CML Semiconductor Products Cordless Telephone Scrambler D/128/1 October 1997 FX128 Provisional Information Features • Full-Duplex Audio Processing • Excellent Audio Quality • On-Chip Filters • Low Power Operation (3.0V) • Carrier Rejection >55dB • ECPA* Qualified Voice Protection • Uses IF (10.24MHz) Clock • Battery Powered Portability • Requires No Extra Crystal • Cordless Telephones and Wireless PBX Applications 1.1 Brief Description The FX128 is a full-duplex frequency inversion scrambler designed to provide secure conversations for 46/49 MHz cordless telephone users. The Rx and Tx audio paths consist of the following: 1. 2. 3. 4. A switched-capacitor balanced modulator with high baseband and carrier rejection. A 3.3kHz inversion carrier (injection tone). A 3100Hz lowpass filter. Input op-amps with externally adjustable gain. The FX128 uses mixed signal CMOS switched-capacitor filter technology and operates from a single supply in the range of 3.0 to 5.5 volts. The inversion carrier's frequency and filter switching clock are generated on-chip using an external 10.24MHz or 3.58/3.6864 MHz crystal or clock input (selectable). This device is available in 16-pin SOIC (FX128D4) and 16-pin plastic DIL (FX128P3) packages. *Electronics Communications Privacy Act (Title 18, US Code 2510 etc.). 1 Cordless Telephone Scrambler FX128 CONTENTS Section Page 1.1 Brief Description........................................................................................ 1 1.2 Block Diagram........................................................................................... 3 1.3 Signal List ................................................................................................. 4 1.4 External Components ................................................................................ 5 1.5 Application .............................................................................................. 6 1.6 Application Notes .................................................................................... 6 1.7 Performance Specification....................................................................... 7 1.7.1 Electrical Performance ............................................................. 7 1.7.2 Packaging................................................................................ 10 2 Cordless Telephone Scrambler 1.2 FX128 Block Diagram RX GAIN AMP OUT Rx CHANNEL + RXIN RXOUT VBIAS CLR XTAL/CLOCK 10.24/3.58 MHz 3.3kHz CLOCKS AND LOGIC XTALN CLOCK SELECT VDD VDD 2 212kHz 0V VBIAS VSS VBIAS TXIN TX GAIN AMP OUT + - TXOUT Tx CHANNEL Figure 1 Block Diagram 3 Cordless Telephone Scrambler 1.3 FX128 Signal List Package D4/P3 Signal Description Pin No. Name Type 1 XTALN O/P This is the output of the clock oscillator inverter. 2 XTAL/CLOCK I/P 10.24MHz or 3.58/3.6864 MHz or an externally derived clock is injected at this pin. See Figure 2. 3 - N/C No connection should be made to this pin. 4 TXOUT O/P This is the analogue output of the transmit channel. It is internally biased at VDD/2. 5 TX GAIN AMP OUT O/P This is the output pin of the transmit gain adjusting opamp. See Figure 3 for gain setting components. 6 TXIN I/P This is the analogue signal input to the transmit channel. This input goes to a gain adjusting op-amp whose gain is set by external components. See Figure 3. 7 - N/C No connection should be made to this pin. 8 VSS POWER 9 VBIAS O/P This is an internally generated bias voltage output (VDD/2) 10 - N/C No connection should be made to this pin. 11 RXIN I/P This is the analogue signal input to the receive channel. This input goes to a gain adjusting op-amp whose gain is set by external components. See Figure 3. 12 RX GAIN AMP OUT O/P This is the output pin of the receive gain adjusting opamp. See Figure 3 for gain setting components. 