Datasheet

ManualsBrandsTEXAS INSTRUMENTS ManualsPMICsPMIC - DC/DC voltage regulator Holder SOT 23 5

GND

L1:2.2 PH

OUT

10 PF

4.7 PF

LM3674

2.7V to 5.5V

LM3674

www.ti.com

SNVS405F –DECEMBER 2005–REVISED MAY 2013

LM3674 2MHz, 600mA Step-Down DC-DC Converter in SOT-23

Check for Samples: LM3674

FEATURES

DESCRIPTION

The LM3674 step-down DC-DC converter is

• 600mA Max Load Current

optimized for powering low voltage circuits from a

• Input Voltage Range from 2.7V to 5.5V

single Li-Ion cell battery and input voltage rails from

• Available in Fixed and Adjustable Output

2.7V to 5.5V. It provides up to 600mA load current,

Voltages Ranging from 1.0V to 3.3V

over the entire input voltage range. There are several

fixed output voltages and adjustable output voltage

• Operates from a Single Li-Ion Cell Battery

versions.

• Internal Synchronous Rectification for High

The device offers superior features and performance

Efficiency

for mobile phones and similar portable systems.

• Internal Soft Start

During PWM mode, the device operates at a fixed-

• 0.01 µA Typical Shutdown Current

frequency of 2 MHz (typ). Internal synchronous

rectification provides high efficiency during Pulse

• 2 MHz PWM Fixed Switching Frequency (typ)

Width Modulation (PWM) mode operation. In

• 5-Pin SOT-23 Package

shutdown mode, the device turns off and reduces

• Current Overload Protection and Thermal

battery consumption to 0.01 µA (typ).

Shutdown Protection

The LM3674 is available in a 5-pin SOT-23 package

in leaded (PB) and lead-free (NO PB) versions. A

APPLICATIONS

high switching frequency of 2 MHz (typ) allows use of

• Mobile Phones

only three tiny external surface-mount components,

an inductor and two ceramic capacitors.

• PDAs

• MP3 Players

• Portable Instruments

• W-LAN

• Digital Still Cameras

• Portable Hard Disk Drives

TYPICAL APPLICATION CIRCUITS

Figure 1. Typical Application Circuit

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 (23 pages)

