MAX9787ETI+T Maxim Integrated Products, MAX9787ETI+T Datasheet - Page 9

• Manufacturer Part Number: MAX9787ETI+T
• Description: IC AMP AUDIO PWR 2.2W AB 28TQFN
• Manufacturer: Maxim Integrated Products
• Type: Class ABr

Specifications of MAX9787ETI+T

• Output Type: 2-Channel (Stereo)
• Max Output Power X Channels @ Load: 2.2W x 2 @ 3 Ohm
• Voltage - Supply: 4.5 V ~ 5.5 V
• Features: Depop, Short-Circuit and Thermal Protection, Shutdown, Volume Control
• Mounting Type: Surface Mount
• Package / Case: 28-TQFN Exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

PV
stant; the step sizes are 0.5dB/step at the upper
extreme, 2dB/step in the midrange, and 4dB/step at the
lower extreme. Figure 3 shows the transfer function of
the volume control for a 5V supply.
An audible alert beep input (BEEP) accepts a mono
system alert signal and mixes it into the stereo audio
path. When the amplitude of V
800mV
nal is greater than 400Hz, the beep signal is mixed into
the active audio path (speaker or headphone). If the
signal at V
the BEEP signal is not mixed into the audio path. The
amplitude of the BEEP signal at the device output is
Figure 3. Volume Control Transfer Function
Figure 4. Beep Input
DD
are negated. The gain step sizes are not con-
P-P
(Figure 4) and the frequency of the beep sig-
BEEP(OUT)
-10
-20
-30
-40
-50
-60
-70
-80
20
10
0
0
SOURCE 1
SOURCE 2
SOURCE 3
_______________________________________________________________________________________
1
TRANSFER FUNCTION
is either < 800mV
VOLUME CONTROL
MAX9787
0.47µF
0.47µF
0.47µF
2
V
VOL
(V)
47kΩ
47kΩ
47kΩ
R
R
R
2.2W Stereo Audio Power Amplifier
3
S1
S2
S3
GAIN1 = GAIN2 = 0
BEEP(OUT)
TAPER POT
AUDIO
4
P-P
BEEP Input
BEEP
5
BIAS
or <400Hz,
exceeds
with Analog Volume Control
47kΩ
R
INT
(0.3V
(300Hz THRESHOLD)
roughly the amplitude of V
the selected signal path.
The input resistor (R
amplifier, and thus the amplitude of V
Choose R
where R
resistor (47kΩ) and V
Note that the BEEP amplifier can be set up as either an
attenuator, if the original alert signal amplitude is too
large, or set to gain up the alert signal if it is below
800mV
the value of the coupling capacitor as described in the
Input Filtering section. Multiple beep inputs can be
summed (Figure 4).
The MAX9787 features a 0.2µA, low-power shutdown
mode that reduces quiescent current consumption and
extends battery life. Driving SHDN low disables the
drive amplifiers, bias circuitry, and charge pump, and
drives BIAS and all outputs to GND. Connect SHDN to
V
The MAX9787 speaker amplifiers feature Maxim’s com-
prehensive, industry-leading click-and-pop suppres-
sion. During startup, the click-and-pop suppression
circuitry eliminates any audible transient sources inter-
nal to the device. When entering shutdown, both ampli-
fier outputs ramp to GND quickly and simultaneously.
FREQUENCY
V
P-P
DETECTOR
DETECTOR
OUT(BEEP)
WINDOW
DD
THRESHOLD)
for normal operation.
P-P
INT
B
. AC-couple the alert signal to BEEP. Choose
based on:
is the value of the BEEP amplifier feedback
R
SPEAKER AMPLIFIER
B
MAX9787
B
Click-and-Pop Suppression
) sets the gain of the BEEP input
≤
INPUTS
IN
V
is the BEEP input amplitude.
IN
BEEP(OUT)
0 3
x R
.
INT
times the gain of
Shutdown
BEEP(OUT)
9
.