CMAMP110 Microphone Amplifier Features Product Description • • • • • • • • The CMAMP110 Microphone Amplifier selects (via MIC_SELECT) between and amplifies Internal and External Microphone input signals. The device is designed to be compliant with Microsoft PC99 and PC2001 specifications. The CMAMP110 contains the equivalent of 7 operational amplifiers and 19 precision resistors, and is intended for use in PC audio applications. The Internal Microphone input is differential, but it can also be used single-ended by simply grounding one of the inputs through a capacitor. The External Microphone input is single-ended. A logic high level on the MIC_SELECT pin selects the external microphone input. Since the chip supplies the DC bias for the external microphone (EXT_MIC_BIAS), both dynamic and electret type microphones may be used. The output amplifier is unity gain stable and is capable of driving a resistive load in excess of 10KΩ. • • Microsoft PC99 & PC2001 compliant Differential and Single-ended Microphone Inputs Internally frequency compensated for unity gain 20dB DC voltage gain (maximum) Buffered DC bias voltage for external microphone Very low supply current (< 3.0 mA) 20KΩ minimum input impedance Low Total Harmonic Distortion (0.03% at 1 KHz typical) Small MSOP package Lead-free version available Applications • • • • • • Computers Mobile Phones PDA's MP3 Players Digital Cameras Video Tape Recorders The CMAMP110 Microphone Amplifier is housed in a space saving MSOP-8 package and is optionally available with lead-free finishing. Electrical Schematic V+ 500K 4 8 3 EXT_MIC_BIAS RBIAS 500K EXT_MIC_IN 2.5K VREF SW1 500K SW2 5 500K INT_MIC− 6 7 MIC_SELECT VOUT 500K INT_MIC+ 500K 2 V− 1 © 2004 California Micro Devices Corp. All rights reserved. 01/09/04 430 McCarthy Blvd., Milpitas, California 95035▲ Tel: (408) 263-3214 ▲ Fax: (408) 263-7846 ▲ www.calmicro.com 1 CMAMP110 PACKAGE / PINOUT DIAGRAM Top View MIC_SELECT 1 8 EXT_MIC_IN VOUT 2 7 V− EXT_MIC_BIAS 3 6 INT_MIC+ V+ 4 5 INT_MIC− 8-pin MSOP Note: This drawing is not to scale. PIN DESCRIPTIONS PIN NAME 1 MIC_SELECT 2 VOUT 3 EXT_MIC_BIAS 4 V+ 5 INT_MIC− Inverting internal microphone differential input. Can be operated as a single-ended input by connecting a 0.22µF (or greater) capacitor between pin 6 and V−. 6 INT_MIC+ Non-inverting internal microphone differential input. Can be operated as a single-ended input by connecting a 0.22µF (or greater) capacitor between pin 5 and V−. 7 V− 8 EXT_MIC_IN DESCRIPTION Microphone Select logic input control. The external microphone input is selected when the MIC_SELECT signal (pin 1) is at Logic "1" (> 3.5 volts), and the internal microphone inputs are selected by applying Logic "0" to the pin (< 1.5V). Amplifier output pin. External microphone bias output. Positive supply pin. Negative supply pin. External microphone signal input. Ordering Information PART NUMBERING INFORMATION Standard Finish Lead-free Finish Pins Package Ordering Part Number1 Part Marking Ordering Part Number1 Part Marking 8 MSOP-8 CMAMP110M A110 CMAMP110MR R110 Note 1: Parts are shipped in Tape & Reel form unless otherwise specified. © 2004 California Micro Devices Corp. All rights reserved. 2 430 McCarthy Blvd., Milpitas, California 95035 ▲Tel: (408) 263-3214 ▲ Fax: (408) 263-7846 ▲ www.calmicro.com 01/09/04 CMAMP110 Specifications ABSOLUTE MAXIMUM RATINGS(SEE NOTE 1) PARAMETER ESD Protection (HBM, Note 2) Differential Input Voltage Voltage at any Input/Output Pin Storage Temperature Range RATING UNITS +2000 V +/− Supply Voltage V [(V−) - 0.3] to [(V+) + 0.3] V -40 to +150 °C Junction Operating Temperature +125 °C Lead Soldering Temperature (10 seconds) +260 °C 7.5 V Current at Input Pin 5 mA Current at Output Pin (Note 3) 15 mA Current at Power Supply Pin 15 mA