DATA SHEET SKY12347-362LF: DC-3.0 GHz Six-Bit Digital Attenuator with Serial or Parallel Driver (0.5 dB LSB) Applications • Cellular, 3G/4G, WiMAX, and LTE Infrastructures Features • Broadband operation: DC to 3.0 GHz • Attenuation: 31.5 dB with 0.5 dB LSB • TTL/CMOS-compatible serial, parallel, or latched parallel control interface • Single supply voltage: +3.3 or +5 V • Small, QFN (24-pin, 4 x 4 mm) package (MSL1, 260 °C per JEDEC J-STD-020) Figure 1. SKY12347-362LF Block Diagram Description The SKY12347-362LF is a GaAs pHEMT six-bit broadband digital attenuator with a 0.5 dB Least Significant Bit (LSB). A Transistorto-Transistor Logic (TTL)/CMOS-compatible, dual-mode serial or parallel interface controller is integrated into the device. The attenuator features low insertion loss, excellent attenuation accuracy, a 31.5 dB attenuation range, and high linearity performance. The SKY12347-362LF is an ideal choice for a wide variety of cellular 3G and 4G infrastructure applications. Attenuation is controlled by a Serial Peripheral Interface (SPI). Depending on the SPI sequence applied to the SDI pin, the attenuation state between the RF1 and RF2 pins can vary between a low insertion loss state or up to 31.5 dB. The D0 through D5 DC control pins determine the attenuation state if parallel mode is enabled. The device is provided in a 4 x 4 mm, 24-pin Quad Flat No-Lead (QFN) package. A functional block diagram is shown in Figure 1. The pin configuration and package are shown in Figure 2. Signal pin assignments and functional pin descriptions are provided in Table 1. Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 201371B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice • April 7, 2011 1 DATA SHEET • SKY12347-362LF SIX-BIT DIGITAL ATTENUATOR Figure 2. SKY12347-362LF Pinout – 24-Pin QFN (Top View) Table 1. SKY12347-362LF Signal Descriptions Pin # Name Description Pin # Name Description 1 P/S Selects serial or parallel operation. Logic low enables parallel mode. 13 RF2 RF input/output to digital attenuator. 2 CLK Serial clock input 14 GND Ground 3 SDI Serial data input 15 SDO Serial data output 4 LE On rising edge of pulse, shifts six most recent clocked-in bits to set attenuation state. In parallel mode, if latch enable is logic high, changes to pins 19 to 24 occur directly. If latch enable is logic low, the attenuator does not change states until the signal is raised. 16 PUP2 Sets device power-up attenuation state. See Table 7. 5 GND Ground 17 PUP1 Sets device power-up attenuation state. See Table 7. 6 RF1 RF input/output to digital attenuator. 18 VDD DC power supply 7 NC_GND No connection. Can be grounded without affecting performance. 19 D5 TTL/CMOS DC control pin for parallel mode operation. D5 is MSB. 8 NC_GND No connection. Can be grounded without affecting performance. 20 D4 TTL/CMOS DC control pin for parallel mode operation 9 NC_GND No connection. Can be grounded without affecting performance. 21 D3 TTL/CMOS DC control pin for parallel mode operation 10 NC_GND No connection. Can be grounded without affecting performance. 22 D2 TTL/CMOS DC control pin for parallel mode operation 11 NC_GND No connection. Can be grounded without affecting performance. 23 D1 TTL/CMOS DC control pin for parallel mode operation 12 NC_GND No connection. Can be grounded without affecting performance. 24 D0 TTL/CMOS DC control pin for parallel mode operation. D0 is LSB. Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 2 April 7, 2011 • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice • 201371B DATA SHEET • SKY12347-362LF SIX-BIT DIGITAL ATTENUATOR Functional Description Power-up sequence is as follows: The SKY12347-362LF is a six bit digital attenuator comprised of a GaAs attenuator and a silicon CMOS driver. The attenuation setting is controlled by an SPI. Attenuation is set by a stream of data that is clocked into the shift registers of the silicon chip by the clock signal. To set the attenuation state, a latch signal is sent to the appropriate pin to send the correct bias voltages to the GaAs attenuator. 