UM3750 UMC | Alldatasheet

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Technical content

Features

1 Single chip contains both Encoder and Decoder 1 Schmitt Trigger input provides excellent noise

§ 3V 10 11V operation immunity ® On chip oscillator uses non-critical RC components ™ Applications; alarm control system, security system, = Cross interference of receiver is virtually cordless telephone, remote control eliminated by circuitry which requires 4 valid 8 Interfaces with RF, ultrasonic, or infrared words to be received, each within 64ms of the other modulators and demodulators = 2' = 4096 different codes General Description The UM3750A Encoder/Decoder is a CMOS/LSI digital begin its comparison on the next word. If all 12 bits code Transmitter-eceiver system. Working in the ate received correctly, a ‘valid’ signal is generated. transmit (encoder) mode, the UM3750A will sequentially This signal dears a 64ms counter and triggers a encode and transmit 12 bits of input. Each of the 3etage counter, The Jstage counter counts the 12 bits may be 1 ‘or 0 to allow 4096 different codes. “valid™ pulses and when 4 pulses have been detected, the TX/RX output pin goes low. After the TX/RX output In the receive (decoder) mode, the incoming signal is pin goes low, the next’ ‘valid” must be received compared to the local code in a sequential manner. within 128ms, otherwise, the TX/RX output will be Once an error is detected the system will reset and disabled. Pin Configurations a. Che 20) Yoo as CH: ae) po. oz Tj2 a9 [1] txerx ourrur oz Cle 17 1D rer oureur as Cs se [[] Receiver os (Js a6 [D) recerver s we Che Str DD move sevect oe Ch SE as [move smecr = s a=Os SS #pow es en pow wn o ve Cle Gs Pee. avout oo Os = as[lee. eur => a Or we waz a C7 12D az oo Cle a Daa ee Ce aa [J aa wo Oe az) aso ao Che 301) aso we [1] 10 1D) we

@ume UM3750A Block Diagram Bene vom SAMPLING az para [mee | sract mmo 64m8 73206 a ee arp 4 wo nxo neo RxELKT wiaalz peek ot Block Diagram Description CPLK: | CLKofComparator CLR: Clear signal of Comparator MXGCLKR: CLK of Multiplexer when in Receiver mode ERROR: — Error signal from Comparator MXCLKT: CLK of Muttiplexer when in Transmitter mode TIMO: TIMER time-out signal (64ms or 128ms) MXD: Output data of Multiplexer (one of A1, A2, TX/RX OUT: Transmitter /Receiver output pin ~A12) INIT: Reset signal of Valid 4 Counter RID: Sampled data bySampling CKT WD: Word detected signal VLD: "valid" signal. Used to trigger Valid 4 TXO: Transmitter output Counter and reset 64ms/128ms Timer RXO: Receiver output

@umc UM3750A -_ eee Absolute Maximum Ratings” *Comments bee ee eee. GND O3V < VIN < Voo +0.3V those indicated in the operational sections of this Specification is not implied and exposure to absolute maximum rating conditions for extended periods may . affect device reliability. [__ renee [sr] me] [me [ome] cote | Operingvorage [| vo | ao | - [ n |v[ Ss peraingcuren [me [| - | - [iz [ml] SSCS” Schmitt Trigger v Input Level Other Pins Vis Vop-0.5 v Level 1 Input Level Vin GND +0.5 Level 0 Output Pin Vor Voo- 0.5 Vv Isource = 5 vA Logic Level Vou GND +14 Isink = 2 mA Inpurnesisortovoo [| - | aook | - | iw te | S~*S ‘ 18% exclusive ° or Frequency pe | fe] fie| of extemal part (For Reference) Pin Description (for UM3750A) ee AL-A12 These data select lines are used to set the addresses of the encoder/decoder pair. They have on-chip pultup resistors RG.INPUT R.C. input pin for single pin oscillator. A resistor is connected from this ~~ pin to Von and a capacitor from this pin to GND. The frequency = 2/RC This pin changes the IC from Receive mode to Transmh mode. By grounding MODE SELECT] this pin the IC is put into the Receive mode. By connecting to Vop the IC is put into the Transmit mode | ow | RECEIVER The feceiver input receives the digital PCM waveform from the detect circuit

17 TX/RX In the transmit mode, this output pin produces the PCM waveform for

. OUTPUT Wansmitting. In the receive moda, this output pin provides the comparison tesult and detects low if comparison is ok |e fe The positive power supply pin of the UM3750A, Note: The only difference between UM3750A and UM3750AM is that the latter has two extra NC pins.

@ume UM3750A -_— Application Circuits (for reference only) ‘ Beaty Beaiv 100% rox SNOUT Eo unarsoa | = i Mr znput oo yeost ao Pin Connections for Receiver Mode Pin Connections for Transmit Mode : R J e $ + OEReer LH sa {tener 4 stcpen toms G UM3750A UM375DA j4#s~— a aw oo Fffor fe 4 more: ¢= Ze ctupteat FeLoowe> ee Output Waveform (based on 100 KHz) Set onsite | oSSeas | | o%%bne | Fy

@umc UM3750A ee Decoder Flowchart Crowes ow) aeser cout Fives Pca, Baers. tine

Ordering Information

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