MAX9850ETI+T Maxim Integrated Products, MAX9850ETI+T Datasheet - Page 19

• Manufacturer Part Number: MAX9850ETI+T
• Description: IC AMP AUDIO .095W STER 28TQFN
• Manufacturer: Maxim Integrated Products
• Series: DirectDrive™r
• Type: Class ABr

Specifications of MAX9850ETI+T

• Output Type: Headphones, 2-Channel (Stereo)
• Max Output Power X Channels @ Load: 95mW x 2 @ 16 Ohm
• Voltage - Supply: 1.8 V ~ 3.6 V
• Features: DAC, Depop, Digital Inputs, I²C, I²S, Line Level Inputs & Outputs, Mute, Shutdown, Volume Control
• Mounting Type: Surface Mount
• Package / Case: 28-WQFN Exposed Pad, 28-HWQFN
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Slave modes of operation allow the MAX9850 to operate
in any audio system where the LRCLK and BCLK must be
supplied from an external source. When operating in
slave mode, the MCLK supplied to the MAX9850 may be
either synchronous or asynchronous with LRCLK. Use the
slave integer mode if ICLK is synchronous and has an
integer multiple of 16 x LRCLK. Integer mode ensures
that the highest levels of full-scale-input signal perfor-
mance can be achieved. Slave noninteger mode offers
the highest degree of clock flexibility. ICLK does not
need to be synchronous or an integer multiple of
LRCLK when operating in slave noninteger mode.
Master modes of operation allow the MAX9850 to gener-
ate and supply an LRCLK and BCLK to other elements in
the system. Use master integer mode if the provided
ICLK is an integer multiple of 16 x LRCLK. Integer mode
ensures that the highest levels of full-scale input signal
performance can be achieved. Master noninteger mode
allows the MAX9850 to supply virtually any frequency
LRCLK with an accuracy better than ±0.5%.
The slave noninteger mode provides maximum flexibility
for ICLK and LRCLK frequencies. The ICLK and LRCLK
can be asynchronous and noninteger related. Connect
any available system clock that is listed on Table 5 in
the Internal Timing section. In slave noninteger mode,
the acceptable MCLK frequency range is the same as
master mode.
The MAX9850 generates the LRCLK and BCLK in mas-
ter mode. LRCLK is an integer factor of ICLK by the fol-
lowing equation:
where:
f
f
N
(register 0x9, bits B7–B0).
f
For example:
f
48kHz.
Solve the above equation for N
mode if N
mode if N
ICLK
LRCLK
LRCLK
ICLK
LSB
= decimal value of the data contained in LSB(7:0)
= ICLK frequency. f
= 12.228MHz and N
for proper DAC operation.
= LRCLK frequency.
LSB
LSB
is not an integer.
Master Integer Mode (MAS = 1, IM = 1)
is an integer. Use master noninteger
f
LRCLK
______________________________________________________________________________________
=
16
ICLK
LSB
f
×
ICLK
LSB
Stereo Audio DAC with DirectDrive
must be at least 160 x
= 16 (0x10), f
N
LSB
. Use master integer
LRCLK
=
The MAX9850 accepts LRCLK and BCLK from an
external digital audio source when in slave integer
mode. LRCLK must be an exact integer multiple of
ICLK to ensure proper operation. Program LSB(7:0)
(register 0x9, bits B7–B0) with the LRCLK division ratio.
Use the following equation to find the value that needs
to be programmed to LSB(7:0):
where:
f
proper DAC operation.
f
N
(register 0x9, bits B7–B0).
For example:
f
(0x10).
Solve the above equation for N
mode if N
if N
In slave noninteger mode, the MAX9850 accepts an
external LRCLK and converts the digital audio signal
using any asynchronous ICLK within the acceptable
operating range. The MAX9850 uses internal clock
recovery circuitry to generate all required internal clocks.
This allows the MAX9850 to operate in systems that do
not have dedicated clock sources or crystal oscillators.
Virtually any existing system clock will work. f
be at least 176 x f
The ICLK frequency in some applications may not be
an integer multiple of the desired LRCLK frequency.
The MAX9850, operating in master noninteger mode,
can generate and output any LRCLK frequency
between 8kHz to 48kHz (±0.5%) with any ICLK frequen-
cy within the acceptable operating range. In this mode,
the MAX9850 generates LRCLK by dividing MCLK by
the ratio programmed into MSB(14:8) and LSB(7:0)
(register 0x8, bits B7–B0 and register 0x9, bits B6–B0).
The LRCLK sample frequency can have any noninteger
relationship with respect to MCLK. Calculate the values
for MSB(14:8) and LSB(7:0) with the following equation:
ICLK
LRCLK
ICLK
LSB
LSB
Headphone Amplifier
= ICLK frequency. f
= 11.2896MHz and f
= decimal value of the data contained in LSB(7:0)
= supplied LRCLK frequency.
is not an integer.
N
LSB
MSB LSB
Master Noninteger Mode (MAS = 1, IM = 0)
is an integer. Use slave noninteger mode
,
N
Slave Integer Mode (MAS = 0, IM = 1)
LRCLK
LSB
Slave Noninteger (MAS = 0, IM = 0)
=
ROUND
=
for proper operation.
16
ICLK
LRCLK
×
f
⎛
⎜ ⎜
⎝
ICLK
2
must be 160 x f
f
LRCLK
22
LSB
= 44.1kHz, N
f
×
ICLK
. Use slave integer
f
LRCLK
⎞
⎟ ⎟
⎠
ICLK
LRCLK
LSB
must
= 16
for
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