1 publication d/118/3 july 1994 cml semiconductor products product information duplex frequency inverter for cordless telephones fx118 features/applications frequency inversion scrambling full-duplex operation high baseband and carrier rejection audio lowpass and bandpass filtering on-chip xtal oscillator stabilty low power requirement (3.0 volt minimum) cordless telephones base and handheld applications input gain adjustment plastic dil and s.o.i.c. package styles fx118 c1 amp out c1 in lpf(1) out b mod(1) in c1 out lpf(1) input amp bal mod (1) bpf(1) lpf(2) out b mod(2) in c2 amp out c2 in lpf(2) bal mod (2) bpf(2) c2 out clocks and logic xtal/clock carrier 3.3khz filter clocks 111khz v dd v ss v bias input amp v bias v bias xtal channel 1 (c1) channel 2 (c2) +0.5db -4.0db +4.0db +0.5db -4.0db +4.0db fig.1 fx118 duplex frequency inverter brief description the fx118 is a low-power, full-duplex frequency inverter available to provide voice privacy for cordless telephone systems by mixing the incoming audio with an internally produced carrier frequency (3.3khz). this chip contains two completely separate audio channels (c1 and c2) each comprising a component- adjustable input amplifier, a 10th-order lowpass filter, a balanced modulator and a 14th-order bandpass filter output. the on-chip modulation process has the properties of high baseband and carrier frequency rejection which when combined with high-order output filtering, produces a high-quality recovered voiceband audio. the frequency stability of the fx118 is achieved by an on-chip oscillator employing an external 4.433619mhz xtal or clock input to produce the common carrier frequency and the sampling clocks for the switched capacitor low and bandpass filters. this microcircuit has a low power requirement of 3.0 volts (min.) and is encapsulated in either 16-pin dil or small outline smd (s.o.i.c.) plastic packages both of which are of a physical size suitable for either base or handset type telephone instruments as well as battery- portable and mobile communications systems.
2 pin number function fx118dw fx118p 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 xtal: output of clock oscillator inverter. no internal connection: it is recommended that, to improve noise conditions, this pin is connected to v ss . lpf(1) out: the output of the channel 1 lowpass filter. it is to be coupled to b mod(1) in via a 1.0 m f capacitor C see figure 2. b mod(1) in: the input to channel 1 balanced modulator. internally biased at v dd /2 it is to be coupled to lpf(1) via a 1.0 m f capacitor C see figure 2. v ss : negative supply (gnd). c1 out: the analogue output of channel 1. c1 amp output: channel 1 amplifier with external components (see figure 2) can be used to provide gain in the signal path. c1 in: the negative input of channel 1 amplifier. recommended external components are shown in figure 2. c2 in: the negative input of channel 2 amplifier. recommended external components are shown in figure 2. c2 amp output: channel 2 amplifier with external components (see figure 2) can be used to provide gain in the signal path. c2 out: the analogue output of channel 2. v bias : the internal analogue bias line at v dd /2. it should be decoupled to v ss via a 1.0 m f or greater capacitor. see figure 2. b mod(2) in: the input to channel 2 balanced modulator. internally biased at v dd /2 it is to be coupled to lpf(2) via a 1.0 m f capacitor C see figure 2. lpf(2) out: the output of the channel 2 lowpass filter. it is to be coupled to b mod(2) in via a 1.0 m f capacitor C see figure 2. v dd : the positive supply rail. a single positive supply voltage (3.0v C 5.0v) is required. levels and voltages within the duplex frequency inverter are dependent upon this supply. xtal/clock: 4.433619 mhz xtal or externally derived clock is injected at this pin. see figure 2. operation of the fx118 without a xtal or clock input may cause device damage.
