LM48821 Evaluation Board
User's Guide
National Semiconductor
Application Note 1589
Kevin Hoskins
May 2007
Quick Start Guide
Connect the I
2
C signal generation and interface board to a
computer’s parallel port.
Install LM48821 control software: “LM48821_Software.”
Amplifier output mode:
Apply a 2.0V to 4.0V power supply’s positive voltage output
to the “VDD” pin on jumper J6. Apply the power supply’s
ground return to the “GND“ pin on J6.
Connect the supplied 5-wire cable between the I
2
C signal
generation and interface board and the 5-pin connector (I2C
Interface) on the LM48821 demonstration board.
Apply a stereo audio signal to jumpers JP2(Left) and JP3
(Right). Apply the source’s +input and -input to the “+” pin and
the “-“ pin, respectively.
Connect a load (
≥
16Ω
) to JP(Right) and another load to JP5
(Left). JP4’s “+” pin and JP’s “+” pin carries the output signals
from the two amplifiers found on pins OUTR and OUTL, re-
spectively.
Apply power. Make measurements. Plug in a pair of head-
phones. Enjoy.
Introduction
To help the user investigate and evaluate the LM48821's per-
formance and capabilities, a fully populated demonstration
board is available from the National Semiconductor
Corporation's Audio Products Group. This board is shown in
Figure 1. Connected to an external power supply (2.0V to
4.0V), a signal source and an I
2
C controller (or signal source),
the LM48821 demonstration board easily demonstrate the
amplifier's features.
30009811
FIGURE 1. The LM48821 Demonstration Board
© 2007 National Semiconductor Corporation
300098
www.national.com
LM48821 Evaluation Board User's Guide
AN-1589
