LM4855

Manufacturer Part NumberLM4855
ManufacturerTexas Instruments
LM4855 datasheet
 


Specifications of LM4855

Speaker ChannelsMonoSpeaker Output Power/ch(w)1.1
Speaker Psrr(db)57Headphone Output Power/ch(mw)115
Headphone Psrr(db)63Audio Mode ControlSPI
Supply Voltage(min)(v)2.6Supply Voltage(max)(v)5
Pin/package18DSBGA, 24QFN, 24WQFN  
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LM4855
LM4855 Integrated Audio Amplifier System
Literature Number: SNAS164B

LM4855 Summary of contents

  • Page 1

    ... LM4855 LM4855 Integrated Audio Amplifier System Literature Number: SNAS164B ...

  • Page 2

    ... The industry leading micro SMD package only utilizes 2mm x 2.3mm of PCB space, making the LM4855 the most space efficient audio sub system available today. Typical Application FIGURE 1. Typical Audio Amplifier Application Circuit Boomer ® ...

  • Page 3

    ... LM4855IBL LLP Package Top View Order Number LM4855LQ See NS Package Number LQA24A for Exposed-DAP LLP www.national.com 18-Bump micro SMD Marking (ITL) 200395B0 Order Number LM4855ITL, LM4855IBL See NS Package Number TLA18AAA, BLA18AAB 200395D3 2 200395E4 Top View XY- Date Code TT - Die Traceability G - Boomer Family ...

  • Page 4

    ... Output modes 0V; No loads IN Output modes 0V; Loaded (Fig Output mode SPKR ; R = 4Ω OUT L THD 1kHz, LM4855LQ SPKR ; R = 8Ω OUT L THD 1kHz R and 32Ω OUT OUT L THD+N = 0.5 1kHz SPKR OUT ...

  • Page 5

    ... Input referred minimum gain and Input referred maximum gain BTL gain from Phone_In _IHF to SPKR OUT Output Mode Maximum gain setting Mininum gain setting Maximum gain setting Mininum gain setting 4 LM4855 Units (Limits) Typical Limits (Note 5) (Note (min) B ...

  • Page 6

    ... Output modes 0V; No loads IN Output modes 0V; Loaded (Fig Output mode SPKR ; R = 4Ω OUT L THD 1kHz, LM4855LQ SPKR ; R = 8Ω OUT L THD 1kHz R and 32Ω OUT OUT L THD+N = 0.5 1kHz SPKR OUT ...

  • Page 7

    ... Note 8: All voltages are measured with respect to the ground pin, unless otherwise specified. Note 9: The given θ and θ are for an LM4855 mounted on a demonstration board with a 4in JA JC Note 10: Please refer to the Output Noise vs Output Mode table in the Typical Performance Characteristics section for more details. ...

  • Page 8

    ... C This is the BYPASS pin capacitor. It filters the V B Typical Performance Characteristics THD+N vs Frequency LM4855LQ THD+N vs Frequency Functional Description also creates a highpass filter with the internal resistor voltage and helps maintain the LM4855’s PSRR. DD 200395F0 200395B1 7 (Input Impedance pin and helps maintain ...

  • Page 9

    Typical Performance Characteristics THD+N vs Frequency THD+N vs Frequency THD+N vs Frequency www.national.com (Continued) THD+N vs Frequency 200395B3 THD+N vs Frequency 200395B5 THD+N vs Frequency 200395B7 8 200395B4 200395B6 200395B8 ...

  • Page 10

    ... Typical Performance Characteristics THD+N vs Output Power LM4855LQ THD+N vs Output Power THD+N vs Output Power (Continued) THD+N vs Output Power 200395F2 THD+N vs Output Power 200395B9 THD+N vs Output Power 200395C1 9 LM4855LQ 200395F3 200395C0 200395C2 www.national.com ...

  • Page 11

    Typical Performance Characteristics Power Supply Rejection Ratio Power Supply Rejection Ratio Power Supply Rejection Ratio www.national.com (Continued) Power Supply Rejection Ratio 200395C3 Power Supply Rejection Ratio 200395C5 Power Supply Rejection Ratio 200395C7 10 200395C4 200395C6 200395C8 ...

