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document # eeprom106 rev 03 revised october 2014 PYA28HC256 high speed 32k x 8 eeprom features access times of 70, 90 and 120ns single 5v10% power supply simple byte and page write low power cmos: - 80 ma active current - 3 ma standby current fast write cycle times software data protection cmos & ttl compatible inputs and outputs endurance: - 10,000 write cycles - 100,000 write cycles (optional) data retention: 10 years available in the following package: C 28-pin 600 mil ceramic dip C 32-pin ceramic lcc (450x550 mils) functional block diagram pin config uration dip (c5-1) description the PYA28HC256 is a 5 volt 32kx8 eeprom. the device supports 64-byte page write operation. the PYA28HC256 features data and toggle bit polling as well as a system software scheme used to indicate early completion of a write cycle. the device also includes user-optional soft - ware data protection. data retention is 10 years. the device is available in a 28-pin 600 mil wide ceramic dip and 32-pin lcc. lcc (l6)
PYA28HC256 - high speed 32k x 8 eeprom page 2 document # eeprom106 rev 03 operatio n read read operations are initiated by both oe and ce low. the read operation is terminated by either ce or oe re - turning high. this two line control architecture elimi - nates bus contention in a system environment. the data bus will be in a high impedance state when either oe or ce is high. byte write write operations are initiated when both ce and we are low and oe is high. the PYA28HC256 supports both a ce and we controlled write cycle. that is, the address is latched by the falling edge of either ce or we , which - ever occurs last. similarly, the data is latched internally by the rising edge of either ce or we , whichever occurs frst. a byte write operation, once initiated, will automati - cally continue to completion. pa ge write the page write feature of the PYA28HC256 allows 1 to 64 bytes of data to be consecutively written to the PYA28HC256 during a single internal programming cycle. the host can fetch data from another device within the system during a page write operation (change the source address), but the page address (a 6 through a 14 ) for each subsequent valid write cycle to the part during this opera - tion must be the same as the initial page address. the bytes within the page to be written are specifed with the a 0 through a 5 inputs. the page write mode can be initiated during any write operation. following the initial byte write cycle, the host can write an additional 1 to 63 bytes in the same man - ner as the frst byte was written. each successive byte load cycle, started by the we high to low transition, must begin within 150s of the falling edge of the pre - ceding we . if a subsequent we high to low transition is not detected within 150s, the internal automatic pro - gramming cycle will commence. there is no page write window limitation. effectively, the page write window is infnitely wide, so long as the host continues to access the device within the byte load cycle time of 150s. write status bits the PYA28HC256 provides the user two write operation status bits. these can be used to optimize a system write cycle time. the status bits are mapped onto the i/o bus as shown below. data polli ng the PYA28HC256 features data polling as a meth - od to indicate to the host system that the byte write or page write cycle has completed. data polling allows a simple bit test operation to determine the status of the PYA28HC256, eliminating additional interrupts or external hardware. during the internal programming cycle, any at - tempt to read the last byte written will produce the comple - ment of that data on i/o 7 (i.e., write data=0xxx xxxx, read data=1xxx xxxx). once the programming cycle is com - plete, i/o 7 will refect true data. note: if the PYA28HC256 is in the protected state and an illegal write operation is attempted, data polling will not operate. to ggle bit the PYA28HC256 also provides another method for de - termining when the internal write cycle is complete. dur - ing the internal programming cycle, i/o 6 will toggle from high to low and low to high on subsequent attempts to read the device. when the internal cycle is complete the toggling will cease and the device will be accessible for addtional read or write operations. data protectio n pyramid has incorporated both hardware and software features that will protect the memory against inadvertent writes during transitions of the host system power sup - ply. hardware protection hardware features protect against inadvertent writes to the pya28c256 in the following ways: (a) vcc sense - if vcc is below 3.8v (typical) the write function is inhibited; (b) vcc power-on delay - once vcc has reached 3.8v the device will automatically time out 5 ms (typical) before allowing a write; (c) write inhibit - holding any one of oe low, ce high or we high inhibits write cycles; and (d) noise flter - pulses of less than 15 ns (typical) on the we or ce inputs will not initiate a write cycle. software data protection a software controlled data protection feature has been implemented on the pya28c256. when enabled, the software data protection (sdp), will prevent inadvertent writes. the sdp feature may be enabled or disabled by the user; the pya28c256 is shipped from pyramid with sdp disabled. sdp is enabled by the host system issuing a series of
PYA28HC256 - high speed 32k x 8 eeprom page 3 document # eeprom106 rev 03 three write commands; three specifc bytes of data are written to the three specifc addresses (refer to "software data protection" algorithm). after writing the 3-byte com - mand sequence and after twc the entire pya28c256 will be protected against inadvertent write operations. it should be noted, that once protected the host may still perform a byte or page write to the pya28c256. this is done by preceding the data to be written by the same 3-byte command sequence used to enable sdp. once set, sdp will remain active unless the disable com - mand sequence is issued. power transitions do not dis - able sdp and sdp will protect the pya28c256 during power-up and power-down conditions. all command se - quences must conform to the page write timing specif - cations. the data in the enable and disable command sequences is not written to the device and the memory addresses used in the sequence may be written with data in either a byte or page write operation. after setting sdp, any attempt to write to the device with - out the 3-byte command sequence will start the internal write timers. no data will be written to the device; howev - er, for the duration of twc, read operations will effectively be polling operations. device iden tification an extra 64 bytes of eeprom memory are available to the user for device identifcation. by raising a9 to 12v 0.5v and using address locations 7fc0h to 7fffh the additional bytes may be written to or read from in the same manner as the regular memory array. option al chip erase mode the entire device can be erased using a 6-byte software code. please see "software chip erase" application note at the end of this datasheet for details.
