pt2240b encoder ic tel: 886-66296288 ? fax: 886-29174598 ? http://www.princeton.com.tw ? 2f, 233-1, baociao road, si ndian, taipei 23145, taiwan description pt2240b is encoder utilizing cmos technology specially designed for remote control applications. it has 2 20 address. it can support up to 4 data bits and is housed in 8 pin sop package. it encodes address and data codes into a coded waveform suitable for rf modulation. the pin assignments and application circuit are optimized for easy pcb layout and cost saving advantage. furthermore, pt2240b?s intrinsic feature of being able to support 4 data bits considerably reduces inventory pressures. applications ? burglar alarm system ? car security system ? car/garage door controller ? home/office security system ? personal alarm system features ? cmos technology ? low power consumption ? least external components ? high noise immunity ? single resistor oscillator ? operating voltage: 1.8~15v ? 4 data pins ? 2 20 address codes ? available in sop package ? reduction of inventory pressures block diagram
pt2240b v1.2 2 september, 2009 application circuit 8 pins power failure circuit warning: be cautious to use this circuit which will cause the ic shutdown or even damaged.
pt2240b v1.2 3 september, 2009 order information valid part number package type top code PT2240B-S 8 pins, sop, 150mil PT2240B-S pin configuration pin description pin name i/o description pin no. vdd - positive power supply 1 vss - negative power supply 2 dout o data output pin normal=?low? 3 d0, d1, d2, d3 i data pin 7, 6, 5, 4 osc i oscillator pin 8
pt2240b v1.2 4 september, 2009 function description pt2240b encodes the address code and data set at d0 ~ d3 and a0 ~ a19 into a special waveform and outputs it to the dout. this waveform is fed to the rf modulator for transmission. code bits a code bit is the basic component of the encoded waveform, and can be classified as either an (address/data) bit or a sync (synchronous) bit. address/data bit waveform an address/data bit can be designated as either bit ?0? or ?1? if it is in high or low state respectively. one bit waveform consists of one pulse cycle and each pulse cycle has 128 oscillati ng time periods. for further details, please refer to the diagram below: where the oscillating time period, =1/f and (f is the oscillation frequency) as you can see in the diagram above, bi t ?0? consist of a ?high? pulse for 32 (where =oscillating time period) then changes to ?low? pulse for 96 . likewise, for bit ?1?, the ?high? pulse for 96 is followed by ?low? pulse for 32 . synchronous (sync.) bit waveform the synchronous bit waveform is 8 bits long with 1/ 32 bit width pulse. please refer to the diagram below:
pt2240b v1.2 5 september, 2009 code word a group of code bits is called a code word. a code word cons ists of 20 address/4 data bi ts followed by one sync bit. please refer to the diagram below: a0 a1 a2 a3 a16 a17 a18 a19 d3 d2 d1 d0 sync. bit single resistor oscillator the built-in oscillator circuit of pt2240b allows a precision o scillator to be constructed by connecting an external resistor (rosc) to the osc pin. the typical oscillator frequency wi th various resistor values for pt2240b is given below: 0 100 200 300 400 500 600 15 14 13 12 11 10 9 8 7 6 5 4 3 2.5 2 1.8 vcc (v) frequency (khz) 430k 470k 1m 1.2m 1.5m 2m 2.2m
pt2240b v1.2 6 september, 2009 absolute maximum ratings parameter symbol condition rating unit operating voltage vdd -0.3 ~ 15 v input voltage vin vdd=12v all outputs not connected vss-0.3 ~ vdd+0.3 v operating temperature topr vdd=12v -40 ~ +85 storage temperature tstg -65 ~ +150 dc electrical characteristics (unless otherwise specified, ta=25 , vdd=12v) parameter symbol condition min. typ. max. unit operating voltage vdd 1.8 12 15 v stand-by current isb osc connected to ?low? other pins floating - - 1 a operating current iop connect one data pin to ?high? -* - 5 ma vdd=12v, voh=5v 30 25 - vdd=9v, voh=4.5v 12 15 - dout output current ioh vdd=3v, voh=1.5v 1.2 1.4 - ma
pt2240b v1.2 7 september, 2009 package information 8 pins, sop, 150mil millimeter symbol min. nom. max. a 1.35 1.60 1.75 a1 0.10 0.15 0.25 a2 1.25 1.40 1.65 b 0.33 - 0.51 c 0.17 - 0.25 d 4.80 4.90 5.00 e 5.80 6.00 6.20 e1 3.80 3.90 4.00 e 1.27bsc l 0.40 0.60 1.27 l1 1.04ref 0 - 8 notes: 1. refer to jedec ms-012aa 2. all dimensions are in millimeter
pt2240b v1.2 8 september, 2009 important notice princeton technology corporation (ptc ) reserves the right to make co rrections, modifications, enhancements, improvements, and other changes to its products and to discontinue any product without notice at any time. ptc cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a ptc product. no circuit patent licenses are implied. princeton technology corp. 2f, 233-1, baociao road, sindian, taipei 23145, taiwan tel: 886-2-66296288 fax: 886-2-29174598 http://www.princeton.com.tw
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