Datasheet

ManualsBrandsTEXAS INSTRUMENTS ManualsPMICsPMIC - DC/DC voltage regulator Boost, SEPIC VSSOP 8

Battery or Power

Source

4.5V-5.5V

10PH

22PF, 10V

OUT

10PF

FB2

3.48k

FB1

30.1k

4.7 nF

12V

400mA

24.9k

1 4

FSLCT

GND

SHDN

LM2698

: LMK316F226Z (TAIYO YUDEN)

OUT

: EMK325B5106K (TAIYO YUDEN)

L: DO3316-103 (COILCRAFT)

D: 0MQ040N (MOTOROLA)

LM2698

www.ti.com

SNVS153E –MAY 2001–REVISED APRIL 2013

LM2698 SIMPLE SWITCHER

1.35A Boost Regulator

Check for Samples: LM2698

FEATURES

DESCRIPTION

The LM2698 is a general purpose PWM boost

• 1.9A, 0.2Ω, Internal Switch (typical)

converter. The 1.9A, 18V, 0.2ohm internal switch

• Operating Voltage as Low as 2.2V

enables the LM2698 to provide efficient power

• 600kHz/1.25MHz Adjustable Frequency

conversion to outputs ranging from 2.2V to 17V. It

Operation

can operate with input voltages as low as 2.2V and

as high as 12V. Current-mode architecture provides

• Switchers Made Simple® Software

superior line and load regulation and simple

• 8-Lead VSSOP package

frequency compensation over the device's 2.2V to

12V input voltage range. The LM2698 sets the

APPLICATIONS

standard in power density and is capable of supplying

12V at 400mA from a 5V input. The LM2698 can also

• 3.3V to 5V, 5V to 12V Conversion

be used in flyback or SEPIC topologies.

• Distributed Power

The LM2698 SIMPLE SWITCHER

features a pin

• Set-Top Boxes

selectable switching frequency of either 600kHz or

• DSL Modems

1.25MHz. This promotes flexibility in component

• Diagnostic Medical Instrumentation

selection and filtering techniques. A shutdown pin is

available to suspend the device and decrease the

• Boost Converters

quiescent current to 5µA. An external compensation

• Flyback Converters

pin gives the user flexibility in setting frequency

• SEPIC Converters

compensation, which makes possible the use of

small, low ESR ceramic capacitors at the output.

Switchers Made Simple® software is available to

ensure a quick, easy and assured design. The

LM2698 is available in a low profile 8-lead VSSOP

(DGK) package.

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.

2SIMPLE SWITCHER is a registered trademark of Texas Instruments.

3All other 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)

