SNVS837B June   2013  – April 2016 LM3263

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 System Characteristics
    7. 6.7 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1  PWM Operation
      2. 7.3.2  PFM Operation
      3. 7.3.3  Active Current Assist and Analog Bypass (ACB)
      4. 7.3.4  Bypass Operation
      5. 7.3.5  Dynamic Adjustment of Output Voltage
      6. 7.3.6  DC-DC Operating Mode Selection
      7. 7.3.7  Internal Synchronous Rectification
      8. 7.3.8  Current Limit
      9. 7.3.9  Timed Current Limit
      10. 7.3.10 Thermal Overload Protection
      11. 7.3.11 Start-Up
    4. 7.4 Device Functional Modes
      1. 7.4.1 Shutdown Mode
      2. 7.4.2 Low-Power Mode
      3. 7.4.3 Standby Mode
      4. 7.4.4 Active Mode
      5. 7.4.5 User States
    5. 7.5 Programming
      1. 7.5.1 RFFE Interface
      2. 7.5.2 Supported Command Sequences
      3. 7.5.3 Device Enumeration
      4. 7.5.4 GPO1
      5. 7.5.5 Trigger Registers
      6. 7.5.6 Control Interface Timing Parameters
    6. 7.6 Register Map
  8. 8 Application Information
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Recommended External Components
          1. 8.2.2.1.1 Inductor Selection
          2. 8.2.2.1.2 Capacitor Selection
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout Considerations
    1. 10.1 Layout Guidelines
      1. 10.1.1 1. Overview
      2. 10.1.2 2. PCB
        1. 10.1.2.1 Energy Efficiency
        2. 10.1.2.2 EMI
      3. 10.1.3 3. Manufacturing Considerations
    2. 10.2 4. Layout Examples
      1. 10.2.1 DC-DC Converter
        1. 10.2.1.1 Star Connection Between VBATT, DC-DC Converter, and PA
          1. 10.2.1.1.1 VBATT Star Connection
    3. 10.3 DSBGA Package Assembly and Use
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Third-Party Products Disclaimer
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 Community Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

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8 Application Information

NOTE

Information in the following applications sections is not part of the TI component specification, and TI does not warrant its accuracy or completeness. TI’s customers are responsible for determining suitability of components for their purposes. Customers should validate and test their design implementation to confirm system functionality.

8.1 Application Information

The LM3262 DC-DC converter steps down an input voltage from 2.7 V to 5.5 V to a dynamically adjustable output voltage of 0.4 V to 3.6 V.

8.2 Typical Application

LM3263 typapp_snvs837.gif Figure 27. LM3263 Typical Application

8.2.1 Design Requirements

For typical DC-DC converter applications use the parameters listed in Table 2.

Table 2. Design Parameters

DESIGN PARAMETER EXAMPLE VALUE
Input voltage range 2.7 V to 5.5 V
Output voltage range 0.4 V to 3.6 V
Output current 1 A
Minimum effective output capacitance (including effects of AC bias, DC bias, temperature) 10 µF

8.2.2 Detailed Design Procedure

8.2.2.1 Recommended External Components

8.2.2.1.1 Inductor Selection

A 1.5-µH inductor is needed for optimum performance and functionality of the LM3263. In the case of 2G transmission current bursts, the effective overall RMS current requirements are reduced. Therefore, consult with the inductor manufacturers to determine if some of their smaller components are suitable even if the inductor specification does not appear to meet the LM3263 RMS current specifications.

The LM3263 automatically manages the inductor peak and RMS current (or steady-state current peak) through the SW pin. The SW pin has two positive current limits. The first is the 1.45-A typical (or 1.65-A maximum) overcurrent protection. It sets the upper steady-state inductor peak current (as detailed in Electrical Characteristics ILIM,PFET,SteadyState). It is the dominant factor limiting the inductors ISAT requirement. The second is an over-limit current protection. It limits the maximum peak inductor current during large signal transients (for example, < 20 µs) to 1.9 A typical (or 2.1 A maximum). A minimum inductance of 0.3 µH must be maintained at the second current limit.

