HT66FV1x0 Integrated Audio Amplifier Application Guideline
AN0486EN V1.10
5 / 16
June 8, 2021
Symbol
Parameter
Test Condition
Min.
Typ.
Max.
Unit
V
DD
Condition
AV
DD_PA
Audio Power Amplifier
Operating Voltage
–
–
2.2
–
5.5
V
(THD+N)/S (THD+N)/S
5V
8Ω
load,
Output power
=500mW
–
0.2
–
%
P
OUT
Output Power
3V
8Ω
load,
(THD+N)/S=
1%
–
410
–
mW
8Ω
load,
(THD+N)/S=
10%
–
550
–
mW
5V
8Ω
load,
(THD+N)/S=
1%
–
1200
–
mW
8Ω
load,
(THD+N)/S=
10%
–
1500
–
mW
Note: Sine wave input @1kHz & -6dB.
Operating Principles
The HT66FV1x0 includes an integrated Class AB high output power audio amplifier, which will
be introduced in this section. Using its integrated SPI interface the HT66FV1x0 reads digital audio
data from the external Flash ROM and writes it into the 16-bit DAC data registers PLADH and
PLADL. Each piece of data will be converted into a corresponding audio analog voltage signal by
the DAC after which the speaker will play the corresponding sound.
The HT66FV1x0 voice playing function block diagram is shown as follows. DAEN and PAEN are
the DAC and amplifier enable bits respectively, which can be cleared to zero to reduce power
consumption when the voice playing function is not used. The USVC[6:0] field is used for digital
volume adjustment.
PLADH
PLADL
USVC[6:0]
16-bit D/A +
Power Amplifier
ker
Voice Playing Controller Registers
The overall voice playing function of the HT66FV1x0 is controlled using a series of registers. Two
control registers exist to control the 16-bit D/A converter and power amplifier functions together
with the speaker mute control. Two data registers exist to store the data which is to be played.
USVC Register
Bit
7
6
5
4
3
2
1
0
Name
MUTEB USVC6
USVC5
USVC4
USVC3
USVC2
USVC1
USVC0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
0
0
0
0
0
0
0
0
Bit7
MUTEB
: Speaker mute control
0: Mute speaker output
1: Enable speaker output
Bit6~0
USVC6~USVC0
: Speaker volume control
These bits are used to control the volume which ranges from -32dB to 6dB.