PAGE 1
LM2698 www.ti.com SNVS153E – MAY 2001 – REVISED APRIL 2013 LM2698 SIMPLE SWITCHER® 1.35A Boost Regulator Check for Samples: LM2698 FEATURES DESCRIPTION • • • The LM2698 is a general purpose PWM boost converter. The 1.9A, 18V, 0.2ohm internal switch enables the LM2698 to provide efficient power conversion to outputs ranging from 2.2V to 17V. It can operate with input voltages as low as 2.2V and as high as 12V.
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LM2698 SNVS153E – MAY 2001 – REVISED APRIL 2013 www.ti.com Connection Diagram Top View 1 8 VC NC FB FSLCT 2 7 3 SHDN 4 GND VIN 6 VSW 5 Figure 1. 8-Lead Plastic VSSOP Pin Functions 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 4 GND Analog and power ground. 5 VSW Power switch input. Switch connected between SW pin and GND pin.
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LM2698 www.ti.
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LM2698 SNVS153E – MAY 2001 – REVISED APRIL 2013 Absolute Maximum Ratings www.ti.com (1) −0.3V ≤ VIN ≤ 12V VIN −0.3V ≤ VSW ≤ 18V SW Voltage FB Voltage −0.3V ≤ VFB ≤ 7V VC Voltage 0.965 < VC < 1.565 SHDN Voltage (2) −0.3V ≤ VSHDN ≤ 7V FSLCT (2) −0.3V ≤ VFSLCT ≤ 12V Maximum Junction Temperature Power Dissipation 150°C (3) Internally Limited Lead Temperature 300°C Vapor Phase (60 sec.) 215°C Infrared (15 sec.
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LM2698 www.ti.com SNVS153E – MAY 2001 – REVISED APRIL 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 Parameter Quiescent Current Min Typ Max (1) Units 1.3 2.0 mA 5 10 µA 1.2285 1.26 1.2915 V 1.35 1.9 2.4 A 0.013 0.1 %/V 0.
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LM2698 SNVS153E – MAY 2001 – REVISED APRIL 2013 www.ti.com Typical Performance Characteristics Efficiency vs Load Current (VOUT = 8V, fS = 600kHz) Efficiency vs Load Current (VOUT = 8V, fS = 1.25MHz) Figure 2. Figure 3. Iq vs VIN (600 kHz, non-switching) 2.0 Iq vs VIN (600 kHz, switching) 4.0 R 3.5 1.8 TA = 85R C 1.7 3.0 TA = 85R C 1.6 Iq (mA) Iq (mA) TA = 25R C TA = 25 C 1.9 TA = -40R C 1.5 TA = -40R C 2.5 1.4 2.0 1.3 1.2 1.5 1.1 1.0 1.
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LM2698 www.ti.com SNVS153E – MAY 2001 – REVISED APRIL 2013 Typical Performance Characteristics (continued) Iq(SHDN) vs VIN 12 RDS(ON) vs VIN 250 TA = 85R C 11 200 10 RDS(ON) (m:) Iq (PA) TA = 85R C TA = 25R C 9 R TA = -40 C 8 7 150 TA = 25R C 100 TA = -40R C 6 50 5 4 0 2 4 6 8 VIN (V) 12 10 0 14 4 2 Figure 8. 10 12 14 Figure 9. Switching Frequency vs VIN (600kHz) Switching Frequency vs VIN (1.25MHz) 650 1.4 645 TA = -40R C 640 635 630 625 620 TA = 25R C 615 1.36 1.
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LM2698 SNVS153E – MAY 2001 – REVISED APRIL 2013 www.ti.com Operation Continuous Conduction Mode L D COUT VIN RLOAD PWM L X + + L COUT VIN RLOAD VI N COUT R LOAD V OU V OUT T - Cycle 1 (a) - Cycle 2 (b) Figure 14. Simplified Boost Converter Diagram (a) First Cycle of Operation (b) Second Cycle Of Operation The LM2698 is a current-mode, PWM boost regulator. A boost regulator steps the input voltage up to a higher output voltage.
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LM2698 www.ti.com SNVS153E – MAY 2001 – REVISED APRIL 2013 Inductor IL (A) VIN - VOUT VIN L L 'iL IL(AVG) t (s) D*Ts Ts (a) ID (A) VIN - VOUT L ID(AVG) = IOUT(AVG) t (s) D*Ts Ts (b) Figure 15. (a) Inductor Current (b) Diode Current The inductor is one of the two energy storage elements in a boost converter. Figure 15 shows how the inductor current varies during a switching cycle.
PAGE 10
