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LM2700

www.ti.com

SNVS152C –MAY 2001–REVISED MARCH 2013

LM2700 600kHz/1.25MHz, 2.5A, Step-up PWM DC/DC Converter

Check for Samples: LM2700

FEATURES

DESCRIPTION

The LM2700 is a step-up DC/DC converter with a

• 3.6A, 0.08Ω, Internal Switch

3.6A, 80mΩ internal switch and pin selectable

• Operating Input Voltage Range of 2.2V to 12V

operating frequency. With the ability to produce

• Input Undervoltage Protection

500mA at 8V from a single Lithium Ion battery, the

LM2700 is an ideal part for biasing LCD displays. The

• Adjustable Output Voltage up to 17.5V

LM2700 can be operated at switching frequencies of

• 600kHz/1.25MHz Pin Selectable Frequency

600kHz and 1.25MHz allowing for easy filtering and

Operation

low noise. An external compensation pin gives the

• Over Temperature Protection

user flexibility in setting frequency compensation,

which makes possible the use of small, low ESR

• Small 14-Lead TSSOP or WSON Package

ceramic capacitors at the output. The LM2700

features continuous switching at light loads and

APPLICATIONS

operates with a switching quiescent current of 2.0mA

• LCD Bias Supplies

at 600kHz and 3.0mA at 1.25MHz. The LM2700 is

available in a low profile 14-lead TSSOP package or

• Handheld Devices

a 14-lead WSON package.

• Portable Applications

• GSM/CDMA Phones

• Digital Cameras

Typical Application Circuit

Figure 1. 600 kHz Operation

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 (26 pages)

