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LM3102

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SNVS515G –SEPTEMBER 2007–REVISED JANUARY 2012

LM3102/LM3102Q SIMPLE SWITCHER Synchronous 1MHz 2.5A

Step-Down Voltage Regulator

Check for Samples: LM3102

FEATURES

KEY SPECIFICATIONS

• LM3102Q is an Automotive Grade Product that

• Input Voltage Range 4.5–42 V

is AEC-Q100 Grade 1 Qualified (-40°C to

• Output Current 2.5A A

+125°C Operating Junction Temperature)

• Reference 0.8V, ±1.5%

• Low Component Count and Small Solution

• Integrated Dual N-Channel Main and

Size

Synchronous MOSFETs

• Stable with Ceramic and Other Low ESR

• Thermally Enhanced TSSOP-20 Package

Capacitors

• No Loop Compensation Required

DESCRIPTION

• High Efficiency at a Light Load by DCM

The LM3102 Synchronously Rectified Buck Converter

Operation

features all required functions to implement a highly

efficient and cost effective buck regulator. It is

• Pre-bias Startup

capable of supplying 2.5A to loads with an output

• Ultra-fast Transient Response

voltage as low as 0.8V. Dual N-Channel synchronous

• Programmable Soft-start

MOSFET switches allow a low component count, thus

reducing complexity and minimizing board size.

• Programmable Switching Frequency up to 1

MHz

Different from most other COT regulators, the

LM3102 does not rely on output capacitor ESR for

• Valley Current Limit

stability, and is designed to work exceptionally well

• Output Over-voltage Protection

with ceramic and other very low ESR output

• Precision Internal Reference for an Adjustable

capacitors. It requires no loop compensation, results

Output Voltage Down to 0.8V

in a fast load transient response and simple circuit

implementation. The operating frequency remains

• Thermal Shutdown

nearly constant with line variations due to the inverse

relationship between the input voltage and the on-

APPLICATIONS

time. The operating frequency can be externally

• 5VDC, 12VDC, 24VDC, 12VAC, and 24VAC

programmed up to 1 MHz. Protection features include

Systems

under-voltage lock-out, output over-voltage

protection, thermal shutdown, and gate drive under-

• Embedded Systems

voltage lock-out. The LM3102 is available in the

• Industrial Control

thermally enhanced TSSOP-20 package as well as a

• Automotive Telematics and Body Electronics

DSBGA low profile chip-scale package with reduced

output current.

• Point of Load Regulators

• Storage Systems

• Broadband Infrastructure

• Direct Conversion from 2/3/4 Cell Lithium

Batteries Systems

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 (24 pages)

