LM4951 Datasheet, PDF (1/18 Pages) National Semiconductor (TI) – Wide Voltage Range 1.8 Watt Audio Amplifier

November 2005
LM4951
Wide Voltage Range 1.8 Watt Audio Amplifier
General Description
The LM4951 is an audio power amplifier primarily designed
for demanding applications in Portable Handheld devices. It
is capable of delivering 1.8W mono BTL to an 8Ω load,
continuous average power, with less than 1% distortion
(THD+N) from a 7.5V_DC power supply.
Boomer audio power amplifiers were designed specifically to
provide high quality output power with a minimal amount of
external components. The LM4951 does not require boot-
strap capacitors, or snubber circuits.
The LM4951 features a low-power consumption active-low
shutdown mode. Additionally, the LM4951 features an inter-
nal thermal shutdown protection mechanism.
The LM4951 contains advanced pop & click circuitry that
eliminates noises which would otherwise occur during
turn-on and turn-off transitions.
The LM4951 is unity-gain stable and can be configured by
external gain-setting resistors.
Key Specifications
j Wide Voltage Range
j Quiescent Power Supply Current
(V_DD = 7.5V)
j Power Output BTL at 7.5V,
1% THD
j Shutdown Current
j Fast Turn on Time
2.7V to 9V
2.5mA (typ)
1.8W (typ)
0.01µA (typ)
25mS (typ)
Features
n Pop & click circuitry eliminates noise during turn-on and
turn-off transitions
n Low current, active-low shutdown mode
n Low quiescent current
n Thermal shutdown protection
n Unity-gain stable
n External gain configuration capability
Applications
n Portable Handheld Devices up to 9V
n Cell Phone
n PDA
Typical Application
200942F4
* R_C is needed for over/under voltage protection. If inputs are less than V_DD +0.3V and greater than –0.3V, and if inputs are
disabled when in shutdown mode, then R_C may be shorted.
FIGURE 1. Typical Bridge-Tied-Load (BTL) Audio Amplifier Application Circuit
Boomer^® is a registered trademark of National Semiconductor Corporation.
© 2005 National Semiconductor Corporation DS200942
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