0. Connect ground More than one attenuator can be cascaded together and the data may be passed through one device to the other using the SDO signal (pin 15). The DC bias voltage to the silicon CMOS chip is applied to pin 18 (VDD). 1. Apply VDD 2. Set all inputs (CLK, SDI, LE) The power-down sequence is the reverse of above. Figure 4 shows an example of how to set the attenuator to the 0.5 dB state. The progression of the bit states vs the clock signal is shown. The timing diagram shows that when the latch enable signal goes high, the voltages D0 to D5 set the attenuator to the 0.5 dB state. Electrical and Mechanical Specifications Power-Up/Power-Down Timing Serial input data (SDI pin) is shifted into the register on the rising edge of the clock (CLK pin), Least Significant Bit (LSB) first. The attenuator changes states on the rising edge of the latch enable (LE pin) signal, according to the most recent six bits of shifted data accepted since the previous falling edge of the latch enable signal. The serial data output is the serial input data delayed by six clock cycles. The absolute maximum ratings of the SKY12347-362LF are provided in Table 4. Electrical specifications are provided in Tables 5 and 6. Typical performance characteristics of the SKY12347-362LF are illustrated in Figures 5 through 11. The state of the SKY12347-362LF is determined by the logic provided in Table 7. Refer to the timing diagram in Figure 3 and timing parameter specifications in Table 2. Table 3 shows the transition states based on the LE and CLK signals. Figure 3. Power-Up/Power-Down Timing Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 201371B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice • April 7, 2011 3 DATA SHEET • SKY12347-362LF SIX-BIT DIGITAL ATTENUATOR Table 2. Power-Up/Power-Down Timing Parameters Parameter Symbol VDD = 5 V Minimum Typical VDD = 3.3 V Maximum Minimum Typical Maximum Serial input setup time ts 5 5 ns Hold time from serial input to shift clock th 5 5 ns Setup time from shift clock to latch enable tlsup Propagation delay, latch enable to C0.5 through C8 tpd Setup time from reset to shift clock – Clock frequency fCLK 40 100 ns 30 20 70 ns 10 MHz 50 ns 30 Table 3. Transition State Logic LE (Pin 4) CLK (Pin 2) X Function Shift register clocked X Contents of shift register transferred to digital attenuator Figure 4. Example for Setting 0.5 dB State Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 4 Units April 7, 2011 • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice • 201371B DATA SHEET • SKY12347-362LF SIX-BIT DIGITAL ATTENUATOR Table 4. SKY12347-362LF Absolute Maximum Ratings Parameter Symbol Minimum Maximum Units 6.0 V Supply voltage VDD 3.3 Control voltage VCTL 0 RF input power PIN Operating temperature TOP Storage temperature TSTG Note: VDD V +30 dBm –40 +85 °C –40 +125 °C Exposure to maximum rating conditions for extended periods may reduce device reliability. There is no damage to device with only one parameter set at the limit and all other parameters set at or below their nominal value. Exceeding any of the limits listed here may result in permanent damage to the device. CAUTION: Although this device is designed to be as robust as possible, Electrostatic Discharge (ESD) can damage this device. This device must be protected at all times from ESD. Static charges may easily produce potentials of several kilovolts on the human body or equipment, which can discharge without detection. Industry-standard ESD precautions should be used at all times. Table 5. SKY12347-362LF Electrical Specifications (Note 1) (1 of 2) (VDD = 5 V, VCTL = 5 V, TOP = +25 °C, PIN = 0 dBm, Characteristic Impedance [ZO] = 50 Ω, , Unless Otherwise Noted) Parameter Symbol Test Condition Min Typical Max Units 1.2 2.0 1.3 2.2 dB dB 31.5 dB RF Specifications Insertion loss IL Attenuation range DC to 0.8 GHz 0.8 to 3.0 GHz DC to 3.0 GHz Return loss RL Attenuation accuracy 0.5 DC to 3.0 GHz 15 dB ±(0.1 + 5% of attenuation setting