LTC3872ETS8#TRMPBF Linear Technology, LTC3872ETS8#TRMPBF Datasheet

IC DC/DC CNTRLR TSOT23-8

LTC3872ETS8#TRMPBF

Manufacturer Part Number
LTC3872ETS8#TRMPBF
Description
IC DC/DC CNTRLR TSOT23-8
Manufacturer
Linear Technology
Type
Step-Up (Boost)r
Datasheet

Specifications of LTC3872ETS8#TRMPBF

Internal Switch(s)
No
Synchronous Rectifier
No
Number Of Outputs
1
Voltage - Output
1.2 ~ 60 V
Current - Output
10A
Frequency - Switching
550kHz
Voltage - Input
2.75 ~ 9.8 V
Operating Temperature
-40°C ~ 85°C
Mounting Type
Surface Mount
Package / Case
TSOT-23-8, TSOT-8
Primary Input Voltage
9.8V
No. Of Outputs
1
Output Voltage
60V
No. Of Pins
8
Operating Temperature Range
-40°C To +85°C
Msl
MSL 1 - Unlimited
Supply Voltage Range
2.75V To 9.8V
Rohs Compliant
Yes
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Power - Output
-
Other names
LTC3872ETS8#TRMPBF
LTC3872ETS8#TRMPBFTR

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Company
Part Number
Manufacturer
Quantity
Price
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Part Number:
LTC3872ETS8#TRMPBFLTC3872ETS8
Manufacturer:
LT
Quantity:
10 000
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Part Number:
LTC3872ETS8#TRMPBFLTC3872ETS8#PBF
Manufacturer:
LINEAR/凌特
Quantity:
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Company:
Part Number:
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Manufacturer:
LINEAR/凌特
Quantity:
20 000
Company:
Part Number:
LTC3872ETS8#TRMPBFLTC3872ETS8-1
Manufacturer:
LT
Quantity:
10 000
Company:
Part Number:
LTC3872ETS8#TRMPBFLTC3872ETS8-2
Manufacturer:
LT
Quantity:
10 000
FeaTures
n
n
n
n
n
n
n
n
n
n
applicaTions
n
n
n
n
Typical applicaTion
1.8nF
No Current Sense Resistor Required
V
Constant Frequency 550kHz Operation
Internal Soft-Start and Optional External Soft-Start
Adjustable Current Limit
Pulse Skipping at Light Load
V
±1.5% Voltage Reference Accuracy
Current Mode Operation for Excellent Line and Load
Transient Response
Low Profile (1mm) SOT-23 and 2mm × 3mm DFN
Packages
Telecom Power Supplies
42V Automotive Systems
24V Industrial Controls
IP Phone Power Supplies
OUT
IN
High Efficiency 3.3V Input, 5V Output Boost Converter
17.4k
47pF
Range: 2.75V to 9.8V
11k
1%
up to 60V
V
IN
34.8k
1%
I
IPRG
GND
V
TH
FB
RUN/SS
LTC3872
1nF
NGATE
V
SW
IN
M1
1µH
100µF
D1
×2
3872 TA01
10µF
V
3.3V
V
5V
2A
IN
OUT
DescripTion
The LTC
boost DC/DC controller that drives an N-channel power
MOSFET and requires very few external components. The
No R
resistor, improves efficiency and saves board space.
The LTC3872 provides excellent AC and DC load and line
regulation with ±1.5% output voltage accuracy. It incor-
porates an undervoltage lockout feature that shuts down
the device when the input voltage falls below 2.3V.
High switching frequency of 550kHz allows the use of a
small inductor. The LTC3872 is available in an 8-lead low
profile (1mm) ThinSOT
DFN package.
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and
No R
are the property of their respective owners.
SENSE
SENSE
and ThinSOT are trademarks of Linear Technology Corporation. All other trademarks
®
3872 is a constant frequency current mode
Efficiency and Power Loss vs Load Current
100
TM
90
80
70
60
50
40
30
20
10
0
architecture eliminates the need for a sense
1
Current Mode Boost
DC/DC Controller
10
LOAD CURRENT (mA)
TM
package and 8-pin 2mm × 3mm
100
1000
No R
3872 TA01b
LTC3872
10000
10
0.1
1
0.01
0.001
SENSE
3872fb
1

Related parts for LTC3872ETS8#TRMPBF

LTC3872ETS8#TRMPBF Summary of contents

Page 1

... High switching frequency of 550kHz allows the use of a small inductor. The LTC3872 is available in an 8-lead low profile (1mm) ThinSOT DFN package. L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and No R and ThinSOT are trademarks of Linear Technology Corporation. All other trademarks SENSE are the property of their respective owners ...

Page 2

LTC3872 absoluTe MaxiMuM raTings Input Supply Voltage (V ), RUN/SS .......... –0.3V to 10V IN IPRG Voltage ................................. –0. Voltages ....................................... –0. Voltage ................................................ –0.3V to 60V pin conFiguraTion TOP ...

Page 3

T PARAMETER Input Voltage Range Input DC Supply Current Normal Operation Shutdown UVLO Undervoltage Lockout Threshold Shutdown Threshold (at RUN/SS) Regulated Feedback Voltage Feedback Voltage Line Regulation Feedback Voltage Load Regulation V ...

