19-2515; Rev 0; 7/02 Electret Condenser Microphone Cartridge Preamplifier Features ♦ Replaces FET in Electret Condenser Microphone ♦ 2.3V to 5.5V Single-Supply Operation ♦ Low-Impedance Output (<0.4Ω) ♦ High PSRR: 82dB ♦ Three High-Gain Options: MAX9810A: 24dB MAX9810B: 27dB MAX9810C: 30dB ♦ Internal Bias Voltage ♦ Low Supply Current (670µA) ♦ Rail-to-Rail® Output ♦ No Output Phase Reversal During Overload Conditions ♦ Available in a Tiny 4-Bump UCSP Ordering Information PART TEMP RANGE BUMPPACKAGE TOP MARK MAX9810AEBS-T -40oC to +85oC 4 UCSP-4 AFS MAX9810BEBS-T -40oC to +85oC 4 UCSP-4 AFT 4 UCSP-4 AFU Applications Electret Condenser Microphone Cartridges In: Cell Phones Notebooks PDAs Portable Audio MAX9810CEBS-T o -40 C to +85 C Selector Guide BUMP-PACKAGE GAIN (dB) MAX9810AEBS-T 4 UCSP-4 24 MAX9810BEBS-T 4 UCSP-4 27 MAX9810CEBS-T 4 UCSP-4 30 PART Functional Diagram/ Typical Application Circuit o POWER Pin Configuration VDD ELECTRET MIC MAX9810 OUTPUT TOP VIEW (BUMP SIDE DOWN) 1 2 VDD OUT A GND MAX9810 GND B ECM CARTRIDGE Rail-to-Rail is a registered trademark of Nippon Motorola Ltd. IN GND UCSP USCP is a trademark of Maxim Integrated Products, Inc. ________________________________________________________________ Maxim Integrated Products 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. 1 MAX9810 General Description The MAX9810 microphone preamplifier is intended for use inside electret condenser microphone (ECM) cartridges. Current solutions use a FET as an impedance converter. FETs have limited gain, are susceptible to noise and require additional components external to the ECM cartridge for biasing and amplification. The MAX9810 replaces the FET with a high-gain, high-noise rejection, low-output-impedance amplifier. Designed to be integrated inside the ECM cartridge, the MAX9810 offers a flat frequency response, tightly controlled gain, increased sensitivity, and high-noise rejection greatly simplifying system design. Target applications include ECM cartridges in cell phones, PDAs, notebooks, and other portable audio devices. The MAX9810 operates from a single 2.3V to 5.5V supply and consumes only 670µA of quiescent current. The device features an internally generated 1.5V DC bias, and is available in three internally fixed gain options (24dB, 27dB, and 30dB). The MAX9810 is specified over the extended temperature range (-40°C to +85°C) and comes in a tiny 4-bump chip-scale package (UCSP™) that is designed to fit inside the ECM cartridge. MAX9810 Electret Condenser Microphone Cartridge Preamplifier ABSOLUTE MAXIMUM RATINGS VDD to GND ..............................................................-0.3V to +6V All Other Pins to GND.................................-0.3V to (VDD + 0.3V) Continuous Current (IN, OUT) ..........................................±20mA Output Short-Circuit Duration (to GND or VDD)..........Continuous Continuous Power Dissipation (TA = +70°C) 4-Bump UCSP (derate 3.0mW°C above +70°C) .......238.8mW Operating Temperature Range ...........................