19-0144; rev. 0; 9/93 _______________general description the MAX562 is designed specifically for notebook and palmtop computers that need to transfer data quickly. it runs at data rates up to 230kbps, and has a guaran- teed 4v/? slew rate. this device meets the new eia/tia-562 standard that guarantees compatibility with rs-232 interfaces. the MAX562 has low-power shutdown and keep-awake modes. in keep-awake mode, the transmitters are dis- abled but all receivers are active, allowing unidirection- al communication. in shutdown mode, the entire chip is disabled and all outputs are in a high-impedance state. the MAX562 is available in a standard 28-pin so pack- age, and in a smaller footprint shrink small-outline package (ssop). ________________________applications palmtop, notebook, and subnotebook computers peripherals battery-powered equipment ____________________________features ? 230kbps data rate, laplink compatible ? operates from a 2.7v to 5.25v supply ? designed for eia/tia-562 and eia/tia-232 applications ? guaranteed 4.0v/? slew rate ? 3 drivers, 5 receivers ? flow through pinout ? low-power shutdown and keep-awake modes ? low-cost, surface-mount external capacitors ______________ordering information * contact factory for dice specifications. MAX562 complete 230kbps, 2.7v to 5.25v serial interface for notebook computers ________________________________________________________________ maxim integrated products 1 28 27 26 25 24 23 22 21 20 19 18 17 16 15 1 2 3 4 5 6 7 8 9 10 11 12 13 14 v cc gnd v- c2+ c2- r1 in shdn r2 in r3 in r4 in r5 in t1 out t2 out t3 out en t3 in t2 in t1 in r5 out r4 out r3 out r2 out r1 out c1a- c1b- c1b+ c1a+ v+ MAX562 so/ssop top view __________________pin configuration t1 t2 t3 r1 r2 r3 r4 r5 5k 5k 5k 5k 5k gnd 19 shdn r5 in r4 in r3 in r2 in r1 in t3 out t2 out t1 out r5 out r4 out r3 out r2 out r1 out en t3 in t2 in t1 in voltage
doubler/tripler voltage
inverter 20 21 22 23 16 17 18 26 28
4 53 2 1 25 12 24 11 13 6 7 8 9 10 14 27 15 c2- c2+ v- c1a c1b c1a+ c1a- c1b+ c1b- v cc v+ c3 0.68? c4 0.33? 0.33? +2.7v to
+5.25v input 0.33? 0.33? 0.33? cmos
inputs cmos
outputs eia/tia
-562
inputs eia/tia
-562
outputs c2 MAX562 __________typical operating circuit call toll free 1-800-998-8800 for free samples or literature. part temp. range pin-package MAX562cwi 0? to +70? 28 so MAX562cai 0? to +70? 28 ssop MAX562c/d 0? to +70? dice* MAX562ewi -40? to +85? 28 so MAX562eai -40? to +85? 28 ssop laplink is a registered trademark of traveling software, inc.
MAX562 complete 230kbps, 2.7v to 5.25v serial interface for notebook computers 2 _______________________________________________________________________________________ absolute maximum ratings v cc ......................................................................... -0.3v to +6v v+ ................................................................ (v cc - 0.3v) to +6v v- ............................................................................ +0.3v to -6v c1a+, c1b+.................................................. -6v to (v+ + 0.3v) c1a-, c1b-, c2+ ........................................ -0.3v to (v+ + 0.3v) c2- .................................................................. (v- - 0.3v) to +6v input voltages t in , en, shdn ........................................ -0.3v to (v cc + 0.3v) r in ....................................................................................?5v output voltages t out ............................................................................... ?5v r out ...................................................... -0.3v to (v cc + 0.3v) short-circuit duration t out to gnd ........................................................ continuous r out to gnd, v cc ................................................ continuous continuous power dissipation (t a = +70?) so (derate 12.50mw/? above +70?) .................. 1000mw ssop (derate 9.52mw/? above +70?) ................. 762mw operating temperature ranges: MAX562c_ _ ..................................................... 