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19-0764; Rev 0; 3/07
KIT ATION EVALU BLE AVAILA
Microphone Amplifier with AGC and Low-Noise Microphone Bias
General Description Features
o Automatic Gain Control (AGC) o Three Gain Settings (40dB, 50dB, 60dB) o Programmable Attack Time o Programmable Attack and Release Ratio o 2.7V to 5.5V Supply Voltage Range o Low Input-Referred Noise Density of 30nV/Hz o Low THD: 0.04% (typ) o Low-Power Shutdown Mode o Internal Low-Noise Microphone Bias, 2V o Available in the Space-Saving 12-Bump UCSP (1.5mm x 2mm) and 14-Pin TDFN (3mm x 3mm) Packages o -40C to +85C Extended Temperature Range
MAX9814
The MAX9814 is a low-cost, high-quality microphone amplifier with automatic gain control (AGC) and lownoise microphone bias. The device features a low-noise preamplifier, variable gain amplifier (VGA), output amplifier, microphone-bias-voltage generator and AGC control circuitry. The low-noise preamplifier has a fixed 12dB gain, while the VGA gain automatically adjusts from 20dB to 0dB, depending on the output voltage and the AGC threshold. The output amplifier offers selectable gains of 8dB, 18dB, and 28dB. With no compression, the cascade of the amplifiers results in an overall gain of 40dB, 50dB, or 60dB. A trilevel digital input programs the output amplifier gain. An external resistive divider controls the AGC threshold and a single capacitor programs the attack/release times. A trilevel digital input programs the ratio of attack-to-release time. The hold time of the AGC is fixed at 30ms. The low-noise microphone-biasvoltage generator can bias most electret microphones. The MAX9814 is available in the space-saving 12-bump UCSPTM (1.5mm x 2mm) and 14-pin TDFN packages. This device is specified over the -40C to +85C extended temperature range.
Ordering Information
PART MAX9814EBC+T MAX9814ETD+T TEMP RANGE PINPACKAGE PKG CODE B12-3 T1433-2
Applications
Digital Still Cameras Digital Video Cameras PDAs Bluetooth Headsets Entertainment Systems (e.g., Karaoke) Two-Way Communicators High-Quality Portable Recorders IP Phones/Telephone Conferencing
-40C to +85C 12 UCSP-12 -40C to +85C 14 TDFN-14
+Denotes a lead-free package.
Pin Configurations appear at end of data sheet. UCSP is a trademark of Maxim Integrated Products, Inc.
Simplified Block Diagram
2.7V TO 5.5V
SHDN MICBIAS RMICBIAS CIN MICIN LNA +12dB LOW-NOISE REFERENCE
VDD
AGC
MAX9814
VGA +20dB/0dB
GAIN +8/+18/ +28dB
COUT OUT
GND
________________________________________________________________ Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim's website at www.maxim-ic.com.
Microphone Amplifier with AGC and Low-Noise Microphone Bias MAX9814
ABSOLUTE MAXIMUM RATINGS
VDD to GND ..............................................................-0.3V to +6V All Other Pins to GND.................................-0.3V to (VDD + 0.3V) Output Short-Circuit Duration.....................................Continuous Continuous Current (OUT, MICBIAS) .............................100mA All Other Pins ....................................................................20mA Continuous Power Dissipation (TA = +70C) 12-Bump UCSP (derate 6.5mW/C above +70C).......518mW 14-Pin TDFN (derate 16.7mW/C above +70C) ....1481.5mW Operating Temperature Range ...........................-40C to +85C Junction Temperature ......................................................+150C Lead Temperature (soldering, 10s) .................................+300C Bump Temperature (soldering) Reflow............................+235C
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.
