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| LSI/CSI UL (R) LS7083/7084 (631) 271-0400 FAX (631) 271-0405 October 2000 LSI Computer Systems, Inc. 1235 Walt Whitman Road, Melville, NY 11747 A3800 QUADRATURE CLOCK CONVERTER FEATURES: * x1 and x4 mode selection * Up to 16 MHz output clock frequency * Programmable output clock pulse width * On-chip filtering of inputs for optical or magnetic encoder applications. * TTL and CMOS compatible I/Os * +4.5V to +10.0V operation (VDD-VSS) * LS7083, LS7084 (DIP) LS7083-S, LS7084-S (SOIC) - See Figure 1 DESCRIPTION: The LS7083 and LS7084 are monolithic CMOS silicon gate quadrature clock converters. Quadrature clocks derived from optical or magnetic encoders, when applied to the A and B inputs of the LS7083/LS7084, are converted to strings of Up Clocks and Down Clocks (LS7083) or to a Clock and an Up/Down direction control (LS7084). These outputs can be interfaced directly with standard Up/Down counters for direction and position sensing of the encoder. INPUT/OUTPUT DESCRIPTION: RBIAS (Pin 1) Input for external component connection. A resistor connected between this input and VSS adjusts the output clock pulse width (Tow). For proper operation, the output clock pulse width must be less than or equal to the A,B pulse separation (TOWTPS). VDD (Pin 2) Supply Voltage positive terminal. VSS (Pin 3) Supply Voltage negative terminal. A (Pin 4) Quadrature Clock Input A. This input has a filter circuit to validate input logic level and eliminate encoder dither. B (Pin 5) Quadrature Clock Input B. This input has a filter circuit identical to input A. x4/x1 (Pin 6) This input selects between x1 and x4 modes of operation. A high-level selects x4 mode and a low-level selects the x1 mode. In x4 mode, an output pulse is generated for every transition at either A or B input. In x1 mode, an output pulse is generated in one combined A/B input cycle. (See Figure 2.) 7083/84-100600-1 PIN ASSIGNMENT - TOP VIEW LSI LS7083 LSI LS7084 FIGURE 1 RBIAS 1 8 7 6 UPCK VDD(+V) 2 VSS(-V) 3 A4 DNCK x4/x1 5 B RBIAS VDD(+V) 1 2 8 7 6 CLK UP/DN x4/x1 VSS(-V) 3 A 4 5 B LS7083 - DNCK (Pin 7) In LS7083, this is the DOWN Clock Output. This output consists of low-going pulses generated when A input lags the B input. LS7084 - UP/DN (Pin 7) In LS7084, this is the count direction indication output. When A input leads the B input, the UP/DN output goes high indicating that the count direction is UP. When A input lags the B input, UP/DN output goes low, indicating that the count direction is DOWN. LS7083 - UPCK (Pin 8) In LS7083, this is the UP Clock output. This output consists of low-going pulses generated when A input leads the B input. LS7084 - CLK (Pin 8) In LS7084, this is the combined UP Clock and DOWN Clock output. The count direction at any instant is indicated by the UP/DN output (Pin 7). NOTE: For the LS7084, the timing of CLK and UP/DN requires that the counter interfacing with LS7084 counts on the rising edge of the CLK pulses. ABSOLUTE MAXIMUM RATINGS: PARAMETER SYMBOL DC Supply Voltage VDD - VSS Voltage at any input VIN Operating temperature TA Storage temperature TSTG DC ELECTRICAL CHARACTERISTICS: (All voltages referenced to VSS, TA = 0C to 70C.) PARAMETER Supply voltage Supply current SYMBOL VDD IDD VALUE 11.0 VSS -.3 to VDD +.3 0 to +70 -55 to +150 UNITS V V C C MIN 4.5 - MAX 10.0 6.0 UNITS V A CONDITION VDD = 10.0V, All input frequencies = 0 Hz RBIAS = 2M x4/x1 Logic Low A,B Logic Low VIL VIL 0.3VDD 0.7VDD 3.1 5.0 5.6 0.6 1.0 1.1 - V V V V V V V V VDD = 4.5V VDD = 9V VDD = 10.0V VDD = 4.5V VDD = 9V VDD = 10.0V x4/x1Logic High A,B Logic High VIH VIH ALL OUTPUTS: Sink Current VOL = 0.4V IOL 1.75 5.0 5.7 1.0 2.5 3.0 - mA mA mA mA mA mA VDD = 4.5V VDD = 9V VDD = 10.0V VDD = 4.5V VDD = 9V VDD = 10.0V Source Current VOH = VDD - 0.5V TRANSIENT CHARACTERISTICS: (TA = 0C to 70C) PARAMETER A,B inputs: Validation Delay IOH SYMBOL TvD MIN TVD+TOW MAX 85 100 160 Infinite UNITS ns ns ns ns CONDITION VDD = 10.0V VDD = 9V VDD = 4.5V - A,B inputs: Pulse Width A to B or B to A Phase Delay TPW TPS TOW Infinite 1 2TPW ns - A,B frequency fA,B - Hz - Input to Output Delay TDS - 120 150 235 ns ns ns VDD = 10.0V VDD = 9V VDD = 4.5V Includes input validation delay See Fig. 4 & 5 Output Clock Pulse Width TOW 50 - ns 7083/84-100100-2 TPW A B UPCK (x1/7083) DNCK (x1/7083) UPCK (x4/7083) DNCK (x4/7083) CLK (x1/7084) CLK (x4/7084) UP/DN (7084) TPS TDS TOW TDS FIGURE 2. LS7083/LS7084 INPUT/OUTPUT TIMING DIAGRAM RBIAS 1 CURRENT MIRROR A 4 FILTER DUAL ONE-SHOT CLOCK AND DIRECTION DECODE x4 CLOCK 8 x1 CLOCK MUX 7 DNCK or UP/DN UPCK or CLK B 5 FILTER DUAL ONE-SHOT UP/DN x4/x1 V DD 6 2 +V -V V SS 3 FIGURE 3. LS7083/LS7084 BLOCK DIAGRAM The information included herein is believed to be accurate and reliable. However, LSI Computer Systems, Inc. assumes no responsibilities for inaccuracies, nor for any infringements of patent rights of others which may result from its use. 7083/84-100100-3 1500 VDD=5V 30 VDD=5V 25 OUTPUT CLOCK PULSE WIDTH, Tow, ns VDD=9V VDD=10.0V 1000 OUTPUT CLOCK PULSE WIDTH, Tow, s 1250 20 VDD=9V 750 15 VDD=10.0V 500 10 250 5 100 200 300 400 500 2 4 6 8 10 12 Figure 4. Tow vs RBIAS, K Figure 5. Tow vs RBIAS, M +V 6 x4/x1 A CLOCK 4 ENCODER B CLOCK 5 A B 2 VDD UPCK LS7083 DNCK VSS 3 8 5 +V 16 VDD CK-UP 40193 CK-DN 7 4 1 RB RBIAS VSS 8 FIGURE 6A. TYPICAL APPLICATION FOR LS7083 IN x4 MODE MODE SELECT R 6 x4/x1 A CLOCK 4 ENCODER B CLOCK 5 1 RB A B RBIAS VSS 3 +V 2 VDD CLK LS7084 UP/DN 8 7 15 CK 10 UP/DN VSS 8 4516 +V 16 VDD FIGURE 6B. TYPICAL APPLICATION FOR LS7084 WITH x4/x1 MODE SELECTION 7083/84-100100-4 |
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