7083ns-14-062713-1 ? features: ? x1 and x4 mode selection ? up to 16mhz 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 ? +3v to +12v operation (v dd ? v ss ) ? LS7083NS-14 (soic) ? see figure 1 . applications: ? interface incremental encoders to up/down counters (see figure 6a and 6b) description: the LS7083NS-14 is a cmos quadrature clock conver ter. quadrature clocks derived from optical or magnetic encoders, when applied to the a and b inputs of the LS7083NS-14 are converted to strings of up clocks and down clocks. these outputs can be interfaced directly with standard up/down counters for direction and position sensing of the encoder. input/output description: v dd (pin 2) supply voltage positive terminal. rbias (pin 3) input for external component connection. a resistor connected between this input and v ss adjusts the output clock pulse width (t ow ). for proper operation, the output clock pulse width must be less than or equal to the a, b pulse separation (t ow t ps ). v ss (pin 4) supply voltage negative terminal. a (pin 5) quadrature clock input a. this input has a filt er circuit to validate input logic level and eliminate encoder dither. b (pin 10) quadrature clock input b. this input has a filter circuit identical to input a. mode (pin 11) mode is a 3-state input to select resolutions x1, x2, or x4. the selected resolution multiplies the input quadrature clock rate by 1, 2 and 4 respectively; in producing the outputs upck/dnck and clk (see figure 2). the mode input logic levels selects resolutions as follows: logic 0 = x1 float = x2 logic 1 = x4 dnck (pin 12) this is the down clock output. this output consists of low-going pulses generated when a input lags the b input. upck (pin 13) this is the up clock output. this output consists of low-going pulses generated when a input leads the b input. . quadrature clock converter june 2013 pin assignment top view figure 1. ls7083ns \ 14 ????? ????? ????? ?????
7083ns-14-062713-2 absolute maximum ratings: parameter symbol value unit dc supply voltage v dd - v ss 16.0 v voltage at any input v in v ss ? 0.3 to v dd + 0.3 v operating temperature t a 0 to +70 c storage temperature t stg -55 to +150 c dc electrical characteristics: (all voltages referenced to vss, ta = 0 c to 70 c.) parameter symbol min max unit conditions supply voltage v dd 3.0 12.0 v - supply current i dd - 100 a v dd = 12v, all input frequencies = 0hz rbias = 2m mode logic low v il - 0.5v dd v - a, b logic low v il - 0.7 v v dd = 3v - 1.0 v v dd = 5v - 2.8 v v dd = 12v mode logic high v ih v dd - 0.5 - v - a, b logic high v ih 2.0 - v v dd = 3v 3.0 - v v dd = 5v 6.6 - v v dd = 12v all outputs: sink current i ol 1.3 - ma v dd = 3v v ol = 0.4v 1.9 - ma v dd = 5v 2.9 - ma v dd = 12v source current i oh 0.83 - ma v dd = 3v v oh = v dd - 0.5v 1.1 - ma v dd = 5v 1.6 - ma v dd = 12v transient characteristics: (t a = 0 c to 70 c.) parameter symbol min max unit conditions a,b inputs: validation delay t vd - 250 ns v dd =3v - 170 ns v dd = 5v - 71 ns v dd = 12v a,b inputs: pulse width t pw t vd +t ow infinite ns - a to b or b to a phase delay t ps t ow infinite ns - a,b frequency f a,b - 1 / 2t pw hz - input to output delay t ds - 280 ns v dd = 3v - 220 ns v dd = 5v - 120 ns v dd = 12v includes input validation delay output clock pulse width t ow 50 - ns see fig. 4 & 5
? 7083ns-14-062713-3 note: output clocks labeled 1,2 and 4 have the following interpretations. 1. generated in x1, x2 and x4 modes. 2. generated in x2 and x4 modes only. 3. generated in x4 mode only. figure 2. LS7083NS-14 input/output timing figure 3. LS7083NS-14 block diagram the information included herein is believed to be accurate and reliable. however, lsi computer systems, inc. assumes no responsibilities for inaccuracies, or for any infringements of patent rights of others which may result from its use.
? 7083ns-14-062713-4 figure 4. t ow vs rbias, k figure 5. t ow vs rbias, m figure 6a. typical application for LS7083NS-14 in x4 mode figure 6b. typical application for LS7083NS-14 in x2 mode
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