ELECTRICAL CHARACTERISTICS
(VDD = 3.3V, SHDN = VDD, CCT = 470nF, CCG = 2F, GAIN = VDD, TA = TMIN to TMAX, unless otherwise specified. Typical values are at TA = +25C.) (Note 1)
PARAMETER GENERAL Operating Voltage Supply Current Shutdown Supply Current Input-Referred Noise Density Output Noise Signal-to-Noise Ratio Dynamic Range SNR DR VDD IDD ISHDN en BW = 20kHz, all gain settings BW = 20kHz BW = 22Hz to 22kHz (500mVRMS output signal) A-weighted (Note 2) fIN = 1kHz, BW = 20Hz to 20kHz, RL = 10k, VTH = 1V (threshold = 2VPP), VIN = 0.5mVRMS, VCT = 0V fIN = 1kHz, BW = 20Hz to 20kHz, RL = 10k, VTH = 0.1V (threshold = 200mVP-P), VIN = 30mVRMS, VCT = 2V 1.14 1% THD GAIN = VDD Maximum Gain A GAIN = GND GAIN = unconnected GAIN = VDD Minimum Gain Maximum Output Level Regulated Output Level AGC Attack Time Attack/Release Ratio tATTACK A/R VOUT_RMS GAIN = GND GAIN = unconnected 1% THD+N, VTH = MICBIAS AGC enabled, VTH = 0.7V CT = 470nF (Note 3) A/R = GND A/R = VDD A/R = unconnected 1.26 39.5 49.5 59.5 18.7 29.0 38.7 Guaranteed by PSRR test 2.7 3.1 0.01 30 430 61 64 60 0.04 % 0.2 1.23 100 100 40 50 60 20 30 40 0.707 1.40 1.1 1:500 1:2000 1:4000 ms/ms 1.54 40.5 50.6 60.5 20.5 30.8 40.5 VRMS VP-P ms dB dB 1.32 V mVP-P k dB 5.5 6 1 V mA A nV/Hz VRMS dB SYMBOL CONDITIONS MIN TYP MAX UNITS
Total Harmonic Distortion Plus Noise
THD+N
Amplifier Input BIAS Maximum Input Voltage Input Impedance
VIN VIN_MAX ZIN
2
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Microphone Amplifier with AGC and Low-Noise Microphone Bias
ELECTRICAL CHARACTERISTICS (continued)
(VDD = 3.3V, SHDN = VDD, CCT = 470nF, CCG = 2F, GAIN = VDD, TA = TMIN to TMAX, unless otherwise specified. Typical values are at TA = +25C.) (Note 1)
PARAMETER MICOUT High Output Voltage MICOUT Low Output Voltage MICOUT Bias Output Impedance Minimum Resistive Load Maximum Capacitive Drive Maximum Output Current Output Short-Circuit Current ZOUT RLOAD_MIN CLOAD_MAX IOUT_MAX ISC AGC mode; VDD = 2.7V to 5.5V (Note 4) Power-Supply Rejection Ratio PSRR f = 217Hz, VRIPPLE = 100mVP-P (Note 5) f = 1kHz, VRIPPLE = 100mVP-P (Note 5) f = 10kHz, VRIPPLE = 100mVP-P (Note 5) MICROPHONE BIAS Microphone Bias Voltage Output Resistance Output Noise Voltage Power-Supply Rejection Ratio TRILEVEL INPUTS (A/R, GAIN) A/R or GAIN = VDD Tri-Level Input Leakage Current A/R or GAIN = GND Input High Voltage Input Low Voltage Shutdown Enable Time Shutdown Disable Time DIGITAL INPUT (SHDN) SHDN Input Leakage Current Input High Voltage Input Low Voltage AGC THRESHOLD INPUT (TH) TH Input Leakage Current -1 +1 A VIH VIL -1 1.3 0.5 +1 A V V VIH VIL tON tOFF 60 40 0.5VDD 0.5VDD 0.5VDD / 180k / 100k / 50k VDD x 0.7 VDD x 0.3 V V ms ms 0.5VDD 0.5VDD 0.5VDD / 180k / 100k / 50k mA VMICBIAS RMICBIAS IMICBIAS = 0.5mA IMICBIAS = 1mA DC, VDD = 2.7V to 5.5V PSRR IMICBIAS = 0.5mA, VRIPPLE = 100mVP-P, fIN = 1kHz 70 1.84 2.0 1 5.5 80 71 dB 2.18 V VRMS 1% THD, RL = 500 3 35 SYMBOL VOH VOL CONDITIONS IOUT sourcing 1mA IOUT sinking 1mA MICOUT unconnected 1.14 MIN TYP 2.45 3 1.23 50 5 200 1 8 50 55 52.5 43 dB 2 1.32 MAX UNITS V mV V k pF mA mA
MAX9814
VMICBIAS_NOISE IMICBIAS = 0.5mA, BW = 22Hz to 22kHz
Note 1: Note 2: Note 3: Note 4: Note 5:
Devices are production tested at TA = +25C. Limits over temperature are guaranteed by design. Dynamic range is calculated using the EIAJ method. The input is applied at -60dBFS (0.707VRMS), fIN = 1kHz. Attack time measured as time from AGC trigger to gain reaching 90% of its final value. CG is connected to an external DC voltage source, and adjusted until VMICOUT = 1.23V. CG connected to GND with 2.2F.