PYA28HC256 - high speed 32k x 8 eeprom page 4 document # eeprom106 rev 03 dc electrical characteristics (over recommended operating temperature & supply voltage) (2) sym parameter value unit v cc power supply pin with respect to gnd -0.3 to +6.25 v v term terminal voltage with respect to gnd (up to 6.25v) -0.5 to +6.25 v t a operating temperature -55 to +125 c t bias temperature under bias -55 to +125 c t stg storage temperature -65 to +150 c p t power dissipation 1.0 w i out dc output current 50 ma maximum r atings (1) recommen ded operating conditions grade (2) ambient temp gnd v cc military -55c to +125c 0v 5.0v 10% capacita nces (4) (v cc = 5.0v, t a = 25c, f = 1.0mhz) sym parameter conditions typ unit c in input capacitance v in = 0v 10 pf c out output capacitance v out = 0v 10 pf sym parameter test conditions min max unit v ih input high voltage 2.0 v cc + 0.3 v v il input low voltage -0.5 (3) 0.8 v v hc cmos input high voltage v cc - 0.2 v cc + 0.5 v v lc cmos input low voltage -0.5 (3) 0.2 v v ol output low voltage (ttl load) i ol = +2.1 ma, v cc = min 0.45 v v oh output high voltage (ttl load) i oh = -0.4 ma, v cc = min 2.4 v i li input leakage current v cc = max v in = gnd to v cc -10 +10 a i lo output leakage current v cc = max, ce = v ih , v out = gnd to v cc -10 +10 a i sb standby power supply current (ttl input levels) ce v ih , oe = v il , v cc = max, f = max, outputs open 90, 120ns 3 ma 70ns 60 ma i sb1 standby power supply current (cmos input levels) ce v hc , v cc = max, f = 0, outputs open, v in v lc or v in v hc 300 a i cc supply current ce = oe = v il , we = v ih , all i/o's = open, inputs = v cc = 5.5v 80 ma notes: 1. stresses greater than those listed under maximum ra tings 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 specifcation is not implied. exposure to maximum rating conditions for extended periods may affect reliability. 2. extended temperature operation guaranteed with 400 linear feet per minute of air fow. 3. transient inputs with v il and i il not more negative than -3.0v and -100ma, respectively, are permissible for pulse widths up to 20ns. 4. this parameter is sampled and not 100% tested.
PYA28HC256 - high speed 32k x 8 eeprom page 5 document # eeprom106 rev 03 sym parameter -70 -90 -120 unit min max min max min max t avav read cycle time 70 90 120 ns t avqv address access time 70 90 120 ns t elqv chip enable access time 70 90 120 ns t olqv output enable access time 35 40 50 ns t elqx chip enable to output in low z 0 0 0 ns t ehqz chip disable to to output in high z 35 40 50 ns t olqx output enable to output in low z 0 0 0 ns t ohqz output disable to output in high z 35 40 50 ns t avq x output hold from address change 0 0 0 ns ac electrical characteristicsread cycle (v cc = 5v 10%, all temperature ranges) (2) timing waveform of read cycle power-up timi ng symbol parameter max unit t pur power-up to read operation 100 s t puw power-up to write operation 5 ms
PYA28HC256 - high speed 32k x 8 eeprom page 6 document # eeprom106 rev 03 ac characteristicswrite cycle (v cc = 5v 10%, all temperature ranges) (2) symbol parameter 70 / 90 / 120 unit min max t whwl1 t ehel1 write cycle time 10 ms t avel t avwl address setup time 0 ns t elax t wlax address hold time 50 ns t wlel t elwl write setup time 0 ns t wheh write hold time 0 ns t ohel t ohwl oe setup time 10 ns t whol oe hold time 10 ns t eleh t wlwh we pulse width 100 ns t dveh t dvwh data setup time 50 ns t ehdx t whdx data hold time 0 ns t ehel2 t whwl2 byte load cycle time 0.2 150 s t elwl ce setup time 1 s t ovhwl output setup time 1 s t ehwh ce hold time 1 s t whoh oe hold time 1 s
PYA28HC256 - high speed 32k x 8 eeprom page 7 document # eeprom106 rev 03 timing waveform of byte write cycle ( ce controlled) timing waveform of byte write cycle ( we controlled)
PYA28HC256 - high speed 32k x 8 eeprom page 8 document # eeprom106 rev 03 timing waveform of page write cycle notes: ? for each successive write within the page write operation, a 6 -a 14 should be the same. otherwise, writes to an un - known address could occur. ? between successive byte writes within a page write operation, oe can be strobed low. for example, this can be done with ce and we high to fetch data from another memory device within the system for the next write. alterna - tively, this can be done with we high and ce low, effectively performing a polling operation. ? the timings shown above are unique to page write operations. individual byte load operations within the page write must conform to either the ce or we controlled write cycle timing.
