WM8750BLGEFL/R Wolfson Microelectronics, WM8750BLGEFL/R Datasheet - Page 36

• Manufacturer Part Number: WM8750BLGEFL/R
• Description: Audio CODECs STEREO CODEC w/ HP 32-pin
• Manufacturer: Wolfson Microelectronics

Specifications of WM8750BLGEFL/R

• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Package / Case: QFN-32
• Minimum Operating Temperature: - 25 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

WM8750BL
w
HEADPHONE OUTPUT
Analogue outputs LOUT1/ROUT1, LOUT2/ROUT2, and OUT3, can drive a 16Ω or 32Ω headphone
load, either through DC blocking capacitors, or DC coupled without any capacitor.
Figure 13 Recommended Headphone Output Configurations
When DC blocking capacitors are used, then their capacitance and the load resistance together
determine the lower cut-off frequency, f
response. Smaller capacitance values will diminish the bass response. Assuming a 16 Ohm load and
C1, C2 = 220µF:
f
In the DC coupled configuration, the headphone “ground” is connected to the OUT3 pin, which must
be enabled by setting OUT3 = 1 and OUT3SW = 00. As the OUT3 pin produces a DC voltage of
AVDD/2 (=VREF), there is no DC offset between LOUT1/ROUT1 and OUT3, and therefore no DC
blocking capacitors are required. This saves space and material cost in portable applications.
It is recommended to connect the DC coupled headphone outputs only to headphones, and not to
the line input of another device. Although the built-in thermal shutdown circuit will prevent any
damage to the headphone outputs, such a connection may be noisy, and may not function properly if
the other device is grounded.
SPEAKER OUTPUT
LOUT2 and ROUT2 can differentially drive a mono 8Ω speaker as shown below.
Figure 14 Speaker Output Connection
The right channel is inverted by setting the ROUT2INV bit, so that the signal across the loudspeaker
is the sum of left and right channels.
c
= 1 / 2π R
Headphone Output using DC blocking
L
C
1
= 1 / (2π x 16Ω x 220µF) = 45 Hz
capacitors
c
. Increasing the capacitance lowers f
DC Coupled Headphone Output
(OUT3SW = 00)
PD, Rev 4.0, August 2008
c
, improving the bass
Production Data
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