ltc3528-2 Linear Technology Corporation, ltc3528-2 Datasheet

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ltc3528-2

Manufacturer Part Number
ltc3528-2
Description
Ltc3528-2 - 1a, 2mhz Synchronous Step-up Dc/dc Converter In 2mm ? 3mm Dfn
Manufacturer
Linear Technology Corporation
Datasheet
FEATURES
APPLICATIONS
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TYPICAL APPLICATION
1.8V TO 3.2V
Delivers 3.3V at 200mA from a Single Alkaline/
NiMH Cell or 3.3V at 400mA from Two Cells
V
0.50V to 5.5V Input Range
1.6V to 5.25V V
Up to 94% Efficiency
Output Disconnect
2MHz Fixed Frequency Operation
V
Integrated Soft-Start
Current Mode Control with Internal Compensation
Burst Mode
Internal Synchronous Rectifier
Logic Controlled Shutdown: <1µA
Anti-Ringing Control
Low Profile (2mm × 3mm × 0.75mm) DFN Package
Medical Instruments
Noise Canceling Headphones
Wireless Mice
Bluetooth Headsets
IN
IN
Start-Up Voltage: 700mV
> V
V
IN
OUT
OFF ON
Operation
®
4.7µF
Operation with 12µA Quiescent Current
OUT
2.2µH
V
PGOOD
SHDN
IN
LTC3528-2
Range
GND
SW
V
OUT
FB
499k
287k
68pF
35282 TA01a
10µF
V
3.3V
400mA
OUT
Step-Up DC/DC Converter
DESCRIPTION
The LTC
DC/DC converter with output disconnect. High efficiency
synchronous rectification, in addition to a 700mV start-
up voltage and operation down to 500mV once started,
provides longer run-time for single or multiple cell battery-
powered products.
A switching frequency of 2MHz minimizes solution
footprint by allowing the use of tiny, low profile induc-
tors and ceramic capacitors. The current mode PWM is
internally compensated, simplifying the design process.
The LTC3528-2 enters Burst Mode operation at light loads.
Anti-ringing circuitry reduces EMI by damping the induc-
tor in discontinuous mode. Additional features include a
low shutdown current, open-drain power good output,
short-circuit protection and thermal overload protection.
The LTC3528-2 is offered in an 8-lead 2mm × 3mm ×
0.75mm DFN package.
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.
®
1A, 2MHz Synchronous
3528-2 is a synchronous, fixed frequency step-up
100
70
60
40
30
20
10
90
80
50
0
0.01
V
V
in 2mm × 3mm DFN
OUT
IN
= 2.4V
Efficiency and Power Loss
= 3.3V
0.1
EFFICIENCY
LOAD CURRENT (mA)
1
POWER LOSS
10
LTC3528-2
100
35282 TA01b
1000
1000
100
10
1
0.1
0.01
35282fa
1

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ltc3528-2 Summary of contents

Page 1

... Additional features include a low shutdown current, open-drain power good output, short-circuit protection and thermal overload protection. The LTC3528-2 is offered in an 8-lead 2mm × 3mm × 0.75mm DFN package. L, LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo are registered trademarks and ThinSOT is a trademark of Linear Technology Corporation ...

Page 2

... LTC3528-2 ABSOLUTE MAXIMUM RATINGS (Note 1) V Voltage ................................................... –0. Voltage DC ............................................................ –0. Pulsed < 100ns ........................................ –0. SHDN, FB Voltage ........................................ –0. ............................................................. –0. OUT PGOOD ......................................................... –0. Operating Junction Temperature Range (Notes 2, 5) ............................................ –40°C to 125°C Junction Temperature ........................................... 125°C Storage Temperature Range ................... – ...

Page 3

... Note 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliability and lifetime. Note 2: The LTC3528-2 is tested under pulsed load conditions such that T ≈ The LTC3528E-2 is guaranteed to meet specifications from 0°C to ...

Page 4

... LTC3528-2 TYPICAL PERFORMANCE CHARACTERISTICS Efficiency vs Load Current and V for V = 3.3V IN OUT 100 EFFICIENCY POWER 60 LOSS 0.01 0 100 1000 LOAD CURRENT (mA) 35282 G02 Maximum Output Current 800 700 600 500 400 300 200 V = 1.8V OUT ...

Page 5

... TEMPERATURE (˚C) Output Voltage vs Load Current for V = 3.3V OUT 0. 1.2V IN 0.15 0.10 0.05 0 –0.05 –0.10 –0.15 –0.20 600 0 50 100 150 LOAD CURRENT (mA) LTC3528 25°C unless otherwise noted DS(ON) OUT 450 400 350 300 PMOS 250 200 NMOS 150 100 4.5 5 1.5 2 2.5 3 3.5 V (V) ...

