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www.azmicrotek.com 1630 s stapley dr, suite 127 +1 - 480- 962- 5881 mesa, az 85204 usa request a sample may 2012, rev 1.2 b lock d iagram p ackage a vailability ? son8 o 1.5mm x 1.0mm x 0.4mm o green/rohs compliant/pb - free d escription the AZT70 is a digitally programmed capacitor specifically designed to tune a crystal or saw based oscillator to a desired center frequency. the desired capacitance value for production trimming is set by a serial data stream when placed into a programming mode. th e AZT70 is designed to be a labor and cost saving device within the oscillator production process. using eeprom technology, the capacitance can be re - tuned as needed during the production process by repeating the programming steps thereby increasing produc tion yield. the AZT70 is available in an son8 package (1.5mm x 1.0mm) for very small form factor oscillators. f eatures ? capacitive tuning range of 2.8pf to 14.55pf (see azt71 for different values) ? 0.063pf minimum step size ? re program mable through nonvolatile eeprom storage ? may be placed in parallel for greate r capacitance values ? very low supply current ? 2.5v to 3.6 v supply voltage a pplications ? fast production tuning of crystal or saw oscillators ? filters requiring capacitive tuning az t70 programmable capacitive tuning ic order number package marking AZT70qg 1 son8 t 2 1 tape & reel - add 'r1' at end of order number for 7in (1k parts), 'r2' (2.5k) for 13in 2 see www.azmicrotek.com for date code format www.azmicrotek.com
arizona microtek, inc. AZT70 programmable capacitive tuning ic www.azmicrotek.com +1 - 480- 962- 5881 2 request a sample may 2012, rev 1.2 p in d escription and c onfiguration table 1 - pin description pin name type function 1 x 1 output capacitance 2 nc n/a not connected 3 v ss power negative supply (gnd) 4 v dd power positive supply 5 da input programming data input 6 clk input programming clock input 7 nc n/a not connected 8 pv input programming voltage e ng ineering n otes c apacitor s tructure the AZT70 capacitance value is composed of three parallel capacitor banks, c f is a fixed capacitor value of 2.8pf and c mid & c lo are variable capacitors of differing ranges and resolutions as seen in table 2 . capacitors composing c mid and c lo are set with a binary control word through an 11 - bit shift register described in p rogramming the AZT70 . the values of each c lo and c mid stepping are detailed in the complete n ominal capacitance b inary m apping spreadsheet. c total = c f + c mid + c lo table 2 - AZT70 capacitor structure internal capacitor min value (pf) max value (pf) step size (pf) c f 2.8 2.8 n/a c mid 0 9.8 1.4 c lo 0 1.953 0.063 total 2.8 14.553 figure 1 ? pin configuration 1 x 1 nc v ss v dd da clk nc pv 2 3 4 8 7 6 5 t
arizona microtek, inc. AZT70 programmable capacitive tuning ic www.azmicrotek.com +1 - 480- 962- 5881 3 request a sample may 2012, rev 1.2 p rogramming the AZT70 c ontrol w ord the capacitance in the AZT70 is controlled by an 11 - bit shift register with the data input bit definitions shown in table 3 . the control word data is i nputted serially on the rising edge of the clk signal with bit0 first and bit10 last. table 3 - AZT70 control word definition 11- bit control word bit10 bit9 bit8 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 not used not used c mid c lo not used msb --- lsb msb --- --- --- lsb the control word mapping is a binary word for each of c mid and c lo where higher number bits are more significant. figure 2 shows the capacitance value mapping for the AZT70. the detailed n ominal capacitance b inary m apping can be located on the azm website. figure 2 ? AZT70 capacitance value mapping