-40°C to +85°C Junction Temperature ......................................................+150°C Storage Temperature Range .............................-65°C to +150°C Bump Temperature (soldering) (Note 1) Infrared (15s) ................................................................+220°C Vapor Phase (60s) ........................................................+215°C Note 1: This device is constructed using a unique set of packaging techniques that impose a limit on the thermal profile the device can be exposed to during board level solder attach and rework. This limit permits only the use of the solder profiles recommended in the industry standard specification, JEDEC 020A, paragraph 7.6, Table 3 for IR/VPR and convection reflow. Preheating is required. Hand or wave soldering is not allowed. 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. DC ELECTRICAL CHARACTERISTICS (VDD = 3V, GND = 0, RL = ∞, VIN = 0, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) (Note 2) PARAMETER SYMBOL CONDITIONS Supply Voltage Range VDD Inferred from PSRR test Quiescent Supply Current IDD 2.3V ≤ VDD ≤ 5.5V Output Bias Voltage Input Bias Current Input Resistance Power-Supply Rejection Ratio Output Voltage Swing High VBIAS IBIAS VOL Output Short-Circuit Current ISCC Voltage Gain 2 AV MAX UNITS 5.5 V 670 950 µA 1.3 1.48 1.7 MAX9810B 1.3 1.53 1.7 MAX9810C 1.3 1.58 1.8 5 100 0.025 5 GΩ 70 86 dB RL = 10kΩ connected to 1.5V VDD 0.04 VDD 0.015 RL = 1kΩ connected to 1.5V VDD 0.15 VDD 0.07 (Note 3) 2.3V < VDD < 5.5V (Note 4) VOH Output Voltage Swing Low TYP 2.3 MAX9810A RIN PSRR MIN V pA V RL = 10kΩ connected to 1.5V 0.005 0.015 RL = 1kΩ connected to 1.5V 0.045 0.08 VDD = 5V 12 VDD = 2.3V 10 VIN = ±20mV mA MAX9810A 23 24 25 MAX9810B 26 27 28 MAX9810C 29 30 31 _______________________________________________________________________________________ V dB Electret Condenser Microphone Cartridge Preamplifier (VDD = 3V, GND = 0, RL = 10kΩ connected to 1.5V, CL = 20pF, CIN = 30pF connected to GND, VIN = 0, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER Small-Signal -3dB Bandwidth SYMBOL CONDITIONS MIN TYP MAX UNITS BWSS VOUT = 10mVP-P 900 kHz Slew Rate SR VOUT = 1V step 0.03 V/µs Settling Time to 0.1% ts VOUT = 1V step 1 µs Input-Noise Voltage Density en RS = 0 (Note 5) Input-Noise Current Density in Total Integrated Noise 10Hz 60 1kHz 16 10kHz 15 nV/√Hz 10Hz 5 1kHz 1 10kHz 1 Noise bandwidth = 20Hz to 7kHz 4 µVRMS pA/√Hz Signal-to-Noise Ratio SNR VOUT = 2VP-P, noise bandwidth = 20Hz to 7kHz 90 dB Output Impedance ZOUT fIN = 1kHz 0.4 Ω Power-Supply Rejection Ratio PSRR VDD = 3V, VRIPPLE = 100mV, fRIPPLE = 1kHz 82 dB 1GHz—carrier, 1kHz—AM tone 82 dB 0.02 % RF Noise Immunity Total Harmonic Distortion Plus Noise THD + N fIN = 1kHz, VOUT = 1VP-P, noise bandwidth = 22Hz to 22kHz Input Capacitance CIN 3 pF Turn-On Time tON 10 µs Note 2: Note 3: Note 4: Note 5: All specifications are 100% tested at TA = +25°C, temperature limits are guaranteed by design. Guaranteed by design. Not production tested. PSRR is input-referred. Noise measurement includes the noise contribution