LM2698 SNVS153E – MAY 2001 – REVISED APRIL 2013 www.ti.com The inductance value will also affect the stability of the converter. Because the LM2698 utilizes current mode control, the inductor value must be carefully chosen. See the Compensation section for recommended inductance values. Choosing an appropriate core size for the inductor involves calculating the average and peak currents expected through the inductor.
PAGE 11
LM2698 www.ti.com SNVS153E – MAY 2001 – REVISED APRIL 2013 Input Capacitor Due to the presence of an inductor at the input of a boost converter, the input current waveform is continuous and triangular. The inductor ensures that the input capacitor sees fairly low ripple currents. However, as the inductor gets smaller, the input ripple increases.
PAGE 12
LM2698 xxxx xxxx xxxx xxxx SNVS153E – MAY 2001 – REVISED APRIL 2013 50 45 25 30 20 Inductance (PH) 35 Q = 0.5 25 20 15 10 xxx xxx xxx VOUT = 12V VOUT = 12V 40 Inductance (PH) www.ti.com 15 Q = 0.5 10 5 Q=5 5 1 0 0.1 0.2 0.3 0.4 0.5 0.6 Q=5 1 0.7 0.8 0 0.1 0.2 Duty Cycle (1-VIN/VOUT) 0.3 0.4 0.5 0.6 0.7 0.8 Duty Cycle (1-VIN/VOUT) (a) (b) Figure 17. Minimum Inductance Requirements for (a) fS = 600kHz Figure 18. Minimum Inductance Requirements for (b) fS = 1.
PAGE 13
LM2698 www.ti.com SNVS153E – MAY 2001 – REVISED APRIL 2013 Quick Compensator Design Calculate: ZPI(MAX) | 1 (rad/s) COUTRLOAD(MIN) (14) where, RLOAD(MIN) = VOUT IOUT(MAX) (15) 2 RLOAD(MIN) VIN(MIN) VOUT (rad/s) ZRHP(MIN) = L ( ( (16) 1 Set ZP2 = 2S(40)(rad/s) | (rad/s) CC1ROUT (17) where ROUT = 875kΩ Choose CC1 = 4.
PAGE 14
LM2698 SNVS153E – MAY 2001 – REVISED APRIL 2013 www.ti.com Additional Comments on the Open Loop Frequency Response The procedure used here to pick the compensation network will provide a good starting point. In most cases, these values will be sufficient for a stable design. It is always recommended to check the design in a real test setup. This is easy to do with the aid of a dynamic load. Set the high and low load values to your system requirements and switch between the two at about 1kHz.
PAGE 15
LM2698 www.ti.com SNVS153E – MAY 2001 – REVISED APRIL 2013 L1 10PH D0-1608 CSEPIC 1PF D (Schottky) 2.2V - 12V L2 10PH D0-1608 5 SW 6 7 VIN FSLCT LM2698 3 Battery or Power Source SHDN FB VC 2 RFB1 20k 3.3V GND 1 4 COUT 10PF Ceramic CIN 22PF Ceramic RC 10k RFB2 12.1k CC 680pF Figure 21. 3.3V SEPIC Converter 3.3V SEPIC The LM2698 can be used to implement a SEPIC technology.
PAGE 16
LM2698 SNVS153E – MAY 2001 – REVISED APRIL 2013 www.ti.com CIN should be chosen using the same relationship as in the boost converter (see the CIN section). CIN must be able to provide the necessary RMS current. L1 6.8PH 12V CSEPIC 1PF 5 SW 500 6 VIN FSLCT 6.8V 3 Battery or Power Source SHDN FB VC 0.1PF 2 RFB1 30.1k GND 4 1 CIN 47PF L2 6.8PH 7 LM2698 D (Schottky) COUT 10PF RC 10k RFB2 10k CC 680pF -5V, 400mA Figure 22.
PAGE 17
LM2698 www.ti.com SNVS153E – MAY 2001 – REVISED APRIL 2013 Figure 23. Figure 24. Figure 25. Figure 26. Figure 27.
PAGE 18
LM2698 SNVS153E – MAY 2001 – REVISED APRIL 2013 www.ti.com REVISION HISTORY Changes from Revision D (April 2013) to Revision E • 18 Page Changed layout of National Data Sheet to TI format ..........................................................................................................
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PACKAGE OPTION ADDENDUM www.ti.
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PACKAGE MATERIALS INFORMATION www.ti.com 23-Sep-2013 TAPE AND REEL INFORMATION *All dimensions are nominal Device LM2698MM-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 VSSOP DGK 8 1000 178.0 12.4 5.3 3.4 1.4 8.0 12.0 Q1 LM2698MMX-ADJ/NOPB VSSOP DGK 8 3500 330.0 12.4 5.3 3.4 1.4 8.0 12.
PAGE 21
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) LM2698MM-ADJ/NOPB VSSOP DGK 8 1000 210.0 185.0 35.0 LM2698MMX-ADJ/NOPB VSSOP DGK 8 3500 367.0 367.0 35.
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