Digilent PmodAMP1 User Manual
Digilent Hardware
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www.digilentinc.com
Revision: April 27, 2007
Note: This document applies to REV B of the board.
215 E Main Suite D | Pullman, WA 99163
(509) 334 6306 Voice and Fax
Doc: 502-131
page 1 of 2
Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners.
Overview
The PmodAMP1 Speaker/Headphone
Amplifier (PmodAMP1) amplifies low power
audio signals to drive either stereo headphones
or a monophonic speaker. The speaker is driven
from the left stereo input.
The audio inputs to the module are provided
through a Digilent 6-pin Pmod connector. A
1/8-inch stereo audio jack is used for the
headphone output and a 1/8-inch mono audio
jack is used for the speaker output. An
inexpensive speaker and enclosure suitable for
use with the PmodAMP1 is available from
Digilent.
Unlike most Digilent Pmod modules, which
accept only digital inputs, the PmodAMP1
accepts analog inputs as well as pulse width
modulated digital inputs.
Features include:
• National Semiconductor LM4838 audio
amplifier IC
• 1/8-inch stereo headphone jack
• 1/8-inch mono speaker jack
• a 6-pin header for inputs
• 3V-5V operating voltage
• small form factor (0.80” x 1.15”).
Functional Description
The PmodAMP1 accepts either digital or
analog inputs. The input voltage range is 0-
Vcc. Typically the module will use power
supplied by a Digilent system board and will be
(6) Vcc (3.3 - 5V)
(5) GND
(1) Left
(2) N/C
(3) Right
(4) N/C
Figure 2 PmodAMP1 Input Connector, J1
operated at 3.3V. The maximum power supply
voltage is 5.0V. The inputs for the amplifier
and the power to the module are provided on
connector J1.
The PmodAMP1 provides a band-pass filter on
the input with a high pass cutoff frequency of
Speaker
Jack
J1
J2
J3
Left
Right
Vcc
GND
Filter
Filter
Amplifier
Headphone
Jack
L
R
R2
Volume
Figure 1 PmodAMP1 Block Diagram