Supply Voltage [(V+) - (V−)] Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. For guaranteed specifications and the test conditions, see the Electrical Operating Characteristics. Note 2: Human Body Model, 1.5KΩ in series with 100pF (MIL-STD-883, Method 3015). Note 3: Continuous short circuit operation at elevated ambient temperatures can result in exceeding the maximum allowed junction temperature of 150°C. STANDARD OPERATING CONDITIONS(SEE NOTE 1) PARAMETER RATING UNITS 200 mW Ambient Operating Temperature Range 0 to +70 °C Supply Voltage 3.3 to 5.5 V Maximum Power Dissipation Note 1: Operating conditions indicate ratings for which the device is intended to be functional, but specific performance is not guaranteed. For guaranteed specifications and the test conditions, see the Electrical Operating Characteristics. © 2004 California Micro Devices Corp. All rights reserved. 01/09/04 430 McCarthy Blvd., Milpitas, California 95035▲ Tel: (408) 263-3214 ▲ Fax: (408) 263-7846 ▲ www.calmicro.com 3 CMAMP110 Specifications (cont’d) ELECTRICAL OPERATING CHARACTERISTICS(SEE NOTE 1) SYMBOL PARAMETER CONDITIONS RIN Input Impedance All Inputs AV AC Voltage Gain VIN = 100 mV rms, RL=10KΩ VMIC_IN VOUT VEXT_MIC_BIAS MIN TYP 20 40 18 Microphone Input Signal Level Output Signal Level RL=10KΩ MAX UNITS KΩ 20 dB 110 mV rms 1 V rms External Microphone Bias Voltage No Load ISOURCE = 0.8mA 2.0 4.6 2.6 V V 2.0 2.5 KΩ RBIAS Microphone Bias Resistor GBW Gain Bandwidth Product RL=10KΩ 2.0 MHz Slew Rate RL=10KΩ 1.3 V/µs Total Harmonic Distortion f = 1KHz, VIN = 100mV rms, RL=10KΩ 0.03 % SR T.H.D. VIH MIC_SELECT Logic High Voltage VIL MIC_SELECT Logic Low Voltage tSW Microphone Switching Time ISUP Supply Current ISC Output Short Circuit Current RL Load Impedance Applied to VOUT 3.5 V 1.5 µs 2 1.5 VOUT = 0V V 3.0 15 10 mA mA KΩ Note 1: All tests at 25°C, V+ = +5V, V- = 0V unless otherwise noted. © 2004 California Micro Devices Corp. All rights reserved. 4 430 McCarthy Blvd., Milpitas, California 95035 ▲Tel: (408) 263-3214 ▲ Fax: (408) 263-7846 ▲ www.calmicro.com 01/09/04 CMAMP110 Application Information CMAMP110 Design Considerations 1. General Overview The CMAMP110 is very straightforward to apply, but a few precautions are worth noting. It is recommended that the power supply pin, V+ (pin 4), be bypassed with a parallel combination of a 4.7µF and a 0.1µF capacitor to minimize noise and hum pickup. In addition, a 100Ω resistor may be inserted in series to form a RC filter between the the power supply feed and the V+ pin to the CMAMP110. Also, in that regard, lead dress for the microphone inputs on the PCB should either be shielded from or spaced from noise sources. The V− input on the device (pin 7) should be connected to the “clean analog ground”. 2. Passive Component Selection Selection of the microphone input coupling capacitors can be made using the following equation: 1 C = ----------------------------------2π ⋅ R IN ⋅ f MIN Where: RIN = Microphone Input Impedance (40KΩ typical) ƒMIN = Minimum Input Frequency For example, for ƒMIN = 20Hz, C should be selected for 0.22µF (or greater). The above equation may also be used to select the output coupling capacitor. Where: VBMIC = 4.6 volts RBIAS = 2.5 KΩ VB = Desired Microphone Bias Voltage IB = Microphone Bias Current For example, an electret condenser microphone that operates on 1.5V and 0.5mA, REXT should be selected to be 3.9KΩ (nearest standard value). 4. Microphone Select The CMAMP110 has provisions for the selection of either the internal microphone and external microphone inputs. The external microphone is selected when the MIC_SELECT signal (pin 1) is at Logic "1" (> 3.5 volts), and the internal microphone is selected by applying Logic "0" to the pin (< 1.5V). The switching time is approximately 2 ms. For static applications where only one input is used, pin 1 can simply be strapped to either V− or V+. 