Datasheet

ManualsBrandsTEXAS INSTRUMENTS ManualsPMICsPMIC - DC/DC voltage regulator Converter/amplifier WSON 12

LOAD (mA)

EFFICIENCY (%)

100

0 1 10 100 1000

= 3.3V

= 3.6V

= 2.5V

= 2.7V

= 5.5V

2.8V/3.3V

SW1

SW2

LM3668

PGND

SYNC/MODE

VSEL

L = 2.8V

H = 3.3V

VIN = 2.5V - 5.5V

SGND

VOUT

VDD

22 PF

10 PF

2.2 PH

LM3668

www.ti.com

SNVS449M –JUNE 2007–REVISED MAY 2013

LM3668 1A, High-Efficiency Dual-Mode Single-Inductor Buck-Boost DC/DC Converter

Check for Samples: LM3668

FEATURES

Time After V

Settled

• 0.01 µA Typical Shutdown Current

• 45 µA Typical Quiescent Current

• Current Overload and Thermal Shutdown

• For 2.8V/3.3V and 3.0/3.4V Versions:

Protection

– 1A Maximum Load Current for

• Frequency Sync Pin: 1.6 MHz to 2.7 MHz

= 2.8V to 5.5V

– 800 mA Maximum Load Current for

APPLICATIONS

= 2.7V

• Handset Peripherals

– 600 mA Maximum Load Current for

= 2.5V • MP3 Players

• For 4.5/5.0V • Pre-Regulation for Linear Regulators

– 1A Maximum Load Current for • PDAs

= 3.9V to 5.5V

• Portable Hard Disk Drives

– 800 mA Maximum Load Current for

• WiMax Modems

= 3.4V to 3.8V

– 700mA Maximum Load Current for DESCRIPTION

= 3.0V to 3.3V

The LM3668 is a synchronous buck-boost DC-DC

converter optimized for powering low voltage circuits

– 600mA Maximum Load Current for

from a Li-Ion battery and input voltage rails between

= 2.7V to 2.9V

2.5V and 5.5V. It has the capability to support up to

• 2.2 MHz PWM Fixed Switching Frequency

1A output current over the output voltage range. The

(typ.)

LM3668 regulates the output voltage over the

• Automatic PFM-PWM Mode or Forced PWM

complete input voltage range by automatically

switching between buck or boost modes depending

Mode

on the input voltage.

• Wide Input Voltage Range: 2.5V to 5.5V

• Internal Synchronous Rectification for High

Efficiency

• Internal Soft Start: 600 µs Maximum Startup

Typical Applications

Figure 1. Typical Application Circuit Figure 2. Efficiency at 3.3V Output

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of

Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

2All trademarks are the property of their respective owners.

PRODUCTION DATA information is current as of publication date.

Products conform to specifications per the terms of the Texas

Instruments standard warranty. Production processing does not

necessarily include testing of all parameters.

Summary of content (27 pages)