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3
Microphone Amplifier with AGC and Low-Noise Microphone Bias MAX9814
Typical Operating Characteristics
(VDD = 5V, CCT = 470nF, CCG = 2.2F, VTH = VMICBIAS x 0.4, GAIN = VDD (40dB), AGC disabled, no load, RL = 10k, COUT = 1F, TA = +25C, unless otherwise noted.)
GAIN vs. FREQUENCY
MAX9814 toc01
POWER-SUPPLY REJECTION RATIO vs. FREQUENCY
MAX9814 toc02
MICBIAS POWER-SUPPLY REJECTION RATIO vs. FREQUENCY
-40 -50 PSRR (dB) -60 -70 -80 -90 -100 VRIPPLE = 200mVP-P -110 10 100 1k FREQUENCY (Hz) 10k 100k
MAX9814 toc03
80 70 60 GAIN (dB) GAIN = UNCONNECTED
0 -10 -20 PSRR (dB) -30 -40 -50
-30
50 40 30 20 10 0 10 100 1k FREQUENCY (Hz) 10k 100k GAIN = 0 GAIN = 1
-60 -70 VRIPPLE = 200mVP-P -80 10 100 1k FREQUENCY (Hz) 10k 100k
SUPPLY CURRENT vs. SUPPLY VOLTAGE
MAX9814 toc04
SHUTDOWN CURRENT vs. SUPPLY VOLTAGE
MAX9814 toc05
MICROPHONE BIAS VOLTAGE vs. MICROPHONE BIAS SOURCE CURRENT
MAX9814 toc06
3.5 3.4 3.3 SUPPLY CURRENT (mA) 3.2 3.1 3.0 2.9 2.8 2.7 2.6 2.5 2.5 3.0 3.5 4.0 4.5 5.0 5.5
0.5
2.5
SHUTDOWN CURRENT (nA)
0.4
2.0 VMICBIAS VOLTAGE (V)
0.3
1.5
0.2
1.0
0.1
0.5
0 6.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 SUPPLY VOLTAGE (V) SUPPLY VOLTAGE (V)
0 0 5 10 15 IMICBIAS (mA) 20 25 30
TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY
MAX9814 toc07
TOTAL HARMONIC DISTORTION PLUS NOISE vs. OUTPUT VOLTAGE
MAX9814 toc08
INPUT-REFERRED NOISE vs. FREQUENCY
INPUT-REFERRED NOISE (VRMS/Hz) MICIN AC-COUPLED TO GND
MAX9814 toc09
10 VOUT = 800mVRMS
10
1000
1 THD+N (%) THD+N (%)
1
fIN = 300Hz, 1kHz, and 3kHz
100
0.1
0.1
10
fIN = 10kHz 0.01 10 100 1k FREQUENCY (Hz) 10k 100k 0.01 0 0.5 1.0 1.5 OUTPUT VOLTAGE (VRMS)
1 0.01 0.1 1 FREQUENCY (kHz) 10 100
4
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Microphone Amplifier with AGC and Low-Noise Microphone Bias
Typical Operating Characteristics (continued)
(VDD = 5V, CCT = 470nF, CCG = 2.2F, VTH = VMICBIAS x 0.4, GAIN = VDD (40dB), AGC disabled, no load, RL = 10k, COUT = 1F, TA = +25C, unless otherwise noted.)
