Datasheet

ManualsBrandsLINEAR TECHNOLOGY ManualsPMICsPMIC - DC/DC voltage regulator Boost SC 70 6

LTC3525-3/

LTC3525-3.3/LTC3525-5

3525fb

LOAD (mA)

0.01 0.1

EFFICIENCY (%)

100

POWER LOSS (mW)

100

0.1

0.01

1 10 1000100

LT3525 • TA02

EFFICIENCY

POWER LOSS

= 3V

= 2.4V

= 1.2V

400mA Micropower

Synchronous Step-Up DC/DC

Converter with Output Disconnect

The LTC

3525-3/LTC3525-3.3/LTC3525-5 are high ef-

ficiency synchronous step-up DC/DC converters with

output disconnect that can start up with an input as low

as 1V. They offer a compact, high efficiency alternative to

charge pumps in single cell or dual cell alkaline or Li-Ion

applications. Only three small external components are

required. The LTC3525 is offered in fixed output voltages

of 3V, 3.3V or 5V.

The device includes a 0.5Ω N-channel MOSFET switch

and a 0.8Ω P-channel synchronous rectifier. Peak switch

current ranges from 150mA to 400mA, depending on

load, providing enhanced efficiency. Quiescent current

is an ultralow 7µA, maximizing battery life in portable

applications.

Other features include <1µA shutdown current, anti-

ringing control and thermal shutdown. The LTC3525 is

available in a tiny 6-pin SC70 package.

MP3 Players

Portable Instruments

Glucose Meters

Digital Cameras

Up to 95% Efficiency

Output Disconnect and Inrush Current Limit

Fixed Output Voltages of 3V, 3.3V or 5V

Delivers 65mA at 3V from a 1V Input

Delivers 60mA at 3.3V from a 1V Input,

or 140mA at 3.3V from a 1.8V Input

Delivers 175mA at 5V from a 3V Input

Burst Mode

Operation: I

= 7µA

Only Three External Components

> V

OUT

Operation

<1µA Shutdown Current

Antiringing Control

Short-Circuit and Overtemperature Protection

Very Low Profile of 1mm

Tiny 6-Pin SC70 Package

LTC3525-3.3 Efficiency and Power

Loss vs Load Current

L, LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo are registered trademarks

and ThinSOT is a trademark of Linear Technology Corporation. All other trademarks are the

property of their respective owners. Patents pending.

TYPICAL APPLICATION

FEATURES DESCRIPTION

APPLICATIONS

L1*

10µH

3525 TA01

LTC3525-3.3

*MURATA LQH32CN100K53

OUT

3.3V

60mA

OUT

GND

SHDN

GND

1V TO 1.6V

10µF

1µF

OFF ON

Summary of content (14 pages)

