Datasheet

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

LM3224

FB1

OUT

FB2

GND

OUT

Battery or

Power Source

Optional

FSLCT

6 7

SHDN

LM3224

www.ti.com

SNVS277C –DECEMBER 2004–REVISED MARCH 2013

LM3224 615kHz/1.25MHz Step-up PWM DC/DC Converter

Check for Samples: LM3224

FEATURES

DESCRIPTION

The LM3224 is a step-up DC/DC converter with a

• Operating Voltage Range of 2.7V to 7V

0.15Ω (typ.), 2.45A (typ.) internal switch and pin

• 615kHz/1.25MHz Pin Selectable Frequency

selectable operating frequency. With the ability to

Operation

convert 3.3V to multiple outputs of 8V, -8V, and 23V,

• Over Temperature Protection

the LM3224 is an ideal part for biasing TFT displays.

With the high current switch it is also ideal for driving

• Optional Soft-Start Function

high current white LEDs for flash applications. The

• 8-Lead VSSOP Package

LM3224 can be operated at switching frequencies of

615kHz and 1.25MHz allowing for easy filtering and

APPLICATIONS

low noise. An external compensation pin gives the

user flexibility in setting frequency compensation,

• TFT Bias Supplies

which makes possible the use of small, low ESR

• Handheld Devices

ceramic capacitors at the output. An external soft-

• Portable Applications

start pin allows the user to control the amount of

inrush current during start up. The LM3224 is

• GSM/CDMA Phones

available in a low profile 8-lead VSSOP package.

• Digital Cameras

• White LED Flash/Torch Applications

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.

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)