arizona microtek, inc. AZT70 programmable capacitive tuning ic www.azmicrotek.com +1 - 480- 962- 5881 4 request a sample may 2012, rev 1.2 AZT70 f unctional m odes the AZT70 is designed to be used in 2 functional modes, programming and operational. in the p rogramming mode , the AZT70 is used by the manufacturer to set the capacitance value to control the desired center frequency of the oscillator. the programming mo de uses either the shift registers or eeprom (detailed later) and gives the manufacturer access to pins da, clk, and pv which allow the AZT70 to be programmed with an accompanying programming board ( figure 3 ). arizona microtek can provide this board ( azpb70 ) along with software that works through all the progra mming steps/functions described in the next sections. in the o perational mode , the eeprom internal to the AZT70 has already been programmed with the desired factory settings. pins da, clk, and pv are to be disconnected, thereby allowing the AZT70?s interna l pull - downs to place the pins at ground potential. in the operational mode, only 3 pins are necessary for hookup ( figure 4 ). AZT70 programming board (prt70) x 1 da clk pv da clk pv v ss v dd resonator out oscillator figure 3 ? AZT70 in programming mode AZT70 x 1 da clk pv v ss v dd resonator out oscillator nc nc nc figure 4 ? AZT70 in operational mode
arizona microtek, inc. AZT70 programmable capacitive tuning ic www.azmicrotek.com +1 - 480- 962- 5881 5 request a sample may 2012, rev 1.2 p rogramming m odes the AZT70 has two capacitance setting modes from which bits are set and the matching capacitors are selected. ? reading directly from the shift register o this is useful for testing the capacitance and subsequent oscillator frequency. this mode is active after the last bit is shifted in and when the clk pin is left logic high. for the shift register, capacitors are selected when bits are active high. ? reading from the value contained in the eeprom o prevents customer adjustment and retains factory programming and is active when the clk pin is at logic low or not connected. for the eeprom , capacitors are selected when bits are active low. p rogramming from the s hift r egister to initially determine the capacitance value for the desired center frequency of the oscillator one should set the capacitance of the AZT70 directly from the active shi ft register bits. to accomplish this, the clk pin is left high after the last control word bit has been shifted in. figure 5 shows the control word 11001100100 has been serially entered into the register. note that bit0 is the 1 st bit to enter and bit10 is the last. in the AZT70, bit0, bit9 & bit10 do not affect the capacitance value but still must be included in the serial bit stream. for the shift register, capacitors are selected when bits are active high. t da clk bit 0 bit 1 bit 2 bit 3 bit 4 bit 5 bit 6 bit 7 bit 8 bit 9 bit 10 register data active when clk is high bit 0 loaded 1 st figure 5 - shift register programming w riting d ata to the eeprom once the desired capacitance value has been determined, the digital control word can be written or re - written into the eeprom. by storing the control word in the eeprom, the customer is prevented from making adjustments from the factory set programming dat a. this is accomplished within the AZT70 with internal pull - downs on the da, pv, and clk pins. the detailed sequence for writing data to the eeprom within the AZT70 is described in table 4 . note that with eeprom, capacitors are selected when bits are active low.
arizona microtek, inc. AZT70 programmable capacitive tuning ic www.azmicrotek.com +1 - 480- 962- 5881 6 request a sample may 2012, rev 1.2 table 4 ? data writing sequence for eeprom step action 1 determine the desired capacitor control word with the operational power supply voltage and desired oscillator conditions 2 set the v dd supply voltage to +5.0v 3 if eeprom is not already erased, erase eeprom (see e rasing the eeprom ) 4 read the current state of the eeprom bits (see r eading b ack from the eeprom ) 5 compare the desired control word to t he stored eeprom control word. count the number of differences so as to prevent double/redundant writing 6 one bit at a time, load the first desired control word bit (bit selection for eeprom is active low) 7 set the pv pin to +6v (5.6v, 6.1v) with the pulse and idle shown in timing diagram ( figure 8 ) 8 progress through all necessary control word bits by repeating steps 5 & 6 until all bits are set to the desired control word. 9 verify the correct eeprom contents by reading back the individual bits for an example of writing bits into the eeprom, suppose the desired capacitance is 