PAGE 1
LM3668 www.ti.com SNVS449M – JUNE 2007 – REVISED MAY 2013 LM3668 1A, High-Efficiency Dual-Mode Single-Inductor Buck-Boost DC/DC Converter Check for Samples: LM3668 FEATURES 1 • • 2 • • • • • • 45 µA Typical Quiescent Current For 2.8V/3.3V and 3.0/3.4V Versions: – 1A Maximum Load Current for VIN = 2.8V to 5.5V – 800 mA Maximum Load Current for VIN = 2.7V – 600 mA Maximum Load Current for VIN = 2.5V For 4.5/5.0V – 1A Maximum Load Current for VIN = 3.9V to 5.
PAGE 2
LM3668 SNVS449M – JUNE 2007 – REVISED MAY 2013 www.ti.com DESCRIPTION (CONTINUED) The LM3668 has 2 N-channel MOSFETS and 2 P-channel MOSFETS arranged in a topology that provides continuous operation through the buck and boost operating modes. There is a MODE pin that allows the user to choose between an intelligent automatic PFM-PWM mode operation and forced PWM operation. During PWM mode, a fixed-frequency 2.2 MHz (typ.) is used. PWM mode drives load up to 1A.
PAGE 3
LM3668 www.ti.com SNVS449M – JUNE 2007 – REVISED MAY 2013 Connection Diagrams VOUT 1 12 FB SW2 2 11 VSEL PGND 3 10 MODE/ SYNC DAP SW1 4 9 SGND PVIN 5 8 NC* EN 6 7 VDD FB 12 1 VOUT VSEL 11 2 SW2 MODE/ SYNC 10 3 PGND SGND 9 4 SW1 NC* 8 5 PVIN VDD 7 6 EN Figure 4. Top View See Package Number DQB (WSON) DAP Figure 5.
PAGE 4
LM3668 SNVS449M – JUNE 2007 – REVISED MAY 2013 www.ti.com These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam during storage or handling to prevent electrostatic damage to the MOS gates. ABSOLUTE MAXIMUM RATINGS (1) (2) (3) PVIN, VDD, SW1, SW2 & VOUT Pins: Voltage to SGND & PGND FB, EN, and MODE/SYNC pins PGND to SGND Continuous Power Dissipation –0.2V to 0.
PAGE 5
LM3668 www.ti.com SNVS449M – JUNE 2007 – REVISED MAY 2013 ELECTRICAL CHARACTERISTICS (1) (2) Limits in standard typeface are for TJ = +25°C. Limits in boldface type apply over the full operating ambient temperature range (−40°C ≤ = TA ≤ +85°C). Unless otherwise noted, specifications apply to the LM3668. VIN = 3.6V = EN, VOUT = 3.3V. For VOUT = 4.5/5.0V, VIN = 4V. Symbol Parameter Conditions Min VFB Feedback Voltage See (2) –3 ILIM Switch Peak Current Limit Open loop (3) 1.
PAGE 6
LM3668 SNVS449M – JUNE 2007 – REVISED MAY 2013 www.ti.com TYPICAL PERFORMANCE CHARACTERISTICS Typical Application Circuit (Figure 1): VIN = 3.6V, L = 2.2 µH, CIN = 10 µF, COUT = 22 µF (1), TA = 25°C , unless otherwise stated. Supply Current vs Temperature (Not switching) (VOUT = 3.4V) Switching Frequency vs. Temperature (VOUT = 3.4V) 900 2.4 VIN = 2.5V IQ_5.5V 800 2.3 IQ_PWM (éA) FREQUENCY (MHz) IQ_3.6V 700 600 500 400 IQ_2.5V 2.2 VIN = 3.6V 2.1 VIN = 5.5V 2.
PAGE 7
LM3668 www.ti.com SNVS449M – JUNE 2007 – REVISED MAY 2013 TYPICAL PERFORMANCE CHARACTERISTICS (continued) Typical Application Circuit (Figure 1): VIN = 3.6V, L = 2.2 µH, CIN = 10 µF, COUT = 22 µF(1), TA = 25°C , unless otherwise stated. ILIMIT vs. Temperature (VOUT = 3.4V) Efficiency at VOUT = 2.8V (Forced PWM Mode) 2.00 100 90 1.95 EFFICIENCY (%) 80 ILIMIT (A) 1.90 VIN = 3.6V 1.85 1.80 VIN = 2.5V 70 60 VIN = 2.7V 50 40 30 VIN = 5.0V 20 1.75 VIN = 5.5V 10 1.
PAGE 8
LM3668 SNVS449M – JUNE 2007 – REVISED MAY 2013 www.ti.com TYPICAL PERFORMANCE CHARACTERISTICS (continued) Typical Application Circuit (Figure 1): VIN = 3.6V, L = 2.2 µH, CIN = 10 µF, COUT = 22 µF(1), TA = 25°C , unless otherwise stated. Efficiency at VOUT = 3.3V (Auto Mode) Efficiency at VOUT = 3.4V (Forced PWM Mode) 100 100 90 90 80 VIN = 2.5V 70 60 EFFICIENCY (%) EFFICIENCY (%) 80 VIN = 2.7V VIN = 3.3V 50 40 VIN = 3.6V 30 VIN = 5.
