MAX9860ETG+T Maxim Integrated Products, MAX9860ETG+T Datasheet - Page 30

• Manufacturer Part Number: MAX9860ETG+T
• Description: IC CODEC MONO AUD 16BIT 24TQFN
• Manufacturer: Maxim Integrated Products
• Type: Audio Codecr

Specifications of MAX9860ETG+T

• Data Interface: Serial
• Resolution (bits): 16 b
• Number Of Adcs / Dacs: 1 / 2
• Sigma Delta: Yes
• Dynamic Range, Adcs / Dacs (db) Typ: 81 / 90
• Voltage - Supply, Analog: 1.7 V ~ 1.9 V
• Voltage - Supply, Digital: 1.7 V ~ 1.9 V
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 24-TQFN Exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

16-Bit Mono Audio Voice Codec
The MAX9860 includes AGC on both microphone
inputs. AGC is enabled by setting the hold time through
AGCHLD. AGC dynamically controls the analog PGA
microphone input gain to hold the level constant over a
20dB input range, enhancing the voice path operation
for various use conditions. When AGC is enabled, it
monitors the signal level at the output of the ADC and
then makes gain adjustments by controlling the analog
microphone PGA. When AGC is enabled, PGAM is not
user programmable.
Table 10. AGC and Noise Gate Registers
30
REGISTER ADDRESS
______________________________________________________________________________________
AGCSRC
AGCHLD
AGCRLS
AGCATK
BITS
0x0E
0x0F
Automatic Gain Control (AGC)
AGC/Noise Gate Signal Source Select
0 = The left ADC output is used by the AGC and noise gate.
1 = The sum of the left and right ADC outputs is used by the AGC and noise gate.
AGC Release Time
Time taken by the AGC circuit to increase the gain from minimum to maximum.
AGC Attack Time
The time constant of the AGC gain reduction curve.
AGC Hold Time
Time the AGC circuit waits before beginning to increase gain when a signal below the threshold is
detected.
AGCSRC
B7
CODE
CODE
CODE
000
001
010
011
100
101
110
111
00
01
10
11
00
01
10
11
and Noise Gate
B6
ANTH
AGC disabled
TIME (ms)
TIME (ms)
156ms
312ms
625ms
78ms
1.25s
TIME
2.5s
AGCRLS
10s
200
100
400
5s
12
50
50
3
B5
Since AGC increases the level of all signals below a
user-defined threshold, the noise floor effectively is
increased by 20dB. To counteract this, a noise gate is
included to reduce the gain at low levels. Unlike typical
noise gates that completely silence the output below a
threshold, the noise gate in the MAX9860 reduces the
gain for signals below the defined level. As the signal
level becomes further below the threshold, the gain is
further reduced. The Automatic Gain Control
Thresholds and Noise Gate Thresholds graphs in the
Typical Operating Characteristics show the resulting
steady-state transfer curves when AGC and the noise
gate are enabled.
B4
FUNCTION
B3
AGCATK
B2
AGCTH
B1
AGCHLD
B0