PYA28HC256 - high speed 32k x 8 eeprom page 9 document # eeprom106 rev 03 write sequen ce for software data protection software seque n ce to de-activate software data protectio n
PYA28HC256 - high speed 32k x 8 eeprom page 10 document # eeprom106 rev 03 ac test conditions truth table input pulse levels gnd to 3.0v input rise and fall times 10ns input timing reference level 1.5v output timing reference level 1.5v output load see figure 1 mode ce oe we i/o read l l h d out write l h l d in write inhibit x l x write inhibit x x h standby h x x high z output disable x h x high z figure 1. output load
PYA28HC256 - high speed 32k x 8 eeprom page 11 document # eeprom106 rev 03 applicatio n n ote - software chip erase chip erase cycle waveforms chip erase cycle characteristics notes: data format: (hex); address format: (hex). 1. after loading the 6-byte code, no byte loads are allowed 2. until the completion of the erase cycle. the erase cycle will time itself to completion in 20 ms (max). t he fow diagram shown is for a x8 part. for a x16 part, 3. the data should be 16 bits long (e.g., the data to be loaded should be aaaa for step 1 in the algorithm). chip erase software al gorithm (1)(3) the entire device can be erased at one time by using a 6-byte software code. the software chip erase code consists of 6-byte load commands to specifc address locations with specifc data patterns. once the code has been entered, the device will set each byte to the high state (ffh). after the software chip erase has been initiated, the device will inter - nally time the erase operation so that no external clocks are required. the maximum time required to erase the whole chip is t ec (20 ms). the software data protection is still enabled even after the software chip erase is performed. symbol parameter t ec chip erase cycle time 20 ms max notes: oe 1. must be high only when we and ce are both low.
PYA28HC256 - high speed 32k x 8 eeprom page 12 document # eeprom106 rev 03 applicatio n n ote - software chip erase chip erase cycle characteristics notes: data format: (hex); address format: (hex). 1. after loading the 6-byte code, no byte loads are 2. allowed until the completion of the erase cycle. the erase cycle will time itself to completion in 20 ms (max). t he fow diagram shown is for a x8 part. for a 3. x16 part, the data should be 16 bits long (e.g., the data to be loaded should be aaaa for step 1 in the algorithm). chip erase software al gorithm (1)(3) the entire device can be erased at one time by using a 6-byte software code. the software chip erase code consists of 6-byte load commands to specifc address locations with specifc data patterns. once the code has been entered, the device will set each byte to the high state (ffh). after the software chip erase has been initiated, the device will inter - nally time the erase operation so that no external clocks are required. the maximum time required to erase the whole chip is t ec (20 ms). the software data protection is still enabled even after the software chip erase is performed. symbol parameter t ec chip erase cycle time 20 ms max notes: oe 1. must be high only when we and ce are both low. chip erase cycle waveforms
PYA28HC256 - high speed 32k x 8 eeprom page 13 document # eeprom106 rev 03 ordering in formation [1] parts are not mil-std-883 compliant. parts are processed per test method 5004.
PYA28HC256 - high speed 32k x 8 eeprom page 14 document # eeprom106 rev 03 side brazed dual i n-lin e package (600 mils) pkg # l6 # pins 32 symbol min max a 0.060 0.075 a1 0.050 0.065 b1 0.022 0.028 d 0.442 0.458 d1 0.300 bsc d2 0.150 bsc d3 - 0.458 e 0.540 0.560 e1 0.400 bsc e2 0.200 bsc e3 - 0.558 e 0.050 bsc h 0.040 ref j 0.020 ref l 0.045 0.055 l1 0.045 0.055 l2 0.075 0.095 nd 7 ne 9 recta ng ular leadless chip carrier pkg # c5-1 # pins 28 (600 mil) symbol min max a - 0.232 b 0.014 0.026 b2 0.045 0.065 c 0.008 0.018 d - 1.490 e 0.500 0.610 ea 0.600 bsc e 0.100 bsc l 0.125 0.200 q 0.015 0.060 s1 0.005 - s2 0.005 -
PYA28HC256 - high speed 32k x 8 eeprom page 15 document # eeprom106 rev 03 revisions document number eeprom106 document title PYA28HC256 - high speed 32k x 8 eeprom rev issue date origin ator description of change or jan 2011 jdb new data sheet a nov 2011 jdb updated ordering info 02 jul 2014 jdb added software chip erase app note 03 oct 2014 jdb replaced mil-std-883 class b process fow with t est method 5004

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