0? to +70? MAX562e_ _ .................................................. -40? to +85? storage temperature range ........................... -65? to +160? lead temperature (soldering, 10sec) ........................... +300? electrical characteristics (v cc = 2.7v to 5.25v, c1a = c1b = c2 = c4 = 0.33?, c3 = 0.68?, t a = t min to t max , unless otherwise noted.) stresses beyond those listed under ?bsolute maximum ratings?may cause permanent damage to the device. these are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. parameter min typ max units input voltage operating range ?5 v input threshold low 0.8 v input threshold high 2.4 v input hysteresis no hysteresis when shdn = 0v 0.3 v input resistance -15v < v in < 15v 3 5 7 k output voltage swing all transmitter outputs loaded with 3k to gnd ?.7 ?.5 ?.0 v v cc = 2.7v to 3.6v 0.6 input logic threshold low t in , en, shdn v cc = 5.0v +5%, -10% 0.8 v v cc = 2.7v to 3.6v 1.8 input logic threshold high t in , en, shdn v cc = 5.0v +5%, -10% 3.0 v output voltage low i out = 1.6ma 0.4 v output voltage high i out = -1.0ma v output leakage current en = gnd, 0v r out v cc 0.05 ?0 ? operating supply voltage 2.7 5.25 v no load 20 33 v cc power-supply current v cc = 3.3v all outputs loaded 3k 24 ma en = v cc , shdn = gnd, t a = +25? 45 130 ? shutdown supply current shdn = en = gnd, t a = +25? 1 50 ? output leakage current ?0 ? output resistance v cc = v+ = v- = 0v, v out = ?v 300 output short-circuit current v out = 0v ?0 ma shutdown supply current with receivers active v cc -0.5 conditions eia/tia-562 transmitters eia/tia-562 receivers power supply
MAX562 complete 230kbps, 2.7v to 5.25v serial interface for notebook computers _______________________________________________________________________________________ 3 ac characteristics parameter conditions min typ max units receiver propagation delay, normal operation 250 500 ns c l = 150pf, shdn = gnd figure 2 3000 4000 receiver propagation delay, keep-awake mode 2000 3000 ns receiver-output enable time figure 4 100 250 ns receiver-output disable time figure 4 250 500 ns data rate 1000pf || 3k load each transmitter output, 150pf load each receiver output 230.4 280.0 kbits/sec transmitter slew rate c l = 50pf to 2500pf, r l = 3k to 7k . measured from +3v to -3v, or -3v to +3v 4 6 30 v/? c l = 2500pf 0.22 3.1 transmitter rise/fall time r l = 3k measured from +3.3v to -3.3v or -3.3v to +3.3v c l = 1000pf 0.22 2.1 ? t phlt 900 1700 transmitter propagation delay 2500pf || 3k load, figure 1 t plht 1000 1700 ns transmitter-output enable time 100 ? transmitter-output disable time figure 3 600 ns c l = 150pf, shdn = v cc figure 2 t phlr 100 250 t et t dt t plhr t phls t plhs t er t dr
MAX562 complete 230kbps, 2.7v to 5.25v serial interface for notebook computers 4 _______________________________________________________________________________________ __________________________________________typical operating characteristics 8.0
7.5
7.0
6.5
6.0
5.5
5.0
4.5
4.0
0 2000 3000 4000 5000 c l (pf) slew rate (v/?) 1000 slew- slew+ all outputs loaded
3k w ii c l transmitter slew rate
vs. load capacitance 6
5
4
3
2
1
0
-1
-2
-3
-4
-5
-6
-40 40 80 temperature (?) transmitter output voltage (v-, v+) 0 -3.7v eia/tia-562 t_ out + transmitter output voltage
vs. temperature t_ out - +3.7v eia/tia-562 all transmitters loaded 3k w ..... ..... 6
5
4
3
2
1
0
-1
-2
-3
-4
-5
-6
0 2000 3000 4000 5000 c l (pf) transmitter output voltage (v-, v+) 1000 t_ out - t_ out + all transmitters
loaded 3k w ii c l transmitter output voltage
vs. load capacitance, to 231kbps 38
36
34
32
30
28
26
24
22
20
2.5 3.5 4.0 v cc (v) supply current (ma) 3.0 supply current
vs. supply voltage all transmitters loaded 3k w 4.5 5.0 5.5 38
36
34
32
30
28
26
24
22
-40 40 80 temperature (?) supply current (ma) 0 supply current
vs. temperature v cc = +2.7v all transmitters loaded 3k w v cc = +3.3v 55
50
45
40
35
30
25
20
0 100 150 data rate (kbps) supply current (ma) 50 supply current
vs. transmitter data rate 1 output loaded
3k w ii 2500pf 2 outputs loaded
3k w ii 2500pf 3 outputs loaded
3k w ii 2500pf 200 250 60
55
50
45
40
35
-40 40 80 temperature (?) supply current (?) 0 supply current
vs. temperature v cc = +2.7v v cc = +3.3v shdn = 0, en = 1
all transmitters loaded 3k w __________________________________________typical operating characteristics (v cc = 3.3v, c1a = c1b = c2 = c4 = 0.33?, c3 = 0.68?, t a =+25?, unless otherwise noted.)
