Datasheet

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LTC3529

3529fb

1 100010010

3529 TA01b

POWER LOSS (W)

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

POWER LOSS

EFFICIENCY

= 3.6V

INDUCTOR = 4.7μH,

COOPER BUSSMANN SD25-4R7

LOAD CURRENT (mA)

EFFICIENCY (%)

100

3529 TA01a

LTC3529

3.3μF

370Ω

Li-Ion

2.5V

4.2V

OUT

500mA

4.7μH

FAULT SNSGND

RST V

OUT

SHDN PGND

OUT

10μF

ONOFFAUTO-RESTART

ONOFF

TYPICAL APPLICATION

FEATURES

APPLICATIONS

DESCRIPTION

1.5A, 1.5MHz Step-Up

DC/DC Converter in

2mm × 3mm DFN

The LTC

3529 is a 5V output, synchronous, ﬁ xed frequency

step-up DC/DC converter optimized for USB On-The-Go

(OTG) hosting applications. This compact USB OTG 5V

BUS

converter features a 1.5MHz switching frequency,

internal compensation and a tiny 2mm × 3mm DFN pack-

age. The LTC3529 can operate from input voltages as low

as 1.8V.

USB OTG-speciﬁ c features include a fault ﬂ ag with 22ms

deglitching to indicate when the bus is overloaded, output

disconnect and short-circuit protection. Following a fault,

the LTC3529 can be programmed to either latchoff or

restart after a time-out duration.

Additional features include a <1μA shutdown mode,

soft-start, inrush current limiting and thermal overload

protection. Anti-ring circuitry reduces EMI during low

power operation. The LTC3529 is offered in an 8-lead

2mm × 3mm × 0.75mm DFN package.

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

Technology Corporation. All other trademarks are the property of their respective owners.

Protected by U.S. Patents including 6404251, 6166527.

Li-Ion Battery to 5V Synchronous Boost Converter

Compact Solution for 5V USB On-The-Go

BUS

Power

5V at 500mA from Single Li-Ion Cell

Automatic Fault Detection

High Efﬁ ciency: Up to 95%

Range: 1.8V to 5.25V

Fixed 5V Output

Short-Circuit Protection

1.5MHz Low Noise, Fixed Frequency PWM

Inrush Current Limiting and Internal Soft-Start

Output Disconnect

<1μA Quiescent Current in Shutdown

> V

OUT

Operation

8-Lead, 2mm × 3mm DFN Package

Personal Media Players

Digital Video Cameras

Digital Multimedia Broadcast Tuners

Digital Cameras

Smart Phones

Efﬁ ciency vs Load Current

Summary of content (12 pages)