PAGE 9
LM3668 www.ti.com SNVS449M – JUNE 2007 – REVISED MAY 2013 TYPICAL PERFORMANCE CHARACTERISTICS (continued) Typical Application Circuit (Figure 1): VIN = 3.6V, L = 2.2 µH, CIN = 10 µF, COUT = 22 µF(1), TA = 25°C , unless otherwise stated. Efficiency at VOUT = 5.0V (Auto Mode) Line Transient in Buck Mode ( VOUT = 3.4V, Load = 500mA) 100 4.5V 90 EFFICIENCY (%) 80 VIN 3.7V 70 VIN =5.0V VIN = 3.6V 60 40 30 VOUT_AC 100 mV/DIV 50 VIN = 5.5V 5V/DIV SW2 5V/DIV SW1 VIN = 2.
PAGE 10
LM3668 SNVS449M – JUNE 2007 – REVISED MAY 2013 www.ti.com TYPICAL PERFORMANCE CHARACTERISTICS (continued) Typical Application Circuit (Figure 1): VIN = 3.6V, L = 2.2 µH, CIN = 10 µF, COUT = 22 µF(1), TA = 25°C , unless otherwise stated. 10 Load Transient in Buck-Boost Operation (Forced PWM Mode) VIN = 3.44V, VOUT = 3.4V, Load = 0-500mA Load Transient in Buck Mode (Forced PWM Mode) VIN = 4.2V, VOUT = 3.0V, Load = 0-500mA Figure 27. Figure 28. Load Transient in Boost Mode (Forced PWM Mode) VIN = 2.
PAGE 11
LM3668 www.ti.com SNVS449M – JUNE 2007 – REVISED MAY 2013 TYPICAL PERFORMANCE CHARACTERISTICS (continued) Typical Application Circuit (Figure 1): VIN = 3.6V, L = 2.2 µH, CIN = 10 µF, COUT = 22 µF(1), TA = 25°C , unless otherwise stated. Load Transient in Buck-Boost Mode (Auto Mode) VIN = 3.6V, VOUT = 3.3V, Load = 50-150mA Load Transient in Buck Mode (Forced PWM Mode) VIN = 5.5V, VOUT = 5.0V, Load = 0-500mA Figure 33. Figure 34. Load Transient in Boost Mode (Forced PWM Mode) VIN = 3.5V, VOUT = 5.
PAGE 12
LM3668 SNVS449M – JUNE 2007 – REVISED MAY 2013 www.ti.com TYPICAL PERFORMANCE CHARACTERISTICS (continued) Typical Application Circuit (Figure 1): VIN = 3.6V, L = 2.2 µH, CIN = 10 µF, COUT = 22 µF(1), TA = 25°C , unless otherwise stated. Typical Switching Waveform in Buck Mode (PFM Mode) VIN = 3.6V, VOUT = 3.0V, Load = 50mA Typical Switching Waveform in Boost Mode (PWM Mode) VIN = 3V, VOUT = 3.
PAGE 13
LM3668 www.ti.com SNVS449M – JUNE 2007 – REVISED MAY 2013 TYPICAL PERFORMANCE CHARACTERISTICS (continued) Typical Application Circuit (Figure 1): VIN = 3.6V, L = 2.2 µH, CIN = 10 µF, COUT = 22 µF(1), TA = 25°C , unless otherwise stated. Start up in PWM Mode (VOUT = 3.4V, Load = 500mA) Figure 45.
PAGE 14
LM3668 SNVS449M – JUNE 2007 – REVISED MAY 2013 www.ti.com FUNCTIONAL DESCRIPTION The LM3668, a high-efficiency Buck or Boost DC-DC converter, delivers a constant voltage from either a single Li-Ion or three cell NIMH/NiCd battery to portable devices such as mobile phones and PDAs. Using a voltage mode architecture with synchronous rectification, the LM3668 has the ability to deliver up to 1A depending on the input voltage, output voltage, ambient temperature and the chosen inductor.
PAGE 15
LM3668 www.ti.com SNVS449M – JUNE 2007 – REVISED MAY 2013 Boost Operation When the input voltage is smaller than the output voltage, the device enters boost mode operation where P1 is always ON, while switches N2 & P2 control the output. Figure 48 shows the simplified circuit for boost mode operation. P1 SW1 P2 SW2 VIN + - Load N2 Figure 48.
PAGE 16