MAX562 complete 230kbps, 2.7v to 5.25v serial interface for notebook computers _______________________________________________________________________________________ 5 input output t plht 0v v oh 0v v ol t phlt +3v figure 1. transmitter propagation delay timing input output t phlr
t phls v cc 0v t plhr
t plhs 50% 50% +3v 50% gnd 50% figure 2. receiver propagation delay timing ______________________________________________________________pin description pin name function 28 v+ positive charge-pump output, typically 5.8v 2, 5 c1a+, c1a- terminals for positive charge-pump capacitor 3, 4 c1b+, c1b- terminals for positive charge-pump capacitor 6, 7, 8, 9, 10 r_ out ttl/cmos receiver outputs. 11, 12, 13 t_ in ttl/cmos driver inputs 14 en receiver enable, see shutdown and enable control section. 15 shdn shutdown control, see shutdown and enable control section. 16, 17, 18 t_ out eia/tia-562 driver outputs 19, 20, 21, 22, 23 r_ in eia/tia-562 receiver inputs 24, 25 c2+, c2- terminals for negative charge-pump capacitor 26 v- negative charge-pump output, typically -5.2v 27 gnd ground 1v cc +2.7v to +5.25v supply voltage
MAX562 complete 230kbps, 2.7v to 5.25v serial interface for notebook computers 6 _______________________________________________________________________________________ _______________detailed description the MAX562 has three sections: the charge-pump voltage converter, the drivers (transmitters), and the receivers. charge-pump voltage converter the charge-pump voltage converter is used to produce a positive and a negative supply to drive the transmitters. the positive voltage (v+) is generated by a regulated charge pump working as either a doubler or a tripler (depending on the v cc level) and using capacitors c1a, c1b and c3 (see typical operating circuit ). the negative voltage (v-) derives from v+ using a simple charge-pump inverter that employs capacitors c2 and c4. these charge-pump converters are regulated to give output voltages of +5.8v and -5.2v. having regulated supplies generated on-chip makes the MAX562's performance insen- sitive to variations in v cc from 2.7v to 5.25v, transmitter load- ing changes, and operating temperature changes. when shdn is low, the charge pumps are disabled, v+ is internally connected to v cc , and v- is internally connected to gnd. eia/tia-562 drivers the driver output voltage is guaranteed to meet the ?.7v eia/tia-562 specification over the full range of operating temperatures and voltages, when each transmitter is loaded with up to 3k and operated up to 230kbps (see typical operating characteristics ). the typical driver out- put voltage swing exceeds ?v with a 3k load on all transmitter outputs. the open-circuit output voltage swing is typically from (v+ - 0.7v) to (v- + 0.7v). output swing is not significantly dependent on v cc since the charge pumps are regulated. input thresholds are cmos and ttl compatible. connect unused inputs to v cc or to gnd. when shdn is low, the driver outputs are off and their leak- age currents are less than 10?, even if the transmitter outputs are back-driven between -7v and +15v. taking shdn low does not disable the receivers. when shdn and en are both low, the entire chip is disabled and all outputs are high impedance. power consumption is lowest in this condition. exiting shutdown takes about 100?, but depends on v cc . figure 5 shows shdn v oh v ol +3v 0v output disable time (t dt ) +3v -3v 0v a. timing diagram 1 or 0 t x 3k 50pf b. test circuit transmitter
outputs figure 3. transmitter-output disable timing en v oh -1v,
v ol +1.6v r_ in r_ out 1k 150pf a. test circuit b. enable timing en input receiver
outputs +3v 0v output enable time (t er ) v oh v ol en receiver
outputs en +3v 0v output disable time (t dr ) v oh -0.5v v ol +0.5v en input v oh v ol c. disable timing r_ figure 4. receiver-output enable and disable timing
