LTC3531-3 Linear Technology, LTC3531-3 Datasheet

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LTC3531-3

Manufacturer Part Number
LTC3531-3
Description
Buck-Boost Synchronous DC/DC Converters
Manufacturer
Linear Technology
Datasheet
www.DataSheet4U.com
FEATURES
TYPICAL APPLICATIO
APPLICATIO S
Regulated Output with Input Above, Below or Equal
to the Output
Single Inductor
Up to 90% Effi ciency
V
200mA at 3.3V
125mA at 3V
Fixed V
Adjustable V
Burst Mode
Ultra Low Quiescent Current: 16µA, Shutdown
Current <1µA
Only 3 External Components Required
Short-Circuit Protection
Output Disconnect in Shutdown
Available in 6-Pin ThinSOT and 3mm × 3mm DFN
Packages
Handheld Instruments
MP3 Players
Handheld computers
PDA/GPS
IN
Range: 1.8V to 5.5V
3.1V TO
4.2V
Li-Ion
V
OUT
IN
Versions (TSOT, DFN): 3.3V, 3V
®
+
OUT
OUT
Operation, No External Compensation
OUT
Version (DFN): 2V to 5V
U
from 2.5V Input
2.2µF
from 3.6V Input
ON OFF
V
SW1
SHDN
LTC3531-3.3
IN
10µH
V
SW2
GND
OUT
U
3531 TA01a
V
3.3V
160mA
10µF
OUT
DESCRIPTIO
The LTC
buck-boost DC/DC converters that operate from input
voltages above, below or equal to the output voltage. The
topology incorporated in the ICs provides a continuous
transfer through all operating modes, making the product
ideal for single cell Li-Ion and multicell alkaline or nickel
applications. The converters operate in Burst Mode, mini-
mizing solution footprint and component count as well as
providing high conversion effi ciency over a wide range of
load currents.
The devices include two 0.5Ω N-channel MOSFET switches
and two P-channel switches (0.5Ω, 0.8Ω). Quiescent
current is typically 16µA, making the parts ideal for bat-
tery power applications. Other features include a <1µA
shutdown current, current limiting, thermal shutdown
and output disconnect. The parts are offered in a 6-pin
ThinSOT
3mm DFN package for fi xed and adjustable versions.
All other trademarks are the property of their respective owners.
Burst Mode is a registered trademark of Linear Techonology Corporation.
ThinSOT is a trademark of Linear Techonology Corporation.
Protected by U.S. Patents including 6166527.
, LTC and LT are registered trademarks of Linear Technology Corporation.
®
LTC3531-3.3/LTC3531-3
TM
3531/LTC3531-3.3/LTC3531-3 are synchronous
package for fi xed voltage versions or a 3mm ×
Synchronous DC/DC
100
95
90
85
80
75
70
65
60
1.5
200mA Buck-Boost
2
U
BOOST
MODE
Effi ciency vs V
2.5
INPUT VOLTAGE (V)
3
MODE
4SW
3.5
3.3V
Converters
IN
4
OUT
4.5
LTC3531/
MODE
BUCK
AT 100mA
3531 TA01b
5
5.5
1
3531f

Related parts for LTC3531-3

LTC3531-3 Summary of contents

Page 1

... SW2 V OUT V 3.3V OUT 160mA 10µF GND 3531 TA01a LTC3531/ LTC3531-3.3/LTC3531-3 200mA Buck-Boost Synchronous DC/DC Converters U ® 3531/LTC3531-3.3/LTC3531-3 are synchronous TM package for fi xed voltage versions or a 3mm × Effi ciency 100 95 90 BOOST MODE 85 BUCK MODE 80 4SW MODE ...

Page 2

... V OUT SHDN 4 5 FB* DD PACKAGE 8-LEAD (3mm × 3mm) PLASTIC DFN T = 125°C, θ = 43°C/W JMAX JA EXPOSED PAD IS GND (PIN 9), MUST BE SOLDERED TO PCB *NC FOR LTC3531-3.3V, LTC3531-3.0V. DD PART MARKING LBVC LBWH LCBV = 3.3V unless otherwise noted. MIN TYP ● 1.65 ● 3.25 3.32 ● 2.95 3.02 ● ...

Page 3

... Version) 100 90 10µ 22µ 5.5 1.5 2 2 (V) IN 3531 G04 LTC3531/ LTC3531-3.3/LTC3531-3 = 3.3V unless otherwise noted. MIN TYP 0.8 0.9 295 365 0 0. 25°C unless otherwise specifi ed. A Sleep Currents VIN PEAK ...

Page 4

... LTC3531/ LTC3531-3.3/LTC3531-3 W TYPICAL PERFOR A CE CHARACTERISTICS Start-Up into Resistive Load L = 10µ 1.5 2 2.5 3 3.5 4 4.5 V (V) IN Switch On Resistances 1000 3.3V D (PMOS) OUT 900 800 700 A (PMOS) 600 500 B,C (NMOS) 400 –40 – TEMPERATURE (° ...

