Datasheet

ManualsBrandsTEXAS INSTRUMENTS ManualsPMICsPMIC - voltage regulators - DC DC switch controllers TSSOP 14

LM27x7

BOOT

SEN

PGND

PWGD

FREQ

SGND

EAO

PGND

+5V

= 3.3V

= 1.2V@5A

1,2

2200PF

6.3V, 2.8A

1.5 PH

6.1 A, 9.6 m:

FB2

FADJ

BOOT

10PF

6.3V

10k

2.2k

10k

392k

2.2p

180p

12n

63.4k

2.2PF

10:

0.1P

1,2

FB1

Si4884DY

LM2727, LM2737

www.ti.com

SNVS205D –AUGUST 2002–REVISED MARCH 2013

LM2727/LM2737 N-Channel FET Synchronous Buck Regulator Controller for Low Output

Voltages

Check for Samples: LM2727, LM2737

FEATURES

DESCRIPTION

The LM2727 and LM2737 are high-speed,

• Input Power from 2.2V to 16V

synchronous, switching regulator controllers. They

• Output Voltage Adjustable Down to 0.6V

are intended to control currents of 0.7A to 20A with

• Power Good flag, Adjustable Soft-Start and

up to 95% conversion efficiencies. The LM2727

Output Enable for Easy Power Sequencing

employs output over-voltage and under-voltage latch-

off. For applications where latch-off is not desired, the

• Output Over-Voltage and Under-Voltage Latch-

LM2737 can be used. Power up and down

Off (LM2727)

sequencing is achieved with the power-good flag,

• Output Over-Voltage and Under-Voltage Flag

adjustable soft-start and output enable features. The

(LM2737)

LM2737 and LM2737 operate from a low-current 5V

bias and can convert from a 2.2V to 16V power rail.

• Reference Accuracy: 1.5% (0°C - 125°C)

Both parts utilize a fixed-frequency, voltage-mode,

• Current Limit Without Sense Resistor

PWM control architecture and the switching

• Soft Start

frequency is adjustable from 50kHz to 2MHz by

• Switching Frequency from 50 kHz to 2 MHz adjusting the value of an external resistor. Current

limit is achieved by monitoring the voltage drop

• TSSOP-14 Package

across the on-resistance of the low-side MOSFET,

which enhances low duty-cycle operation. The wide

APPLICATIONS

range of operating frequencies gives the power

• Cable Modems

supply designer the flexibility to fine-tune component

size, cost, noise and efficiency. The adaptive, non-

• Set-Top Boxes/ Home Gateways

overlapping MOSFET gate-drivers and high-side

• DDR Core Power

bootstrap structure helps to further maximize

• High-Efficiency Distributed Power

efficiency. The high-side power FET drain voltage can

be from 2.2V to 16V and the output voltage is

• Local Regulation of Core Power

adjustable down to 0.6V.

Typical Application

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 (32 pages)