MICBIAS NOISE vs. FREQUENCY
MAX9814 toc10
MAX9814
SMALL-SIGNAL PULSE RESPONSE
VMICIN 10mV/div 0V
MAX9814 toc11
TURN-ON RESPONSE
VSHDN 5V/div 0V VMICBIAS 2V/div 0V
MAX9814 toc12
10,000
MICBIAS NOISE (nVRMS/Hz)
1000 VMICOUT 500mV/div 100
0V CL = 10pF 10 10 100 1k FREQUENCY (Hz) 10k 100k 200s/div
VMICOUT 1V/div 0V
20ms/div
VOUT vs. VIN
MAX9814 toc13
VOUT vs. VIN
MAX9814 toc14
VOUT vs. VIN
MAX9814 toc15
1.00 VTH = 1V 0.75 VOUT (VRMS)
1.00 VTH = 1V 0.75 VOUT (VRMS)
1.00 VTH = 1V 0.75 VOUT (VRMS)
0.50 VTH = 0.75V 0.25 VTH = 0.5V 0 0 50 VIN (mVRMS) 100 150 AGC ENABLED GAIN = 1
0.50 VTH = 0.75V 0.25 VTH = 0.5V 0 0 10 20 VIN (mVRMS) AGC ENABLED GAIN = 0 30 40
0.50 VTH = 0.75V 0.25 VTH = 0.5V AGC ENABLED GAIN = UNCONNECTED 0 0 5 VIN (mVRMS) 10 15
ATTACK TIME
MAX9814 toc16
ATTACK TIME
MAX9814 toc17
HOLD AND RELEASE TIME
MAX9814 toc18
VMICOUT 500mV/div
VMICOUT 500mV/div
VMICOUT 500mV/div
0V CCT = 47nF 200s/div
0V CCT = 100nF 200s/div
0V CCT = 47nF A/R = GND 20ms/div
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5
Microphone Amplifier with AGC and Low-Noise Microphone Bias MAX9814
Typical Operating Characteristics (continued)
(VDD = 5V, CCT = 470nF, CCG = 2.2F, VTH = VMICBIAS x 0.4, GAIN = VDD (40dB), AGC disabled, no load, RL = 10k, COUT = 1F, TA = +25C, unless otherwise noted.)
HOLD AND RELEASE TIME
MAX9814 toc19
HOLD AND RELEASE TIME
MAX9814 toc20
VMICOUT 500mV/div
VMICOUT 500mV/div
0V CCT = 47nF A/R = VDD 40ms/div
0V CCT = 47nF A/R = UNCONNECTED 100ms/div
Pin Description
PIN TDFN 1 2 3 4, 11 5 6 7 8 UCSP A1 B2 A2 -- A3 A4 B4 C4 CT SHDN CG N.C. VDD MICOUT GND MICIN Timing Capacitor Connection. Connect a capacitor to CT to control the Attack and Release times of the AGC. Active-Low Shutdown Control Amplifier DC Offset Adjust. Connect a 2.2F capacitor to GND to ensure zero offset at the output. No Connection. Connect to GND. Power Supply. Bypass to GND with a 1F capacitor. Amplifier Output Ground Microphone Noninverting Input Tri-Level Attack and Release Ratio Select. Controls the ratio of attack time to release time for the AGC circuit. A/R = GND: Attack/Release Ratio is 1:500 A/R = VDD: Attack/Release Ratio is 1:2000 A/R = BIAS: Attack/Release Ratio is 1:4000 Tri-Level Amplifier Gain Control. GAIN = VDD, gain set to 40dB. GAIN = GND, gain set to 50dB. GAIN = Unconnected, uncompressed gain set to 60dB. Amplifier Bias. Bypass to GND with a 0.47F capacitor. Microphone Bias Output AGC Threshold Control. TH voltage sets gain control threshold. Connect TH to MICBIAS to disable the AGC. NAME FUNCTION
9
B3
A/R
10
C3
GAIN
12 13 14
C2 C1 B1
BIAS MICBIAS TH
6
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Microphone Amplifier with AGC and Low-Noise Microphone Bias
Detailed Description