The ACB circuit automatically adjusts its output current to keep the steady-state inductor current below the steady-state peak current limit. Thus, the inductor RMS current is always effectively than the ILIM,PFET,SteadyState during the transmit burst. In addition, as in the case with 2G where the output current comes in bursts, the effective overall RMS current would be much lower.

For good efficiency, resistance of the inductor must be less than 0.2 Ω; TI recommends low-DCR inductors (< 0.2 Ω). Table 3 suggests some inductors and their suppliers.

Table 3. Suggested Inductors And Their Suppliers

MODEL VENDOR DIMENSIONS ISAT
(30% DROP IN INDUCTANCE)		 DCR
DFE201610C1R5N
(1285AS-H-1R5M)		 TOKO 2 mm × 1.6 mm × 1 mm 2.2 A 120 mΩ
LQM2MPN1R5MGH Murata 2 mm × 1.6 mm × 1 mm 2 A 104 mΩ
MAKK2016T1R5M Taiyo-Yuden 2 mm × 1.6 mm × 1 mm 1.9 A 115 mΩ
VLS201610MT-1R5N TDK 2 mm × 1.6 mm × 1 mm 1.4 A 151 mΩ
LQM21PN1R5MGH Murata 2 mm × 1.25 mm × 1 mm 1.2 A 110 mΩ

8.2.2.1.2 Capacitor Selection

The LM3263 is designed to use ceramic capacitors for its input and output filters. Use a 10-µF capacitor for the input and approximately 10 µF actual total output capacitance. Capacitor types such as X5R, X7R are recommended for both filters. These provide an optimal balance between small size, cost, reliability, and performance for cell phones and similar applications. Table 4 lists suggested part numbers and suppliers. DC bias characteristics of the capacitors must be considered while selecting the voltage rating and case size of the capacitor. Smaller case sizes for the output capacitor mitigate piezo-electric vibrations of the capacitor when the output voltage is stepped up and down at fast rates. However, they have a bigger percentage drop in value with dc bias. For even smaller total solution size, 0402 (1005) case size capacitors are recommended for filtering. Use of multiple 2.2-µF or 1-µF capacitors can also be considered. For RF PA applications, split the output capacitor between DC-DC converter and RF PAs; TI recomments 10 µF (COUT1) + 4.7 µF (COUT2) + 3 × 1 µF (COUT3)(assuming one 2G PA and three 3G/4G PAs — COUT2 is for 2G PA, and COUT3 is for 3G/4G PA). The optimum capacitance split is application dependent, and for stability the actual total capacitance (taking into account effects of capacitor DC bias, temperature de-rating, aging and other capacitor tolerances) must target 10 µF with 2.5-V DC bias (measured at 0.5 VRMS). Place all the output capacitors very close to the respective device. TI highly recommends placing a high-frequency capacitor (3300 pF) next to COUT1.

Table 4. Suggested Capacitors And Their Suppliers

CAPACITANCE MODEL SIZE (W × L) VENDOR
10 µF GRM185R60J106M 1.6 mm × 0.8 mm Murata
10 µF CL05A106MP5NUN 1 mm × 0.5 mm Samsung
4.7 µF CL05A475MP5NRN 1 mm × 0.5 mm Samsung
1 µF CL03A105MP3CSN 0.6 mm × 0.3 mm Samsung
1 µF C0603X5R0J105M 0.6 mm × 0.3 mm TDK
3300 pF GRM022R60J332K 0.4 mm × 0.2 mm Murata

8.2.3 Application Curves

LM3263 7_Startup_from_Low_Power_Mode.gif
VBATT = 4.2 V VOUT = 3.4 V No load
Figure 28. Start-up From Low-Power Mode
LM3263 8_Startup_from_Standby_Mode.gif
VBATT = 4.2 V VOUT = 3.4 V No load
Figure 29. Start-Up From Standby Mode