PAGE 1
LTC3525-3/ LTC3525-3.3/LTC3525-5 400mA Micropower Synchronous Step-Up DC/DC Converter with Output Disconnect FEATURES n n n n n n n n n n n n n n DESCRIPTION Up to 95% Efficiency Output Disconnect and Inrush Current Limit Fixed Output Voltages of 3V, 3.3V or 5V Delivers 65mA at 3V from a 1V Input Delivers 60mA at 3.3V from a 1V Input, or 140mA at 3.3V from a 1.
PAGE 2
LTC3525-3/ LTC3525-3.3/LTC3525-5 ABSOLUTE MAXIMUM RATINGS (Note 1) PIN CONFIGURATION VIN, VOUT Voltage......................................... – 0.3V to 6V SW Voltage.................................................. – 0.3V to 6V SW Voltage < 100ns..................................... –0.3V to 7V SHDN Voltage.............................................. –0.3V to 6V Operating Temperature Range (Notes 2, 5)...............................................–40°C to 85°C Storage Temperature Range.............
PAGE 3
LTC3525-3/ LTC3525-3.3/LTC3525-5 ELECTRICAL CHARACTERISTICS (LTC3525-3.3) The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VIN = 1.2V, VSHDN = 1.2V, VOUT = 3.3V unless otherwise noted. PARAMETER CONDITIONS MIN Input Start-Up Voltage MAX 0.85 1 UNITS V Output Voltage (Note 6) 3.30 3.40 V Quiescent Current, VOUT SHDN = VIN (Note 4) 7 15 µA Quiescent Current, VIN SHDN = VIN (Note 4) 0.
PAGE 4
LTC3525-3/ LTC3525-3.3/LTC3525-5 TYPICAL PERFORMANCE CHARACTERISTICS TA = 25°C unless otherwise noted. Maximum Output Current vs VIN (for VOUT to Drop 2.5%) 300 Maximum Startup Load vs VIN (Resistive Load) LTC3525-3.3 250 No-Load Input Current vs VIN 45 LTC3525-5 200 40 35 LOAD (mA) LTC3525-3 LTC3525-5 150 150 LTC3525-3.3 IIN (µA) 200 IOUT (mA) 50 250 100 100 30 25 LTC3525-5 20 15 50 50 LTC3525-3 10 LTC3525-3.3 5 0 0.5 1.0 1.5 2.0 2.5 3.0 VIN (V) 4.0 3.5 0 4.5 0.5 1.
PAGE 5
LTC3525-3/ LTC3525-3.3/LTC3525-5 TYPICAL PERFORMANCE CHARACTERISTICS TA = 25°C unless otherwise noted. LTC3525-5 Load Regulation VIN = 2.4V 2.0 1.5 1.5 1.0 1.0 0.5 COUT = 22µF 0 –0.5 –1.0 COUT = 10µF 0.5 COUT = 22µF 0 COUT = 10µF –0.5 –1.0 900 800 700 –2.0 –2.0 400 40 60 80 100 LOAD (mA) 120 140 –2.5 0 50 100 LOAD (mA) 150 3525 G09 0.3 30 0.2 15 10 COUT = 22µF 5 0 0.1 1 LOAD (mA) 2.5 3.0 VIN (V) 3.5 4.0 4.5 120 100 0.1 0 –0.1 –0.2 80 60 40 20 –0.3 10 2.
PAGE 6
LTC3525-3/ LTC3525-3.3/LTC3525-5 TYPICAL PERFORMANCE CHARACTERISTICS TA = 25°C unless otherwise noted. LTC3525-3.3 Output Voltage Ripple LTC3525-3.3 Output Voltage Ripple IOUT 5mA IOUT 5mA IOUT 40mA 50mV/DIV IOUT 100mA IOUT 80mA VIN = 1.2V COUT = 22µF 3525 G17 50µs/DIV VIN = 2.4V COUT = 22µF 3525 G18 50µs/DIV LTC3525-5 Output Voltage Ripple LTC3525-5 Output Voltage Ripple IOUT 20mA IOUT 5mA IOUT 50mA 50mV/DIV IOUT 100mA 50mV/DIV IOUT 200mA IOUT 150mA VIN = 2.
PAGE 7
LTC3525-3/ LTC3525-3.3/LTC3525-5 PIN FUNCTIONS SHDN (Pin 1): Logic-Controlled Shutdown Input. Connect to a voltage >1V to enable the LTC3525. Connect to a voltage <0.4V to disable the LTC3525. VOUT (Pin 4): Output Voltage Sense and the Output of the Synchronous Rectifier. Connect the output filter capacitor from VOUT to GND, close to the IC. A minimum value of 10µF ceramic is recommended. Use 22µF for reduced output ripple. The output disconnect feature disconnects VOUT from VIN when SHDN is <0.4V.