The MAX9814 is a low-cost, high-quality microphone amplifier with automatic gain control (AGC) and a lownoise microphone bias. The MAX9814 consists of several distinct circuits: a low-noise preamplifier, a variable gain amplifier (VGA), an output amplifier, a microphonebias-voltage generator, and AGC control circuitry. An internal microphone bias voltage generator provides a 2V bias that is suitable for most electret condenser microphones. The MAX9814 amplifies the input in three distinct stages. In the first stage, the input is buffered and amplified through the low-noise preamplifier with a gain of 12dB. The second stage consists of the VGA controlled by the AGC. The VGA/AGC combination is capable of varying the gain from 20dB to 0dB. The output amplifier is the final stage in which a fixed gain of 8dB, 18dB, 20dB is programmed through a single tri-level logic input. With no compression from the AGC, the MAX9814 is capable of providing 40dB, 50dB, or 60dB gain. The MAX9814's AGC controls the gain by first detecting that the output voltage has exceeded a preset limit. The microphone amplifier gain is then reduced with a selectable time constant to correct for the excessive output-voltage amplitude. This process is known as the attack time. When the output signal subsequently lowers in amplitude, the gain is held at the reduced state for a short period before slowly increasing to the normal value. This process is known as the hold and release time. The speed at which the amplifiers adjust to changing input signals is set by the external timing capacitor C CT and the voltage applied to A/R. The AGC threshold can be set by adjusting V TH . Gain reduction is a function of input signal amplitude with a maximum AGC attenuation of 20dB. Figure 2 shows the effect of an input burst exceeding the preset limit, output attack, hold and release times. If the attack and release times are configured to respond too fast, audible artifacts often described as "pumping" or "breathing" can occur as the gain is rapidly adjusted to follow the dynamics of the signal. For best results, adjust the time constant of the AGC to accommodate the source material. For applications in which music CDs are the main audio source, a 160s attack time with an 80ms release time is recommended. Music applications typically require a shorter release time than voice or movie content.
MAX9814
Automatic Gain Control (AGC)
A device without AGC experiences clipping at the output when too much gain is applied to the input. AGC prevents clipping at the output when too much gain is applied to the input, eliminating output clipping. Figure 1 shows a comparison of an over-gained microphone input with and without AGC.
MAX9814 AGC DISABLED
MAX9814 fig01a
MAX9814 AGC ENABLED
MAX9814 fig01b
0V
VMICIN 100mV/div
0V
VMICIN 100mV/div
0V
VMICOUT (AC-COUPLED) 1V/div
0V
VMICOUT (AC-COUPLED) 1V/div
400s/div
400s/div
Figure 1. Microphone Input with and Without AGC
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7
Microphone Amplifier with AGC and Low-Noise Microphone Bias MAX9814
and setting the attack-to-release time ratio by configuring A/R as shown in Table 1:
HOLD VCT 500mV/div ATTACK 0V VMICOUT (AC-COUPLED) 1V/div RELEASE
* Use a small ratio to maximize the speed of the AGC. * Use a large ratio to maximize the sound quality and prevent repeated excursions above the threshold from being independently adjusted by the AGC.
0V
AGC Output Threshold The output threshold that activates AGC is adjustable through the use of an external resistive divider. Once the divider is set, AGC reduces the gain to match the output voltage to the voltage set at the TH input.