  • Page 12

    Typical Performance Characteristics Output Power vs Supply Voltage Output Power vs Load Resistance Power Dissipation vs Output Power (Continued) Output Power vs Supply Voltage 200395D7 Output Power vs Load Resistance 200395D9 Power Dissipation vs Output Power 200395E1 11 200395D8 200395E0 ...

  • Page 13

    Typical Performance Characteristics Supply Current vs Supply Voltage Frequency Response www.national.com (Continued) Channel Separation 200395C9 Frequency Response 200395D4 Frequency Response 200395D6 12 200395D0 200395D5 ...

  • Page 14

    Typical Performance Characteristics Output Mode gain from gain from LIN/RIN to LOUT/ROUT A - weighted filter used (Continued) Output Noise vs Output Mode (V = 3V, 5V) DD ...

  • Page 15

    ... The serial data bits are organized into a field which contains 8 bits of data defined by TABLE 1. The Data 0 to Data 2 bits determine the output mode of the LM4855 as shown in TABLE 2. The Data 3 to Data 7 bits determine the volume level setting as illustrated by TABLE 3. For each SPI transfer, TABLE 1 ...

  • Page 16

    APPLICATION INFORMATION TABLE 3. Volume Control Settings Gain (dB Phone_In_HS OUT OUT OUT OUT -34.5 -40.5 -33.0 -39.0 -31.5 -37.5 -30.0 -360 -28.5 -34.5 -27.0 ...

  • Page 17

    ... FIGURE 2. SPI Timing Diagram share the same PCB layer, a nominal 2.5in necessary for 5V operation with a 4Ω load. Heatsink areas not placed on the same PCB layer as the LM4855 should be 2 5in (min) for the same supply voltage and load resistance. ...

  • Page 18

    ... Therefore, making the power supply traces as wide as possible helps maintain full output voltage swing. BRIDGE CONFIGURATION EXPLANATION As shown in Figure 1, the LM4855 consists of three pairs of output amplifier blocks (A4-A6). A4, A5, and A6 consist of bridged-tied amplifier pairs that drive LOUT, ROUT, and SPKROUT respectively. The LM4855 drives a load, such as a speaker, connected between outputs, SPKROUT+ and SPKROUT- ...

  • Page 19

    ... SA Equation (9 example when using a speaker with a low frequency limit of 150Hz shown in Figure 1 allows the LM4855 to drive high effi- i ciency, full range speaker whose response extends below 40Hz. Bypass Capacitor Value Selection Besides minimizing the input capacitor size, careful consid- eration should be paid to value of C nected to the BYPASS pin ...

  • Page 20

    Demonstration Board Layout FIGURE 3. Recommended IBL, ITL PC Board Layout: Top Silkscreen FIGURE 5. Recommended IBL, ITL PC Board Layout: Middle Layer 200395A7 FIGURE 4. Recommended IBL, ITL PC Board Layout: Top Layer 200395A5 FIGURE 6. Recommended IBL, ITL ...

  • Page 21

    Demonstration Board Layout FIGURE 7. Recommended LD PC Board Layout: Top Silkcreen Layer FIGURE 9. Recommended LD PC Board Layout: Inner Layer 1 www.national.com (Continued) 200395E5 FIGURE 8. Recommended LD PC Board Layout: Top Layer 200395E7 FIGURE 10. Recommended LD ...

  • Page 22

    Demonstration Board Layout FIGURE 11. Recommended LD PC Board Layout: Bottom Layer (Continued) 200395E9 21 www.national.com ...

  • Page 23

    ... Physical Dimensions X www.national.com inches (millimeters) unless otherwise noted 18-Bump mciro SMD Order Number LM4855IBL NS Package Number BLA18AAB Dimensions are in millimeteres ± ± = 1.996 0. 2.225 0. ± = 0.945 0.01 ...

  • Page 24

    ... Physical Dimensions inches (millimeters) unless otherwise noted (Continued) 24-Lead MOLDED PKG, Leadless Leadframe Package LLP Order Number LM4855LQ NS Package Number LQA24A 23 www.national.com ...

  • Page 25

    ... National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications. inches (millimeters) unless otherwise noted (Continued) 18-Bump micro SMD Order Number LM4855ITL NS Package Number TLA18AAA ...

  • Page 26

    ... Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications, enhancements, improvements, and other changes to its products and services at any time and to discontinue any product or service without notice. Customers should obtain the latest relevant information before placing orders and should verify that such information is current and complete. All products are sold subject to TI’ ...