of the internal gain-setting resistors. _______________________________________________________________________________________ 3 MAX9810 AC ELECTRICAL CHARACTERISTICS Electret Condenser Microphone Cartridge Preamplifier MAX9810 Typical Operating Characteristics (VDD = 3V, GND = 0, RL = 10kΩ connected to 1.5V, CL = 20pF, CIN = 30pF connected to GND, VIN = 0, TA = +25°C, unless otherwise noted.) POWER-SUPPLY REJECTION RATIO vs. FREQUENCY 80 80 PSRR (dB) 70 PSRR (dB) 60 50 80 70 70 60 60 50 40 40 90 PSRR (dB) 90 MAX9810 toc02 90 MAX9810 toc01 100 POWER-SUPPLY REJECTION RATIO vs. FREQUENCY MAX9810 toc03 POWER-SUPPLY REJECTION RATIO vs. FREQUENCY 50 40 30 30 30 20 VDD = 5V VRIPPLE = 100mVP-P 10 20 VDD = 3V VRIPPLE = 100mVP-P 10 0 0 100 1k 10k 100k 0 10 1M 100 1k 10k 100k 10 100 1k 10k 100k FREQUENCY (Hz) FREQUENCY (Hz) FREQUENCY (Hz) MAX9810A GAIN AND PHASE vs. FREQUENCY INPUT-NOISE VOLTAGE vs. FREQUENCY INPUT-NOISE VOLTAGE vs. FREQUENCY 180 1000 GAIN 60 20 PHASE 0 0 -60 -20 PHASE (DEGREES) 120 40 -120 -40 INPUT-NOISE VOLTAGE (nV/√Hz) VDD = 5V 100 1000 VDD = 3V INPUT-NOISE VOLTAGE (nV/√Hz) MAX9810 toc04 60 GAIN (dB) 1M MAX9810 toc05 10 VDD = 2.3V VRIPPLE = 100mVP-P 10 1M MAX9810 toc06 20 100 RL = 10kΩ -60 100 1k 10k 100k 1M -180 10M 10 10 100 1k 10k 100k 10 100 1k 10k FREQUENCY (Hz) INPUT-NOISE CURRENT vs. FREQUENCY INPUT-NOISE CURRENT vs. FREQUENCY SIGNAL-TO-NOISE RATIO vs. SUPPLY VOLTAGE 100 MAX9810 toc08 VDD = 3V A-WEIGHTED FILTER 1kHz TONE 95 90 SNR (dB) 10 100 INPUT-NOISE CURRENT (pA/√Hz) VDD = 5V 100k MAX9810 toc09 FREQUENCY (Hz) 100 INPUT-NOISE CURRENT (pA/√Hz) 10 FREQUENCY (Hz) MAX9810 toc07 10 10 85 80 75 1 1 10 100 1k FREQUENCY (Hz) 4 10k 100k 70 10 100 1k FREQUENCY (Hz) 10k 100k 2 3 4 SUPPLY VOLTAGE (V) _______________________________________________________________________________________ 5 6 Electret Condenser Microphone Cartridge Preamplifier 1kHz REJECTION vs. SWEPT AC SIGNAL ON POWER SUPPLY 50 40 30 NO BYPASS CAPACITOR VDD = 2.3V -0.20 VDD = 3V -0.25 -0.30 600 700 800 900 MAX9810 toc12 0.25 VDD = 2.3V 0.20 0.15 VDD = 3V 0.10 -0.35 0.05 0 -0.45 1000 0.1k 1k 10k 100k 1M 0.1k 10M 1k 10k 100k 1M 10M CARRIER FREQUENCY (MHz) LOAD (Ω) LOAD (Ω) OUTPUT IMPEDANCE vs. FREQUENCY TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY 0.1 VDD = 3V VIN = 20mVRMS 22Hz TO 22kHz BANDWIDTH THD + N (%) THD + N (%) 10 VDD = 5V VIN = 35mVRMS 22Hz TO 22kHz BANDWIDTH 0.01 MAX9810 toc15 0.1 MAX9810 toc13 100 MAX9810 toc14 500 0.01 1 0.001 0.1 10 100 1k 10k 100k 1M 0.001 10 100 1k 10k 100k 10 100 1k 10k 100k FREQUENCY (Hz) FREQUENCY (Hz) FREQUENCY (Hz) TOTAL HARMONIC DISTORTION PLUS NOISE vs. OUTPUT VOLTAGE TOTAL HARMONIC DISTORTION PLUS NOISE vs. OUTPUT VOLTAGE TOTAL HARMONIC DISTORTION PLUS NOISE vs. OUTPUT VOLTAGE THD + N (%) 10 VDD = 3V fIN = 1kHz 1 0.1 10 1 VDD = 2.3V fIN = 1kHz THD + N (%) VDD = 5V fIN = 1kHz 0.1 MAX9810 toc18 10 MAX9810 toc16 100 MAX9810 toc17 OUTPUT IMPEDANCE (Ω) -0.15 0.30 -0.40 10 0 THD + N (%) -0.10 0.35 OUTPUT VOLTAGE LOW (V) 60 20 -0.05 OUTPUT VOLTAGE HIGH (V) 1nF BYPASS CAPACITOR 70 MAX9810 toc11 