AZT71 Programmable Capacitive Tuning IC www.azmicrotek.com DESCRIPTION FEATURES The AZT71 is a digitally programmed capacitor designed to tune a filter or a crystal/SAW based oscillator to a desired center frequency. Through a bank of registers, the capacitance value is set by a serial data stream and if desired, can be permanently stored in the nonvolatile EEPROM memory. The AZT71 is designed to be a labor and cost saving device within the oscillator production process and provide the desired functionality for tunable filter banks. • (See AZT70 for different values) • • While incorporating very small step sizes (0.063pF), multiple AZT71 devices can also be used in parallel to obtain higher overall capacitance values. • • The AZT71 is available in an SON8 package (1.5mm x 1.0mm) for very small form factor designs. Also available in MLP6 and TSOT6. BLOCK DIAGRAM X1 DA • • CF 6.6pF CONTROLLER PV 0.063pF minimum step size Continually programmable with register or EEPROM data storage May be placed in parallel for greater capacitance values 2.5V to 3.6V supply voltage APPLICATIONS VDD CLK Capacitive tuning range of 6.6pF to 37.553pF b10-b9 b8-b6 Chi 0-19.2pF Filters requiring capacitive tuning Fast production tuning of crystal and SAW oscillators PACKAGE AVAILABILITY Cmid 0-9.8pF Clo 0-1.953pF b5-b1 VSS • • • SON8 MLP6 TSOT6 • Green/RoHS/Pb-Free Order Number Package Marking AZT71QG1 SON8 Y<Date Code>2 AZT71HG1 TSOT6 Y1G <Date Code>2 AZT71MG1 MLP6 Y1G <Date Code>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 +1-480-962-5881 Request a Sample 1630 S Stapley Dr, Suite 127 Mesa, AZ 85204 USA Jan 2013, Rev 1.3 Arizona Microtek, Inc. AZT71 Programmable Capacitive Tuning IC PIN DESCRIPTION AND CONFIGURATION Table 1 - Pin Description SON8 Package (1.5mm x 1.0mm) Name Type Function 1 X1 Output Capacitance 2 NC n/a not connected 3 VSS Power Negative Supply (GND) 4 VDD 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 1 X1 NC 2 VSS 3 VDD 4 Y <date code> Pin 8 PV 7 NC 6 CLK 5 DA Figure 1 - Pin Configuration SON8 Table 2 - Pin Description TSOT6 Package Name Type Function 1 X1 Output Capacitance 2 VSS Power Negative Supply (GND) 3 4 5 6 PV CLK DA VDD Input Input Input Power Programming Voltage Programming Clock Input Programming Data Input Positive Supply X1 1 Y1 <date code> Pin VSS 2 PV 3 6 VDD 5 DA 4 CLK Figure 2 - Pin Configuration TSOT6 Table 3 - Pin Description 6MLP Package (2.0mm x 2.0mm) Name Type Function 1 X1 Output Capacitance 2 VSS Power Negative Supply (GND) 3 4 5 6 VDD DA CLK PV Power Input Input Input Positive Supply Programming Data Input Programming Clock Input Programming Voltage X1 1 VSS 2 VDD 3 YG1 <date code> Pin 6 PV 5 CLK 4 DA Figure 3 - Pin Configuration 6MLP www.azmicrotek.com +1-480-962-5881 Request a Sample 2 Jan 2013, Rev 1.3 Arizona Microtek, Inc. AZT71 Programmable Capacitive Tuning IC ENGINEERING NOTES CAPACITOR STRUCTURE The AZT71 capacitance value is composed of four parallel capacitors banks, CF is a fixed capacitor value of 6.6pF and Chi, Cmid & Clo are variable capacitors of differing ranges and resolutions as seen in Table 4. Capacitors composing Chi, Cmid and Clo are set with a binary control word through an 11-bit shift register described in PROGRAMMING THE AZT71. The values of each Chi, Cmid and Clo stepping are detailed in the complete Nominal Capacitance Binary Mapping spreadsheet. CTotal = CF + Chi + Cmid + Clo Table 4 - AZT71 Capacitor Structure Internal Capacitor Min Value (pF) Max Value (pF) Step Size (pF) CF Chi Cmid Clo 6.6 0 0 0 6.6 19.2 9.8 1.953 n/a 6.4 1.4 0.063 Total 6.6 37.553 FUNCTIONAL MODES The AZT71 has two methods for setting the capacitance value on the X1 pin. • READING THE CONTROL WORD DIRECTLY FROM THE SHIFT REGISTER In tunable filter applications, reading from the shift register will be desirable as the control word can be constantly varied. New control words can be serially inputted as