Evaluates: MAX9814 19-0760 Rev 0 4/07 MAX9814 Evaluation Kit General Description Features The MAX9814 evaluation kit (EV kit) is a fully assembled 2.7V to 5.5V Single-Supply Operation and tested PCB that is used to evaluate the single- 20dB of Dynamic Gain Compression supply MAX9814 low-noise microphone amplifier IC. The MAX9814 IC contains a low-noise amplifier, an out- Selectable Gain Control put amplifier, a microphone bias-voltage generator, and Programmable Attack Time automatic gain-control (AGC) internal circuitry. The overall gain of the microphone amplifier is selectable to Selectable Attack/Release Ratio 40dB, 50dB, or 60dB without compression. The Low-Power Shutdown Mode MAX9814 incorporates compressor/limiter circuitry that limits the microphone output to a set voltage. Fully Assembled and Tested The MAX9814 EV kit operates over a 2.7V to 5.5V range. The EV kit also features low quiescent current, Ordering Information and shutdown control to minimize power consumption. The MAX9814 IC is available in a 14-pin TDFN (3mm x PART TEMP RANGE IC PACKAGE 3mm x 0.8mm) exposed paddle package. MAX9814EVKIT+ 0C to +70C* 14 TDFN-EP** + Denotes a lead-free and RoHS-compliant EV kit. *EV kit PCB temperature range only. **EP = exposed paddle. Component List DESIGNATION QTY DESCRIPTION DESIGNATION QTY DESCRIPTION Nonswitched PC-mount RCA jack, 0.22F 10%, 6.3V X5R ceramic J1 1 black capacitor (0402) C1 1 TDK C1005X5R0J224K Nonswitched PC-mount RCA jack, J2 1 red 0.1F 10%, 10V X5R ceramic C2, C7, C9 3 capacitors (0402) JU1, JU2, JU3 3 3-pin headers TDK C1005X5R1A104K JU4, JU5, JU6 3 2-pin headers R1 1 150k 1% resistor (0402) 0.047F 10%, 25V X7R ceramic C3 1 capacitor (0402) R2 1 100k 1% resistor (0402) TDK C1005X7R1E223K R3 1 2.21k 1% resistor (0402) U1 1 MAX9814ETD+ (14-pin TDFN) 0.022F 10%, 25V X7R ceramic C4 1 capacitor (0402) 6 Shunts (JU1JU6) TDK C1005X7R1E223K 1 PCB: MAX9814 Evaluation Kit 2.2F 10%, 6.3V X5R ceramic C5 1 capacitor (0603) TDK C1608X5R0J225K Component Supplier SUPPLIER PHONE WEBSITE 1F 10%, 6.3V X5R ceramic capacitor (0603) C6 1 TDK Corp. 847-803-6100 www.component.tdk.com TDK C1608X5R1A105KB Note: Indicate that you are using the MAX9814 when contacting this component supplier. 0.47F 10%, 6.3V X5R ceramic C8 1 capacitor (0402) TDK C1005X5R0J474K Maxim Integrated Products 1 For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct at 1-888-629-4642, or visit Maxims website at www.maxim-ic.com.MAX9814 Evaluation Kit Quick Start Detailed Description The MAX9814 EV kit is used to evaluate the MAX9814 Recommended Equipment low-noise microphone amplifier IC, which is designed 5V 200mA power supply for single-supply applications. The power supply must Function generator provide a minimum 200mA to the MAX9814 EV kit, Digital multimeter (DMM) which has an operating range of 2.7V to 5.5V. The MAX9814 IC contains a low-noise amplifier, a vari- Oscilloscope able gain amplifier (VGA) with automatic gain control, Procedure an output amplifier, and a microphone bias-voltage The MAX9814 EV kit is fully assembled and tested. generator. The low-noise preamplifier gain is fixed to a Follow the steps listed below to verify board operation. 12dB gain, while the VGA has a dynamic gain from 0dB Caution: Do not turn on the power supply until all to 20dB and the output amplifier has gains of 8dB, connections are completed: 18dB, and 28dB. Without compression, the sum of all of the gain blocks result in an overall gain of 40dB, 50dB, 1) Verify that shunts are installed across pins 1-2 of or 60dB. The MAX9814 IC incorporates attack-/hold- jumpers JU1 (MAX9814 enabled), JU2 (gain = and-release timing circuitry that limits the MICOUT pin 40dB), and JU3 (attack/release ratio = 1:2000). to a set voltage. 2) Verify that a shunt is not installed across jumpers The MAX9814 compression circuitry monitors MICOUT JU4, JU5, JU6 (attack time 53s). and limits the peak voltage to TH. Gain compression is 3) Set the power supply to 5V. realized by the VGA, which automatically adjusts its 4) Set the function generators output for a sine wave gain to keep the output voltage peak equal to the set with 10mV , 1kHz frequency, and 0V offset. P-P threshold. The VGA has 20dB of dynamic gain, which results in a maximum gain compression of 20dB. The 5) Turn off the power supply and function generator. amplifier overall gain, with the AGC disabled, can be 6) Connect channel 1 of the oscilloscope to the set to 40dB, 50dB, or 60dB using jumper JU2. With the MIC IN pad and channel 2 of the oscilloscope to AGC on and the output voltage fully compressed, the the MIC OUT pad. Connect the ground leads of the overall gain will be 20dB, 30dB, or 40dB. oscilloscope to the respective SGND pads. The amplifiers output is compressed when the peak 7) Connect the 5V terminal of the power supply to the voltage amplitude at MICOUT exceeds the voltage set VCC pad and the ground terminal of the power sup- at TH. The MAX9814 EV kit compression threshold is ply to the GND pad. preset at 800mV. A custom threshold voltage can be 8) Connect the positive output of the function genera- programmed using resistors R1 and R2, and the 2V tor to the MIC IN pad on the EV kit and the ground microphone bias output MICBIAS. Removing resistor lead of the function generator to the SGND IN pad. R1 and applying a voltage source at the TH pad can also externally control the MICOUT threshold. 9) Connect the positive terminal of the digital multime- ter to the TH pad and the ground terminal to the The input signal can either be applied to the RCA jack GND pad. J2, or a microphone can be connected between the MIC IN and SGND IN pads. The 2V microphone bias 10) Turn on the power supply. MICBIAS is connected to the MIC IN node via R3. 11) Verify that the TH voltage is approximately 800mV. The MAX9814 attack time and attack/release ratio are 12) Turn on the function generator. set through jumpers JU3JU6. 13) Using the oscilloscope, verify that the signal at the Jumper Selection MIC OUT pad is 1V . P-P Shutdown 14) Increase the function generator to 50mV . P-P Jumper JU1 controls the shutdown mode of the 15) Verify that MIC OUT amplitude is 1.6V . P-P MAX9814 EV kit . The shutdown function can be activat- ed on the EV kit by installing a shunt across pins 2-3. The shutdown function can also be controlled by 2 Evaluates: MAX9814