PAGE 1
LM3102 www.ti.com SNVS515G – SEPTEMBER 2007 – REVISED JANUARY 2012 LM3102/LM3102Q SIMPLE SWITCHER Synchronous 1MHz 2.
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LM3102 SNVS515G – SEPTEMBER 2007 – REVISED JANUARY 2012 www.ti.com TYPICAL APPLICATIONS CONNECTION DIAGRAM Figure 1. 20-lead Plastic TSSOP Package Number PWP0020A A B C D E F G 4 VIN VIN BST SW AGND RON EN 3 SW SW SW SW AGND AGND AGND 2 SW SW SW SW 1 PGND PGND PGND PGND VCC AGND SS VCC AGND FB Top Mark Figure 2.
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LM3102 www.ti.com SNVS515G – SEPTEMBER 2007 – REVISED JANUARY 2012 PIN DESCRIPTIONS Pin Ball 1,9,10,12,19,2 0 Name Description Application Information N/C No Connection These pins must be left unconnected. 2, 3 A2, A3, B2, B3, C2, C3, D2, D3, D4 SW Switching Node Internally connected to the source of the main MOSFET and the drain of the Synchronous MOSFET. Connect to the inductor. 4, 5 A4, B4 VIN Input supply voltage Supply pin to the device. Nominal input range is 4.5V to 42V.
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LM3102 SNVS515G – SEPTEMBER 2007 – REVISED JANUARY 2012 www.ti.com ABSOLUTE MAXIMUM RATINGS (1) (2) VIN, RON to AGND -0.3V to 43.5V SW to AGND -0.3V to 43.5V SW to AGND (Transient) -2V (< 100ns) VIN to SW -0.3V to 43.5V BST to SW -0.3V to 7V All Other Inputs to AGND -0.3V to 7V ESD Rating (3) Human Body Model ±2kV Storage Temperature Range -65°C to +150°C Junction Temperature (TJ) (1) (2) (3) 150°C Absolute Maximum Ratings are limits beyond which damage to the device may occur.
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LM3102 www.ti.com SNVS515G – SEPTEMBER 2007 – REVISED JANUARY 2012 ELECTRICAL CHARACTERISTICS (continued) Specifications with standard type are for TJ = 25°C only; limits in boldface type apply over the full Operating Junction Temperature (TJ) range. Minimum and Maximum limits are specified through test, design, or statistical correlation. Typical values represent the most likely parametric norm at TJ = 25°C, and are provided for reference purposes only.
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LM3102 SNVS515G – SEPTEMBER 2007 – REVISED JANUARY 2012 www.ti.com TYPICAL PERFORMANCE CHARACTERISTICS All curves are taken at VIN = 18V with the configuration in the typical application circuit for VOUT = 3.3V shown in this datasheet. TA = 25°C, unless otherwise specified. 6 Quiescent Current, IIN vs VIN VCC vs ICC Figure 3. Figure 4. VCC vs VIN ton vs VIN Figure 5. Figure 6. Switching Frequency, fSW vs VIN VFB vs Temperature Figure 7. Figure 8.
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LM3102 www.ti.com SNVS515G – SEPTEMBER 2007 – REVISED JANUARY 2012 TYPICAL PERFORMANCE CHARACTERISTICS (continued) All curves are taken at VIN = 18V with the configuration in the typical application circuit for VOUT = 3.3V shown in this datasheet. TA = 25°C, unless otherwise specified. RDS(on) vs Temperature Efficiency vs Load Current (VOUT = 3.3V) Figure 9. Figure 10. VOUT Regulation vs Load Current (VOUT = 3.3V) Efficiency vs Load Current (VOUT = 0.8V) Figure 11. Figure 12.
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LM3102 SNVS515G – SEPTEMBER 2007 – REVISED JANUARY 2012 www.ti.com TYPICAL PERFORMANCE CHARACTERISTICS (continued) All curves are taken at VIN = 18V with the configuration in the typical application circuit for VOUT = 3.3V shown in this datasheet. TA = 25°C, unless otherwise specified. 8 Enable Transient (VOUT = 3.3V, 2.5A Loaded) Shutdown Transient (VOUT = 3.3V, 2.5A Loaded) Figure 15. Figure 16. Continuous Mode Operation (VOUT = 3.3V, 2.5A Loaded) Discontinuous Mode Operation (VOUT = 3.3V, 0.
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LM3102 www.ti.com SNVS515G – SEPTEMBER 2007 – REVISED JANUARY 2012 TYPICAL PERFORMANCE CHARACTERISTICS (continued) All curves are taken at VIN = 18V with the configuration in the typical application circuit for VOUT = 3.3V shown in this datasheet. TA = 25°C, unless otherwise specified. DSBGA Valley Current Limit VOUT = 5.0V @ 25°C VALLEY CURRENT LIMIT (A) 1.8 1.75 1.7 1.65 1.6 1.55 25°C 1.5 0 10 20 30 40 50 INPUT VOLTAGE (V) Figure 21.
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LM3102 SNVS515G – SEPTEMBER 2007 – REVISED JANUARY 2012 www.ti.com SIMPLIFIED FUNCTIONAL BLOCK DIAGRAM Figure 22.
