max9718aeubt Maxim Integrated Products, Inc., max9718aeubt Datasheet - Page 10

• Manufacturer Part Number: max9718aeubt
• Description: Low-cost, Mono/stereo, 1.4w Differential Audio Power Amplifiers
• Manufacturer: Maxim Integrated Products, Inc.

Low-Cost, Mono/Stereo,
1.4W Differential Audio Power Amplifiers
The MAX9718/MAX9719 are 1.4W BTL speaker ampli-
fiers. The MAX9718 is a mono speaker amplifier, while
the MAX9719 is a stereo speaker amplifier. Both
devices feature a low-power shutdown mode, and
industry-leading click-and-pop suppression. The
MAX9718 features a two-input shutdown scheme to
configure shutdown for active high or active low. These
devices consist of high output-current audio amps con-
figured as BTL amplifiers (see the Functional Diagrams).
Both adjustable and fixed gain (0dB, 3dB, 6dB) versions
are available.
These devices operate from a single 2.7V to 5.5V sup-
ply and feature an internally generated, common-mode
bias voltage of V
vides both click-and-pop suppression and sets the DC
bias level for the audio outputs. Choose the value of the
bypass capacitor as described in the BIAS Capacitor
section. Do not connect external loads to BIAS as this
can affect the overall performance.
The MAX9718/MAX9719 feature a 100nA low-power
shutdown mode that reduces quiescent current con-
sumption. Entering shutdown disables the device’s bias
circuitry, the amplifier outputs go high impedance, and
BIAS is driven to GND. The MAX9718 SHDM input con-
trols the polarity of SHDN. Drive SHDM high for an
active-high SHDN input. Drive SHDM low for an active-
low SHDN input (see Table 1). The MAX9719 features
an active-low shutdown input, SHDN.
The MAX9718/MAX9719 feature Maxim’s industry-lead-
ing click-and-pop suppression circuitry. During startup,
the amplifier common-mode bias voltage ramps to the
DC bias point. When entering shutdown, the amplifier
outputs are high impedance to 100kΩ between both
outputs. This scheme minimizes the energy present in
the audio band.
10
TDFN/
µMAX
EP
—
—
—
______________________________________________________________________________________
MAX9718
UCSP
—
—
—
—
CC
/ 2 referenced to ground. BIAS pro-
Click-and-Pop Suppression
TQFN
Detailed Description
PIN
12
15
16
EP
MAX9719
UCSP
D4
D2
D1
—
Shutdown Mode
TSSOP
EP
14
1
2
BIAS
OUTR+
OUTR-
NAME
INR-
EP
Right-Channel Bridge Amplifier Positive Output
Right-Channel Bridge Amplifier Negative Output
Right-Channel Inverting Input
Exposed Pad. Connect EP to GND.
The MAX9718/MAX9719 are designed to drive a load
differentially, a configuration referred to as bridge-tied
load or BTL. The BTL configuration (Figure 1) offers
advantages over the single-ended configuration, where
one side of the load is connected to ground. Driving the
load differentially doubles the output voltage compared
to a single-ended amplifier under similar conditions.
Substituting 2 x V
equations yields four times the output power due to
doubling of the output voltage:
Since the differential outputs are biased at midsupply,
there is no net DC voltage across the load. This elimi-
nates the need for DC-blocking capacitors required for
single-ended amplifiers. These capacitors can be
large, expensive, consume board space, and degrade
low-frequency performance.
Table 1. Shutdown Mode Selection
(MAX9718 Only)
SHDM
0
0
1
1
Pin Description (continued)
Applications Information
OUT(P-P)
SHDN
V
0
1
0
1
RMS
P
OUT
FUNCTION
=
for V
=
V
OUT P P
V
RMS
2 2
R
OUT(P-P)
OPERATIONAL MODE
L
(
2
−
Normal operation
Normal operation
)
Shutdown
Shutdown
BTL Amplifier
into the following