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LM3674 www.ti.com SNVS405F – DECEMBER 2005 – REVISED MAY 2013 LM3674 2MHz, 600mA Step-Down DC-DC Converter in SOT-23 Check for Samples: LM3674 FEATURES DESCRIPTION • • • The LM3674 step-down DC-DC converter is optimized for powering low voltage circuits from a single Li-Ion cell battery and input voltage rails from 2.7V to 5.5V. It provides up to 600mA load current, over the entire input voltage range. There are several fixed output voltages and adjustable output voltage versions.
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LM3674 SNVS405F – DECEMBER 2005 – REVISED MAY 2013 www.ti.com VIN 2.7V to 5.5V L1: 2.2 PH VIN 1 CIN: 4.7 PF GND 5 VOUT SW LM3674ADJ 2 C1 R1 C2 R2 COUT: 10 PF FB EN 3 4 Figure 2. Typical Application Circuit for Adjustable Voltage Option PIN DIAGRAM SW 5 VIN 1 FB 4 GND 2 EN 3 Figure 3. Top View 5-Pin SOT-23 Package See Package Number DBV0005A Note: The actual physical placement of the package marking will vary from part to part.
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LM3674 www.ti.com SNVS405F – DECEMBER 2005 – REVISED MAY 2013 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. ORDERING INFORMATION (1) (2) LM3674 (5 Pin SOT-23) Ordering Information Voltage Option (V) LM3674MF-1.2 LM3674MFX-1.2 1.2 LM3674MF-1.2/NOPB LM3674MFX-1.2/NOPB LM3674MF-1.5 LM3674MFX-1.5 1.5 LM3674MF-1.5/NOPB LM3674MFX-1.
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LM3674 SNVS405F – DECEMBER 2005 – REVISED MAY 2013 www.ti.com Absolute Maximum Ratings (1) (2) −0.2V to 6.0V VIN Pin: Voltage to GND EN, FB, SW Pin: (GND−0.2V) to (VIN + 0.2V) Continuous Power Dissipation (3) Internally Limited Junction Temperature (TJ-MAX) +125°C Storage Temperature Range −65°C to +150°C Maximum Lead Temperature (Soldering, 10 sec.
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LM3674 www.ti.com SNVS405F – DECEMBER 2005 – REVISED MAY 2013 Electrical Characteristics (1) (2) (3) Limits in standard typeface are for TJ = 25°C. Limits in boldface type apply over the full operating junction temperature range (−30°C ≤ TJ ≤ 125°C). Unless otherwise noted, specifications apply to the LM3674 with VIN = EN = 3.6V Parameter Test Condition Min Typ Max Units +4 % Feedback Voltage (4) (5) IO = 10mA Line Regulation 2.7V ≤ VIN ≤ 5.5V IO = 100 mA 0.
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LM3674 SNVS405F – DECEMBER 2005 – REVISED MAY 2013 www.ti.com Block Diagram VIN EN SW Current Limit Comparator Thermal Shutdown Ramp Generator Soft Start + Undervoltage Lockout Ref1 2 MHz Oscillator Bandgap PWM Comparator Error Amp VREF 0.5V + - + - + - Control Logic Driver Vcomp 1.0V Frequency Compensation Adjustable Version Fixed Version GND FB Figure 4.
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LM3674 www.ti.com SNVS405F – DECEMBER 2005 – REVISED MAY 2013 Typical Performance Characteristics (unless otherwise stated: VIN = 3.6V, VOUT = 1.5V, TA = 25°C) Quiescent Current vs. Supply Voltage (FB = 0V, No Switching) IQ Shutdown vs. Temp 0.40 EN = GND SHUTDOWN CURRENT (PA) 0.35 0.30 0.25 0.20 VIN = 5.5V 0.15 VIN = 3.6V 0.10 VIN = 2.7V 0.05 0.00 -30 -10 10 30 50 70 90 TEMPERATURE (°C) Figure 5. Figure 6. Feedback Bias Current vs. Temp Output Voltage vs. Supply Voltage Figure 7.
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LM3674 SNVS405F – DECEMBER 2005 – REVISED MAY 2013 www.ti.com Typical Performance Characteristics (continued) (unless otherwise stated: VIN = 3.6V, VOUT = 1.5V, TA = 25°C) 600 Efficiency vs. Output Current (VOUT = 1.2V, L = 2.2uH, DCR = 200mΩ) RDSON vs. Temperature VIN = 2.7V 550 VIN = 4.5V 500 VIN = 3.6V RDS(ON) (m:) 450 PFET 400 VIN = 2.7V 350 300 VIN = 4.5V 250 NFET 200 150 100 -30 VIN = 3.6V -10 10 30 50 70 90 110 TEMPERATURE (°C) Figure 11. Figure 12. Efficiency vs.
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LM3674 www.ti.com SNVS405F – DECEMBER 2005 – REVISED MAY 2013 Typical Performance Characteristics (continued) (unless otherwise stated: VIN = 3.6V, VOUT = 1.5V, TA = 25°C) Open/Closed Loop Current Limit vs. Temperature Line Transient Response 20 mV/DIV AC Coupled VOUT 3.6V VIN 3.0V VOUT = 1.5V IOUT = 400 mA 40 Ps/DIV Figure 17. Figure 18. Load Transient Start Up (Output Current = 300mA) Figure 19. Figure 20. Start Up (Output Current = 10mA) Figure 21.
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LM3674 SNVS405F – DECEMBER 2005 – REVISED MAY 2013 www.ti.com OPERATION DESCRIPTION DEVICE INFORMATION The LM3674, a high efficiency step down DC-DC switching buck converter, delivers a constant voltage from a single Li-Ion battery and input voltage rails from 2.7V to 5.5V to portable devices such as cell phones and PDAs.
