1 ps8175b 11/06/98 pi3b16861/pi3b162861 3.3v, hot insertion, 20-bit, 2-port busswitch 1234567890123456789012345678901212345678901234567890123456789012123456789012345678901234567890121234567890123456789012345678901 2123456789012 product description pericom semiconductors pi3b series of bus switch circuits are produced in the companys advanced 0.35 micron cmos technology, achieving industry leading speed. the pi3b16861 is configured as a 3.3 volt, hot insertion, 20-bit, 2-port bus switch designed with a low on resistance (5 w ) allowing inputs to be connected directly to outputs. the bus switch creates no additional propagational delay or additional ground bounce noise. the switch is turned on by the bus enable (bex) input signal. the pi3b162861 device has a built-in 25-ohm series resistor to reduce noise resulting from reflections, thus eliminating the need for an external terminating resistor. 1234567890123456789012345678901212345678901234567890123456789012123456789012345678901234567890121234567890123456789012345678901 2123456789012 1234567890123456789012345678901212345678901234567890123456789012123456789012345678901234567890121234567890123456789012345678901 2123456789012 function be x a 19-a0 disconnect h hi-z connect l b 19-b0 truth table (1) note: 1. h = high voltage level l = low voltage level hi-z = high impedance pin name description bex bus enable inputs (active low) a 19-a0 bus a b 19-b0 bus b product pin description product pin configuration pi3b16861 pi3b162861 (25 w w w w w ) 3.3v, hot insertion, 20-bit, 2-port busswitch product features ? near-zero propagation delay ?5 w or 25w switches connect inputs to outputs ? fast switching speed - 5ns (max.) ? direct bus connection when switches are on ? permits hot insertion ? 32x384 function with flow through pinout make board layout easier ? vcc operating range: 3.0v to 3.6v ? industrial operating temperature: C40c to +85c ? packages available: C 48-pin 240-mil wide plastic tssop (a) C 48-pin 300-mil wide plastic ssop (v) C 48-pin 150-mil wide plastic bqsop (b) logic block diagram be 1 a 9 a 0 b 9 b 0 be 2 a 19 a 10 b 19 b 10 nc a 0 a 1 a 2 a 3 a 4 a 5 a 6 a 7 a 8 a 9 gnd nc a 10 a 11 a 12 a 13 a 14 a 15 a 16 a 17 a 18 a 19 gnd 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 vcc be 1 b 0 b 1 b 2 b 3 b 4 b 5 b 6 b 7 b 8 b 9 vcc be 2 b 10 b 11 b 12 b 13 b 14 b 15 b 16 b 17 b 18 b 19 48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25
2 ps8175b 11/06/98 pi3b16861/pi3b162861 3.3v, hot insertion, 20-bit, 2-port busswitch 1234567890123456789012345678901212345678901234567890123456789012123456789012345678901234567890121234567890123456789012345678901 2123456789012 dc electrical characteristics (over the operating range, t a = C40c to +85c, v cc = 3.0v to 3.6v) parameters description test conditions (1) min. typ (2) max. units v ih input high voltage guaranteed logic high level 2.0 v v il input low voltage guaranteed logic low level C0.5 0.8 v i ih input high current v cc = max., v in = v cc 1a i il input low current v cc = max., v in = gnd 1 a i ozh high impedance output current 0 a, b v cc 1a v ik clamp diode voltage v cc = min., i in = C18ma C0.7 C1.2 v r on switch on resistance (3) v cc = min., v in = 0.0v, 1 6861 5 8 w i on = 48ma 162861 20 28 40 v cc = min., v in = 2.4v, 16861 10 15 w i on = 15ma 162861 20 35 48 storage temperature ................................................................. C65c to +150c ambient temperature with power applied .................................. C0c to +85c supply voltage range .................................................................. C0.5v to +4.6v dc input voltage ......................................................................... C0.5v to +4.6v dc output current ................................................................................... 120 ma power dissipation ......................................................................................... 0.5w maximum ratings (above which the useful life may be impaired. for user guidelines, not tested.) capacitance (t a = 25c, f = 1 mhz) parameters (4) description test conditions typ units c in input capacitance v in = 0v 3.0 pf c off a/b capacitance, switch off v in = 0v 8.5 pf c on a/b capacitance, switch on v in = 0v 17.0 pf notes: 1. for max. or min. conditions, use appropriate value specified under electrical characteristics for the applicable device type. 2. typical values are at vcc = 3.3v, t a = 25c ambient and maximum loading. 3. measured by the voltage drop between a and b pin at indicated current through the switch. on resistance is determined by the lower of the voltages on the two (a,b) pins. 4. this parameter is determined by device characterization but is not production tested. note: stresses greater than those listed under maximum ratings may cause permanent damage to the device. this is a stress rating only and functional operation of the device at these or any other conditions above those indicated in the operational sections of this specification is not implied. exposure to absolute m aximum rating conditions for extended periods may affect reli- ability.
3 ps8175b 11/06/98 1234567890123456789012345678901212345678901234567890123456789012123456789012345678901234567890121234567890123456789012345678901 2123456789012 pi3b16861/pi3b162861 3.3v, hot insertion, 20-bit, 2-port busswitch pi3b16861/pi3b162861 com. parameters description conditions (1) min. max. units t plh propagation delay (2,3) c l = 50pf 16861 0.25 t phl ax to bx, bx to ax r l = 500 w 162861 1.25 t pzh bus enable time c l = 50pf, 1 4.5 ns t pzl be to ax or bx r l = 500 w, t phz bus disable time r = 500 w 1 5 t plz be to ax or bx switching characteristics over operating range notes: 1. see test circuit and waveforms. 2. this parameter is guaranteed but not tested on propagation delays. 3. the bus switch contributes no propagational delay other than the rc delay of the on resistance of the switch and the load capacitance. the time constant for the switch alone is of the order of 0.25ns for 50pf load. since this time constant is much smaller than the rise/fall times of typical driving signals, it adds very little propagational delay to the system. propagatio nal delay of the bus switch when used in a system is determined by the driving circuit on the driving side of the switch and its interaction with the load on the driven side. pericom semiconductor corporation 2380 bering drive ? san jose, ca 95131 ? 1-800-435-2336 ? fax (408) 435-1100 ? http://www.pericom.com power supply characteristics parameters description test conditions (1) min. typ (2) max. units i cc quiescent power v cc = max. v in = gnd or v cc 10 a supply current d i cc supply current per v cc = max. v in = 3.0v (3) 750 a input @ ttl high i ccd supply current per v cc = max. 0.25 ma/ input per mhz (4) a and b pins open mhz be = gnd control input toggling 50% duty cycle notes: 1. for max. or min. conditions, use appropriate value specified under electrical characteristics for the applicable device. 2. typical values are at vcc = 3.3v, +25c ambient. 3. per ttl driven input (control inputs only); a and b pins do not contribute to icc. 4. this current applies to the control inputs only and represent the current required to switch internal capacitance at the specified frequency. the a and b inputs generate no significant ac or dc currents as they transition. this parameter is not tested, but is guaranteed by design.
|
