AMIS-14935

AMIS-14935 Audio Amplifier Description T he AMIS-14935 (former MSC-LX1792) offers a patent pending, low-voltage, low-power and high efficiency amplifier for driving a high impedance speaker such as a hearing aid receiver or a headset. The AMIS-14935 consists of a pre-amplifier followed by a fixed gain class D amplifier. The input resistor and feedback resistor is external in the AMIS-14935 making it possible to set the gain arbitrarily, up to approximately 40dB. The feedback resistor can also be potentiometer to facilitate volume control. Key Features • Low Operating Current: 120µA Typical • Low Operating Voltage: 0.9V minimum • Gain Set by External Resistors • 3 output switch resistance settings: 48, 24 & 16Ω • 5µVrms Input Referred Noise Applications • Hearing aid applications • High impedance speaker/transducer applications Important: For the most current data, consult AMI Semiconductor’s website: http://www.amis.com. Product Highlight Package Order Info TJ (°C): 1 0…15 J: Ceramic Dip 14-Pin NQFP: Plastic MLPM 8-Pin BD: Bare Die Note for hearing aid applications are covered by Knowles patents numbers US 4,592,087 & 4,689,819: AMI Semiconductor policy is not to sell the AMIS-14935 into hearing aid applications unless a patent license exist between customer and Knowles Corporation. Please contact AMIS for assistance with this. AMI Semiconductor www.amis.com 1 AMIS-14935 Audio Amplifier Absolute Maxium Ratings Input Logic Supply Voltage (VDD) Operating Temperature Range -0.3V to +3.0V 10°C to 55°C Note: Exceeding these ratings could cause damage to the device. All voltages are with respect to Ground. Currents are positive into, negative out of specified terminal. Package Pin Out PACKAGE (Top View) PACKAGE (Top View) Settings Pin IMPSEL IMPSEL=VSS 16Ω IMPSEL=VDD 24Ω IMPSEL=Floating 48Ω Functional Pin Description Pin Name Pin No 14 Pin J (Evaluation Samples) 13 2 8 14 1 9 6 Pin No 8 Pin Description VDD VSS IN OUTP OUTN PREOUT IMPSEL 8 1 5 7 2 6 3 Supply Voltage Ground Analog Audio Input Positive Output Voltage Negative Output Voltage Pre-Amplifier Output Output Resistance Select. See Settings table below for selections. AMI Semiconductor www.amis.com 2 AMIS-14935 Audio Amplifier Recommended Operating Conditions Parameter OPERATING CONDITIONS Supply Voltage Ground Symbol VDD VSS Test Conditions Min 0.9 0 AMIS-14935 Typ Max 1.5 Units V V Electrical Characteristics Unless otherwise specified, the following specifications apply over the operating ambient temperature TA=25°C except where otherwise noted. Test conditions: VDD=1.3V, Parameter Switch Output Resistance @ Low Drive Switch Output Resistance @ Med Drive Switch Output Resistance @ High Drive Quiescent Current @ Low Drive Quiescent Current @ Med Drive Quiescent Current @ High Drive 3dB Bandwidth – Min Frequency 3dB Bandwidth – Max Frequency Output Switching Frequency Gain1 Power Supply Rejection Ratio Total Harmonic Distortion Symbol ROUT-L ROUT-M ROUT-HI IDDQL IDDQM IDDQH FMIN FMAX FCLK A1 PSRR THD1 R1=50k, R2=500k R1=25k, R2=500k Input Reference R1=50k, R2=500k R1=50k, R2=500k, Vin=5mVrms, Fin=1kHz R1=25k, R2=500k, Vin=5mVrms, Fin=1kHz R1=50k, R2=500k, 100Hz-10kHz, No weighting R1=25k, R2=500k, 100Hz-10kHz, No weighting 140 No input signal 0 R1=50k, R2=1000k, Fin=1kHz 10 200 32 37 45 0.3 0.5 4 µVrms 3 200 0.5 300 5 kHz mV kHz kHz dB dB % No load Test Conditions VSS=0V, Circuit connected as application schematic on page 5, Output loaded with 200Ohm in series with 60mH. AMIS-14935 Min Typ 48 24 16 110 120 130 40 Max Units Ω 19 µA 100 Hz Input Referred Noise Output Clock Frequency Max Absolute DC Offset OutN-OutP VN-20 FCLK VOFF-NP AMI Semiconductor www.amis.com 3 AMIS-14935 Audio Amplifier Charts Note: Graphs show distortion with no load outputs. AMI Semiconductor www.amis.com 4 AMIS-14935 Audio Amplifier Figure 2 – H-Bridge Impedance vs. Supply Voltage (Lowest Impedance Setting). AMI Semiconductor www.amis.com 5 AMIS-14935 Audio Amplifier