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LM2700 www.ti.com SNVS152C – MAY 2001 – REVISED MARCH 2013 LM2700 600kHz/1.25MHz, 2.5A, Step-up PWM DC/DC Converter Check for Samples: LM2700 FEATURES DESCRIPTION • • • • • The LM2700 is a step-up DC/DC converter with a 3.6A, 80mΩ internal switch and pin selectable operating frequency. With the ability to produce 500mA at 8V from a single Lithium Ion battery, the LM2700 is an ideal part for biasing LCD displays. The LM2700 can be operated at switching frequencies of 600kHz and 1.
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LM2700 SNVS152C – MAY 2001 – REVISED MARCH 2013 www.ti.com Connection Diagram Figure 2. Top View 14-Lead TSSOP or WSON PIN DESCRIPTION 2 Pin Name 1 VC Compensation network connection. Connected to the output of the voltage error amplifier. Function 2 FB Output voltage feedback input. 3 SHDN Shutdown control input, active low. 4 AGND Analog ground. 5 PGND Power ground. PGND pins must be connected together directly at the part. 6 PGND Power ground.
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LM2700 www.ti.com SNVS152C – MAY 2001 – REVISED MARCH 2013 Block Diagram Detailed Description The LM2700 utilizes a PWM control scheme to regulate the output voltage over all load conditions. The operation can best be understood referring to the block diagram and Figure 17 of the Operation section. At the start of each cycle, the oscillator sets the driver logic and turns on the NMOS power device conducting current through the inductor, cycle 1 of Figure 17(a).
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LM2700 SNVS152C – MAY 2001 – REVISED MARCH 2013 www.ti.com Absolute Maximum Ratings (1) (2) VIN 12V SW Voltage 18V FB Voltage 7V VC Voltage 0.965V ≤ VC ≤ 1.565V SHDN Voltage (3) 7V FSLCT (3) 12V Maximum Junction Temperature Power Dissipation 150°C (4) Internally Limited Lead Temperature 300°C Vapor Phase (60 sec.) 215°C Infrared (15 sec.
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LM2700 www.ti.com SNVS152C – MAY 2001 – REVISED MARCH 2013 Electrical Characteristics Specifications in standard type face are for TJ = 25°C and those with boldface type apply over the full Operating Temperature Range (TJ = −40°C to +125°C) Unless otherwise specified. VIN =2.2V and IL = 0A, unless otherwise specified. Symbol IQ Typ Max (1) Units FB = 2.2V (Not Switching) FSLCT = 0V 1.2 2 mA FB = 2.2V (Not Switching) FSLCT = VIN 1.
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LM2700 SNVS152C – MAY 2001 – REVISED MARCH 2013 www.ti.com Typical Performance Characteristics 6 Efficiency vs. Load Current (VOUT = 8V, fS = 600 kHz) Efficiency vs. Load Current (VOUT = 8V, fS = 1.25 MHz) Figure 3. Figure 4. Efficiency vs. Load Current (VOUT = 5V, fS = 600 kHz) Efficiency vs. Load Current (VOUT = 12V, fS = 600 kHz) Figure 5. Figure 6. Switch Current Limit vs. Temperature Switch Current Limit vs. VIN Figure 7. Figure 8.
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LM2700 www.ti.com SNVS152C – MAY 2001 – REVISED MARCH 2013 Typical Performance Characteristics (continued) RDSON vs. VIN (ISW = 2A) IQ vs. VIN (600 kHz, not switching) Figure 9. Figure 10. IQ vs. VIN (600 kHz, switching) IQ vs. VIN (1.25 MHz, not switching) Figure 11. Figure 12. IQ vs. VIN (1.25 MHz, switching) IQ vs. VIN (In shutdown) Figure 13. Figure 14.
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LM2700 SNVS152C – MAY 2001 – REVISED MARCH 2013 www.ti.com Typical Performance Characteristics (continued) 8 Frequency vs. VIN (600 kHz) Frequency vs. VIN (1.25 MHz) Figure 15. Figure 16.
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LM2700 www.ti.com SNVS152C – MAY 2001 – REVISED MARCH 2013 Operation Figure 17. Simplified Boost Converter Diagram (a) First Cycle of Operation (b) Second Cycle Of Operation CONTINUOUS CONDUCTION MODE The LM2700 is a current-mode, PWM boost regulator. A boost regulator steps the input voltage up to a higher output voltage. In continuous conduction mode (when the inductor current never reaches zero at steady state), the boost regulator operates in two cycles.
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LM2700 SNVS152C – MAY 2001 – REVISED MARCH 2013 www.ti.com INTRODUCTION TO COMPENSATION Figure 18. (a) Inductor current. (b) Diode current. The LM2700 is a current mode PWM boost converter. The signal flow of this control scheme has two feedback loops, one that senses switch current and one that senses output voltage. To keep a current programmed control converter stable above duty cycles of 50%, the inductor must meet certain criteria.
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LM2700 www.ti.com SNVS152C – MAY 2001 – REVISED MARCH 2013 where RO is the output impedance of the error amplifier, approximately 850kΩ. For most applications, performance can be optimized by choosing values within the range 5kΩ ≤ RC ≤ 20kΩ (RC can be up to 200kΩ if CC2 is used, see High Output Capacitor ESR Compensation) and 680pF ≤ CC ≤ 4.7nF. Refer to the Application Information section for recommended values for specific circuits and conditions.
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LM2700 SNVS152C – MAY 2001 – REVISED MARCH 2013 www.ti.com INPUT AND OUTPUT CAPACITOR SELECTION The switching action of a boost regulator causes a triangular voltage waveform at the input. A capacitor is required to reduce the input ripple and noise for proper operation of the regulator. The size used is dependant on the application and board layout. If the regulator will be loaded uniformly, with very little load changes, and at lower current outputs, the input capacitor size can often be reduced.
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LM2700 www.ti.com SNVS152C – MAY 2001 – REVISED MARCH 2013 Now RC can be chosen with the selected value for CC. Check to make sure that the pole fPC is still in the 10Hz to 500Hz range, change each value slightly if needed to ensure both component values are in the recommended range. After checking the design at the end of this section, these values can be changed a little more to optimize performance if desired.
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LM2700 SNVS152C – MAY 2001 – REVISED MARCH 2013 www.ti.com LAYOUT CONSIDERATIONS The LM2700 uses two separate ground connections, PGND for the driver and NMOS power device and AGND for the sensitive analog control circuitry. The AGND and PGND pins should be tied directly together at the package. The feedback and compensation networks should be connected directly to a dedicated analog ground plane and this ground plane must connect to the AGND pin.
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LM2700 www.ti.com SNVS152C – MAY 2001 – REVISED MARCH 2013 APPLICATION INFORMATION Figure 19. 600 kHz operation, 8V output Figure 20. 1.25 MHz operation, 8V output Figure 21.
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LM2700 SNVS152C – MAY 2001 – REVISED MARCH 2013 www.ti.com VIN = 3.3V, IOUT = 200mA⇝ 700mA ⇝ 200mA CH1: IOUT 0.5A/div DC Coupled CH2: VOUT 500mV/div AC Coupled CH3: Inductor Current 1A/div DC Coupled 20µs/div Figure 22. Load Transient for Figure 21 Figure 23.
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LM2700 www.ti.com SNVS152C – MAY 2001 – REVISED MARCH 2013 VIN = 3.3V, IOUT = 50mA⇝ 350mA ⇝ 50mA CH1: IOUT 0.5A/div DC Coupled CH2: VOUT 500mV/div AC Coupled CH3: Inductor Current 1A/div DC Coupled 50µs/div Figure 24. Load Transient for Figure 23 Figure 25.
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LM2700 SNVS152C – MAY 2001 – REVISED MARCH 2013 www.ti.com VIN = 3.3V, IOUT = 500mA CH1: VIN 2V/div DC Coupled CH2: VOUT 5V/div DC Coupled CH3: Inductor Current 500mA/div DC Coupled 1ms/div Figure 26. Start Up Waveform for Figure 25 VIN = 3.3V, IOUT = 50mA⇝ 375mA ⇝ 50mA CH1: IOUT 0.2A/div DC Coupled CH2: VOUT 2V/div AC Coupled CH3: Inductor Current 1A/div DC Coupled 500µs/div Figure 27.
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LM2700 www.ti.com SNVS152C – MAY 2001 – REVISED MARCH 2013 REVISION HISTORY Changes from Revision B (March 2013) to Revision C • Page Changed layout of National Data Sheet to TI format ..........................................................................................................
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PACKAGE OPTION ADDENDUM www.ti.
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PACKAGE OPTION ADDENDUM www.ti.com 1-Nov-2013 (6) Lead/Ball Finish - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead/Ball Finish values may wrap to two lines if the finish value exceeds the maximum column width. Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided.
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PACKAGE MATERIALS INFORMATION www.ti.com 23-Sep-2013 TAPE AND REEL INFORMATION *All dimensions are nominal Device LM2700LD-ADJ/NOPB 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 4.3 4.3 1.3 8.0 12.0 Q1 WSON NHE 14 1000 178.0 12.4 LM2700LDX-ADJ/NOPB WSON NHE 14 4500 330.0 12.4 4.3 4.3 1.3 8.0 12.0 Q1 LM2700MTX-ADJ/NOPB TSSOP PW 14 2500 330.0 12.4 6.95 8.3 1.6 8.0 12.
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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) LM2700LD-ADJ/NOPB WSON NHE 14 1000 213.0 191.0 55.0 LM2700LDX-ADJ/NOPB WSON NHE 14 4500 367.0 367.0 35.0 LM2700MTX-ADJ/NOPB TSSOP PW 14 2500 367.0 367.0 35.
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MECHANICAL DATA NHE0014A LDA14A (REV A) www.ti.
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