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LM3102 www.ti.com SNVS515G – SEPTEMBER 2007 – REVISED JANUARY 2012 FUNCTIONAL DESCRIPTION The LM3102 Step Down Switching Regulator features all required functions to implement a cost effective, efficient buck power converter capable of supplying 2.5A to a load. It contains Dual N-Channel main and synchronous MOSFETs. The Constant ON-Time (COT) regulation scheme requires no loop compensation, results in fast load transient response and simple circuit implementation.
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LM3102 SNVS515G – SEPTEMBER 2007 – REVISED JANUARY 2012 www.ti.com REGULATION COMPARATOR The feedback voltage at the FB pin is compared to a 0.8V internal reference. In normal operation (the output voltage is regulated), an on-time period is initiated when the voltage at the FB pin falls below 0.8V. The main MOSFET stays on for the on-time, causing the output voltage and consequently the voltage of the FB pin to rise above 0.8V.
PAGE 13
LM3102 www.ti.com SNVS515G – SEPTEMBER 2007 – REVISED JANUARY 2012 Figure 24 illustrates an inductor current waveform. On average, the output current IOUT is the same as the inductor current IL, which is the average of the rippled inductor current. In case of current limit (the current limit portion of Figure 24), the next on-time will not initiate until that the current drops below 2.7A (assume the voltage at the FB pin is lower than 0.8V).
PAGE 14
LM3102 SNVS515G – SEPTEMBER 2007 – REVISED JANUARY 2012 www.ti.com Figure 25. Alternate Shutdown Implementation THERMAL PROTECTION The junction temperature of the LM3102 should not exceed the maximum limit. Thermal protection is implemented by an internal Thermal Shutdown circuit, which activates (typically) at 165°C to make the controller enter a low power reset state by disabling the main MOSFET, disabling the on-timer, and grounding the SS pin.
PAGE 15
LM3102 www.ti.com SNVS515G – SEPTEMBER 2007 – REVISED JANUARY 2012 RON: Equation 2 can be used to select RON if a desired operating frequency is selected. But the minimum value of RON is determined by the minimum on-time. It can be calculated as follows: RON t VIN(MAX) x 150 ns 1.3 x 10-10 (8) If RON calculated from Equation 2 is smaller than the minimum value determined in Equation 8, a lower frequency should be selected to re-calculate RON by Equation 2.
PAGE 16
LM3102 SNVS515G – SEPTEMBER 2007 – REVISED JANUARY 2012 www.ti.com Figure 29. Inductor selection for VOUT = 0.8V Figure 28 and Figure 29 show curves on inductor selection for various VOUT and RON. For small RON, according to Equation 8, VIN is limited. Some curves are therefore limited as shown in the figures. CVCC: The capacitor on the VCC output provides not only noise filtering and stability, but also prevents false triggering of the VCC UVLO at the main MOSFET on/off transitions.
PAGE 17
LM3102 www.ti.com SNVS515G – SEPTEMBER 2007 – REVISED JANUARY 2012 PC BOARD LAYOUT The LM3102 regulation, over-voltage, and current limit comparators are very fast so they will respond to short duration noise pulses. Layout is therefore critical for optimum performance. It must be as neat and compact as possible, and all external components must be as close to their associated pins of the LM3102 as possible.
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PACKAGE OPTION ADDENDUM www.ti.
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PACKAGE OPTION ADDENDUM www.ti.com 11-Apr-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.
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PACKAGE MATERIALS INFORMATION www.ti.com 8-Apr-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) LM3102MHX/NOPB HTSSOP PWP 20 2500 330.0 16.4 6.95 LM3102QMHX/NOPB HTSSOP PWP 20 2500 330.0 16.4 6.95 LM3102TL-1/NOPB DSBGA YPA 28 250 178.0 12.4 2.64 LM3102TLX-1/NOPB DSBGA YPA 28 1000 178.0 12.4 2.64 3.
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PACKAGE MATERIALS INFORMATION www.ti.com 8-Apr-2013 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) LM3102MHX/NOPB HTSSOP PWP 20 2500 367.0 367.0 35.0 LM3102QMHX/NOPB HTSSOP PWP 20 2500 367.0 367.0 35.0 LM3102TL-1/NOPB DSBGA YPA 28 250 210.0 185.0 35.0 LM3102TLX-1/NOPB DSBGA YPA 28 1000 210.0 185.0 35.
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MECHANICAL DATA PWP0020A MXA20A (Rev C) www.ti.
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MECHANICAL DATA YPA0028 D 0.600 ±0.075 E TLC28XXX (Rev A) D: Max = 3.676 mm, Min =3.615 mm E: Max = 2.48 mm, Min = 2.419 mm 4215064/A NOTES: A. All linear dimensions are in millimeters. Dimensioning and tolerancing per ASME Y14.5M-1994. B. This drawing is subject to change without notice. www.ti.
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