Page 5

... L = 10μ 22μF OUT 5μs/DIV 3531 G13 , IN 5μs/DIV 3531 G15 100mA 5μs/DIV 3531 G17 LTC3531/ LTC3531-3.3/LTC3531 25°C unless otherwise specifi ed. A Buck Mode 3.3V 100mA OUT SW1 5V/DIV SW2 5V/DIV V (AC) OUT ...

Page 6

... LTC3531/ LTC3531-3.3/LTC3531-3 W TYPICAL PERFOR A CE CHARACTERISTICS Boost Mode Waveforms at 2.5V , 3.3V IN OUT SW1 5V/DIV SW2 5V/DIV V (AC) OUT 50mV/DIV I L 200mA/DIV L = 10μ 22μF OUT Shorted Output SW1 5V/DIV SW2 5V/DIV V (AC) OUT 50mV/DIV I L 200mA/DIV L = 10μ 22μF ...

Page 7

... GND pins as possible. OUT ⎯ S ⎯ H ⎯ D ⎯ N (Pin 4/Pin 4): External Shutdown Pin. An applied voltage of < 0.4V shuts down the converter. A voltage above >1.4V will enable the converter. LTC3531-3.3/LTC3531-3 V (Pin 5/Pin 2): Input Supply Pin for the Buck-Boost IN Converter. A minimum 2.2µF Ceramic Capacitor should ...

Page 8

... LTC3531/ LTC3531-3.3/LTC3531-3 W BLOCK DIAGRA V IN PEAK CURRENT LIMIT 365mA V IN UVLO 1.65V SHDN SHUTDOWN 8 SW1 SW2 SW A GATE DRIVERS AND ANTICROSS CONDUCTION BEST BUCK, 4SW, MODE DETECT BOOST STATE MACHINE AND LOGIC V OUT COMPARATOR THERMAL SHUTDOWN PGND GND ...

Page 9

... U OPERATIO The LTC3531, LTC3531-3.3 and LTC3531-3 synchro- nous buck-boost converters utilize a Burst Mode control technique to achieve high effi ciency over a wide dynamic range of load currents accurate comparator is used to monitor the output voltage programmed reference threshold no switching occurs and only quiescent current is drawn from the power source (sleep mode) ...

Page 10

... LTC3531/ LTC3531-3.3/LTC3531-3 U OPERATIO Buck Mode ~800mV above V , the LTC3531 operates in IN OUT buck or step-down mode. The higher offset between V and V (800mV) is required to ensure suffi cient mag- OUT netizing voltage across the inductor when the R are taken into account. At the beginning of a buck mode ...

Page 11

... CDRH3D16/HP Japan: 81-3-3607-5111 Toko D312C (847) 297-0070 D412C DB320C LTC3531-3.3/LTC3531 ductor value with a >500mA current rating and <400mΩ DCR is recommended. For applications where radiated noise is a concern, a toroidal or shielded inductor can be OUT used. Table 2 contains a list of inductor manufacturers. ...

Page 12

... LTC3531/ LTC3531-3.3/LTC3531 APPLICATIO S I FOR ATIO SHUTDOWN C OUT GND V – – SHDN OUT 5 – V GND – – SW1 SW2 – 1 SOT PIN-OUT Recommended Layout (SOT Versions) V OUT GND 3531f ...

Page 13

... OUT 80mA 10µF GND 3531 TA03a USB to 5V with 3 × 3 DFN (Adjustable Version) 10µH SW2 V OUT V 5V OUT 200mA R2 1M 10µ GND 324k 3531 TA04a LTC3531/ LTC3531-3.3/LTC3531 POWER LOSS 100 1000 ...

Page 14

... LTC3531/ LTC3531-3.3/LTC3531-3 PACKAGE DESCRIPTIO 0.62 0.95 MAX REF 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 PLATING Package 6-Lead Plastic TSOT-23 (Reference LTC DWG # 05-08-1636) 1.22 REF 1.50 – ...

Page 15

... 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. LTC3531-3.3/LTC3531 Package 8-Lead Plastic DFN (3mm × 3mm) (Reference LTC DWG # 05-08-1698) 0.675 ± ...

Page 16

... GND 100k PROG 22µF SHDN WALL NTC 100k 0.1µF www.linear.com ● L1 10µH SW1 SW2 V OUT 3. OUT 160mA LTC3531-3.3 C2 SHDN 10µF GND 3531 TA05 COMMENTS V : 2.6V to 16V 34V, IN OUT(MAX 4.2mA/5.5mA, I < 1µA, ThinSOT Package 0.85V to 5V 5V, IN OUT(MAX 19µ ...

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