VOICE-RECORD-RD Silicon Laboratories Inc, VOICE-RECORD-RD Datasheet - Page 3

• Manufacturer Part Number: VOICE-RECORD-RD
• Description: KIT REF DESIGN VOICE RECORD F41X
• Manufacturer: Silicon Laboratories Inc

Specifications of VOICE-RECORD-RD

• Main Purpose: Audio, Voice Record/Playback
• Embedded: Yes, MCU, 8-Bit
• Utilized Ic / Part: C8051F411-GM
• Primary Attributes: MCU, 87 Sec., 8 kHz,
• Secondary Attributes: A Keil Compiler and USB Debug Adapter are required
• Description/function: Audio D/A
• Product: Audio Modules
• For Use With/related Products: C8051F411
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Contains lead / RoHS non-compliant
• Other names: 336-1315

4. Major Components
This section describes each of the major components found on the Voice Recorder board.
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U1—C8051F411:
U2—Transistor:
U3—External Flash:
U4—External Voltage Regulator
U5—Op-Amps:
U6—Speaker Driver:
The C8051F411 controls the sampling, sample storing and retrieving, sample output, and user interaction for the
voice recorder.
The transistor turns off all power to the Flash, op-amps, LEDs, and speaker driver when the ‘F411 goes into
Suspend mode to conserve as much power as possible.
The external Flash communicates with the ‘F411 through the serial interface (SPI) and allows up to 87 seconds of
recording (512 kB with 12-bit samples compressed to 6 bits at an effective 8 kHz sampling rate).
For ease of use in a development environment, the ‘F411 runs off an external voltage regulator that regulates the
9V battery or power supply input to 3.3 V. All components except the ‘F411 use the 3.3 V output, and the internal
‘F411 regulator regulates the 3.3 V down to 2.5 V for the ‘F411 core.
The signal input from the microphone and the output to the speaker driver require some filtering by op-amp filters
to remove any components caused by frequencies outside the signal bandwidth (up to 4 kHz). Additionally, the
op-amp filters smooth the output of the IDAC.
The speaker driver provides the power to the speaker and takes the single-ended output of the IDAC and turns it
into a differential speaker output, which requires less power for the same output amplitude.
Figure 2. Voice Recorder Reference Design Components
Confidential Rev. 0.3
VOICE-RECORD-RD
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