Page 4

LTC3872 Typical perForMance characTerisTics FB Voltage vs Temperature 1.25 1.24 1.23 1.22 1.21 1.20 1.19 1.18 –60 –40 – TEMPERATURE (°C) 3872 G01 Shutdown ...

Page 5

Typical perForMance characTerisTics Gate Drive Rise and Fall Time vs C LOAD 100 RISE TIME 60 FALL TIME 2000 4000 6000 8000 10000 C (pF) LOAD 3872 G07 Frequency vs ...

Page 6

LTC3872 pin FuncTions (TS8/DD8) IPRG (Pin 1/Pin 4): Current Sense Limit Select Pin. I (Pin 2/Pin 3): It serves as the error amplifier com- TH pensation point. Nominal voltage range for this pin is 0.7V to 1.9V. V (Pin 3/Pin ...

Page 7

Main Control Loop The LTC3872 constant frequency, current SENSE mode controller for DC/DC boost, SEPIC and flyback converter applications. The LTC3872 is distinguished from conventional current mode controllers because the current control loop can be ...

Page 8

LTC3872 applicaTions inForMaTion Output Voltage Programming The output voltage is set by a resistor divider according to the following formula:  R2  = 1.2V •     The external resistor divider is connected ...

Page 9

V IN(MIN • D MAX ∆I • where: I O(MAX) = χ • ∆I L 1– D MAX Remember that boost converters are not ...

Page 10

LTC3872 applicaTions inForMaTion to 30V or less, and the switch node can ring during the turn-off of the MOSFET due to layout parasitics. Check the switching waveforms of the MOSFET directly across the drain and source terminals using the actual ...

Page 11

Calculating Power MOSFET Switching and Conduction Losses and Junction Temperatures In order to calculate the junction temperature of the power MOSFET, the power dissipated by the device must be known. This power dissipation is a function of the ...

Page 12

LTC3872 applicaTions inForMaTion For a 1% contribution to the total ripple voltage, the ESR of the output capacitor can be determined using the fol- lowing equation: 0.01• ESR ≤ COUT I IN(PEAK) where: I χ   O(MAX) ...

Page 13

In the case of tantalum critical that the capacitors have been surge tested for use in switching power supplies. An excellent choice is AVX TPS series of surface mount tantalum. ...

Page 14

LTC3872 applicaTions inForMaTion output current. Assuming an efficiency of 90%, this sense resistor power dissipation represents 1.3% of the overall input power. In other words, for this application, the use of V sensing would increase the efficiency by DS approximately ...

Page 15

And so the inductor value is: V 3.3V IN(MIN • MAX ∆I • f 1.3A • 550kHz L The component chosen is a 2.2µH inductor made by Sumida (part number CEP125-H 1ROMH). 3. Assuming ...

Page 16

LTC3872 Typical applicaTions High Efficiency 3.3V Input, 12V Output Boost Converter 2.2nF 23.2k 100pF 11.8k 1% AC-COUPLED STEP FROM 500mA TO 1.5A 16 4.7M 0.1µF I RUN/ IPRG 2.2µH LTC3872 GND SW V NGATE M1 PDS1040 ...

Page 17

Typical applicaTions High Efficiency 5V Input, 12V Output Boost Converter 4.7M 1nF 2.2nF 11k I RUN/ 100pF IPRG LTC3872 GND SW V NGATE FB 11.8k 1% 107k TAIYO YUDEN TMK325BJ226MM OUT1 L1: TOKO D124C ...

Page 18

LTC3872 Typical applicaTions 63.4k 2.2nF 12.1k 1% Soft-Start RUN/SS 5V/DIV I L 5A/DIV V OUT 20V/DIV 40ms/DIV 18 High Efficiency 5V Input, 48V Output Boost Converter 1M 0.33µF I RUN/ IPRG L1 10µH LTC3872 ...

Page 19

DescripTion package DescripTion 0.61 ±0.05 (2 SIDES) 0.70 ±0.05 2.55 ±0.05 1.15 ±0.05 PACKAGE OUTLINE 0.25 ± 0.05 0.50 BSC 2.20 ±0.05 (2 SIDES) RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS NOTE: 1. DRAWING CONFORMS TO VERSION (WECD-1) IN JEDEC ...

Page 20

LTC3872 package DescripTion 0.40 MAX 3.85 MAX 2.62 REF RECOMMENDED SOLDER PAD LAYOUT PER IPC CALCULATOR 0.20 BSC DATUM ‘A’ 0.30 – 0.50 REF NOTE: 1. DIMENSIONS ARE IN MILLIMETERS 2. DRAWING NOT TO SCALE 3. DIMENSIONS ARE INCLUSIVE OF ...

Page 21

... Added I-Grade and H-Grade parts. Changes reflected throughout the data sheet. 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. ...

Page 22

... Current Mode Control, 2.5V ≤ V SENSE Step-Up or Step Down, 600kHz, SSOP-16, SSOP-28 Optimized for Driving 6V MOSFETs ThinSOT www.linear.com ● 3. 10µF V OUT 5V 2A ×2 3872 TA02 16V, Miniature Design IN ≤ ≤ 36V IN LT 0311 REV B • PRINTED IN USA  LINEAR TECHNOLOGY CORPORA TION 2007 3872fb ...

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