Page 6

... LTC3528-2 TYPICAL PERFORMANCE CHARACTERISTICS Fixed Frequency V Ripple and OUT Inductor Current Waveforms V OUT 20mV/DIV I L 200mA/DIV 35282 G19 V = 1.2V 500ns/DIV 3.3V OUT C = 10µF OUT C = 33pF 100mA OUT L = 2.2µH Load Step Response (Fixed Frequency, 3.6V to 5V) V OUT 100mV/DIV LOAD CURRENT 200mA/DIV V = 3.6V 20µs/DIV ...

Page 7

... IN 1µF ceramic decoupling capacitor from this pin to ground. GND (Exposed Pad Pin 9): The exposed pad must be soldered to the PCB ground plane. It serves as another ground connection and as a means of conducting heat away from the die. LTC3528-2 to minimize EMI. IN 35282fa 7 ...

Page 8

... LTC3528-2 BLOCK DIAGRAM 4.7µF SHDN 1 SHUTDOWN 4M V REF UVLO START-UP 2MHz OSC PGOOD REF – FB THERMAL SHUTDOWN PGND 2.2µ ANTI-RING V OUT V SEL V BEST V B GATE DRIVERS AND ANTI-CROSS SHUTDOWN CONDUCTION Σ PK COMP V REF – ...

Page 9

... LTC3528-2 achieves high efficiency over a wide range of load current. The LTC3528-2 features continuous 2MHz PWM operation over a wide range of load current. At very light loads, the LTC3528-2 will enter Burst Mode operation to maintain high efficiency. Operation can be best understood by referring to the Block Diagram. ...

Page 10

... L and pin) is low energy, but can cause EMI radiation. Output Disconnect The LTC3528-2 is designed to allow true output discon- nect by eliminating body diode conduction of the internal P-channel MOSFET rectifier. This allows for V zero volts during shutdown, drawing no current from the input source ...

Page 11

... Single Cell to 5V Step-Up Applications Due to the high inductor current slew rate in applications boosting to 5V from a single cell (alkaline, NiCd or NiMH), the LTC3528-2 may not enter Burst Mode operation at in- put voltages below 1.5V. For single cell to 5V applications requiring Burst Mode operation, the 1MHz LTC3528 is recommended ...

Page 12

... PGND rent without saturating. Molded chokes and some chip inductors usually do not have enough core area to support SW the peak inductor currents of 1.5A seen on the LTC3528-2. 35282 F02 MULTIPLE VIAS To minimize radiated noise, use a shielded inductor. See TO GROUND PLANE Table 1 for suggested components and suppliers ...

Page 13

... FB PGOOD OFF ON SHDN GND The internal loop compensation of the LTC3528-2 is de- signed to be stable with output capacitor values of 10µF or greater. Although ceramic capacitors are recommended, low ESR tantalum capacitors may be used as well. A small ceramic capacitor in parallel with a larger tantalum capacitor may be used in demanding applications which have large load transients ...

Page 14

... V IN 0.88V TO 1.6V 475k LTC3528-2 4.7µF PGOOD SHDN OFF ON 2.2µ 4.7µF LTC3528-2 PGOOD SHDN 1 Cell to 3.3V 2.2µ OUT 0.88V TO 1.6V 4.7µF LTC3528-2 PGOOD FB SHDN OFF ON GND OUT1 1.8V V OUT 250mA 68pF 499k FB 10µF 1M GND 0.5V/DIV SW V OUT2 3V V OUT ...

Page 15

... OFF ON GND V OUT 3.3V 400mA 499k 68pF 10µF 287k 35282 TA05a V OUT 5V 300mA 1M 68pF 22µF 316k 35282 TA06a V OUT 5V 400mA 1M 68pF 316k 35282 TA07a LTC3528-2 Efficiency 100 1000 0.01 100 LOAD CURRENT (mA) 35282 TA05b Efficiency ...

Page 16

... LTC3528-2 PACKAGE DESCRIPTION 0.61 ±0.05 (2 SIDES) 2.55 ±0.05 1.15 ±0.05 0.25 ± 0.05 RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS PIN 1 BAR TOP MARK (SEE NOTE 6) 0.200 REF NOTE: 1. DRAWING CONFORMS TO VERSION (WECD-1) IN JEDEC PACKAGE OUTLINE M0-229 2. DRAWING NOT TO SCALE 3. ALL DIMENSIONS ARE IN MILLIMETERS 4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE MOLD FLASH ...

Page 17

... Operations section update to Shutdown 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. LTC3528-2 PAGE NUMBER 2 2,3 ...

Page 18

... LTC3528-2 RELATED PARTS PART NUMBER DESCRIPTION LTC3528/LTC3528 1MHz Synchronous Step-Up DC/DC Converters SW with Output Disconnect LTC3528B 2MHz Synchronous Step-Up DC/DC Converter SW with Output Disconnect LTC3400/LTC3400B 600mA (I ), 1.2MHz, Synchronous Step-Up SW DC/DC Converters LTC3421 3MHz, Synchronous Step-Up DC/DC Converter SW with Output Disconnect LTC3422 1. 3MHz Synchronous Step-Up DC/DC ...

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