XE3005I064TRLF Semtech, XE3005I064TRLF Datasheet - Page 18

• Manufacturer Part Number: XE3005I064TRLF
• Description: IC CODEC LOW PWR 16BIT 20-UCSP
• Manufacturer: Semtech
• Type: Audio Codecr

Specifications of XE3005I064TRLF

• Data Interface: Serial
• Resolution (bits): 16 b
• Number Of Adcs / Dacs: 1 / 1
• Sigma Delta: Yes
• S/n Ratio, Adcs / Dacs (db) Typ: 78 / 78
• Dynamic Range, Adcs / Dacs (db) Typ: 78 / 78
• Voltage - Supply, Analog: 1.8 V ~ 3.6 V
• Voltage - Supply, Digital: 1.8 V ~ 3.6 V
• Operating Temperature: -20°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 20-UCSP®
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: XE3005I064TR

All these parameters are set in the registers L, M, N, O and P.
Reference(7:0)
The reference (7:0) value is related to the absolute value of the 16 bits input signal. The following format is used for the
comparison:
So the reference is compared to the 8 most significant bits of the absolute value of the input signal:
The values in this table are amplitude values, RMS values can be derived by dividing the numbers by √2.
The working mechanism of the Sandman™ function is the following:
The incoming data is compared to the reference after each time step (1/FSYNC = 50µs if FSYNC = 20kHz).
In a first approximation, the following points are recommended:
© Semtech 2005
• On-time (7:0): Time until wakeup. The number of sequential samples that have to be higher than the Reference for
corresponds to
• 16 bit inputs data (2’s-complement) : 0111’1111’1111’1111 = 0x7FFF
• 8 bit reference (unsigned)
• During the On-time phase
• During the Off-time phase
• On-time at least 1ms. If the On-time is shorter than 1 ms, the Sandman™ function becomes sensitive to spikes in
• Off-time at least 10ms, the Off-time should be longer than 1/f
• Reference should be adjusted just above the noise level.
128.-.32640
don’t care
don’t care
the power down signal to become inactive. The Sandman™ function is disabled (SMAD or SMDA at logic 1) if this
parameter is zero. The ADC and DAC have one common On-time value.
If the input data is higher than the reference, a counter will be incremented otherwise the counter is reset.
When the counter reaches the On-time value, then the SMAD or SMDA signal is activated (high level).
If the input data is lower than the reference, a counter will be incremented otherwise the counter is reset.
When the counter reaches the Off-time value, then the SMAD or SMDA signal is deactivated (low level).
the audio input signal AIN.
frequency = 100Hz if FSYNC = 20kHz. The value of f
high-pass filter in the ADC filters out signals below 100Hz.
1.-.255
0
reference(7:0)
255
0
1
2
M
corresponds to
50 µs – 12 ms
On-time(7:0)
don’t care
don’t care
1.-.255
0
Absolute reference
255 × 128 = 32640
128
256
1 - 65535
corresponds to
50 µs - 3.2 sec
Off-time(15:0)
0
M
: 0111’1111’1000’0000 = 0xFF00/2
don’t care
don’t care
0
Sandman (SMAD or SMDA)
logic 1 (disable function)
logic 1 (disable function)
logic 1 (disable function)
logic 1 (signal higher than ref)
logic 0 (signal lower than ref)
AIN (mV) if gain = 4
min
18
scales proportionally with the sampling frequency FSYNC. A
0.00
1.10
2.20
280
M
min
= 10ms, (code = 200). f
max positive value
reference max
XE3005/XE3006
AIN (mV) if gain = 20
Sandman disable
Sandman disable
Sandman disable
Comments
all registers ≠ zero
time for FSYNC =
20kHz
min
0.00
0.27
0.55
70
M
is the minimum audio
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