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LM2651

www.ti.com

SNVS032D –FEBRUARY 2000–REVISED APRIL 2013

LM2651 1.5A High Efficiency Synchronous Switching Regulator

Check for Samples: LM2651

FEATURES

DESCRIPTION

The LM2651 switching regulator provides high

• Ultra High Efficiency up to 97%

efficiency power conversion over a 100:1 load range

• High Efficiency Over a 1.5A to Milliamperes

(1.5A to 15mA). This feature makes the LM2651 an

Load Range

ideal fit in battery-powered applications that demand

• 4V to 14V Input Voltage Range

long battery life in both run and standby modes.

• 1.8V, 2.5V, 3.3V, or ADJ Output Voltage

Synchronous rectification is used to achieve up to

97% efficiency. At light loads, the LM2651 enters a

• Internal MOSFET Switch with Low R

DS(on)

low power hysteretic or “sleep” mode to keep the

75mΩ

efficiency high. In many applications, the efficiency

• 300kHz Fixed Frequency Internal Oscillator

still exceeds 80% at 15mA load. A shutdown pin is

• 7µA Shutdown Current

available to disable the LM2651 and reduce the

supply current to less than 10µA.

• Patented Current Sensing for Current Mode

Control

The LM2651 contains a patented current sensing

• Input Undervoltage Lockout

circuitry for current mode control. This feature

eliminates the external current sensing resistor

• Adjustable Soft-Start

required by other current-mode DC-DC converters.

• Current Limit and Thermal Shutdown

The LM2651 has a 300 kHz fixed frequency internal

• 16-pin TSSOP Package

oscillator. The high oscillator frequency allows the

use of extremely small, low profile components.

APPLICATIONS

A programmable soft-start feature limits current

• Personal Digital Assistants (PDAs)

surges from the input power supply at start up and

• Computer Peripherals

provides a simple means of sequencing multiple

power supplies.

• Battery-Powered Devices

• Handheld Scanners

Other protection features include input undervoltage

lockout, current limiting, and thermal shutdown.

• High Efficiency 5V Conversion

Typical Application

Figure 1. Efficiency vs Load Current Figure 2.

= 5V, V

OUT

= 3.3V)

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 (19 pages)