required to change the capacitance value in real time. (Note: With a serial data input, the capacitance value during transitions between control words is deterministic upon their differences.) The shift register is also useful for testing the capacitance and subsequent oscillator frequency. This mode is active when the CLK pin is left logic high. For the shift register, capacitors are selected when bits are active HIGH. • READING THE CONTROL WORD FROM THE VALUE CONTAINED IN THE EEPROM If a certain control word needs to be stored, it can be written to the nonvolatile EEPROM memory. This is useful in oscillator applications where it prevents customer adjustment and retains factory programming. This mode is active when the CLK pin is at logic low or not connected. For the EEPROM, capacitors are selected when bits are active LOW. www.azmicrotek.com +1-480-962-5881 Request a Sample 3 Jan 2013, Rev 1.3 Arizona Microtek, Inc. AZT71 Programmable Capacitive Tuning IC OSCILLATOR APPLICATION In oscillator applications, the AZT71 is designed to be used in 2 phases, Programming and Operational. In the Programming phase, the AZT71 is used by the manufacturer to set the capacitance value to control the desired center frequency of the oscillator. The programming phase gives the manufacturer access to pins DA, CLK, and PV where the shift registers are used to first determine the required control word. That control word is then stored in the EEPROM memory. Arizona Microtek can provide the programming board (AZPB70) along with software that works through all the programming steps/functions described in the next sections (Figure 4). In the Operational phase, the EEPROM memory internal to the AZT71 has already been programmed with the desired factory settings. Pins DA, CLK, and PV are to be disconnected, thereby allowing the AZT71’s internal pull-downs to place the pins at ground potential. In the operational mode, only 3 pins are necessary for hookup (Figure 5). VDD DA DA AZT71 Programming CLK Board (AZPB70) X1 CLK PV PV VSS OUT RESONATOR OSCILLATOR Figure 4 – AZT71 in Programming Mode VDD NC DA AZT71 X1 NC CLK NC PV VSS OUT RESONATOR OSCILLATOR Figure 5 – AZT71 in Operational Mode www.azmicrotek.com +1-480-962-5881 Request a Sample 4 Jan 2013, Rev 1.3 Arizona Microtek, Inc. AZT71 Programmable Capacitive Tuning IC PROGRAMMING THE AZT71 CONTROL WORD The capacitance in the AZT71 is controlled by an 11-bit shift register with the data input bit definitions shown in Table 5. The control word data is inputted serially on the rising edge of the CLK signal with bit0 first and bit10 last. Table 5 - AZT71 Control Word Definition bit10 bit9 bit8 Chi MSB bit7 11-bit Control Word bit6 bit5 bit4 Cmid LSB MSB --- bit3 bit2 bit1 --- LSB Clo LSB MSB --- --- bit0 Not Used The control word mapping is a binary word for each of Chi, Cmid and Clo where higher number bits are more significant. Figure 6 shows the capacitance value mapping for the AZT71. The detailed Nominal Capacitance Binary Mapping can be located on the AZM website. Figure 6 – AZT71 Capacitance Value Mapping www.azmicrotek.com +1-480-962-5881 Request a Sample 5 Jan 2013, Rev 1.3 Arizona Microtek, Inc. AZT71 Programmable Capacitive Tuning IC PROGRAMMING TO THE SHIFT REGISTER Control word bits are inputted serially through the DA pin timed with the rising edge of the CLK pin. Figure 7 shows the control word 11001100100 has been serially entered into the register. Note that bit0 is the 1st bit to enter and bit10 is the last. In the AZT71, bit0 does 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. For the AZT71 to read from the shift register, the CLK pin must remain HIGH. bit 0 DA 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 1st CLK t Figure 7 - Shift register programming WRITING DATA 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 data. This is accomplished within the AZT71 with internal pull-downs