Datasheet

Microphone Amplifier with AGC and
Low-Noise Microphone Bias
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(V
DD
= 3.3V, SHDN = V
DD
, C
CT
= 470nF, C
CG
= 2µF, GAIN = V
DD
, T
A
= T
MIN
to T
MAX
, unless otherwise specified. Typical values are
at T
A
= +25°C.) (Note 1)
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
V
DD
to GND..............................................................-0.3V to +6V
All Other Pins to GND.................................-0.3V to (V
DD
+ 0.3V)
Output Short-Circuit Duration.....................................Continuous
Continuous Current (MICOUT, MICBIAS).......................±100mA
All Other Pins ....................................................................±20mA
Continuous Power Dissipation (T
A
= +70°C)
14-Pin TDFN-EP
(derate 16.7mW/°C above +70°C)........................1481.5mW
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature......................................................+150°C
Lead Temperature (soldering, 10s) .................................+300°C
Bump Temperature (soldering) Reflow............................+235°C
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
GENERAL
Operating Voltage V
DD
Guaranteed by PSRR test 2.7 5.5 V
Supply Current I
DD
3.1 6 mA
Shutdown Supply Current I
SHDN
0.01 1 µA
Input-Referred Noise Density e
n
BW = 20kHz, all gain settings 30 nV/√Hz
Output Noise BW = 20kHz 430 µV
RMS
BW = 22Hz to 22kHz
(500mV
RMS
output signal)
61
Signal-to-Noise Ratio SNR
A-weighted 64
dB
Dynamic Range DR (Note 2) 60 dB
f
IN
= 1kHz, BW = 20Hz to 20kHz,
R
L
= 10kΩ , V
T H
= 1V ( thr eshol d = 2V
P - P
) ,
V
I N
= 0.5m V
R M S
, V
C T
= 0V
0.04
Total Harmonic Distortion Plus
Noise
THD+N
f
IN
= 1kHz, BW = 20Hz to 20kHz,
R
L
= 10kΩ, V
TH
= 0.1V (threshold =
200mV
P-P
), V
IN
= 30mV
RMS
, V
CT
= 2V
0.2
%
Amplifier Input BIAS V
IN
1.14 1.23 1.32 V
Maximum Input Voltage V
IN_MAX
1% THD 100 mV
P-P
Input Impedance Z
IN
100 kΩ
GAIN = V
DD
39.5 40 40.5
GAIN = GND 49.5 50 50.6
Maximum Gain A
GAIN = unconnected 59.5 60 60.5
dB
GAIN = V
DD
18.7 20 20.5
GAIN = GND 29.0 30 30.8Minimum Gain
GAIN = unconnected 38.7 40 40.5
dB
Maximum Output Level V
OUT_RMS
1% THD+N, V
TH
= MICBIAS 0.707 V
RMS
Regulated Output Level AGC enabled, V
TH
= 0.7V 1.26 1.40 1.54 V
P-P
AGC Attack Time t
ATTACK
C
CT
= 470nF (Note 3) 1.1 ms
A/R = GND 1:500
A/R = V
DD
1:2000
Attack/Release Ratio A/R
A/R = unconnected 1:4000
ms/ms
MAX9814
2
Maxim Integrated