PAGE 8
LTC3525-3/ LTC3525-3.3/LTC3525-5 OPERATION The LTC3525 is a high performance Burst Mode operation only, synchronous boost converter requiring only three small external components. Its simplicity and small size make it a high efficiency alternative to charge pump designs. It is designed to start up from a single alkaline or nickel cell, with input voltages as low as 1V, or from two or three cells (or a Li-Ion battery), with voltages as high as 4.5V. Once started, VIN can be as low as 0.
PAGE 9
LTC3525-3/ LTC3525-3.3/LTC3525-5 OPERATION which point it turns off and the cycle repeats. When the output voltage reaches its regulated value both switches are turned off and the LTC3525 goes to sleep, during which time the output capacitor supplies current to the load. Once the output voltage drops approximately 9mV below the regulation value the IC leaves sleep mode and switching is resumed. The LTC3525 has been designed for low output voltage ripple.
PAGE 10
LTC3525-3/ LTC3525-3.3/LTC3525-5 OPERATION Component Selection Inductor values between 4.7µH and 15µH are recommended. In most applications 10µH will yield the best compromise between size and efficiency. The inductor should be a low loss ferrite design and must be rated for peak currents of at least 400mA without saturating. Inductors with lower DC resistance will improve efficiency.
PAGE 11
LTC3525-3/ LTC3525-3.3/LTC3525-5 TYPICAL APPLICATIONS Single Alkaline or NiMH to 3.3V Converter with 1mm Profile Single Cell to 3V Converter Using 1mm High Monolithic Inductor 6.8µH* 1V TO 1.6V 3 1 + 2 1µF 6.8µH* LTC3525-3 VIN SW SHDN VOUT GND GND 1V TO 1.6V 6 VOUT 3V 65mA 4 5 1 + 2 10µF 4V 1µF 3525 TA03 *FDK MIP3226D6R8M 3 LTC3525-3.3 VIN SHDN VOUT GND GND + + 1 2 1µF *MURATA LQH32CN1002K53 5 10µF** 6.3V 3525 TA04 10µH* LTC3525-3.3 VIN VOUT 3.
PAGE 12
LTC3525-3/ LTC3525-3.3/LTC3525-5 PACKAGE DESCRIPTION SC6 Package 6-Lead Plastic SC70 (Reference LTC DWG # 05-08-1638 Rev B) 0.47 MAX 0.65 REF 1.80 – 2.20 (NOTE 4) 1.00 REF INDEX AREA (NOTE 6) 1.80 – 2.40 1.15 – 1.35 (NOTE 4) 2.8 BSC 1.8 REF PIN 1 RECOMMENDED SOLDER PAD LAYOUT PER IPC CALCULATOR 0.10 – 0.40 0.65 BSC 0.15 – 0.30 6 PLCS (NOTE 3) 0.80 – 1.00 1.00 MAX 0.00 – 0.10 REF GAUGE PLANE 0.15 BSC 0.26 – 0.46 0.10 – 0.18 (NOTE 3) NOTE: 1. DIMENSIONS ARE IN MILLIMETERS 2.
PAGE 13
LTC3525-3/ LTC3525-3.3/LTC3525-5 REVISION HISTORY (Revision history begins at Rev B) REV DATE DESCRIPTION PAGE NUMBER B 09/10 Updated “Shutdown” section 8 3525fb 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.
PAGE 14
LTC3525-3/ LTC3525-3.3/LTC3525-5 TYPICAL APPLICATION 3.3V TO 5V Converter with 1.4mm Profile 10µH* 3 3.3V 1 2 1µF LTC3525-5 VIN SW SHDN VOUT GND GND 6 VOUT 5V 200mA 4 5 *COILCRAFT DO3314-103MXD **MURATA GRM21BR60J226ME39L 22µF** 6.3V 3525 TA07 RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LT 1615/LT1615-1 300mA/80mA (ISW), High Efficiency Step-Up DC/DC Converter VIN: 1V to 15V, VOUT(MAX) = 34V, IQ = 20µA, ISD < 1µA, ThinSOT™ Package LTC1751-3.