LM48555 Datasheet, PDF (1/14 Pages) National Semiconductor (TI) – Ceramic Speaker Driver

March 2007
LM48555
Ceramic Speaker Driver
General Description
The LM48555 is an audio power amplifier designed to drive
ceramic speakers in applications such as cell phones, smart
phones, PDAs and other portable devices. The LM48555 pro-
duces 15.7V_P-P with less than 1% THD+N while operating
from a 3.2V power supply. The LM48555 features a low power
shutdown mode, and differential inputs for improved noise
rejection.
The LM48555 includes advanced click and pop suppression
that eliminates audible turn-on and turn-off transients. Addi-
tionally, the integrated boost regulator features a soft start
function that minimizes transient current during power-up
Boomer audio power amplifiers were designed specifically to
provide high quality output power with a minimal number of
external components. The LM48555 does not require boot-
strap capacitors, or snubber circuits.
The LM48555 is unity-gain stable and uses external gain-set-
ting resistors.
Key Specifications
■ I_DDQ (Boost Converter + Amplifier)
at V_DD = 5V
■ Output Voltage Swing
V_DD = 3.2V, THD ≤ 1%
■ Power Supply Rejection Ratio
f = 217Hz
Features
■ ^{Fully differential amplifier}
■ ^{Externally configurable gain}
■ ^{Soft start function}
■ ^{Low power shutdown mode}
■ ^{Under voltage lockout}
Applications
■ ^{Mobile phones}
■ ^PDA's
■ ^{Digital cameras}
Typical Application
7.5mA (typ)
15.7V_P-P (typ)
80dB (typ)
300099c9
* CF+ and CF- are optional. Refer to “Selecting Input and Feedback Capacitor and Resistor for Audio Amplifier” section.
FIGURE 1. Typical Audio Amplifier Application Circuit
Boomer^® is a registered trademark of National Semiconductor Corporation.
© 2007 National Semiconductor Corporation 300099
www.national.com