Microphone Bias
10ms/div
Figure 2. Input Burst Exceeding AGC Limit
Attack Time The attack time is the time it takes for the AGC to reduce the gain after the input signal has exceeded the threshold level. The gain attenuation during the attack time is exponential, and defined as one-time constant. The time constant of the attack is given by 2400 x CCT seconds (where CCT is the external timing capacitor): * Use a short attack time for the AGC to react quickly to transient signals, such as snare drum beats (music) or gun shots (DVD). * Use a longer attack time to allow the AGC to ignore short-duration peaks and only reduce the gain when a noticeable increase in loudness occurs. Shortduration peaks are not reduced, but louder passages are. This allows the louder passages to be reduced in volume, thereby maximizing output dynamic range. Hold Time Hold time is the delay after the signal falls below the threshold level before the release phase is initiated. Hold time is internally set to 30ms and nonadjustable. The hold time is cancelled by any signal exceeding the set threshold level, and the attack time is reinitiated. Release Time The release time is how long it takes for the gain to return to its normal level after the output signal has fallen below the threshold level and 30ms hold time has expired. Release time is defined as release from a 20dB gain compression to 10% of the nominal gain setting after the input signal has fallen below the TH threshold and the 30ms hold time has expired. Release time is adjustable and has a minimum of 25s. The release time is set by picking an attack time using CCT
8
The MAX9814 features an internal low-noise microphone bias voltage capable of driving most electret condenser microphones. The microphone bias is regulated at 2V to provide that the input signal to the lownoise preamplifier does not clip to ground.
Applications Information
Programming Attack and Release Times
Attack and release times are set by selecting the capacitance value between CT and GND, and by setting the logic state of A/R (Table 1). A/R is a tri-level logic input that sets the attack-to-release time ratio.
Table 1. Attack-and-Release Ratios
A/R GND VDD Unconnected ATTACK/RELEASE RATIO 1:500 1:2000 1:4000
The attack and release times can be selected by utilizing the corresponding capacitances listed in Table 2.
Table 2. Attack-and-Release Time
CCT 22nF 47nF 68nF 100nF 220nF 470nF 680nF 1F tATTACK (ms) 0.05 0.11 0.16 0.24 0.53 1.1 1.63 2.4 tRELEASE (ms) A/R = GND 25 55 80 120 265 550 815 1200 A/R = VDD 100 220 320 480 1060 2200 3260 4800 A/R = UNCONNECTED 200 440 640 960 2120 4400 6520 9600
_______________________________________________________________________________________
Microphone Amplifier with AGC and Low-Noise Microphone Bias
Setting the AGC Threshold
To set the output-voltage threshold at which the microphone output is clamped, an external resistor-divider must be connected from MICBIAS to ground with the output of the resistor-divider applied to TH. The voltage VTH determines the peak output-voltage threshold at which the output becomes clamped. The maximum signal swing at the output is then limited to two times VTH and remains at that level until the amplitude of the input signal is reduced. To disable AGC, connect TH to MICBIAS. Choose CIN such that f-3dB_IN is well below the lowest frequency of interest. Setting f-3dB_IN too high affects the amplifier's low-frequency response. Use capacitors with low-voltage coefficient dielectrics. Aluminum electrolytic, tantalum, or film dielectric capacitors are good choices for AC-coupling capacitors. Capacitors with high-voltage coefficients, such as ceramics (non-C0G dielectrics), can result in increased distortion at low frequencies.
MAX9814
Output Capacitor
The output of the MAX9814 is biased at 1.23V. To eliminate the DC offset, an AC-coupling capacitor (COUT) must be used. Depending on the input resistance (RL) of the following stage, COUT and RL effectively form a highpass filter. The -3dB point of the highpass filter, assuming zero output impedance, is given by: f-3dB_OUT = 1 2 x RL x COUT
Microphone Bias Resistor
MICBIAS is capable of sourcing 20mA. Select a value for RMICBIAS that provides the desired bias current for the electret microphone. A value of 2.2k is usually sufficient for a microphone of typical sensitivity. Consult the microphone data sheet for the recommended bias resistor.
Bias Capacitor
The BIAS output of the MAX9814 is internally buffered and provides a low-noise bias. Bypass BIAS with a 470nF capacitor to ground.
Shutdown
The MAX9814 features a low-power shutdown mode. When SHDN goes low, the supply current drops to 0.01A, the output enters a high-impedance state, and the bias current to the microphone is switched off. Driving SHDN high enables the amplifier. Do not leave SHDN unconnected.