PAGE 1
LM2727, LM2737 www.ti.com SNVS205D – AUGUST 2002 – REVISED MARCH 2013 LM2727/LM2737 N-Channel FET Synchronous Buck Regulator Controller for Low Output Voltages Check for Samples: LM2727, LM2737 FEATURES DESCRIPTION • • • The LM2727 and LM2737 are high-speed, synchronous, switching regulator controllers. They are intended to control currents of 0.7A to 20A with up to 95% conversion efficiencies. The LM2727 employs output over-voltage and under-voltage latchoff.
PAGE 2
LM2727, LM2737 SNVS205D – AUGUST 2002 – REVISED MARCH 2013 www.ti.com Connection Diagram 1 2 3 5 6 7 HG LG PGND SGND Vcc PWGD ISEN PGND LM27x7 4 BOOT SD FREQ FB SS EAO 14 13 12 11 10 9 8 Figure 1. 14-Lead Plastic TSSOP θJA = 155°C/W See Package Number PW0014A PIN DESCRIPTION BOOT (Pin 1) - Supply rail for the N-channel MOSFET gate drive. The voltage should be at least one gate threshold above the regulator input voltage to properly turn on the high-side N-FET.
PAGE 3
LM2727, LM2737 www.ti.com SNVS205D – AUGUST 2002 – REVISED MARCH 2013 Absolute Maximum Ratings (1) (2) VCC 7V BOOTV 21V Junction Temperature 150°C Storage Temperature −65°C to 150°C Soldering Information Lead Temperature (soldering, 10sec) 260°C Infrared or Convection (20sec) 235°C ESD Rating (1) (2) (3) (3) 2 kV Absolute maximum ratings indicate limits beyond which damage to the device may occur. Operating ratings indicate conditions for which the device operates correctly.
PAGE 4
LM2727, LM2737 SNVS205D – AUGUST 2002 – REVISED MARCH 2013 www.ti.com Electrical Characteristics (continued) VCC = 5V unless otherwise indicated. Typicals and limits appearing in plain type apply for TA=TJ=+25°C. Limits appearing in boldface type apply over full Operating Temperature Range. Datasheet min/max specification limits are ensured by design, test, or statistical analysis.
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LM2727, LM2737 www.ti.com SNVS205D – AUGUST 2002 – REVISED MARCH 2013 Typical Performance Characteristics Efficiency (VO = 1.5V) FSW = 300kHz, TA = 25°C Efficiency (VO = 3.3V) FSW = 300kHz, TA = 25°C 100 100 Vin = 5V Vin = 3.3V 90 90 EFFICIENCY (%) EFFICIENCY (%) 80 Vin = 5V 70 60 50 Vin = 12V 40 80 70 50 40 30 30 0.1 20 0.2 1 3 5 9 7 0.5 2 4 6 8 10 OUTPUT CURRENT (A) OUTPUT CURRENT (A) Figure 2. Figure 3.
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LM2727, LM2737 SNVS205D – AUGUST 2002 – REVISED MARCH 2013 www.ti.com Typical Performance Characteristics (continued) RFADJ vs PWM Frequency (in 100 to 800kHz range), TA = 25°C RFADJ vs PWM Frequency (in 900 to 2000kHz range), TA = 25°C 500 30 400 RF-ADJ (k:) RF-ADJ (k:) 25 300 200 20 15 100 0 100 150 200 250 300 350 400450 500 600 700 800 10 9001000110012001300140015001600170018001900 PWM FREQUENCY (kHz) PWM FREQUENCY (kHz) Figure 8. Figure 9.
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LM2727, LM2737 www.ti.com SNVS205D – AUGUST 2002 – REVISED MARCH 2013 Typical Performance Characteristics (continued) Start-Up (Full-Load) VIN = 10V, VO = 1.2V IO = 10A, CSS = 10nF FSW = 300kHz Start Up (No-Load, 10x CSS) VIN = 10V, VO = 1.2V CSS = 100nF, FSW = 300kHz Figure 14. Figure 15. Start Up (Full Load, 10x CSS) VIN = 10V, VO = 1.2V IO = 10A, CSS = 100nF FSW = 300kHz Shutdown VIN = 10V, VO = 1.2V IO = 10A, CSS = 10nF FSW = 300kHz Figure 16. Figure 17.