3.43pf. the control word becomes ?00000010100? ( figure 6 ). also suppose the eeprom bits have been erased and therefore logic high (the AZT70 is initially shipped in this condition). since bit0 is the first bit to be loaded, the bit sequence becomes 0- 0 - 1 - 0 - 1 - 0 - 0 - 0 - 0 - 0 - 0. however, as described before, selecting bits for the eeprom are active low, which will invert the logical values in the sequence to 1 - 1 - 0 - 1 - 0 - 1 - 1 - 1- 1 - 1 - 1 ( figure 7 ). note the differences between the eeprom bits and the converted control word. since there are 2 differences, two write cycles are required as only 1 bit should be written at a time. figure 8 shows the timing for bit2 while figure 9 shows the timing for bit4. bit 0 bit 1 bit 2 bit 3 bit 4 bit 5 bit 6 bit 7 bit 8 bit 9 bit 10 figure 6 ? desired control word bit 0 bit 1 bit 2 bit 3 bit 4 bit 5 bit 6 bit 7 bit 8 bit 9 bit 10 bit 0 bit 1 bit 2 bit 3 bit 4 bit 5 bit 6 bit 7 bit 8 bit 9 bit 10 da eeprom difference difference figure 7 ? converted co ntrol word and differences from known eeprom state s
arizona microtek, inc. AZT70 programmable capacitive tuning ic www.azmicrotek.com +1 - 480- 962- 5881 7 request a sample may 2012, rev 1.2 t da clk bit 0 bit 1 bit 2 bit 3 bit 4 bit 5 bit 6 bit 7 bit 8 bit 9 bit 10 bit 0 loaded 1 st bit 10 loaded last pv 4s min 10ms min 5.6v, 6.1v figure 8 ? first programming cycle to program bit2 into the eeprom t da clk bit 0 bit 1 bit 2 bit 3 bit 4 bit 5 bit 6 bit 7 bit 8 bit 9 bit 10 bit 0 loaded 1 st bit 10 loaded last pv 4s min 10ms min 5.6v, 6.1v figure 9 ? second programming cycle to program bit4 into the eeprom r eading b ack from the eeprom during programming, the pv pin is used to program the necessary control bits into the eeprom. however, it is also used to read the bits currently programmed into the e eprom. when the pv pin is not used during programming, the AZT70 provides a weak pull - up and pull - down on the pin. this allows the eeprom data to be shifted out to the pv pin and read after the clk sequence is complete and when the da & clk pins are high ( figure 10 ). each eeprom bit is selected by setting the da signal low (eeprom selection is active low) during the clk sequence. with an external 68k? resistor pull - up to v dd on the pv pin, a low eeprom bit produces 0.4v level while a high eeprom bit produces a 0.6*v dd level.
arizona microtek, inc. AZT70 programmable capacitive tuning ic www.azmicrotek.com +1 - 480- 962- 5881 8 request a sample may 2012, rev 1.2 t da clk bit 0 bit 1 bit 2 bit 3 bit 4 bit 5 bit 6 bit 7 bit 8 bit 9 bit 10 bit0 loaded 1 st bit10 loaded last pv 0.6*v dd bit5 selected resulting voltage if bit5 was high in eeprom resulting voltage if bit5 was low in eeprom 0.4v indeterminate with an external 68k? resistor pull-up to v dd figure 10 ? timing diagram to read bits from eeprom e rasing the eeprom t he eeprom can be erased by initiating a programming cycle with all da bits set high, including bit9 and bit10. after the programming cycle, all the eeprom bits are set low (logical high) except for the check bit (bit0), which remains high. table 5 ? erase sequence for eeprom step action set te v uppl oltae to v oa te prorain or it all i oouu fiure ) veri te correct m content reain ac te iniiual it t da clk bit 0 bit 1 bit 2 bit 3 bit 4 bit 5 bit 6 bit 7 bit 8 bit 9 bit 10 bit0 loaded 1 st bit10 loaded last pv 4s min 10ms min eeprom has been erased (no capacitors selected) 5.6v, 6.1v figure 11 ? programming sequence for erasing the eeprom
arizona microtek, inc. AZT70 programmable capacitive tuning ic www.azmicrotek.com +1 - 480- 962- 5881 9 request a sample may 2012, rev 1.2 p rogramming v oltage l imit c ircuit some existing programming circuits use a current source connected to a 6.5 ? 8.0 v supply. that circuit produces an excessive voltage on the pv pin, which can damage the AZT70. a simple modification eliminates the issue and maintains full programming compatibility with existing programming methods. a 5.6 v, ? watt zener, 1n5232b or equivalent, placed between the pv pin and ground will limit the voltage while still allowing the programming circuit to generate the current required for programming fuse link type parts.