Input Capacitor
The input AC-coupling capacitor (CIN) and the input resistance (RIN) to the microphone amplifier form a highpass filter that removes any DC bias from an input signal (see the Typical Application Circuit/Functional Diagram). CIN prevents any DC components from the input-signal source from appearing at the amplifier outputs. The -3dB point of the highpass filter, assuming zero source impedance due to the input signal source, is given by: f-3dB_IN = 1 2 x RIN x CIN
Power-Supply Bypassing and PCB Layout
Bypass the power supply with a 0.1F capacitor to ground. Reduce stray capacitance by minimizing trace lengths and place external components as close to the device as possible. Surface-mount components are recommended. In systems where analog and digital grounds are available, connect the MAX9814 to analog ground.
_______________________________________________________________________________________
9
Microphone Amplifier with AGC and Low-Noise Microphone Bias MAX9814
Typical Application Circuit/Functional Diagram
VDD
CBYPASS 1F
SHDN
VDD MICBIAS
MAX9814
BIAS CBIAS 0.47F MICBIAS RMICBIAS 2.21k MICIN CIN 0.1F CT CCT 47nF CG CCG 2.2F GND LNA VGA OUT COUT A/R TH VDD REF AGC GAIN R2 100k R1 150k
ROUT
*THE DEVICE HAS BEEN CONFIGURED WITH AN ATTACK TIME OF 1.1ms, 40dB GAIN, AND AN ATTACK-AND-RELEASE RATIO OF 1:500.
10
______________________________________________________________________________________
Microphone Amplifier with AGC and Low-Noise Microphone Bias
Pin Configurations
MAX9814
MICBIAS
GAIN
BIAS
N.C.
MAX9814 1 2 3 4 14 TH
13
12
11
10
9
A CT B TH C MICBIAS BIAS GAIN MICIN 1 CT 2 SHDN 3 CG 4 N.C. 5 VDD 6 MICOUT 7 GND SHDN A/R GND CG VDD MICOUT
MAX9814 +
UCSP
TDFN
Chip Information
PROCESS: BiCMOS
______________________________________________________________________________________
MICIN 8
TOP VIEW (BUMP SIDE DOWN)
TOP VIEW
A/R
11
Microphone Amplifier with AGC and Low-Noise Microphone Bias MAX9814
Package Information
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information go to www.maxim-ic.com/packages.)
12L, UCSP 4x3.EPS
PACKAGE OUTLINE, 4x3 UCSP 21-0104 F
1 1
12
______________________________________________________________________________________
Microphone Amplifier with AGC and Low-Noise Microphone Bias
Package Information (continued)
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information go to www.maxim-ic.com/packages.) 6, 8, &10L, DFN THIN.EPS ______________________________________________________________________________________ 13
MAX9814
Microphone Amplifier with AGC and Low-Noise Microphone Bias MAX9814
Package Information (continued)
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information go to www.maxim-ic.com/packages.)
COMMON DIMENSIONS SYMBOL A D E A1 L k A2 MIN. 0.70 2.90 2.90 0.00 0.20 MAX. 0.80 3.10 3.10 0.05 0.40
PACKAGE VARIATIONS PKG. CODE T633-2 T833-2 T833-3 T1033-1 T1033-2 T1433-1 T1433-2 N 6 8 8 10 10 14 14 D2 1.500.10 1.500.10 1.500.10 1.500.10 1.500.10 1.700.10 1.700.10 E2 2.300.10 2.300.10 2.300.10 2.300.10 2.300.10 2.300.10 2.300.10 e 0.95 BSC 0.65 BSC 0.65 BSC 0.50 BSC 0.50 BSC 0.40 BSC 0.40 BSC JEDEC SPEC MO229 / WEEA MO229 / WEEC MO229 / WEEC MO229 / WEED-3 MO229 / WEED-3 ------b 0.400.05 0.300.05 0.300.05 0.250.05 0.250.05 0.200.05 0.200.05 [(N/2)-1] x e 1.90 REF 1.95 REF 1.95 REF 2.00 REF 2.00 REF 2.40 REF 2.40 REF
0.25 MIN. 0.20 REF.
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
14 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 (c) 2007 Maxim Integrated Products is a registered trademark of Maxim Integrated Products, Inc.

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