PAGE 8
LM2727, LM2737 SNVS205D – AUGUST 2002 – REVISED MARCH 2013 www.ti.com Typical Performance Characteristics (continued) 8 Load Transient Response (IO = 4 to 0A) VIN = 12V, VO = 1.2V FSW = 300kHz Line Transient Response (VIN =5V to 12V) VO = 1.2V, IO = 5A FSW = 300kHz Figure 20. Figure 21. Line Transient Response (VIN =12V to 5V) VO = 1.2V, IO = 5A FSW = 300kHz Line Transient Response VO = 1.2V, IO = 5A FSW = 300kHz Figure 22. Figure 23.
PAGE 9
LM2727, LM2737 www.ti.com SNVS205D – AUGUST 2002 – REVISED MARCH 2013 Block Diagram SD FREQ Vcc CLOCK & RAMP UVLO PGND PGND SGND 20PA off LOGIC BOOT SHUT DOWN LATCH 10Ps DELAY HG PWGD 3.05V 10PA HIGH LOW LG 0.708V tol.=+/-2% 0.42V tol.=+/-2% hyst.=12% S OUTPUT CLAMP HI: 3.25V LO: 1.25V SS 3.25V oc 95P$ R 1.25V R>S SS CMP off off SYNCHRONOUS DRIVER LOGIC PWM 50PA BG = 0.
PAGE 10
LM2727, LM2737 SNVS205D – AUGUST 2002 – REVISED MARCH 2013 www.ti.com APPLICATION INFORMATION THEORY OF OPERATION The LM2727 is a voltage-mode, high-speed synchronous buck regulator with a PWM control scheme. It is designed for use in set-top boxes, thin clients, DSL/Cable modems, and other applications that require high efficiency buck converters. It has power good (PWRGD), output shutdown (SD), over voltage protection (OVP) and under voltage protection (UVP).
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LM2727, LM2737 www.ti.com SNVS205D – AUGUST 2002 – REVISED MARCH 2013 5V Cb BOOTV + HG Vo LM27x7 + LG Figure 24. BOOTV Supplied by Charge Pump In a system without a separate, higher voltage, a charge pump (bootstrap) can be built using a diode and small capacitor, Figure 24. The capacitor serves to maintain enough voltage between the top FET gate and source to control the device even when the top FET is on and its source has risen up to the input voltage level.
PAGE 12
LM2727, LM2737 SNVS205D – AUGUST 2002 – REVISED MARCH 2013 www.ti.com UVP/OVP The output undervoltage protection and overvoltage protection mechanisms engage at 70% and 118% of the target output voltage, respectively. In either case, the LM2727 will turn off the high side switch and turn on the low side switch, and discharge the soft start capacitor through a MOSFET switch. The chip remains in this state until the shutdown pin has been pulled to a logic low and then released.
PAGE 13
LM2727, LM2737 www.ti.com SNVS205D – AUGUST 2002 – REVISED MARCH 2013 (8) In the case of a desktop computer system, the input current slew rate is the system power supply or "silver box" output current slew rate, which is typically about 0.1A/µs. Total input capacitor ESR is 9mΩ, hence ΔV is 10*0.009 = 90 mV, and the minimum inductance required is 0.9µH. The input inductor should be rated to handle the DC input current, which is approximated by: (9) In this case IIN-DC is about 2.8A.
PAGE 14