5. Internal Microphone The CMAMP110 provides for a differential (floating) input for the Internal microphone where INT_MIC+ (pin 6) is the “non-inverting” input and INT_MIC− (pin 5) is the “inverting” input. The CMAMP110 may be operated single-ended by connecting a 0.22µF (or greater) capacitor between either pin 5 or pin 6 and V−. 6. Start Up 3. Microphone Bias The CMAMP110 provides a nominal 4.6 volt stable reference and 2.5KΩ resistor to bias the microphone. For a bias current of 800µA, a 2.6 volt bias voltage results. However, if other voltages are desired, a resistor can be inserted in series with the microphone bias output (pin 3) whose value, REXT , can be chosen using the following equation: Application of the CMAMP110 requires AC coupling the inputs and outputs (see Passive Component Selection). Both the Internal Microphone inputs (INT_MIC+ and INT_MIC−) and the External Microphone input (EXT_MIC_IN) are DC biased at half the supply voltage with an equivalent impedance of about 500KΩ. As a result, a start up transient will occur as the capacitors charge to half of the rail. The time for the amplifier inputs and outputs to settle is given by: VBMIC – ( I B ⋅ R BIAS ) – V B R EXT = -------------------------------------------------------------IB © 2004 California Micro Devices Corp. All rights reserved. 01/09/04 430 McCarthy Blvd., Milpitas, California 95035▲ Tel: (408) 263-3214 ▲ Fax: (408) 263-7846 ▲ www.calmicro.com 5 CMAMP110 Application Information (cont’d) 7. Evaluation Board An evaluation board, part number CMAMP110-20EV, is available to facilitate easy and rapid checkout of the CMAMP110. The board is about the size of a business card, and samples of it may obtained by calling the factory at (800) 325-4966 or (408) 263-3214 or from your local representative. Ask the operator to be connected to Applications Engineering. Otherwise, you may request samples on our website at www.calmicro.com by navigating to the ’Contact Us’ page, click on the ’Literature & Samples Request’ button and request the above part number. V SUP t = RC IN ⋅ ln ------------------- = 0.69RC IN VSUP ⁄ 2 For an input capacitance of 0.22µF, the turn on transient is about 76ms. V+ 4.7µF 0.1µF 4 V+ 3 EXT MIC INPUT 8 0.22µF EXT_MIC_BIAS VOUT EXT_MIC_IN 2 0.22µF CMAMP110 CODEC 1 MIC_SELECT 6 INT_MIC+ 0.22µF 5 MIC_SELECT INT_MIC+ INT_MICV− 0.22µF 7 Figure 1. CMAMP110 Typical Application Circuit (single-ended input configuration shown for differential INT_MIC inputs). © 2004 California Micro Devices Corp. All rights reserved. 6 430 McCarthy Blvd., Milpitas, California 95035 ▲Tel: (408) 263-3214 ▲ Fax: (408) 263-7846 ▲ www.calmicro.com 01/09/04 CMAMP110 Mechanical Details MSOP Mechanical Specifications: CMAMP110 devices are packaged in 8-pin MSOP packages. Dimensions are presented below. Mechanical Package Diagrams TOP VIEW For complete information on the MSOP-8 package, see the California Micro Devices MSOP Package Information document. D 8 7 6 5 PACKAGE DIMENSIONS Package Pins Dimensions Pin 1 Marking 8 Millimeters Inches Min Max Min Max A 0.87 1.17 0.034 0.046 A1 0.05 0.25 0.002 0.010 B 0.30 (typ) 0.012 (typ) C 0.18 0.007 D E e E H MSOP 2.90 2.90 3.10 3.10 0.114 0.114 0.65 BSC 1 4.78 4.98 0.188 0.196 L 0.52 0.54 0.017 0.025 # per tube 80 pieces* # per tape and reel 4000 pieces 4 A SEATING PLANE A1 B 0.025 BSC H 3 SIDE VIEW 0.122 0.122 2 e END VIEW C Controlling dimension: inches L * This is an approximate number which may vary. Package Dimensions for MSOP-8 © 2004 California Micro Devices Corp. All rights reserved. 01/09/04 430 McCarthy Blvd., Milpitas, California 95035▲ Tel: (408) 263-3214 ▲ Fax: (408) 263-7846 ▲ www.calmicro.com 7