max9789a Maxim Integrated Products, Inc., max9789a Datasheet - Page 13

• Manufacturer Part Number: max9789a
• Description: Windows Vista-compliant, Stereo Class Ab Speaker Amplifiers And Directdrive Headphone Amplifiers Integrated Products
• Manufacturer: Maxim Integrated Products, Inc.

The MAX9789A/MAX9790A combine a 2W BTL speaker
amplifier with an 100mW DirectDrive headphone amplifi-
er. These devices feature comprehensive click-and-pop
suppression and programmable four-level speaker ampli-
fier gain control. The MAX9789A/MAX9790A feature high
+90dB PSRR, low 0.002% THD+N, industry-leading click-
and-pop performance, low-power shutdown mode, and
excellent RF immunity. The MAX9789A incorporates an
integrated LDO that serves as a clean power supply for a
CODEC or other circuits.
The MAX9789A/MAX9790A is Microsoft Windows Vista
compliant. See Table 1 for a comparison of the Microsoft
Windows Vista premium mobile specifications and
MAX9789A/MAX9790A specifications.
The speaker amplifiers use BTL architecture, doubling the
voltage drive to the speakers and eliminating the need for
DC-blocking capacitors. The output consists of two sig-
nals, identical in magnitude, but 180° out of phase.
The headphone amplifiers use Maxim’s patented
DirectDrive architecture to eliminate the bulky output
DC-blocking capacitors required by traditional head-
phone amplifiers. A charge pump inverts a positive
supply (CPV
The headphone amplifiers operate from these bipolar
supplies with their outputs biased about GND. The
benefit of the GND bias is that the amplifier outputs no
longer have a DC component (typically V
feature eliminates the large DC-blocking capacitors
required with conventional headphone amplifiers to
Table 1. Windows Premium Mobile Vista Specifications vs. MAX9789A/MAX9790A
Specifications
Note: THD+N, DR, FREQUENCY ACCURACY, and CROSSTALK should be measured in accordance with AES-17 audio measure-
ments standards.
Dual Mode is a trademark of Maxim Integrated Products, Inc.
Analog Line Output
Jack (R
FS = 0.707V
Analog Headphone
Out Jack (R
FS = 0.300V
DEVICE TYPE
Windows Vista-Compliant, Stereo Class AB Speaker
L
= 10kΩ,
Amplifiers and DirectDrive Headphone Amplifiers
L
RMS
RMS
= 32Ω,
DD
)
)
) to create a negative supply (CPV
______________________________________________________________________________________
THD+N
Dynamic range with
signal present
Line output crosstalk
THD+N
Dynamic range with
signal present
Headphone output
crosstalk
Detailed Description
REQUIREMENT
DD
/ 2). This
WINDOWS PREMIUM MOBILE Vista
SS
).
SPECIFICATIONS
[20Hz, 20kHz]
[20Hz, 20kHz]
[20Hz, 20kHz]
[20Hz, 20kHz]
≤ -80dB FS,
A-weighted
A-weighted
≤ -65dB FS
≤ -45dB FS
≤ -60dB FS,
≤ -50dB
≤ -50dB
conserve board space and system cost, as well as
improve low-frequency response.
The MAX9789A/MAX9790A feature programmable
speaker amplifier gain, allowing the speaker gain to be
set by the logic voltages applied to GAIN1 and GAIN2,
while the headphone amplifiers feature a fixed 3.5dB
gain. Both amplifiers feature an undervoltage lockout
that prevents operation from an insufficient power sup-
ply and click-and-pop suppression that eliminates
audible transients on startup and shutdown. The ampli-
fiers include thermal overload and short-circuit protec-
tion, while the headphone amplifier outputs (IEC Air
Discharge) can withstand ±8kV ESD strikes. An addi-
tional feature of the speaker amplifiers is that there is
no phase inversion from input to output.
The MAX9789A’s low-dropout (LDO) linear regulator
can be used to provide a clean power supply to a
CODEC or other circuitry. The LDO can be enabled
independently of the audio amplifiers. Set LDO_EN =
V
able the LDO. The LDO is capable of providing up to
120mA continuous current and features Maxim’s Dual
Mode™ feedback, easily enabling a fixed 4.75V output
or a user-adjustable output. When LDO_SET is con-
nected to GND, the output is internally set to 4.75V. The
output voltage can be adjusted from 1.21V to 4.75V by
connecting two external resistors as a voltage divider,
at LDO_SET (Figure 1).
DD
to enable the LDO or set LDO_EN = GND to dis-
Low-Dropout Linear Regulator
TYPICAL PERFORMANCE
MAX9789A/MAX9790A
(MAX9789A Only)
[20Hz, 20kHz]
[20Hz, 20kHz]
[20Hz, 20kHz]
[20Hz, 20kHz]
A-weighted
A-weighted
-97dB FS,
-89dB FS,
-94dB FS
-77dB FS
-77dB
-74dB
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