Rainbow Electronics MAX9814 - Manual (Page 3)

MAX9814
Microphone Amplifier with AGC and
Low-Noise Microphone Bias
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Note 1: Devices are production tested at T
A
= +25°C. Limits over temperature are guaranteed by design.
Note 2: Dynamic range is calculated using the EIAJ method. The input is applied at -60dBFS (0.707µV
RMS
), f
IN
= 1kHz.
Note 3: Attack time measured as time from AGC trigger to gain reaching 90% of its final value.
Note 4: CG is connected to an external DC voltage source, and adjusted until V
MICOUT
= 1.23V.
Note 5: CG connected to GND with 2.2µF.
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
MICOUT High Output Voltage V OH I OUT sourcing 1mA 2.45 V
MICOUT Low Output Voltage V OL I OUT sinking 1mA 3 mV
MICOUT Bias MICOUT unconnected 1.14 1.23 1.32 V
Output Impedance Z OUT 50 Ω
Minimum Resistive Load R LOAD_MIN 5 k Ω
Maximum Capacitive Drive C LOAD_MAX 200 pF
Maximum Output Current I OUT_MAX 1% THD, R L = 500 Ω 1 2 mA
Output Short-Circuit Current I
SC
3 8 mA
AGC mode; V DD = 2.7V to 5.5V (Note 4) 35 50
f = 217Hz, V RIPPLE = 100mV P-P (Note 5) 55
f = 1kHz, V RIPPLE = 100mV P-P (Note 5) 52.5
Power-Supply Rejection Ratio PSRR
f = 10kHz, V RIPPLE = 100mV P-P (Note 5) 43
dB
MICROPHONE BIAS
Microphone Bias Voltage V MICBIAS I MICBIAS = 0.5mA 1.84 2.0 2.18 V
Output Resistance R MICBIAS I MICBIAS = 1mA 1 Ω
Output Noise Voltage V
MICBIAS_NOISE
I
MICBIAS
= 0.5mA, BW = 22Hz to 22kHz 5.5 µV
RMS
DC, V DD = 2.7V to 5.5V 70 80
Power-Supply Rejection Ratio PSRR I
MICBIAS
= 0.5mA, V
RIPPLE
= 100mV
P-P
,
f IN = 1kHz
71
dB
TRILEVEL INPUTS (A/R, GAIN)
A/R or GAIN = V DD
0.5V DD
/ 180k Ω
0.5V DD
/ 100k Ω
0.5V DD
/ 50k Ω
Tri-Level Input Leakage Current
A/R or GAIN = GND
0.5V DD
/ 180k Ω
0.5V DD
/ 100k Ω
0.5V DD
/ 50k Ω
mA
Input High Voltage V IH V DD x 0.7 V
Input Low Voltage V IL V DD x 0.3 V
Shutdown Enable Time t ON 60 ms
Shutdown Disable Time t
OFF
40 ms
DIGITAL INPUT (
SHDN)
SHDN Input Leakage Current -1 +1 µA
Input High Voltage V IH 1.3 V
Input Low Voltage V IL 0.5 V
AGC THRESHOLD INPUT (TH)
TH Input Leakage Current -1 +1 µA
ELECTRICAL CHARACTERISTICS (continued)
(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)