on the DA, PV, and CLK pins. The detailed sequence for writing data to the EEPROM within the AZT71 is described in Table 6. Note that with EEPROM, capacitors are selected when bits are active LOW. Table 6 – Data writing sequence for EEPROM Step 1 Action Determine the desired capacitor control word with the operational power supply voltage and desired oscillator conditions 2 Set the VDD supply voltage to +5.0V 3 4 If EEPROM is not already erased, erase EEPROM (see ERASING THE EEPROM) Read the current state of the EEPROM bits (see READING BACK FROM THE EEPROM) Compare the desired control word to the stored EEPROM control word. Count the number of differences so as to prevent double/redundant writing One bit at a time, load the first desired control word bit (bit selection for EEPROM is active LOW) Set the PV pin to +6V (≥5.6V, ≤6.1V) with the pulse and idle shown in timing diagram (Figure 10) Progress through all necessary control word bits by repeating steps 5 & 6 until all bits are set to the desired control word. Verify the correct EEPROM contents by reading back the individual bits 5 6 7 8 9 www.azmicrotek.com +1-480-962-5881 Request a Sample 6 Jan 2013, Rev 1.3 Arizona Microtek, Inc. AZT71 Programmable Capacitive Tuning IC For an example of writing bits into the EEPROM, suppose the desired capacitance is 7.23pF. The control word becomes ‘00000010100’ (Figure 8). Also suppose the EEPROM bits have been erased and therefore logic high (The AZT71 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 9). 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 10 shows the timing for bit2 while Figure 11 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 8 – Desired control word bit 0 bit 1 bit 0 bit 1 bit 2 bit 3 bit 4 bit 5 bit 6 bit 7 bit 8 bit 9 bit 10 bit 5 bit 6 bit 7 bit 8 bit 9 bit 10 DA difference bit 2 difference bit 3 bit 4 EEPROM Figure 9 – Converted control word and differences from known EEPROM states bit 0 DA bit 1 bit 2 bit 3 bit 4 bit 5 bit 6 bit 0 loaded 1st bit 7 bit 8 bit 9 bit 10 bit 10 loaded last CLK 10ms min ≥5.6V, ≤6.1V 4µs min PV t Figure 10 – First programming cycle to program bit2 into the EEPROM www.azmicrotek.com +1-480-962-5881 Request a Sample 7 Jan 2013, Rev 1.3 Arizona Microtek, Inc. bit 0 DA AZT71 bit 1 bit 2 bit 3 bit 4 bit 5 bit 6 Programmable Capacitive Tuning IC bit 7 bit 8 bit 9 bit 10 bit 10 loaded last bit 0 loaded 1st CLK 10ms min ≥5.6V, ≤6.1V 4µs min PV t Figure 11 – Second programming cycle to program bit4 into the EEPROM READING BACK 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 EEPROM. When the PV pin is not used during programming, the AZT71 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 12). Each EEPROM bit is selected by setting the DA signal low (EEPROM selection is active low) during the CLK sequence. With an external 68kΩ resistor pull-up to VDD on the PV pin, a low EEPROM bit produces ≤ 0.4V level while a high EEPROM bit produces a ≥ 0.6*VDD level. bit 0 DA bit 1 bit0 loaded 1st bit 2 bit 3 bit 4 bit 5 bit 6 bit 7 bit 8 bit 9 bit5 selected bit 10 bit10 loaded last CLK ≥ 0.6*VDD PV With an external 68kΩ resistor pull-up to VDD indeterminate ≤ 0.4V Resulting voltage if bit5 was high in EEPROM Resulting voltage if bit5 was low in EEPROM t Figure 12 – Timing diagram to read bits from EEPROM www.azmicrotek.com +1-480-962-5881 Request a Sample 8 Jan 2013, Rev 1.3 Arizona Microtek, Inc. AZT71 Programmable Capacitive Tuning IC ERASING THE EEPROM The 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 7 – Erase sequence for EEPROM Step Action 1 Set the VDD supply voltage to +5.0V 2 3 4 Load the programming word bits all high. Set the PV pin to +6V (≥5.6V, ≤6.1V) with the pulse and idle shown in timing diagram (Figure 13) Verify the correct EEPROM contents by reading back the individual bits bit 0 DA bit 1 bit 2 bit 3 bit 4 bit 5 bit 6 bit 7 bit 8 bit 9 bit0 loaded 1st bit 10 