Datasheet

MAX9880A Evaluation Kit
Evaluates: MAX9880A
26 _____________________________________________________________________________________
Measuring DC Voltages (AUX)
To utilize this feature, configure jumper JU7 according to
Table 19, remove the shunt from jumper JU29, ensure that
a headphone plug is not plugged in to jumper JU3, and
enable the AUX block on the Analog Audio tab, and refer
to the ADC section in the MAX9880A IC data sheet for
setup and configuration details. The applied DC voltage
(V
AUX
) is divided down before measured by the device’s
ADC. The measured DC voltage (V
DC
) is:
DC AUX
R5
V x V
(R5 R6)
=
+
where the default divider ratio is equal to 1/2.
Audio Inputs and Outputs
The U1 device’s audio inputs and outputs are routed
to the various connectors, headers, and pads on the
EV kit. Table 20 lists the audio input connections and
Table 21 lists the audio output connections. Refer to the
MAX9880A IC data sheet and EV kit software for audio
signal routing details (i.e., which audio inputs can be
routed to the available audio outputs).
Headphone Outputs
The U1 device supports three headphone output modes,
single-ended, differential, and capacitorless. All three
modes can be evaluated using the ROUT_ and LOUT_
pads provided on the EV kit, in conjunction with the JU10
and JU11 jumpers. Refer to the Headphone Modes sec-
tion of the MAX9880A IC data sheet.
To facilitate evaluation with single-ended and capaci-
torless output modes, the EV kit provides two 3.5mm
headphone jacks (J3, J4). The J4 headphone jack is
configured for capacitorless output mode and the J3
headphone jack is configured for single-ended output
mode.
On-Board LDOs
The EV kit includes on-board LDO linear regulators (U6,
U8, U9, and U10), allowing the EV kit to operate without
external power supplies. These LDO regulators provide
power to the U1 device’s power-supply pins: DVDD,
MICVDD, PVDD, AVDD, and DVDDS1. The LDO regula-
tor outputs can be isolated from the power-supply pins
through jumpers JU14–JU17, and JU22, respectively.
A fifth LDO linear regulator (U7) provides power to the
MAXQ2000 circuit, level translators (U4, U17), crystal
oscillator (Y2), stereo digital audio transceiver (U11),
USB stereo audio DAC (U12), and S/PDIF connectors
(J5, J6). All the LDO linear regulators are powered by the
USB bus voltage (+5V) from the J7 mini-USB connector.
Table 20. Audio Inputs Table 21. Audio Outputs
*S_ interface pins = SDOUTS_, SDINS_, BCLKS_,
and LRCLKS_.
*S_ interface pins = SDOUTS_, SDINS_, BCLKS_, and LRCLKS_.
AUDIO
INPUT
U1 PIN DESCRIPTION
J1 LINL
Single-ended left line input
(LINEINL)
J2 LINR
Single-ended right line input
(LINEINR)
J6 S1 interface* S/PDIF audio input from U11
J10 S2 interface* USB audio input from U12
MICL_ pad MICL_ Left analog microphone
MICR_ pad MICR_ Right analog microphone
U15 MICL_
Left digital microphone
(DIGMIC_)
U16 MICL_
Right digital microphone
(DIGMIC_)
AUDIO
OUTPUT
U1 PIN DESCRIPTION
J3
ROUTP and
LOUTP
Single-ended headphone
output with jack detection
J4
ROUTP, LOUTP,
and LOUTN
Capless headphone
output
J5 S1 interface*
S/PDIF audio output on
U11
J8 LOUTR
Single-ended line output
(OUTR)
J9 LOUTL
Single-ended line output
(OUTL)
ROUT_ pads ROUT_ Right headphone output
LOUT_ pads LOUT_ Left headphone output