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LM3674 www.ti.com SNVS405F – DECEMBER 2005 – REVISED MAY 2013 VSW 2V/DIV IL 200 mA/DIV VIN = 3.6V VOUT = 1.5V IOUT = 400 mA VOUT 10 mV/DIV AC Coupled TIME (200 ns/DIV) Internal Synchronous Rectification While in PWM mode, the LM3674 uses an internal NFET as a synchronous rectifier to reduce rectifier forward voltage drop and associated power loss.
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LM3674 SNVS405F – DECEMBER 2005 – REVISED MAY 2013 VOUT = VFB * ( • • • • R1 R2 www.ti.com + 1) (4) VOUT = Output Voltage (V) VFB = Feedback Voltage (0.5V typ) R1 = Resistor from VOUT to FB (Ω) R2 = Resistor from FB to GND (Ω) For any output voltage greater than or equal to 1.0V a frequency zero must be added at 45KHz for stability. The formula is: C1 = 1 2 x S x R1 x 45 kHz (5) For output voltages greater than or equal to 2.5V, a pole must also be placed at 45KHz as well.
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LM3674 www.ti.com SNVS405F – DECEMBER 2005 – REVISED MAY 2013 where IRIPPLE = • • • • • • § VIN - VOUT· § VOUT· § 1 · © 2 x L ¹ © VIN ¹ © f ¹ (9) IRipple : average to peak inductor current Ioutmax: maximum load current (600mA) VIN: maximum input voltage in application L: min inductor value including worst case tolerances (30% drop can be considered for method 1) f: minimum switching frequency (1.
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LM3674 SNVS405F – DECEMBER 2005 – REVISED MAY 2013 www.ti.com The output voltage ripple is caused by the charging and discharging of the output capacitor and by the RESR and can be calculated as: Voltage peak-to-peak ripple due to capacitance can be expressed as follow: VPP-C = I ripple fx4xC (11) Voltage peak-to-peak ripple due to ESR = VOUT = VPP-ESR = IPP * RESR (12) Because these two components are out of phase the rms value can be used to get an approximate value of peak-to-peak ripple.
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LM3674 www.ti.com SNVS405F – DECEMBER 2005 – REVISED MAY 2013 Figure 22. Board Layout Design Rules for the LM3674 Good layout for the LM3674 can be implemented by following a few simple design rules, as illustrated in . 1. Place the LM3674, inductor and filter capacitors close together and make the traces short. The traces between these components carry relatively high switching currents and act as antennas. Following this rule reduces radiated noise.
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LM3674 SNVS405F – DECEMBER 2005 – REVISED MAY 2013 www.ti.com REVISION HISTORY Changes from Revision E (April 2013) to Revision F • 16 Page Changed layout of National Data Sheet to TI format ..........................................................................................................
PAGE 17
PACKAGE OPTION ADDENDUM www.ti.com 1-Nov-2013 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Pins Package Drawing Qty Eco Plan Lead/Ball Finish MSL Peak Temp (2) (6) (3) Op Temp (°C) Device Marking (4/5) LM3674MF-1.2 NRND SOT-23 DBV 5 1000 TBD Call TI Call TI -30 to 85 SLRB LM3674MF-1.2/NOPB ACTIVE SOT-23 DBV 5 1000 Green (RoHS & no Sb/Br) CU SN Level-1-260C-UNLIM -30 to 85 SLRB LM3674MF-1.
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PACKAGE OPTION ADDENDUM www.ti.com 1-Nov-2013 (2) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability information and additional product content details. TBD: The Pb-Free/Green conversion plan has not been defined.
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PACKAGE MATERIALS INFORMATION www.ti.com 23-Sep-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) LM3674MF-1.2 SOT-23 DBV 5 1000 178.0 8.4 LM3674MF-1.2/NOPB SOT-23 DBV 5 1000 178.0 LM3674MF-1.5/NOPB SOT-23 DBV 5 1000 178.0 LM3674MF-1.8/NOPB SOT-23 DBV 5 1000 LM3674MF-1.875/NOPB SOT-23 DBV 5 LM3674MF-2.
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PACKAGE MATERIALS INFORMATION www.ti.com 23-Sep-2013 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) LM3674MF-1.2 SOT-23 DBV 5 1000 210.0 185.0 35.0 LM3674MF-1.2/NOPB SOT-23 DBV 5 1000 210.0 185.0 35.0 LM3674MF-1.5/NOPB SOT-23 DBV 5 1000 210.0 185.0 35.0 LM3674MF-1.8/NOPB SOT-23 DBV 5 1000 210.0 185.0 35.0 LM3674MF-1.875/NOPB SOT-23 DBV 5 1000 210.0 185.0 35.0 LM3674MF-2.
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