Document
LM4960 Piezoelectric Speaker Driver
October 2004
LM4960 Piezoelectric Speaker Driver
General Description
The LM4960 utilizes a switching regulator to drive a dual audio power amplifier. It delivers 24VP-P mono-BTL to a ceramic speaker with less than 1.0% THD+N while operating on a 3.0V power supply. The LM4960’s switching regulator is a current-mode boost converter operating at a fixed frequency of 1.6MHz. Boomer audio power amplifiers were designed specifically to provide high quality output power with a minimal amount of external components. The LM4960 does not require output coupling capacitors or bootstrap capacitors, and therefore is ideally suited for mobile phone and other low voltage applications where minimal power consumption is a primary requirement. The LM4960 features a low-power consumption externally controlled micropower shutdown mode. Additionally, the LM4960 features and internal thermal shutdown protection mechanism along with a short circuit protection. The LM4960 is unity-gain stable and can be configured by external gain-setting resistors.
Key Specifications
n VOUT @ VDD = 3.0 THD+N ≤ 1% n Power supply range n Switching Frequency 24VP-P (typ) 3.0 to 7V 1.6MHz (typ)
Features
n n n n n n n n n Stereo BTL amplifier Low current shutdown mode "Click and pop" suppression circuitry Low Quiescent current Unity-gain stable audio amplifiers External gain configuration capability Thermal shutdown protection circuitry Wide input voltage range (3.0V - 7V) 1.6MHz switching frequency
Applications
n Mobile phone n PDA’s
Connection Diagram
LM4960SQ
20076582
Top View Order Number LM4960SQ See NS Package Number
Boomer ® is a registered trademark of National Semiconductor Corporation.
© 2004 National Semiconductor Corporation
DS200765
www.national.com
LM4960
Typical Application
20076581
FIGURE 1. Typical Audio Amplifier Application Circuit
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2
LM4960
Absolute Maximum Ratings (Notes 1, 2)
If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Supply Voltage (VDD) Supply Voltage (V1) (Pin 27 referred to GND) Storage Temperature Input Voltage Power Dissipation (Note 3) ESD Susceptibility (Note 4) ESD Susceptibility (Note 5) 8.5V 18V −65˚C to +150˚C −0.3V to VDD + 0.3V Internally limited 2000V 200V
Junction Temperature Thermal Resistance θJA (LLP)
150˚C ˚C/W
See AN-1187 ’Leadless Leadframe Packaging (LLP).’
Operating Ratings
Temperature Range TMIN ≤ TA ≤ TMAX Supply Voltage (VDD) Supply Voltage (V1) −40˚C ≤ TA ≤ +85˚C 3.0V ≤ VDD ≤ 7V 9.6V ≤ V1 ≤ 16V
The following specifications apply for VDD = 3V, AV = 10, RL = 800nF+20Ω, V1 = 12V unless otherwise specified. Limits apply for TA = 25˚C. Symbol Parameter Conditions LM4960 Typical (Note 6) IDD ISD VOS VSDIH VSDIL TWU TSD VO THD+N eOS PSRR VFB Quiescent Power Supply Current Shutdown Current Output Offset Voltage Shutdown Voltage Input High Shutdown Voltage Inp.