0.1µF BYPASS CAPACITOR 80 OUTPUT VOLTAGE LOW vs. LOAD OUTPUT VOLTAGE HIGH vs. LOAD 0 MAX9810 toc10 1kHz AM-SIGNAL REJECTION RATIO (dB) 90 1 0.1 0.01 0.01 0.001 0 0.25 0.50 0.75 1.00 OUTPUT VOLTAGE (VRMS) 1.25 1.50 0.01 0 0.2 0.4 0.6 0.8 OUTPUT VOLTAGE (VRMS) 1.0 1.2 0 0.2 0.4 0.6 0.8 OUTPUT VOLTAGE (VRMS) _______________________________________________________________________________________ 5 MAX9810 Typical Operating Characteristics (continued) (VDD = 3V, GND = 0, RL = 10kΩ connected to 1.5V, CL = 20pF, CIN = 30pF connected to GND, VIN = 0, TA = +25°C, unless otherwise noted.) Typical Operating Characteristics (continued) (VDD = 3V, GND = 0, RL = 10kΩ connected to 1.5V, CL = 20pF, CIN = 30pF connected to GND, VIN = 0, TA = +25°C, unless otherwise noted.) SUPPLY CURRENT vs. TEMPERATURE 675 MAX9810B 670 665 MAX9810A 690 685 680 675 MAX9810B 670 MAX9810A 665 660 1.600 MAX9810 toc21 MAX9810C 695 SUPPLY CURRENT (µA) 680 700 MAX9810 toc20 MAX9810C SUPPLY CURRENT (µA) 705 MAX9810 toc19 685 OUTPUT BIAS VOLTAGE vs. SUPPLY VOLTAGE MAX9810C 1.575 OUTPUT BIAS VOLTAGE (V) SUPPLY CURRENT vs. SUPPLY VOLTAGE 1.550 MAX9810B 1.525 1.500 MAX9810A 1.475 660 655 655 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 1.450 -50 6.0 -25 0 25 50 75 100 2 TEMPERATURE (°C) SUPPLY VOLTAGE (V) OUTPUT BIAS VOLTAGE vs. TEMPERATURE 3 4 SMALL-SIGNAL PULSE RESPONSE AT 10kHz MAX9810C 1.55 MAX9810B 1.50 MAX9810A MAX9810 toc22 1.60 1.45 -15 10 35 60 MAX9810 toc24 INPUT 2.5mV/div INPUT 25mV/div OUTPUT 100mV/div OUTPUT 1V/div 85 10µs/div 10µs/div TEMPERATURE (°C) DRIVING MAXIMUM CAPACITIVE LOAD WAVEFORM POWER-UP WAVEFORM MAX9810 toc25 MAX9810 toc26 CL = 150pF VDD 1V/div OUTPUT 100mV/div OUTPUT 500mV/div INPUT 10mV/div 5µs/div 6 6 LARGE-SIGNAL PULSE RESPONSE AT 10kHz 1.40 -40 5 SUPPLY VOLTAGE (V) MAX9810 toc23 1.65 OUTPUT BIAS VOLTAGE (V) MAX9810 Electret Condenser Microphone Cartridge Preamplifier 10µs/div _______________________________________________________________________________________ Electret Condenser Microphone Cartridge Preamplifier BUMP NAME A1 VDD A2 OUT B1 IN B2 GND DESCRIPTION Amplifier Power Supply Amplifier Output Amplifier Input Ground Detailed Description The MAX9810 replaces the FET commonly used in ECMs with a high-gain, low-noise, low-output-impedance amplifier, offering improved performance over the traditional FET solution. The MAX9810 features high PSRR (82dB at 1kHz), and is available in three gain options (24dB, 27dB, and 30dB). ECMs with FET impedance converters require additional amplification (Figure 1). The high gain of the MAX9810 eliminates the need for an external preamplifier, allowing the ECM cartridge to be directly connected to front-end devices such as CODECs or ADCs (Figure 2). The MAX9810 also features excellent RF immunity (see the RF Noise Rejection section). Rail-to-Rail Output When operated from a 3V supply, the internal 1.5V DC bias point provides symmetrical, rail-to-rail operation where the output can swing to within 15mV of either rail into a 10kΩ load. The 1.5V bias point is independent of supply, so