LM3668 SNVS449M – JUNE 2007 – REVISED MAY 2013 www.ti.com PFM Operation At very light loads, the converter enters PFM mode and operates with reduced switching frequency and supply current to maintain high efficiency. The part automatically transitions into PFM mode when either of two following conditions occur for a duration of 128 or more clock cycles: A. The inductor current reaches zero. B. The peak inductor current drops below the IMODE level, (Typically IMODE < 45 mA + VIN/80 Ω ).
PAGE 17
LM3668 www.ti.com SNVS449M – JUNE 2007 – REVISED MAY 2013 Region I Region II Boost Buck or Boost Region III VOUT (Target) Buck VIN dV1 - VOUT (TARGET) VOUT (TARGET) + dV2 Figure 51. VOUT vs VIN Transition In the buck PFM operation, P2 is always turned on and N2 is always turned off , P1 and N1 power switches are switching. P1 and N1 are turned off to enter " sleep mode" when the output voltage reaches the "high" comparator threshold. In boost PFM operation, P2 and N2 are switching.
PAGE 18
LM3668 SNVS449M – JUNE 2007 – REVISED MAY 2013 www.ti.com APPLICATION INFORMATION MODE/SYNC Pin If the MODE/SYNC pin is set high, the device is set to operate at PWM mode only. If MODE/SYNC pin is set low, the device is set to automatically transition from PFM to PWM or PWM to PFM depending on the load current. Do not leave this pin floating. The MODE/SYNC pin can also be driven by an external clock to set the desired switching frequency between 1.6 MHz to 2.7 MHz.
PAGE 19
LM3668 www.ti.
PAGE 20
LM3668 SNVS449M – JUNE 2007 – REVISED MAY 2013 www.ti.com Input Capacitor Selection A ceramic input capacitor of at least 10 µF, 6.3V is sufficient for most applications. Place the input capacitor as close as possible to the PVIN pin of the device. A larger value may be used for improved input voltage filtering. Use X7R or X5R types; do not use Y5V. DC bias characteristics of ceramic capacitors must be considered when selecting case sizes like 0805 or 0603.
PAGE 21
LM3668 www.ti.com SNVS449M – JUNE 2007 – REVISED MAY 2013 REVISION HISTORY Changes from Revision L (April 2013) to Revision M • Page Changed layout of National Data Sheet to TI format ..........................................................................................................
PAGE 22
PACKAGE OPTION ADDENDUM www.ti.
PAGE 23
PACKAGE OPTION ADDENDUM www.ti.com 2-May-2013 Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties.
PAGE 24
PACKAGE MATERIALS INFORMATION www.ti.com 11-Oct-2013 TAPE AND REEL INFORMATION *All dimensions are nominal Device Package Package Pins Type Drawing SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant LM3668SD-2833/NOPB WSON DQB 12 1000 178.0 12.4 3.3 3.3 1.0 8.0 12.0 Q1 LM3668SD-3034/NOPB WSON DQB 12 1000 178.0 12.4 3.3 3.3 1.0 8.0 12.0 Q1 LM3668SD-4550/NOPB WSON DQB 12 1000 178.0 12.4 3.3 3.3 1.0 8.0 12.
PAGE 25
PACKAGE MATERIALS INFORMATION www.ti.com 11-Oct-2013 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) LM3668SD-2833/NOPB WSON DQB 12 1000 210.0 185.0 35.0 LM3668SD-3034/NOPB WSON DQB 12 1000 210.0 185.0 35.0 LM3668SD-4550/NOPB WSON DQB 12 1000 210.0 185.0 35.0 LM3668SDX-2833/NOPB WSON DQB 12 4500 367.0 367.0 35.0 LM3668SDX-3034/NOPB WSON DQB 12 4500 367.0 367.0 35.
PAGE 26
PAGE 27
IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, enhancements, improvements and other changes to its semiconductor products and services per JESD46, latest issue, and to discontinue any product or service per JESD48, latest issue. Buyers should obtain the latest relevant information before placing orders and should verify that such information is current and complete.