LM2727, LM2737 SNVS205D – AUGUST 2002 – REVISED MARCH 2013 www.ti.com MOSFETS MOSFETS are a critical part of any switching controller and have a direct impact on the system efficiency. In this case the target efficiency is 85% and this is the variable that will determine which devices are acceptable. Loss from the capacitors, inductors, and the LM2727 itself are detailed in the Efficiency section, and come to about 0.54W. To meet the target efficiency, this leaves 1.
PAGE 15
LM2727, LM2737 www.ti.com SNVS205D – AUGUST 2002 – REVISED MARCH 2013 EFFICIENCY CALCULATIONS A reasonable estimation of the efficiency of a switching controller can be obtained by adding together the loss is each current carrying element and using the equation: (13) The following shows an efficiency calculation to complement the Circuit of Figure 26. Output power for this circuit is 1.2V x 10A = 12W. Chip Operating Loss PIQ = IQ-VCC *VCC (14) 2mA x 5V = 0.
PAGE 16
LM2727, LM2737 SNVS205D – AUGUST 2002 – REVISED MARCH 2013 www.ti.com Example Circuits +5V D1 Rin 10 Cin 2.2u Rfadj 0.1u Q1 BOOT SD Css 12n 2.7 uH 14.4 A, 4.5 m: Rcs ISEN PWGD LM27x7 LG SS PGND SGND PGND Lin + Cin1,2 2 x 10 uF 25V, 3.3A Cinx 1uF 25V HG Vcc FREQ 88.7k 1.2 uH 8.2 A, 6.9 m: Cboot Vin = 12V Vo = 3.3V@10A L1 1.8k Q2 + Co1-4 4 x 100 uF 10V, 55 m: Rfb2 49.9k Rc2 Cc3 FB EAO 8.45k 470p Rfb1 11k Cc1 Cc2 6.8p Rc1 143.3k 270p Figure 25. 5V-16V to 3.
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LM2727, LM2737 www.ti.com SNVS205D – AUGUST 2002 – REVISED MARCH 2013 +12V Vin = 5V Cc 0.1u Rin 10 Cin 2.2u Vcc SD BOOT PWGD Rfadj Css 12n LG SS PGND SGND PGND EAO Cin1 100 uF 10V, 1.9A 2.2 uH 6.1A, 12 m: Rcs ISEN LM27x7 FREQ 43.2k + Q1/Q2 HG Vo = 1.8V@3A L1 2.7k + Rfb2 4.99k Co1 1 x 220 uF 4V, 55 m: FB Rfb1 2.49k Cc1 Cc2 10p 560p Rc1 51.1k Figure 27. 5V to 1.
PAGE 18
LM2727, LM2737 SNVS205D – AUGUST 2002 – REVISED MARCH 2013 www.ti.com +5V D1 1uH 6.4A, 7.3 m: Cboot Rin 10 Vin = 5 to 15V Lin 0.1u + Vcc Cin 2.2u SD BOOT PWGD Rfadj Rcs ISEN LM27x7 FREQ 17.4k LG SS PGND SGND PGND EAO + Rfb2 10k Rc2 66.5 22p Co1 1 x 15uF 25V 3.1mohm Cc3 680p Rfb1 4.99k Cc1 Cc2 Vo = 1.8V@1A L1 1.5k FB Css 1 x 15uF 25V, 3.3A Q1/Q2 3.3uH 4.1A, 17.4 m: HG Rc1 39n 680p 10.7k 1uH 6.4 A, 7.3 m: Vin = 5 to 15V Lin +5V D1 Cboot Rin 10 0.1u Vcc Cin 2.
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LM2727, LM2737 www.ti.com SNVS205D – AUGUST 2002 – REVISED MARCH 2013 To 2nd LM27x7 Vin = 11 to 13V +5V LM78L05 D1 1uH, 6.4A 7.3 m: Cboot 0.1u Cin 2.2u BOOT SD LM27x7 FREQ 32.5k Css 12n Rcs + Cinx 10uF 16V Cin1 680uF 16V, 1.54A Vo = 3.3V@3A ISEN PWGD Rfadj Q1/Q2 4.2uH, 5.5A 15 m: HG Vcc 2k LG SS PGND SGND PGND + Rfb2 10k 2.37k 4.7n Rfb1 2.21k Cc1 Cc2 Cox 10uF 25V Co1,2 2 x 680uF 16V 1.54A Cc3 Rc2 FB EAO Vin = 11 to 13V Lin Rc1 8.2p 52.3k 1n Figure 30.
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LM2727, LM2737 SNVS205D – AUGUST 2002 – REVISED MARCH 2013 www.ti.com Table 1. Bill of Materials for Typical Application Circuit ID U1 Part Number Type Synchronous Controller LM2727 Q1, Q2 Si4884DY L1 RLF7030T-1R5N6R1 N-MOSFET Cin1, Cin2 C2012X5R1J106M MLCC Capacitor Cinx C3216X7R1E105K Co1, Co2 6MV2200WG Cboot VJ1206X104XXA Inductor Size Parameters Qty. Vendor TSSOP-14 TSSOP-14 1 Texas Instruments SO-8 30V, 4.1mΩ, 36nC 1 Vishay 7.1x7.1x3.2mm 1.5µH, 6.1A 9.
