I LOAD 200mA 16 Triple Output TFTLCD Bias Supply D2 C4 1μF 0.22μF ...

  • Page 17

    TYPICAL APPLICATIONS 3.3V REGULATED Q1 C1: AVX TAJC476M010 C2: VITRAMON VJ225Y105KXCAT D1: BAT54 D2, D3: BAV21 High Voltage Supply 350V at 1.2mA 10nF 250V 47μ ...

  • Page 18

    LT1308A/LT1308B PACKAGE DESCRIPTION .245 MIN .030 ±.005 TYP RECOMMENDED SOLDER PAD LAYOUT .010 – .020 (0.254 – 0.508) .008 – .010 (0.203 – 0.254) NOTE: 1. DIMENSIONS IN 2. DRAWING NOT TO SCALE 3. THESE DIMENSIONS DO NOT INCLUDE MOLD ...

  • Page 19

    ... Obsoleted F Package 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. LT1308A/LT1308B PAGE NUMBER ...

  • Page 20

    ... C2 100μF 1308A/B TA01 Q , Operate with V as Low as 1. 250mA Inudctors 50mA from 3V Input Q , 36V, 350mA Switch Q to –34V OUT Output Noise RMS as Low as 1. 1210 REV B • PRINTED IN USA © LINEAR TECHNOLOGY CORPORA TION 1999 1308abfb ...