13 RXOUT O/P This is the analogue output of the receive channel. It is internally biased at VDD/2. 14 CLR I/P A logic 1 on this input selects the invert mode. A logic 0 selects the clear (not inverted) mode. 15 CLOCK SELECT I/P Selects either 10.24 or 3.58/3.6864 MHz clock frequency. A logic “1” selects 10.24MHz and a logic “0” selects 3.58/3.6864 MHz. This input is internally pulled high. 16 VDD POWER Notes: I/P O/P N/C = = = Negative supply (GND) Positive supply of 3.0 to 5.5V. Input Output No Connection 4 Cordless Telephone Scrambler 1.4 FX128 External Components Component X1 R1 C1 C2 C3 Tolerance: Value 10.24MHz Value 3.58/3.6864 MHz 1.0MΩ 0.47µF 22.0pF 22.0pF 1.0MΩ 0.47µF 33.0pF 47.0pF R = ±10% C = ±20% Note: Xtal circuitry shown is in accordance with CML’s Xtal Application Note. Figure 2 Recommended External Components 5 Cordless Telephone Scrambler 1.5 FX128 Application BASE IF AMP RF AMP FM DETECTOR 120pF RXIN RXOUT 12 .1uF 13 100k 11 100k RF AMP 150pF FX128 DTMF Generation CODE ENCODE MODULATOR AF AMP .1uF CODE DETECT µP DE-EMP 100k 120pF PREEMP 5 100k 100k 4 6 100k .1uF 150pF HYBRID TRANSFORMER TELEPHONE LINE AF AMP .1uF TXOUT TXIN PORTABLE IF AMP RF AMP FM DETECTOR 120pF RXIN RXOUT 12 .1uF 11 100k 100k 13 100k RF AMP MODULATOR 150pF FX128 P CODE ENCODE 150pF SPKR .1uF CODE DETECT KEYPAD DE-EMP AF AMP 120pF PREEMP 5 .1uF AF AMP MIC. 100k 100k 4 6 100k TXOUT .1uF TXIN Note: Components shown set a gain of 0dB Figure 3 Block Diagram of a Typical Application of the FX128 (Cordless Phone) 1.6 Application Notes Formulae for calculating the carrier frequency, upper cutoff frequency and lower cutoff frequency with clock select pin high are as follows: Carrier Frequency Upper Cutoff Frequency Lower Cutoff Frequency = = = (3.2995kHz / 10.24MHz) * XTAL frequency (2.800kHz / 10.24MHz) * XTAL frequency (400Hz / 10.24MHz) * XTAL frequency Formulae for calculating the carrier frequency, upper cutoff frequency and lower cutoff frequency with clock select pin low are as follows: Carrier Frequency Upper Cutoff Frequency Lower Cutoff Frequency = = = (3.2995kHz / 3.415MHz) * XTAL frequency (2.800kHz / 3.415MHz) * XTAL frequency (400Hz / 3.415MHz) * XTAL frequency 6 Cordless Telephone Scrambler 1.7 Performance Specification 1.7.1 Electrical Performance FX128 Absolute Maximum Ratings Exceeding these maximum ratings can result in damage to the device. General Supply (VDD - VSS) Voltage on any pin to VSS Current in or out of VDD and VSS pins Current in or out of any other pin D4 and P3 Packages Total Device Dissipation at Tamb = 25°C . . . Derating Storage Temperature Operating Temperature Min - 0.3 -0.3 -30 -20 Max 7.0 (VDD + 0.3) +30 +20 Units V V mA mA -55 -40 800 10 +125 +85 mW mW/°C °C °C Operating Limits Correct operation of the device outside these limits is not implied. Min. 3.0 -40 Supply (VDD - VSS) Operating Temperature Clock Frequency 7 Max. 5.5 +85 10.24 Units V °C MHz Cordless Telephone Scrambler FX128 Operating Characteristics For the following conditions unless otherwise specified: VDD = 3.3V at Tamb = 25°C Clock Frequency = 10.24MHz Audio Level 0dB ref. at 1kHz = (VDD - 1) x 150vrms e.g. VDD = 3.3V 0dB = 345mVrms Notes Min. Typ. Max. Units - 2.0 3.0 mA 100 1.0 10.0 - kΩ MΩ - 1.0 - kΩ 1 1 70% - - 30% VDD VDD 4 -16.0 - 2.5 3 5.0 dB mVrms 3000 - 300 - Hz Hz Passband Ripple (300-3000Hz) Rx Channel Tx Channel 0 0 - 3.6 2.9 dB dB Passband Ripple (500-2750Hz) Rx Channel Tx Channel 0 0 - 2.2 2.0 dB dB Filter Attenuation at 3.3kHz Rx and Tx Channel - 30 - dB Filter Attenuation at 3.6kHz Rx and Tx Channel - 45 - dB -1.5 - 0.5 dB - 211.066 3298 - kHz Hz Static Values Supply Current Input Impedance Digital Amplifiers 2 2 Output Impedance (RXOUT, TXOUT) Input Logic ‘1’ Voltage Input Logic ‘0’ Voltage Dynamic Values General Analog Signal Input Levels Analog Output Noise Clear