PAGE 1
LM2651 www.ti.com SNVS032D – FEBRUARY 2000 – REVISED APRIL 2013 LM2651 1.5A High Efficiency Synchronous Switching Regulator Check for Samples: LM2651 FEATURES DESCRIPTION • • The LM2651 switching regulator provides high efficiency power conversion over a 100:1 load range (1.5A to 15mA). This feature makes the LM2651 an ideal fit in battery-powered applications that demand long battery life in both run and standby modes.
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LM2651 SNVS032D – FEBRUARY 2000 – REVISED APRIL 2013 www.ti.com Connection Diagram Figure 3. 16-Lead TSSOP See Package Number PW PIN DESCRIPTIONS Pin Name 1, 2 SW Switched-node connection, which is connected with the source of the internal high-side MOSFET. Function 3-5 VIN Main power supply pin. 6 VCB Bootstrap capacitor connection for high-side gate drive. 7 AVIN Input supply voltage for control and driver circuits. 8 SD(SS) 9 FB 10 COMP Shutdown and Soft-start control pin.
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LM2651 www.ti.com SNVS032D – FEBRUARY 2000 – REVISED APRIL 2013 Operating Ratings (1) 4V ≤ VIN ≤ 14V Supply Voltage (1) Absolute maximum ratings indicate limits beyond which damage to the device may occur. Operating ratings indicate conditions for which the device is intended to be functional, but device parameter specifications may not be ensured under these conditions. For specifications and test conditions, see the Electrical Characteristics. LM2651-1.
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LM2651 SNVS032D – FEBRUARY 2000 – REVISED APRIL 2013 www.ti.com LM2651-ADJ System Parameters (VOUT = 2.5V unless otherwise specified) Symbol Parameter Conditions Typical Limit Units 1.200 1.263 V V(min) V(max) VFB Feedback Voltage ILOAD = 900 mA 1.238 VOUT Output Voltage Line Regulation VIN = 4V to 14V ILOAD = 900 mA 0.2 % VOUT Output Voltage Load Regulation ILOAD = 10 mA to 1.5A VIN = 5V 1.3 % VOUT Output Voltage Load Regulation ILOAD = 200 mA to 1.5A VIN = 5V 0.
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LM2651 www.ti.com SNVS032D – FEBRUARY 2000 – REVISED APRIL 2013 All Output Voltage Versions (continued) Specifications in standard type face are for TJ = 25°C and those with boldface type apply over full operating junction temperature range. VIN =10V unless otherwise specified. Symbol fOSC DMAX ISS ISHUTDOWN vSHUTDOWN Parameter Oscillator Frequency Maximum Duty Cycle Soft-Start Current Shutdown Pin Current Conditions VIN = 4V VIN = 4V Voltage at the SS pin = 1.
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LM2651 SNVS032D – FEBRUARY 2000 – REVISED APRIL 2013 www.ti.com Typical Performance Characteristics 6 IQ vs Input Voltage IQSD vs Input Voltage Figure 4. Figure 5. IQSD vs Junction Temperature Frequency vs Junction Temperature Figure 6. Figure 7. RDS(ON) vs Input Voltage RDS(ON) vs Junction Temperature Figure 8. Figure 9.
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LM2651 www.ti.com SNVS032D – FEBRUARY 2000 – REVISED APRIL 2013 Typical Performance Characteristics (continued) Current Limit vs Input Voltage (VOUT =2.5V) Current Limit vs Junction Temperature (VOUT =2.5V) Figure 10. Figure 11. Current Limit vs Junction Temperature (VOUT = 3.3V) Current Limit vs Input Voltage (VOUT = 3.3V) Figure 12. Figure 13. Sleep Mode Threshold vs Output Voltage For ADJ version (VIN = 5V) Figure 14.
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LM2651 SNVS032D – FEBRUARY 2000 – REVISED APRIL 2013 www.ti.com Figure 15.
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LM2651 www.ti.com SNVS032D – FEBRUARY 2000 – REVISED APRIL 2013 BLOCK DIAGRAM Operation The LM2651 operates in a constant frequency (300 kHz), current-mode PWM for moderate to heavy loads; and it automatically switches to hysteretic mode for light loads. In hysteretic mode, the switching frequency is reduced to keep the efficiency high. MAIN OPERATION When the load current is higher than the sleep mode threshold, the part is always operating in PWM mode.
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LM2651 SNVS032D – FEBRUARY 2000 – REVISED APRIL 2013 www.ti.com A higher value of ripple current reduces inductance, but increases the conductance loss, core loss, current stress for the inductor and switch devices. It also requires a bigger output capacitor for the same output voltage ripple requirement. A reasonable value is setting the ripple current to be 30% of the DC output current.
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LM2651 www.ti.com SNVS032D – FEBRUARY 2000 – REVISED APRIL 2013 COMPENSATION COMPONENTS In the control to output transfer function, the first pole Fp1 can be estimated as 1/(2πROUTCOUT); The ESR zero Fz1 of the output capacitor is 1/(2πESRCOUT); Also, there is a high frequency pole Fp2 in the range of 45kHz to 150kHz: Fp2 = Fs/(πn(1−D)) where • • D = VOUT/VIN n = 1+0.348L/(VIN−VOUT) (L is in µHs and VIN and VOUT in volts). (7) The total loop gain G is approximately 500/IOUT where IOUT is in amperes.
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LM2651 SNVS032D – FEBRUARY 2000 – REVISED APRIL 2013 www.ti.com Figure 16.
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LM2651 www.ti.com SNVS032D – FEBRUARY 2000 – REVISED APRIL 2013 REVISION HISTORY Changes from Revision C (April 2013) to Revision D • Page Changed layout of National Data Sheet to TI format ..........................................................................................................
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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) LM2651MTC-3.3 NRND TSSOP PW 16 92 TBD Call TI Call TI -40 to 125 2651MTC -3.3 LM2651MTC-3.3/NOPB ACTIVE TSSOP PW 16 92 Green (RoHS & no Sb/Br) CU SN Level-1-260C-UNLIM -40 to 125 2651MTC -3.
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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 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 LM2651MTCX-3.3/NOPB TSSOP PW 16 2500 330.0 12.4 6.95 8.3 1.6 8.0 12.0 Q1 LM2651MTCX-ADJ/NOPB TSSOP PW 16 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) LM2651MTCX-3.3/NOPB TSSOP PW 16 2500 367.0 367.0 35.0 LM2651MTCX-ADJ/NOPB TSSOP PW 16 2500 367.0 367.0 35.
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