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LM2727, LM2737 www.ti.com SNVS205D – AUGUST 2002 – REVISED MARCH 2013 Table 3. Bill of Materials for Circuit of Figure 26 (continued) ID Part Number Size Parameters Qty. Vendor Cc2 VJ1206A102KXX Capacitor Type 1206 1nF 10% 1 Vishay Rin CRCW1206100J Resistor 1206 10Ω 5% 1 Vishay Rfadj CRCW12068872F Resistor 1206 88.7kΩ 1% 1 Vishay Rc1 CRCW12062293F Resistor 1206 229kΩ 1% 1 Vishay Rfb1 CRCW12064991F Resistor 1206 4.
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LM2727, LM2737 SNVS205D – AUGUST 2002 – REVISED MARCH 2013 www.ti.com Table 5. Bill of Materials for Circuit of Figure 28 (continued) ID Part Number Size Parameters Qty. Vendor Cc2 VJ1206A681KXX Capacitor Type 1206 680pF 10% 1 Vishay Rin CRCW1206100J Resistor 1206 10Ω 5% 1 Vishay Rfadj CRCW12064992F Resistor 1206 49.9kΩ 1% 1 Vishay Rc1 CRCW12061473F Resistor 1206 147kΩ 1% 1 Vishay Rfb1 CRCW12061492F Resistor 1206 14.
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LM2727, LM2737 www.ti.com SNVS205D – AUGUST 2002 – REVISED MARCH 2013 Table 8. Bill of Materials for Circuit of Figure 30 ID Part Number U1 LM2727 Synchronous Controller Type Qty. Vendor TSSOP-14 Size U2 LM78L05 Q1/Q2 Si4826DY D1 BAT-54 1 Texas Instrument s Voltage Regulator SO-8 1 Texas Instrument s Assymetric Dual N-MOSFET SO-8 30V, 24mΩ/ 8nC Top 16.5mΩ/ 15nC 1 Vishay SOT-23 30V 1 Vishay TDK Schottky Diode Parameters Lin RLF7030T-1R0N64 Inductor 6.8x7.1x3.2mm 1µH, 6.
PAGE 24
LM2727, LM2737 SNVS205D – AUGUST 2002 – REVISED MARCH 2013 www.ti.com Table 9. Bill of Materials for Circuit of Figure 31 (continued) 24 ID Part Number Size Parameters Qty. Vendor Rfb1 CRCW12061371F Resistor Type 1206 1.37kΩ 1% 1 Vishay Rfb2 CRCW12061002F Resistor 1206 10kΩ 1% 1 Vishay Rcs CRCW1206122F Resistor 1206 1.
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LM2727, LM2737 www.ti.com SNVS205D – AUGUST 2002 – REVISED MARCH 2013 REVISION HISTORY Changes from Revision C (March 2013) to Revision D • 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 9-May-2014 (5) Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation of the previous line and the two combined represent the entire Device Marking for that device. (6) Lead/Ball Finish - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line.
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PACKAGE MATERIALS INFORMATION www.ti.com 11-May-2014 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 LM2727MTCX/NOPB TSSOP PW 14 2500 330.0 12.4 6.95 8.3 1.6 8.0 12.0 Q1 LM2737MTCX TSSOP PW 14 2500 330.0 12.4 6.95 8.3 1.6 8.0 12.0 Q1 LM2737MTCX/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 11-May-2014 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) LM2727MTCX/NOPB TSSOP PW 14 2500 367.0 367.0 35.0 LM2737MTCX TSSOP PW 14 2500 367.0 367.0 35.0 LM2737MTCX/NOPB TSSOP PW 14 2500 367.0 367.0 35.
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