bit10 loaded last CLK EEPROM has been erased (no capacitors selected) 10ms min ≥5.6V, ≤6.1V 4µs min PV t Figure 13 – Programming Sequence for erasing the EEPROM PROGRAMMING VOLTAGE LIMIT CIRCUIT 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 AZT71. A simple modification eliminates the issue and maintains full programming compatibility with existing programming methods. A 5.6 V, ½ 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. www.azmicrotek.com +1-480-962-5881 Request a Sample 9 Jan 2013, Rev 1.3 Arizona Microtek, Inc. AZT71 Programmable Capacitive Tuning IC PERFORMANCE DATA Table 8 – Absolute Maximum Ratings Absolute Maximum Ratings are those values beyond which device life may be impaired. 1 Symbol Characteristic Rating Unit VDD Power Supply 0 to +6.5 V VI1 Input Voltage -0.5 to VDD + 0.5 V TA Operating Temperature Range -40 to +85 °C TSTG Storage Temperature Range -65 to +150 °C ESDHBM Human Body Model TBD V ESDMM Machine Model TBD V ESDCDM Charged Device Model TBD V PV Pin can exceed VDD by 1.2V during the programming interval Table 9 – DC Characteristics DC Characteristics (VDD = 2.375V to 3.6V unless otherwise specified, TA = -40 to 85 °C) Symbol Characteristic CPV Nominal capacitance variation across process CVV Capacitance variation across output voltage CTV Capacitance variation across temperature Conditions Min Typ -15 Voltage variation at X1 pin, 100MHz 100MHz - Zero Code 100MHz - Mid Code Max Unit +15 % ±150 ppm/V 325 1 40 100MHz - Full Scale ppm/°C 130 VIH Input HIGH Voltage DA, CLK 0.8 * VDD V VIL Input LOW Voltage DA, CLK 0.2 * VDD V RPD,D Pull-down Resistor DA 75k Ω RPD,CLK Pull-down Resistor CLK 75k Ω RPD,PV Pull-down Resistor PV 170k Ω VOH Output High Voltage 0.6 * VDD V VOL Output Low Voltage PV Pin when reading EEPROM bits 68kΩ external pull-up resistor to VDD 0.4 V VPP Programming Voltage (VDD=5.0V) PV pin when programming EEPROM IDD Power Supply Current Normal Operation IDDPROG Power Supply Current Programming Mode tMEM EEPROM Data Retention 20 yrs Tprog Programming Temperature 25 °C Cyprog Programming Cycle 1 5.6 10 6.0 6.1 V 7.0 50 µA 20 µA k Bit4, Bit7 High www.azmicrotek.com +1-480-962-5881 Request a Sample 10 Jan 2013, Rev 1.3 Arizona Microtek, Inc. AZT71 Programmable Capacitive Tuning IC Table 10 – AC Characteristics AC Characteristics (VDD = 2.375V to 3.6V unless otherwise specified, TA = -40 to 85 °C) Symbol CF Chi Cmid Clo CLK Tprog Trise Characteristic Fixed Capacitance Step Size Max Value Step Size Max Value Step Size Max Value Max CLK rate Programming Time (VDD=5.0V, PV=6.0V) Power supply ramp time (EEPROM usage only) Q Q Value Conditions 50% duty cycle 5 Unit pF pF pF pF pF pF pF MHz per bit programmed 10 ms Tambient > 80°C 20 us Typ 6.6 6.4 19.2 1.4 9.8 0.063 1.953 20MHz - Full Scale 150 300 20MHz - Mid Scale 80MHz - Full Scale 80MHz - Mid Scale 155MHz - Full Scale 100 200 40 40 25 25 80 80 50 50 155MHz - Mid Scale www.azmicrotek.com +1-480-962-5881 Request a Sample Min Max 11 Jan 2013, Rev 1.3 Arizona Microtek, Inc. AZT71 Programmable Capacitive Tuning IC PACKAGE DIAGRAM SON8 (1.5x1.0x0.4mm) Green/RoHS compliant/Pb-Free MSL=1 www.azmicrotek.com +1-480-962-5881 Request a Sample 12 Jan 2013, Rev 1.3 Arizona Microtek, Inc. AZT71 Programmable Capacitive Tuning IC PACKAGE DIAGRAM TSOT6 Green/RoHS compliant/Pb-Free MSL=1 www.azmicrotek.com +1-480-962-5881 Request a Sample 13 Jan 2013, Rev 1.3 Arizona Microtek, Inc. AZT71 Programmable Capacitive Tuning IC PACKAGE DIAGRAM MLP6 (2.0mm x 2.0mm) Green/RoHS compliant/Pb-Free MSL=1 Arizona 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, nor 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 Microtek, 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 failure 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 hold 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. www.azmicrotek.com +1-480-962-5881 Request a Sample 14 Jan 2013, Rev 1.3