Mechanicals - 8 Pin MLPQ Package Outline LM 8-Pin Plastic MLP-Micro Exposed Pad Dim A B C D E F G H I J K Millimeters Min Max 2.90 3.10 2.90 3.10 0.65 0.75 0.15 0.25 1.841 BSC 0.27 0.43 0.65 BSC 1.22 BSC 0 0.10 0.21 0.37 0 0.10 Inches Min Max 0.114 0.122 0.114 0.122 0.025 0.029 0.005 0.009 0.075 BSC 0.010 0.016 0.025 BSC 0.048 BSC 0 0.003 0.008 0.014 0 0.003 J 14-Pin Ceramic Dip Dim A B C D F G H J K L M Millimeters Min Max 19.30 19.94 5.59 7.11 5.08 0.38 0.51 1.02 1.77 2.54 BSC 2.03 0.20 0.38 3.18 5.08 7.37 7.87 15° Inches Min Max 0.760 0.785 0.220 0.280 0.200 0.015 0.020 0.040 0.070 0.100 BSC 0.080 0.008 0.015 0.125 0.200 0.290 0.310 15° Note: 1. Dimensions do not include mold flash or protrusions; these shall not exceed 0.155mm (.006”) on any side. Lead dimension shall not include solder coverage. AMI Semiconductor www.amis.com 6 AMIS-14935 Audio Amplifier Mechanicals - 7 Pin Bare Die Dim X Y Millimeters Min Max 1.15 1.78 Inches Min Max 0.045 0.070 Note: 1. Dimensions do not include mold flash or protrusions; these shall not exceed 0.155mm (.006”) on any side. Lead dimension shall not include solder coverage. AMI Semiconductor www.amis.com 7 AMIS-14935 Audio Amplifier Using AMIS-14935 in Hearing Assist Applications Notes: 1. When using volume control potentiometer, keep input resistor between 25kOhm to 50kOhm for optimum performance. Using lower than 25k may cause higher distortion and using higher than 50k may cause output noise to increase. 2. Input coupling capacitor (C2) must be present. Forms a high pass filter together with resistor R1 with an approximate corner frequency of 1/(2*3.14*R1*C2). 3. R2 and C3 facilitate supply filtering for microphone. The AMIS-14935 suggested values are indications only and are dependent on microphone characteristic, quality of supply and supply rejection needed. 4. Bypass capacitor may or may not be needed. Shall be kept low (less than 1µF) since a high value capacitance supply to ground may cause audible noise at power down. 5. IMPSel pin (Impedance select) should generally be tied to ground for minimum switch impedance and maximum drive capability. AMI Semiconductor www.amis.com 8 AMIS-14935 Audio Amplifier Using AMIS-14935 as Receiver Driver in H-aid Ultra Low Power Audio System Notes: 1. For optimum noise and distortion performance a 50k input resistor is recommended. 2. Input coupling capacitor (C2) must be present. Forms a high pass filter together with resistor R1 with an approximate corner frequency of 1/(2*3.14*R1*C2). 3. Bypass capacitor (C1) may or may not be needed dependent on the supply quality. This capacitor shall have a AMIS-14935 low value (less than 1µF) since a high value capacitance supply to ground may cause audible noise at power down. If other parts of the system requires a higher capacitor value this capacitor can be placed on the battery side of the switch making the total stored charge on the supply line small when system is powered down (switch is opened). AMI Semiconductor www.amis.com © Copyright 2003 AMI Semiconductor – All rights reserved. Information furnished is believed to be accurate and reliable. However, AMI Semiconductor assumes no responsibility for errors or omissions in the information and for the consequences of use of such information. AMI Semiconductor reserves the right to change the information contained herein at any time without notice. This information is provided “AS IS” without warranty of any kind, either expressed or implied, including, but not limited to, the implied warranties of merchantability, fitness for a particular purpose, or non-infringement of intellectual property. All title and intellectual property rights including, without limitation, copyrights, trademarks, in and to this information and products are owned by AMI Semiconductor, and are protected by applicable laws. No license under any patent or other intellectual property of AMI Semiconductor is granted, by implication, estoppel or otherwise.