arizona microtek, inc. AZT70 programmable capacitive tuning ic www.azmicrotek.com +1 - 480- 962- 5881 10 request a sample may 2012, rev 1.2 p erformance data table 6 ? absolute maximum ratings absolute maximum ratings are those values beyond which device life may be impaired . symbol characteristic rating unit v dd power supply 0 to +6.5 v v i 1 input voltage - 0.5 to v dd + 0.5 v t a operating temperature range - 40 to +85 c t stg storage temperature range - 65 to +150 c esd hbm human body model tbd v esd mm machine model tbd v esd cdm charged device model tbd v 1 pv pin can exceed v dd by 1.2v during the programming interval table 7 ? dc characteristics dc characteristics (v dd = 2.375v to 5.5v unless otherwise specified, t a = - 40 to 85 c) symbol characteristic conditions min typ max unit c pv nominal capacitance variation across process - 15 +15 % c vv capacitance variation across output voltage voltage variation at x 1 pin, 100mhz 150 ppm/v c tv capacitance variation across temperature 100mhz - zero code 325 ppm/ c 100mhz - mid code 1 40 100mhz - full scale 130 v ih input high voltage da, clk 0.8 * v dd v v il input low voltage da, clk 0.2 * v dd v r pd,d pull - down resistor da 55k ? r pd,clk pull - down resistor clk 75k ? r pd,pv pull - down resistor pv 170k ? v oh output high voltage pv pin when reading eeprom bits 68k ? pull - up resistor to v dd 0.6 * v dd v v ol output low voltage 0.4 v v pp programming voltage (v dd =5.0v) pv pin when programming eeprom 5.6 6.0 6.1 v i dd power supply current normal operation 7.0 50 a i ddprog power supply current programming mode 20 a t mem eeprom data retention 20 yrs t prog programming temperature 25 c cy prog programming cycle 10 k 1 bit4, bit7 high
arizona microtek, inc. AZT70 programmable capacitive tuning ic www.azmicrotek.com +1 - 480- 962- 5881 11 request a sample may 2012, rev 1.2 table 8 ? ac characteristics ac characteristics (v dd = 2.375v to 5.5v unless otherwise specified, t a = - 40 to 85 c) symbol characteristic conditions min typ max unit c f fixed capacitance 2.8 pf c mid step size 1.4 pf max value 9.8 pf c lo step size 0.063 pf max value 1.953 pf clk max clk rate 50% duty cycle 5 mhz t prog programming time (v dd =5.0v, pv=6.0v) per bit programmed 10 ms q q value 20mhz - full scale 200 320 20mhz - mid scale 100 200 100mhz - full scale 50 80 100mhz - mid scale 50 70 200mhz - full scale 25 40 200mhz - mid scale 35 50 800mhz - full scale 8 12 800mhz - mid scale 10 15
arizona microtek, inc. AZT70 programmable capacitive tuning ic www.azmicrotek.com +1 - 480- 962- 5881 12 request a sample may 2012, rev 1.2 p ackage d iagram son8 (1.5x1.0 x0.4 mm) green/rohs compliant/pb - free ar izona microtek, inc. reserves the right to change circuitry and specifications at any time without prior notice. arizona microtek, inc. makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, no r does arizona microtek, inc. assume any liability arising out of the application or use of any product or circuit and specifically disclaims any and all liability, including without limitation special, consequential or incidental damages. arizona microte k, inc. does not convey any license rights nor the rights of others. arizona microtek, inc. products are not designed, intended or authorized for use as components in systems intended to support or sustain life, or for any other application in which the f ailure of the arizona microtek, inc. product could create a situation where personal injury or death may occur. should buyer purchase or use arizona microtek, inc. products for any such unintended or unauthorized application, buyer shall indemnify and hol d arizona microtek, inc. and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such claim alleges that arizona microtek, inc. was negligent regarding the design or manufacture of the part.

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