when operated from supplies other than 3V, the MAX9810 output can run out of headroom on one of the supplies (Figure 3). This limits the peak-to-peak output to approximately: VOUT(P-P) = 3V for VDD > 3V VOUT(P-P) = VDD for VDD < 3V The MAX9810 shows no phase reversal when the device is overdriven. If the device output is driven into clipping, the overload behavior is predictable. Applications Information RF Noise Rejection The MAX9810 features excellent RF rejection at common cellular-phone operating frequencies. Figure 4 shows the modulation products of a high-frequency signal coupling into the device power supply, while the device is driven with a 1kHz input. At 1GHz, the MAX9810 exhibits 82dB of rejection. Supply Bypassing Unlike FETs, the MAX9810 requires a separate power source (Figures 1 and 2). VDD must be connected to a 2.3V to 5.5V power supply external to the ECM cartridge, thus the MAX9810 ECM solution requires three electrical connections instead of the two commonly found in current FET solutions. For optimum performance, bypass the MAX9810 as close to the device as possible (inside the cartridge). This yields the best RF rejection and PSRR and is ideal for applications such as cell phones where high-frequency noise is present. The device operates properly if the bypass capacitor is placed on the circuit board outside the cartridge; however, RF rejection is slightly degraded in this configuration (Figure 4). This is well suited for applications where there is less high-frequency interference such as PDAs and notebook computers. UCSP Layout For land pattern and suggested layout of the 4-bump UCSP, see the JEDEC website at www.ipc.org/html/ framesetcatseg.html. _______________________________________________________________________________________ 7 MAX9810 Pin Description MAX9810 Electret Condenser Microphone Cartridge Preamplifier +VS FET IMPEDANCE CONVERTER POWER EXTERNAL PREAMPLIFIER VDD MAX9810 OUTPUT ELECTRET MIC OUTPUT 1.5V BIAS ELECTRET MIC GND GND GND ECM CARTRIDGE ECM CARTRIDGE Figure 2. MAX9810 ECM Figure 1. Conventional FET ECM VDD = 3V 1kHz REJECTION vs. SWEPT AC SIGNAL ON POWER SUPPLY 90 GND NO CLIPPING, SYMMETRICAL RAIL-TO-RAIL OPERATION VDD = 5V 1.5V 1kHz AM-SIGNAL REJECTION RATIO (dB) 1.5V 80 70 0.1µF BYPASS CAPACITOR 1nF BYPASS CAPACITOR 60 50 40 30 20 NO BYPASS CAPACITOR 10 0 500 550 600 650 700 750 800 850 900 950 1000 CARRIER FREQUENCY (MHz) GND OUTPUT SIGNAL CLIPS ON THE NEGATIVE RAIL FIRST VDD = 2.3V Figure 4. MAX9810 RF Rejection 1.5V Chip Information GND OUTPUT CLIPS ON THE POSITIVE RAIL FIRST TRANSISTOR COUNT: 427 PROCESS: BiCMOS Figure 3. Rail-to-Rail Waveforms 8 _______________________________________________________________________________________ Electret Condenser Microphone Cartridge Preamplifier 4L, UCSP 2x2.EPS 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. Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 _____________________ 9 © 2002 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products. MAX9810 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.)