PAGE 1
LM3224 www.ti.com SNVS277C – DECEMBER 2004 – REVISED MARCH 2013 LM3224 615kHz/1.25MHz Step-up PWM DC/DC Converter Check for Samples: LM3224 FEATURES DESCRIPTION • • The LM3224 is a step-up DC/DC converter with a 0.15Ω (typ.), 2.45A (typ.) internal switch and pin selectable operating frequency. With the ability to convert 3.3V to multiple outputs of 8V, -8V, and 23V, the LM3224 is an ideal part for biasing TFT displays.
PAGE 2
LM3224 SNVS277C – DECEMBER 2004 – REVISED MARCH 2013 www.ti.com Connection Diagram 1 8 VC SS FB FSLCT 7 2 3 6 SHDN VIN GND SW 4 5 Figure 1. 8-Lead Plastic VSSOP Top View Package Number DGK0008A PIN DESCRIPTIONS Pin 2 Name Function 1 VC Compensation network connection. Connected to the output of the voltage error amplifier. 2 FB Output voltage feedback input. 3 SHDN 4 GND Analog and power ground. 5 SW Power switch input. Switch connected between SW pin and GND pin.
PAGE 3
LM3224 www.ti.com SNVS277C – DECEMBER 2004 – REVISED MARCH 2013 Block Diagram FSLCT ¦ SS Duty Cycle Limit Oscillator Load Current Measurement SW + PWM COMP - - FB BG Set Reset Drive Reset Driver LOGIC ERROR AMP UVP OVP + BG Thermal SD OVP COMP + BG + Thermal Shutdown Bandgap Voltage Reference VC Shutdown Comparator SHDN UVP COMP VIN GND General Description The LM3224 utilizes a PWM control scheme to regulate the output voltage over all load conditions.
PAGE 4
LM3224 SNVS277C – DECEMBER 2004 – REVISED MARCH 2013 Absolute Maximum Ratings (1) www.ti.com (2) (2) VIN 7.5V SW Voltage 21V FB Voltage (3) 7V VC Voltage (4) 1.26V ± 0.3V SHDN Voltage 7.5V FSLCT 7.5V Maximum Junction Temperature 150°C Power Dissipation (5) Internally Limited Lead Temperature 300°C Vapor Phase (60 sec.) 215°C Infrared (15 sec.
PAGE 5
LM3224 www.ti.com SNVS277C – DECEMBER 2004 – REVISED MARCH 2013 Electrical Characteristics (1) 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). VIN = 2.7V, FSLCT = SHDN = VIN, and IL = 0A, unless otherwise specified. Symbol IQ Typ Max (1) Units FB = 2V (Not Switching) 1.3 2.0 mA VSHDN = 0V 0.1 2.0 µA 1.2285 1.26 1.2915 V 1.9 2.45 2.
PAGE 6
LM3224 SNVS277C – DECEMBER 2004 – REVISED MARCH 2013 www.ti.com Typical Performance Characteristics SHDN Pin Current vs. SHDN Pin Voltage SS Pin Current vs. Temperature 7 11.8 11.6 VIN = 7.0V TJ = -40oC SS PIN CURRENT (PA) SHDN PIN CURRENT (PA) 6 5 TJ 4 =2 o 5C 3 2 o TJ = 125 C 1 11.4 11.2 11.0 10.8 VIN = 2.7V 10.6 10.4 0 0.0 1.0 2.0 4.0 3.0 5.0 6.0 10.2 -40 -25 -10 5 7.0 SHDN PIN VOLTAGE (V) TEMPERATURE (oC) Figure 2. Figure 3. FSLCT Pin Current vs.
PAGE 7
LM3224 www.ti.com SNVS277C – DECEMBER 2004 – REVISED MARCH 2013 Typical Performance Characteristics (continued) 1.25MHz Non-switching IQ vs. Input Voltage 615kHz Switching IQ vs. Input Voltage 2.0 4.5 1.7 1.6 1.5 TJ = -40oC 4.0 1.8 SWITCHING IQ (mA) NON-SWITCHING IQ (mA) 1.9 TJ = 125oC TJ = 25oC 1.4 TJ = -40oC 1.3 3.5 TJ = 25oC 3.0 TJ = 125oC 2.5 2.0 1.2 1.5 1.1 1.0 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 1.0 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.
PAGE 8
LM3224 SNVS277C – DECEMBER 2004 – REVISED MARCH 2013 www.ti.com Typical Performance Characteristics (continued) 1.25MHz Switching Frequency vs. Temperature 615kHz Maximum Duty Cycle vs. Temperature 94.0 VIN = 7.0V 1.32 VIN = 7.0V MAXIMUM DUTY CYCLE (%) SWITCHING FREQUENCY (MHz) 1.34 1.30 1.28 1.26 1.24 VIN = 2.7V 1.22 1.20 93.5 93.0 92.5 VIN = 2.7V 92.0 1.18 1.16 -40 -25 -10 5 20 35 50 65 80 95 110 125 91.
PAGE 9
LM3224 www.ti.com SNVS277C – DECEMBER 2004 – REVISED MARCH 2013 Typical Performance Characteristics (continued) 1.25MHz Efficiency vs. Load Current 100 90 EFFICIENCY (%) 80 V OUT =8V V IN = 2.7V VIN =5.5V 70 V IN = 3.3V 60 VIN = 4. 2V 50 40 30 20 10 0 0. 1 1 10 100 1000 10000 LOAD CURRENT (mA) Figure 20.
PAGE 10
LM3224 SNVS277C – DECEMBER 2004 – REVISED MARCH 2013 www.ti.com OPERATION L D COUT VIN RLOAD PWM L X + + L COUT VIN R LOAD V IN COUT R LOAD V OUT V OUT - - Cycle 1 (a) Cycle 2 (b) Figure 21. Simplified Boost Converter Diagram (a) First Cycle of Operation (b) Second Cycle Of Operation CONTINUOUS CONDUCTION MODE The LM3224 is a current-mode, PWM boost regulator. A boost regulator steps the input voltage up to a higher output voltage.
PAGE 11
LM3224 www.ti.com SNVS277C – DECEMBER 2004 – REVISED MARCH 2013 SOFT-START CAPACITOR The LM3224 has a soft-start pin that can be used to limit the inductor inrush current on start-up. The external SS pin is used to tailor the soft-start for a specific application but is not required for all applications and can be left open when not needed. When used, a current source charges the external soft-start capacitor, Css. The softstart time can be estimated as: Tss = Css*1.
PAGE 12