MAX562 complete 230kbps, 2.7v to 5.25v serial interface for notebook computers _______________________________________________________________________________________ 7 the MAX562 transmitter outputs when shdn rises. two transmitter outputs are shown going to opposite eia/tia- 562 levels (one transmitter input is high, the other is low). each transmitter is loaded with 3k in parallel with 2500pf. the transmitter outputs are well behaved, with no ringing or undesirable transients as they come out of shutdown. driving multiple receivers each transmitter is designed to drive a single receiver. transmitters can be paralleled to drive multiple receivers. eia/tia-562 receivers all 5 receivers are identical and accept eia/tia-562 or eia/tia-232 signals. the cmos receiver outputs swing between v cc and gnd. they are inverting, maintaining compatibility with the driver outputs. the guaranteed 0.8v and 2.4v receiver input thresh- olds are significantly tighter than the ?.0v thresholds required by the eia/tia-562 specification. this allows the receiver inputs to respond to ttl/cmos logic lev- els as well as eia/tia-562/232 levels. also, the MAX562's guaranteed 0.8v lower threshold ensures that receivers shorted to ground will have a logic 1 out- put. the 5k input resistance to ground ensures that a receiver with its input left open will also have a logic 1 output. the receiver inputs have approximately 0.3v hysteresis when shdn is high. this provides clean output transi- tions, even with slowly moving input signals with mod- erate noise and ringing. the receivers are active when en is high. when en is low, the receiver outputs are high impedance. this allows wire-or connection of two eia/tia-562 ports (or ports of different types) at the uart. the receivers are always active,when en is high, irre- spective of shdn 's state. when shdn is high, the receivers have hysteresis and experience the shortest propagation delays (typically 100ns falling, 250ns ris- ing). when shdn is low, the receivers have longer propagation delays (typically 3 s falling, 2? rising) and have no hysteresis. the receiver outputs are not valid for 50? after shdn goes low. shutdown and enable control shdn and en determine the operation of the MAX562 as shown in table 1. __________applications information capacitor selection the capacitor type is not critical for proper MAX562 operation. any low cost ceramic capacitor (e.g., z5u, y5v) is acceptable for operating at room temperature, 0 200 300 100 shdn 5 0 6 4 2 0 -2 -4 v cc = +2.2v v cc = +2.7v v cc = +5.0v v cc = +3.3v time ( m s) volts (v) figure 5. time for transmitters to exit shutdown table 1. MAX562 control pin configurations shdn en charge-pump operation status transmitters t1-t3 receivers r1-r5 supply current typ (a) 0 0 shutdown high-z high-z 1 0 1 shutdown high-z active* 45 1 0 normal operation active high-z 24m 1 1 normal operation active active 24m * active, but with reduced performance (see eia/tia-562 receivers section). this is ?eep-awake?mode.
maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a maxim product. no circuit patent licenses are implied. maxim reserves the right to change the circuitry and specifications without notice at any time. 8 ___________________maxim integrated products, 120 san gabriel drive, sunnyvale, ca 94086 (408) 737-7600 1993 maxim integrated products printed usa is a registered trademark of maxim integrated products. MAX562 complete 230kbps, 2.7v to 5.25v serial interface for notebook computers and x7r ceramic capacitors are recommended for operation over the full temperature range. larger capacitors may be used for c2 and c4 (see typical operating circuit ) to reduce ripple on the trans- mitter output voltages. power-supply decoupling in applications that are sensitive to power-supply noise, decouple v cc to ground with a capacitor similar in value to that of the c1a and c1b charge-pump capaci- tors. connect the bypass capacitor as close as possi- ble to the v cc and gnd pins. v+ and v- as power supplies a small amount of power can be drawn from v+ and v-. excessive loads will cause v+ and v- to fall out of regulation. when v+ or v- are loaded, check for good regulation over the intended operating temperature range. ___________________chip topography 321
28 27 26 25 4 6 7 8 9 10 5 11 12 13 14 15 16 17 18 24 23 22 21 20 19 c1b- c1a- r1 out r2 out r3 out r4 out r5 out c1b+ c1a+ v cc v+ gnd v- c2+ c2- r1 in r2 in r3 in r4 in r5 in t1 in t2 in t3 in en shdn t3 out t2 out t1 out 0.164"
(4.166mm) 0.135"
(3.429mm) table 2. summary of eia/tia-232e/v.28 and eia/tia-562 specifications parameter condition eia/tia-232e/v.28 specification eia/tia-562 specification driver output voltage 0 level 3k to 7k load 5.0v to 15.0v 3.7v to 13.2v 1 level -5.0v to -15.0v -3.7v to -13.2v maximum output level no load ?5v ?3.2v signal rate (3k r l 7k ) c l = 2500pf up to 20kbps up to 20kbps c l = 1000pf not defined up to 64kbps substrate connected to v+ transistor count: 1892
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