3 application information fig.3 example of the fx118 employed in a cordless telephone application v bias c1 amp out v dd c1 in channel 1 input c2 amp out c2 in channel 2 input b mod(1) in lpf(1) out b mod(2) in lpf(2) out v dd xtal xtal/clock c2 out channel 1 output channel 2 output x 1 r 1 c 1 c 3 c 2 c 4 r 3 r 2 c 5 r 4 r 5 v ss v ss c1 out 1 2 3 4 5 6 7 89 10 11 12 13 14 15 16 fx118 v ss c 6 c 7 c 8 t olerances c = 20% r = 10% channel 2 (c2) channel 1 (c1) fx118 af amp de-emphasis detection if amp rf amp rf amp pre- emphasis af amp modulation fm fm rx channel tx channel handheld unit channel 2 (c2) channel 1 (c1) fx118 af amp de-emphasis detection if amp rf amp rf amp pre- emphasis af amp modulation fm fm hybrid transformer telephone line rx channel tx channel base unit fig.2 recommended external components notes 1. configurations r 2 , r 3 , c 5 and r 4 , r 5 , c 6 should be chosen with respect to the specific application. 2. operation of any cml microcircuit without a xtal or clock input may cause device damage. to minimise damage in the event of a xtal/drive failure, it is recommended that the power rail (v dd ) is fitted with a current limiting device (resistor or fast-reaction fuse). component value r 1 = 1.0m w r 2 r 3 c 5 see note r 4 r 5 c 6 see note c 1 47pf c 2 = 33pf c 3 0.47 m f c 4 1.0 m f c 7 = 1.0 m f c 8 1.0 m f x 1 4.433619mhz
4 0.1 0.2 0.3 0.5 2.0 1.0 7.0 frequency khz 3.0 -40 -30 -20 -10 -3 0 +5 gain db audio input level = 275mvrms v = 3.75v dd fig.4 typical audio frequency response of a single scrambled or de-scrambled channel 0 lowpass filtered voiceband for input to balanced modulator 1000hz 2000hz 3000hz 0 carrier frequency (3300hz) generated on-chip for input to balanced modulator 1000 2000 3000 0 bandpass filtered voiceband presented at the ouput after mixing with the carrier frequency in the balanced modulator 1000 2000 3000 speech band input voiceband frequencies 3300 a b c d a b c d (1) (2) (3) (4) how the inverter works carrier frequency minus input voice frequency equals scrambled voice frequency system gains when calculating the external components for the operation of the fx118 the following points should be considered: (a) the input lowpass filter has a (typical) gain of 0.5db. (b) the balanced modulator has a (typical) attenuation of 4.0db. (c) the output bandpass filter has a (typical) gain of 4.5db. application information ...... fig.5 a pictorial explanation of the fx118 scramble operation
5 specification absolute maximum ratings exceeding the maximum rating can result in device damage. operation of the device outside the operating limits is not implied. supply voltage -0.3 to 7.0v input voltage at any pin (ref v ss = 0v) -0.3 to (v dd + 0.3v) sink/source current (supply pins) +/- 30ma (other pins) +/- 20ma total device dissipation @ t amb 25 c 800mw max. derating 10mw/ c operating temperature range: fx118dw/p -40 c to +85 c storage temperature range: fx118dw/p -40 c to +85 c operating limits all device characteristics are measured under the following conditions unless otherwise specified: v dd = 3.75v. t amb = 25 c. xtal/clock f 0 = 4.433619mhz. audio level 0db ref: = 388mv rms @ 1.0khz. characteristics see note min. typ. max. unit static values supply voltage 3.0 3.75 5.5 v supply current C 4.0 6.0 ma input impedance (amplifiers) 1.0 10.0 C m w output impedance (lp filters) C 2.0 C k w output impedance (c1, c2 ) C 200 C w output impedance (c1, c2 amps) C 10.0 C k w on-chip xtal oscillator r in 10.0 C C m w r out C 10.0 C k w inverter gain C 10.0 C v/v gain/bandwidth product C 10.0 C mhz dynamic values analogue signal input levels -16.0 C 4.0 db sinad 6 C 30.0 C db unwanted modulation products 1, 2 C -40.0 C db carrier breakthrough 1, 2 C -55.0 C db baseband breakthrough 1, 2 C -40.0 C db carrier frequency C 3299 C hz analogue output noise 3 C -42.0 C db analogue output noise 5 C -46.0 C dbp filters input lowpass filter 1 cut-off frequency (-3db) C 3100 C hz passband ripple (300hz - 3khz) C 1.0 C db attenuation at 3.3khz C 30.0 C db attenuation at 3.6khz C 45.0 C db passband gain C 0.5 C db output bandpass filter 1, 4 passband frequencies 300 C 3000 hz passband ripple C 1.0 C db low freq. roll-off <200hz 12.0 C C db/oct. high freq. C attenuation at 3.4khz C 48.0 C db passband gain 3.5 4.5 5.5 db overall modulated and de-modulated channel response passband frequencies (tx and rx channel) 300 C 3000 hz passband ripple -3.0 C 2.0 db low freq. roll-off <250hz 18.0 C C db/oct. high freq. C attenuation at 3.4khz C 48.0 C db passband gain 4 C 0.5 C db distortion 1 C 3.0 C % notes: 1. measured with an audio input level of -3.0db. 2. with respect to a single modulated (scrambling) channel. 3. measured with a short circuit input, at any analogue output, in a 30.0khz bandwidth. 4. with input amplifier gain at 0db. 5. measured psophometrically weighted, at any analogue output. 6. measured in a 30khz bandwidth.
package outlines the fx118 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. handling precautions the fx118 is a cmos lsi circuit which includes input protection. however precautions should be taken to prevent static discharges which may cause damage. 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. 6 ordering information fx118dw 16-pin s.o.i.c. (d4) fx118p 16-pin plastic dil (p3) not to scale max. body length 20.57mm max. body width 6.60mm fx118dw 16-pin s.o.i.c. (d4) fx118p 16-pin plastic dil (p3) not to scale max. body length 10.49mm max. body width 7.59mm
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 micro- circuits . 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 communication semiconductors cml microcircuits communication semiconductors cml microcircuits (singapore)pteltd communication semiconductors cml microcircuits (usa) inc. communication semiconductors oval park, langford, maldon, essex, cm9 6wg, england tel: +44 (0)1621 875500 fax: +44 (0)1621 875600 uk.sales@cmlmicro.com 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 us.sales@cmlmicro.com www.cmlmicro.com no 2 kallang pudding road, 09-05/ 06 mactech industrial building, singapore 349307 tel: +65 7450426 fax: +65 7452917 sg.sales@cmlmicro.com www.cmlmicro.com d/cml (d)/1 february 2002
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