Mode Passband -3dB Cutoff Frequencies Low High Passband Gain (@ 1kHz ref.) Rx and Tx Channel Switched-Capacitor Filter Sampling Carrier Frequency 8 Cordless Telephone Scrambler FX128 Notes Invert Mode Combined Tx and Rx Response Passband -3dB Cutoff Frequencies Low High Passband Gain Distortion (@ 1kHz) Passband Gain (@ 1kHz ref.) Low Frequency Roll-off (<200Hz) 3 5 Invert Mode Single Channel Response Unwanted Modulation Products Rx and Tx Channel 3 Carrier Breakthrough Rx and Tx Channel 3 Baseband Breakthrough Rx and Tx Channel 3 Min. Typ. Max. Units 2800 - 400 - Hz Hz -3 -2.5 12 1.75 -1.5 - 0.5 2.75 0 - dB % dB dB/oct. - -40 - dB - -55 - dB - -40 - dB Operating Characteristics Notes: 1. 2. 3. 4. 5. 6. Batch sampled only. By characterisation only. Measured with Input Level 0dB. Short circuit Rx or Tx input, measure noise at corresponding analogue output, in 30kHz bandwidth. Op Amp gain 0dB. Clear mode only. 9 1.7.2 Package Outlines Handling Precautions The FX128 is available in the package styles outlined below. Mechanical package diagrams and specifications are detailed in Section 10 of this document. Pin 1 identification marking is shown on the relevant diagram and pins on all package styles number anti-clockwise when viewed from the top. The FX128 is a CMOS LSI circuit which includes input protection. However precautions should be taken to prevent static discharges which may cause damage. FX128D4 16-pin Plastic S.O.I.C. FX128P3 (DW) NOT TO SCALE 16-pin Plastic DIL (P) NOT TO SCALE Max. Body Length Max. Body Width 10.49mm 7.59mm Max. Body Length Max. Body Width Ordering Information FX128D4 16-pin Plastic S.O.I.C. FX128P3 16-pin Plastic DIL (DW) (P) CML does not assume any responsibility for the use of any circuitry described. No circuit patent licences are implied and CML reserves the right at any time without notice to change the said circuitry. 10 20.57mm 6.60mm CML Microcircuits COMMUNICATION SEMICONDUCTORS CML Product Data In the process of creating a more global image, the three standard product semiconductor companies of CML Microsystems Plc (Consumer Microcircuits Limited (UK), MX-COM, Inc (USA) and CML Microcircuits (Singapore) Pte Ltd) have undergone name changes and, whilst maintaining their separate new names (CML Microcircuits (UK) Ltd, CML Microcircuits (USA) Inc and CML Microcircuits (Singapore) Pte Ltd), now operate under the single title CML Microcircuits. These companies are all 100% owned operating companies of the CML Microsystems Plc Group and these changes are purely changes of name and do not change any underlying legal entities and hence will have no effect on any agreements or contacts currently in force. CML Microcircuits Product Prefix Codes Until the latter part of 1996, the differentiator between products manufactured and sold from MXCOM, Inc. and Consumer Microcircuits Limited were denoted by the prefixes MX and FX respectively. These products use the same silicon etc. and today still carry the same prefixes. In the latter part of 1996, both companies adopted the common prefix: CMX. This notification is relevant product information to which it is attached. Company contact information is as below: CML Microcircuits (UK)Ltd CML Microcircuits (USA) Inc. CML Microcircuits (Singapore)PteLtd COMMUNICATION SEMICONDUCTORS COMMUNICATION SEMICONDUCTORS COMMUNICATION SEMICONDUCTORS Oval Park, Langford, Maldon, Essex, CM9 6WG, England Tel: +44 (0)1621 875500 Fax: +44 (0)1621 875600 [email protected] www.cmlmicro.com 4800 Bethania Station Road, Winston-Salem, NC 27105, USA Tel: +1 336 744 5050, 0800 638 5577 Fax: +1 336 744 5054 [email protected] www.cmlmicro.com No 2 Kallang Pudding Road, 09-05/ 06 Mactech Industrial Building, Singapore 349307 Tel: +65 7450426 Fax: +65 7452917 [email protected] www.cmlmicro.com D/CML (D)/1 February 2002