PAGE 1
LTC3529 1.5A, 1.5MHz Step-Up DC/DC Converter in 2mm × 3mm DFN DESCRIPTION FEATURES n n n n n n n n n n n n n The LTC®3529 is a 5V output, synchronous, ﬁxed frequency step-up DC/DC converter optimized for USB On-The-Go (OTG) hosting applications. This compact USB OTG 5V VBUS converter features a 1.5MHz switching frequency, internal compensation and a tiny 2mm × 3mm DFN package. The LTC3529 can operate from input voltages as low as 1.8V.
PAGE 2
LTC3529 ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (Note 1) VIN, VOUT Voltage ........................................... –0.3 to 6V SHDN, RST, FAULT Voltage ............................ –0.3 to 6V SW Voltage DC.............................................................. –0.3 to 6V Pulsed <100ns .............................................–1V to 7V Operating Temperature Range (Note 2) ...–40°C to 85°C Maximum Junction Temperature (Note 3) ............ 125°C Storage Temperature Range ..................
PAGE 3
LTC3529 ELECTRICAL CHARACTERISTICS The l denotes the speciﬁcations which apply over the full operating temperature range, otherwise speciﬁcations are at TA = 25°C. VIN = 3.6V, VOUT = 5V unless otherwise noted. PARAMETER CONDITIONS FAULT Delay Time VOUT = 0V FAULT Output Low Voltage IFAULT = 5mA, VOUT = 0V FAULT Leakage Current VFAULT = 5.5V MIN TYP MAX 12 22 35 60 ms mV 10 Note 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device.
PAGE 4
LTC3529 TYPICAL PERFORMANCE CHARACTERISTICS Output Voltage Change vs Temperature Maximum Output Current vs VIN 1.90 1.0 1600 1.85 0.8 1400 1.80 0.6 1.75 1.70 1.65 1.60 1.55 0.2 0 –0.2 –0.6 1.45 –0.8 1.40 –45 –25 –5 15 35 55 75 TEMPERATURE (°C) 800 600 400 200 –1.0 –50 95 115 1000 –0.4 1.50 0 50 100 TEMPERATURE (°C) 0 1.5 150 3529 G06 Switching Frequency Variation vs Temperature 18 8 16 6 QUIESCENT CURRENT (mA) NORMALIZED TO 25°C (%) 1μs/DIV VIN = 3.6V COUT = 10μF L = 4.
PAGE 5
LTC3529 PIN FUNCTIONS VOUT (Pin 1): Converter Output, Voltage Sense Input and Drain of the Internal Synchronous Rectiﬁer MOSFET. Driver bias is derived from VOUT. PCB trace length from VOUT to the output ﬁlter capacitor(s) should be as short and wide as possible. SW (Pin 2): Switch Node. This node connects to one side of the inductor. Keep PCB traces as short and wide as possible to reduce EMI and voltage overshoot.
PAGE 6
LTC3529 BLOCK DIAGRAM L1 4.7μH VIN 1.8V TO 5.25V + – 8 CIN 3.3μF 3 VIN SHDN 2 SW BULK CONTROL SIGNALS VIN ANTI-RING 1 VOUT 6 SNSGND CLOCK – + PWM LOGIC AND DRIVERS VOUT, 5V COUT 10μF IZERO COMP CURRENT SENSE FAULT OR THERMAL SHUTDOWN 5 FAULT 22ms FAULT TIMER R1 1.875M – SOFT-START SD GM ERROR AMPLIFIER + – THERMAL SD – + PWM COMP ILIM COMP 1.25V REFERENCE + + 3 + RC 1.25V R2 625k C2 OSCILLATOR 2A CC 7 RST 4 PGND 9 GND (BP) 3529 BD OPERATION The LTC3529 is a 1.
PAGE 7
LTC3529 OPERATION Oscillator An internal oscillator sets the switching frequency to 1.5MHz. Shutdown The LTC3529 is shut down by pulling the SHDN pin below 0.35V, and activated by pulling the SHDN pin above 1V. Note that SHDN can be driven above VIN or VOUT, as long as it is limited to less than the absolute maximum rating. Error Ampliﬁer The error ampliﬁer is a transconductance ampliﬁer with an internal compensation network.
PAGE 8
LTC3529 APPLICATIONS INFORMATION The basic LTC3529 application circuit is shown in the Typical Application on the front page. The external component selection is determined by the desired output current and ripple voltage requirements of each particular application. However, basic guidelines and considerations for the design process are provided in this section. Although ceramic capacitors are recommended, low ESR tantalum capacitors may also be used.
PAGE 9
LTC3529 APPLICATIONS INFORMATION Inductor Selection PCB Layout Guidelines The LTC3529 can utilize small surface-mount chip inductors due to its fast 1.5MHz switching frequency. Larger values of inductance will allow slightly greater output current capability by reducing the inductor ripple current. Increasing the inductance above 10μH will increase component size while providing little improvement in output current capability. The LTC3529 switches large currents at high frequencies.
PAGE 10
LTC3529 TYPICAL APPLICATIONS Li-Ion Battery to 5V at 100mA or 500mA for USB OTG Host Supply L1* 4.7μH + 2.5V TO 4.2V Li-Ion 3.3μF 1.8V LTC3529 VIN SW 1M FAULT SNSGND TO μP AUTO-RESTART OFF ON RST VOUT, 5V VOUT COUT 6.
PAGE 11
LTC3529 PACKAGE DESCRIPTION DCB Package 8-Lead Plastic DFN (2mm × 3mm) (Reference LTC DWG # 05-08-1718 Rev A) 0.70 ±0.05 1.35 ±0.05 3.50 ±0.05 1.65 ± 0.05 2.10 ±0.05 PACKAGE OUTLINE 0.25 ± 0.05 0.45 BSC 1.35 REF RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS APPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED R = 0.115 TYP R = 0.05 5 TYP 2.00 ±0.10 (2 SIDES) 0.40 ± 0.10 8 1.35 ±0.10 1.65 ± 0.10 3.00 ±0.10 (2 SIDES) PIN 1 NOTCH R = 0.20 OR 0.
PAGE 12
LTC3529 RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LTC3400/LTC3400B 600mA (ISW), 1.2MHz, Synchronous Step-Up DC/DC Converter 92% Efﬁciency, VIN: 0.85V to 5V, VOUT(MAX) = 5V, IQ = 19μA/300μA, ISD <1μA, ThinSOT™ Package LTC3401 1A (ISW), 3MHz, Synchronous Step-Up DC/DC Converter 97% Efﬁciency, VIN: 0.85V to 5V, VOUT(MAX) = 5.5V, IQ = 38μA, ISD <1μA, MS10 Package LTC3402 2A (ISW), 3MHz, Synchronous Step-Up DC/DC Converter 97% Efﬁciency, VIN: 0.85V to 5V, VOUT(MAX) = 5.