max485 low-power, slew-rate-limited rs-485/rs-422 transceivers general description the max485 is low-power transceivers for rs-485 and rs- 422 communication. ic contains one driver and one receiver. the driver slew rates of the max 485 is not limited, allowing them to transmit up to 2.5mbps. these transceivers draw between 120a and 500a of supply current when unloaded or fully loaded with disabled drivers. all parts operate from a single 5v supply. drivers are short-circuit current limited and are protected against excessive power dissipation by thermal shutdown circuitry that places the driver outputs into a high-impedance state. the receiver input has a fail-safe feature that guarantees a logic-high output if the input is open circuit. the max485 is designed for half-duplex applications. features ? low quiescent current: 300a ? -7v to +12v common-mode input voltage range ? three-state outputs ? 30ns propagation delays, 5ns skew ? full-duplex and half-duplex versions available ? operate from a single 5v supply ? allows up to 32 transceivers on the bus ? data rate: 2,5 mbps ? current-limiting and thermal shutdown for driver overload protection ? the transmitter outputs and receiver inputs are protected to 15kv air esd. ordering information max485cpa plastic dip MAX485CSA soic tiger electronic co.,ltd
max485 absolute maximum ratings supply voltage (v cc ) 12v continuous power dissipation (t a = +70c) control input voltage -0.5v to (v cc + 0.5v) 8-pin plastic dip (derate 9.09mw/c above +70c) 727mw driver input voltage (di) -0.5v to (v cc + 0.5v) 8-pin sop (derate 5.88mw/c above +70c) 471mw driver output voltage (a, b) -8v to +12.5v operating temperature ranges 0c to +70c receiver input voltage (a, b) -8v to +12.5v storage temperature range -65c to +160c receiver output voltage (ro) -0.5v to (v cc +0.5v) lead temperature (soldering, 10sec) +300c dc electrical characteristics (v cc = 5v 5%, t a = t min to t max , unless otherwise noted.) (notes 1, 2) parameter symbol conditions min ty p max units differential driver output (no load) v od1 5 v r = 50 ? (rs-422) 2 differential driver output (with load) v od2 r = 27 ? (rs-485), figure 4 1.5 5 v change in magnitude of driver differential output voltage for complementary output states ?v od r = 27 ? or 50 ? , figure 4 0.2 v driver common-mode output voltage v oc r = 27 ? or 50 ? , figure 4 3 v change in magnitude of driver common-mode output voltage for complementary output states ?v od r = 27 ? or 50 ? , figure 4 0.2 v input high voltage v ih de, di, re 2.0 v input low voltage v il de, di, re 0.8 v input current i in1 de, di, re 2 a de = 0v; v in = 12v 1.0 input current (a, b) i in2 v cc = 0v or 5.25v, v in = -7v -0.8 ma receiver differential threshold voltage v th -7v v cm 12v -0.2 0.2 v receiver input hysteresis ?v th v cm = 0v 70 mv receiver output high voltage v oh i o = -4ma, vid = 200mv 3.5 v receiver output low voltage v ol i o = 4ma, vid = -200mv 0.4 v three-state (high impedance) output current at receiver i ozr 0.4v v o 2.4v 1 a receiver input resistance r in -7v v cm 12v k ?
max485 dc electrical characteristics (continued) (v cc = 5v 5%, t a = t min to t max , unless otherwise noted.) (notes 1, 2) parameter symbol conditions min ty p max units de = v cc 500 900 re = 0v or v cc 300 500 no-load supply current (note 3) i cc de = 0v a driver short-circuit current, i osd1 -7v v o 12v (note 4) 35 250 ma v o = high driver short-circuit current, i osd2 -7v v o 12v (note 4) 35 250 ma v o = low receiver short-circuit current i osr 0v v o v cc 7 95 ma switching characteristics (v cc = 5v 5%, t a = t min to t max , unless otherwise noted.) (notes 1, 2) parameter symbol conditions min typ max units t plh r diff = 54 10 30 60 driver input to output t phl c l1 = c l2 = 100pf 10 30 60 ns driver output skew to output t skew r diff = 54 , cl1 = cl2 = 100pf 5 10 ns driver enable to output high t zh c l = 100pf, s2 closed 40 70 ns driver enable to output low t zl c l = 100pf, s1 closed 40 70 ns driver disable time from low t lz c l = 15pf, s1 closed 40 70 ns driver disable time from high t hz c l = 15pf, s2 closed 40 70 ns | tplh - tphl | differential t skd r diff = 54 13 ns receiver skew c l1 = c l2 = 100pf receiver enable to output low t zl c rl = 15pf, s1 closed 20 50 ns receiver enable to output high t zh c rl = 15pf, s2 closed 20 50 ns receiver disable time from low t lz c rl = 15pf, s1 closed 20 50 ns receiver disable time from high t hz c rl = 15pf, s2 closed 20 50 ns maximum data rate f max 2.5 mbps
max485
max485 operation timing diagrams of max 485 table of max 485 operation transmitting receiving inputs outputs x inputs outputs re de di z y re de a-b ro x 1 1 0 1 0 0 +0.2v 1 x 1 0 1 0 0 0 -0.2v 0 0 0 x z z 0 0 open 1 1 0 x z z 1 0 x z x-don?t care z-high impedance
max485 n suffix plastic dip (ms ? 001ba) symbol min max a 8.51 10.16 b 6.1 7.11 c 5.33 d 0.36 0.56 f 1.14 1.78 g h j 0 10 k 2.92 3.81 notes: l 7.62 8.26 1. dimensions ?a?, ?b? do not include mold flash or protrusions. m 0.2 0.36 maximum mold flas h or protrus ions 0.25 mm (0.010) per s ide. n 0.38 d suffix soic (ms - 012aa) symbol min max a 4.8 5 b 3.8 4 c 1.35 1.75 d 0.33 0.51 f 0.4 1.27 g h j 0 8 notes: k 0.1 0.25 1. dimensions a and b do not include mold flash or protrusion. m 0.19 0.25 2. maximum mold flas h or protrus ion 0.15 mm (0.006) per s ide p 5.8 6.2 for a; for b ? 0.25 mm (0.010) per s ide. r 0.25 0.5 1.27 5.72 dimens ion, mm dimens ion, mm 2.54 7.62 a b h c k c m j f m p g d r x 45 seating plane 0.25 (0.010) m t -t- 1 8 4 5 l h m j a b f g d seating plane n k 0.25 (0.010) m t -t- c 1 8 4 5
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