Rainbow Electronics MAX9714 - Manual (Page 11)

Sharing Input Sources
In certain systems, a single audio source can be shared
by multiple devices (speaker and headphone ampli-
fiers). When sharing inputs, it is common to mute the
unused device, rather than completely shutting it down,
preventing the unused device inputs from distorting the
input signal. Mute the MAX9713/MAX9714 by driving SS
low through an open-drain output or MOSFET (see the
System Diagram). Driving SS low turns off the class D
output stage, but does not affect the input bias levels of
the MAX9713/MAX9714. Be aware that during normal
operation, the voltage at SS can be up to 7V, depending
on the MAX9713/MAX9714 supply.
Supply Bypassing/Layout
Proper power-supply bypassing ensures low distortion
operation. For optimum performance, bypass V
DD to
PGND with a 0.1µF capacitor as close to each V DD pin
as possible. A low-impedance, high-current power-sup-
ply connection to V
DD is assumed. Additional bulk
capacitance should be added as required depending on
the application and power-supply characteristics. AGND
and PGND should be star connected to system ground.
Refer to the MAX9714 Evaluation Kit for layout guidance.
MAX9713/MAX9714
6W, Filterless, Spread-Spectrum
Mono/Stereo Class D Amplifiers
______________________________________________________________________________________ 11
32 31 30 29 28 27 26
OUTL+ OUTL+ OUTL- OUTL- OUTR+ OUTR+ OUTR-
25
OUTR-
9 10 11 12 13 14 15
INL- INL+
SS
AGND
INR- REG
16
INR+
17
18
19
20
21
22
23
G1
G2
FS1
FS2
V DD
V DD
PGND
8
7
6
5
4
3
2
N.C.
CHOLD
C1P
C1N
V DD
V DD
PGND
MAX9714
1 PGND 24 PGND
TQFN (7mm x 7mm)
SHDN
32 31 30 29 28 27 26
N.C. N.C. OUT+ OUT+ OUT- OUT- N.C.
25
N.C.
9 10 11 12 13 14 15
REG
AGND
IN- IN+ SS G1
16
G2
17
18
19
20
21
22
23
N.C.
FS1
FS2
N.C.
V DD
V DD
PGND
8
7
6
5
4
3
2
N.C.
CHOLD
C1P
C1N
V DD
V DD
PGND
MAX9713
1 PGND 24 PGND
TOP VIEW
TQFN (5mm x 5mm)
SHDN
Pin Configurations
Chip Information
MAX9713 TRANSISTOR COUNT: 3093
MAX9714 TRANSISTOR COUNT: 4630
PROCESS: BiCMOS