LM3224 SNVS277C – DECEMBER 2004 – REVISED MARCH 2013 www.ti.com To keep a current programmed control converter stable above duty cycles of 50%, the inductor must meet certain criteria. The inductor, along with input and output voltage, will determine the slope of the current through the inductor (see Figure 22 (a)). If the slope of the inductor current is too great, the circuit will be unstable above duty cycles of 50%. A 10µH to 15µH inductor is recommended for most 615 kHz applications, while a 4.
PAGE 13
LM3224 www.ti.com SNVS277C – DECEMBER 2004 – REVISED MARCH 2013 The inductor ripple current is important for a few reasons. One reason is because the peak switch current will be the average inductor current (input current or ILOAD/D') plus ΔiL. As a side note, discontinuous operation occurs when the inductor current falls to zero during a switching cycle, or ΔiL is greater than the average inductor current. Therefore, continuous conduction mode occurs when ΔiL is less than the average inductor current.
PAGE 14
LM3224 SNVS277C – DECEMBER 2004 – 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.
PAGE 15
LM3224 www.ti.com SNVS277C – DECEMBER 2004 – REVISED MARCH 2013 Since RC is generally much less than RO, it does not have much effect on the above equation and can be neglected until a value is chosen to set the zero fZC. fZC is created to cancel out the pole created by the output capacitor, fP1. The output capacitor pole will shift with different load currents as shown by the equation, so setting the zero is not exact.
PAGE 16
LM3224 SNVS277C – DECEMBER 2004 – REVISED MARCH 2013 www.ti.com APPLICATION INFORMATION D5 D4 L 10 PH 23V D7 C6 1 PF C5 1 PF C4 1 PF VIN = 2.7V - 5.5V D6 C7 1 PF C1 4.7 PF D1 D3 -8V C2 D2 4.7 PF 5 SW 7 6 FSLCT VIN 3 RFB1 LM3224 SHDN 8V 160k 8 SS VC GND 4 1 CIN 22 PF RC 30k CSS RFB2 COUT1 COUT2 30k 10 PF 10 PF CC2 68 pF CC 1 nF Figure 23.
PAGE 17
LM3224 www.ti.com SNVS277C – DECEMBER 2004 – REVISED MARCH 2013 The 23V output is realized with a series of capacitor charge pumps. It consists of four stages: the first stage includes C4, D4, and the LM3224 switch; the second stage uses C5, D5, and D1; the third stage includes C6, D6, and the LM3224 switch; the final stage is C7 and D7. In the first stage, C4 charges to 8V when the LM3224 switch is closed, which causes D5 to conduct when the switch is open.
PAGE 18
LM3224 SNVS277C – DECEMBER 2004 – REVISED MARCH 2013 www.ti.com The LM3224 can be configured to drive high current white LEDs for the flash and torch functions of a digital camera, camera phone, or any other similar light source.
PAGE 19
LM3224 www.ti.com SNVS277C – DECEMBER 2004 – REVISED MARCH 2013 Table 3. Some Recommended Input And Output Capacitors (Others May Be Used) Manufacturer Capacitor Contact Information Vishay Sprague 293D, 592D, and 595D series tantalum www.vishay.com 407-324-4140 Taiyo Yuden High capacitance MLCC ceramic www.t-yuden.com 408-573-4150 Cornell Dubilier ESRD seriec Polymer Aluminum Electrolytic SPV and AFK series V-chip series www.cde.com MuRata High capacitance MLCC ceramic www.murata.com L 4.
PAGE 20
LM3224 SNVS277C – DECEMBER 2004 – REVISED MARCH 2013 www.ti.com L 10 PH 2.9V - 4.2V 5 6 3 8 Battery or Power Source 12V, 300mA D 332k SW FSLCT VIN SHDN SS CIN LM3224 FB VC 22 PF 7 2 GND 1 4 COUT RC 22 PF ceramic 40.2k 39.2k CC 1.5 nF Figure 28. 1.25MHz, 12V Output L 15 PH 2.9V - 4.2V 5 6 3 8 Battery or Power Source CIN 22 PF 15V, 220mA D 301k SW FSLCT VIN SHDN SS 7 LM3224 FB VC 2 GND 1 4 COUT RC 40.2k 27.4k 22 PF ceramic CC 1.5 nF Figure 29. 1.
PAGE 21
LM3224 www.ti.com SNVS277C – DECEMBER 2004 – REVISED MARCH 2013 REVISION HISTORY Changes from Revision B (March 2013) to Revision C • Page Changed layout of National Data Sheet to TI format ..........................................................................................................
PAGE 22
PACKAGE OPTION ADDENDUM www.ti.
PAGE 23
PACKAGE MATERIALS INFORMATION www.ti.com 11-Oct-2013 TAPE AND REEL INFORMATION *All dimensions are nominal Device LM3224MM-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 LM3224MMX-ADJ/NOPB VSSOP DGK 8 3500 330.0 12.4 5.3 3.4 1.4 8.0 12.
PAGE 24
PACKAGE MATERIALS INFORMATION www.ti.com 11-Oct-2013 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) LM3224MM-ADJ/NOPB VSSOP DGK 8 1000 210.0 185.0 35.0 LM3224MMX-ADJ/NOPB VSSOP DGK 8 3500 367.0 367.0 35.
PAGE 25
PAGE 26
IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, enhancements, improvements and other changes to its semiconductor products and services per JESD46, latest issue, and to discontinue any product or service per JESD48, latest issue. Buyers should obtain the latest relevant information before placing orders and should verify that such information is current and complete.