AN2862
Application note
Demonstration board user guidelines for the TS2007FC
3 W filter-free class D audio amplifier with 6-12 dB fixed gain select
Introduction
This application note concerns the TS2007FC demonstration board, designed to evaluate
the class D audio differential amplifier TS2007FC.
This document provides:
■
■
■
a brief description of the TS2007FC device.
a description of the demonstration board and all of its components.
the layout of the demonstration board.
About the TS2007FC
The TS2007FC is an audio power class D amplifier that can drive up to 1.4 W into an 8
Ω
load at 5 V. It achieves better efficiency compared to a typical class AB audio power
amplifier.
This device allows switching between two different gains: 6 or 12 dB via a logic signal on the
GS pin. Pop and click reduction circuitry provides low on/off switch noise while allowing the
device to start within 1 ms. A standby function (active low) reduces the current consumption
to 1
μA
typical. The TS2007FC also integrates an output short-circuit protection mechanism
and thermal shutdown protection to avoid damage to the amplifier.
Key features of the TS2007FC
■
■
■
■
■
■
■
■
■
■
■
■
■
■
Operating range from V
CC
= 2.4 to 5.5 V.
Standby mode active low.
Output power: 1.4 W at 5 V or 0.5 W at 3.0 V into 8
Ω
with 1% THD+N maximum.
Output power: 2.3 W at 5 V or 0.75 W at 3.0 V into 4
Ω
with 1% THD+N maximum.
Two fixed gain selects: 6 or 12 dB.
Low current consumption.
Efficiency: 88% typical.
Signal-to-noise ratio: 90 dB typical.
PSRR: 68 dB typical at 217 Hz with 6 dB gain.
PWM base frequency: 280 kHz
Low pop and click noise.
Thermal shutdown protection.
Output short-circuit protection.
Flip-chip lead-free 9-bump package.
Refer to the datasheet for complete information on the TS2007FC.
February 2009
Rev 1
1/7
www.st.com
Description of the evaluation board
AN2862
1
Description of the evaluation board
The TS2007FC demonstration board is designed for the TS2007FC class D audio
differential amplifier. The TS2007FC device, in a flip-chip package, is mounted on a two-
layer PCB. Easily-accessible connectors on the board allow changing or driving the gain
select and standby control pins, as well as changing the input configuration of the
TS2007FC.
The TS2007FC’s gain can be set to either 6 or 12 dB via the P1 connector (see
Table 1).
The
input configuration
is either capacitor-coupled or common-mode feedback. On the
evaluation board, the JP3 and JP4 connectors allow you to change the input configuration.
In the
capacitor-coupled configuration,
the -3 dB cut-off frequency in Hz is:
1
1
----------------------------------- = -----------------------------------
-
-
2π
⋅
Z
in
⋅
C
2
2π
⋅
Z
in
⋅
C
1
with Z
in
in
Ω
(Z
in
= 75 kΩ typically), C in Farads and C1 = C2.
More information about component calculations is available in the TS2007FC datasheet.
Table 1.
Evaluation board connectors
Description
Input signal connector (GND, In+, In-, GND).
Output signal connector (GND, Out-, Out+, GND).
Input configuration:
– capacitor-coupled when JP3 and JP4 are open.
– common-mode feedback when JP3 and JP4 are shorted by jumpers.
Gain select control connector:
–
1 2 3
pins 1 and 2 are shorted or pin 2 is floating, the gain is 6 dB.
–
1 2 3
pins 2 and 3 are shorted, the gain is 12 dB.
The connector pins are connected as follows:
– 1 to V
CC
– 2 to GS of the TS2007FC
– 3 to GND
`
`
Connector(s)
JP1
JP1
JP3, JP4
P1
P2
Standby control connector:
–
1 2 3
pins 1 and 2 are shorted, the TS2007FC is in operation mode.
–
1 2 3
pins 2 and 3 are shorted, the TS2007FC is in standby mode.
The connector pins are connected as follows:
– 1 to V
CC
– 2 to STANDBY of the TS2007FC
– 3 to GND
`
`
JP5
Power connector (V
CC
and GND). Power supply voltage from 2.4 to 5.5 V.
Caution:
When you apply the power supply through JP5,
do not
invert the polarity since this will
irreversibly damage the U1 amplifier.
2/7
AN2862
Figure 1.
Schematic diagram
Description of the evaluation board
VCC
VCC
P1
JP5
JP3
1
2
1
2
3
1
2
C3
1uF
A2
B1
C1
JP1
GND
IN-
IN+
GND
1
2
3
4
220nF
C2
C1
A1
U1
B2
TS2007
JP2
OUT+
C3
A3
OUT-
H
Bridge
1
2
3
4
GND
OUT+
OUT-
GND
GS
IN-
Gain
Select
IN+
Standby
Control
Standby
1
2
C2
-
+
Vcc
Vcc
PWM
220nF
Oscillator
Gnd
B3
Protection
Circuit
VCC
JP4
P2
1
2
3
Table 2.
Component list for the demonstration board
Quantity
2
1
2
3
2
1
Description
220 nF/16 V, SMD ceramic capacitors, 0603
1 µF/16 V, SMD ceramic capacitor, 0603
4-pin header 2.54 mm pitch
2-pin header 2.54 mm pitch
3-pin header 2.54 mm pitch
TS2007EIJT
Designation
C1, C2
C3
JP1, JP2
JP3, JP4, JP5
P1, P2
U1
3/7
微控制器 MCU
京公网安备 11010802033920号
Copyright © 2005-2026 EEWORLD.com.cn, Inc. All rights reserved
电子工程世界