max) ±(0.3 + 3% of attenuation setting max) dB dB All attenuation states DC to 0.8 GHz 0.8 to 3.0 GHz 0.1 dB Input Compression Point IP0.1dB DC to 3.0 GHz +30 dBm 3rd Order Input Intercept Point IIP3 DC to 3.0 GHz, PIN = +10 dBm/tone, ΔF = 1 MHz +50 dBm DC Specifications Control voltage: Low High VCTL Supply voltage VDD Supply current IDD 0 3.0 3.3 0.8 VDD 5.0 5.5 100 V V V μA Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 201371B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice • April 7, 2011 5 DATA SHEET • SKY12347-362LF SIX-BIT DIGITAL ATTENUATOR Table 5. SKY12347-362LF Electrical Specifications (Note 1) (2 of 2) (VDD = 5 V, VCTL = 5 V, TOP = +25 °C, PIN = 0 dBm, Characteristic Impedance [ZO] = 50 Ω, , Unless Otherwise Noted) Parameter Symbol Test Condition Min Typical Max Units Switching Speed Specifications 50% control to 90% attenuation VDD = 3.3 V, Bit = 3.3 V VDD = 5.0 V, Bit = 3.3 V VDD = 5.0 V, Bit = 5.0 V 91 48 47 ns ns ns 50% control to 10% attenuation VDD = 3.3 V, Bit = 3.3 V VDD = 5.0 V, Bit = 3.3 V VDD = 5.0 V, Bit = 5.0 V 19 28 28 ns ns ns 10% to 90% attenuation VDD = 3.3 V, Bit = 3.3 V VDD = 5.0 V, Bit = 3.3 V VDD = 5.0 V, Bit = 5.0 V 47 24 26 ns ns ns 90% to 10% attenuation VDD = 3.3 V, Bit = 3.3 V VDD = 5.0 V, Bit = 3.3 V VDD = 5.0 V, Bit = 5.0 V 35 18 18 ns ns ns Note 1: Performance is guaranteed only under the conditions listed in this Table. Typical Performance Characteristics (VDD = 5 V, VCTL = 5 V, TOP = +25 °C, PIN = 0 dBm, Characteristic Impedance [ZO] = 50 Ω, , Unless Otherwise Noted) Figure 5. Insertion Loss vs Frequency Figure 6. Input Return Loss vs Frequency Figure 7. Output Return Loss vs Frequency Figure 8. Normalized Attenuation vs Frequency Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 6 April 7, 2011 • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice • 201371B DATA SHEET • SKY12347-362LF SIX-BIT DIGITAL ATTENUATOR Figure 9. Attenuation Error vs Attenuation Setting Figure 10. Step Error vs Attenuation Setting Figure 11. Major State Bit Error vs Frequency Figure 12. 31.5 dB State Relative Phase vs Temperature Figure 13. Relative Phase vs Frequency Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 201371B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice • April 7, 2011 7 DATA SHEET • SKY12347-362LF SIX-BIT DIGITAL ATTENUATOR Table 6. SKY12347-362LF Parallel Mode Truth Table RF1/RF2 (Pins 6 & 13) Attenuation D5 (Pin 19) D4 (Pin 20) D3 (Pin 21) D2 (Pin 22) D1 (Pin 23) D0 (Pin 24) Insertion loss 1 1 1 1 1 1 0.5 dB 1 1 1 1 1 0 1.0 dB 1 1 1 1 0 1 2.0 dB 1 1 1 0 1 1 4.0 dB 1 1 0 1 1 1 8.0 dB 1 0 1 1 1 1 16 dB 0 1 1 1 1 1 31.5 dB 0 0 0 0 0 0 Initial Attenuation State LE (Pin 4) PUP1 (Pin 17) PUP2 (Pin 16) 31.5 dB 0 0 0 24.0 dB 0 1 0 16.0 dB 0 0 1 Insertion Loss 0 1 1 State is determined by signal logic at pins D0 to D5. See Table 6. 1 X X Note: “1” = high control voltage: +3.0 to VDD. “0” = low control voltage: 0 to +0.8 V. Table 7. SKY12347-362LF Power-Up Truth Table Note: “1” = Logic high “0” = Logic low “X” = don’t care Evaluation Board Description Package and Handling Information The SKY12347-362LF Evaluation Board is used to test the performance of the SKY12347-362LF digital attenuator. An assembly drawing for the Evaluation Board is shown in Figure 14 and an Evaluation Board schematic diagram is shown in Figure 15. Instructions on the shipping container label regarding exposure to moisture after the container seal is broken must be followed. Otherwise, problems related to moisture absorption may occur when the part is subjected to high temperature during solder assembly. Package Dimensions THE SKY12347-362LF is rated to Moisture Sensitivity Level 1 (MSL1) at 260 °C. It can be used for lead or lead-free soldering. For additional information, refer to the Skyworks Application Note, Solder Reflow Information, document number 200164. The PCB layout footprint for the SKY12347-362LF is shown in Figure 16. Typical case markings are noted in Figure 17. Package dimensions for the 24-pin QFN are shown in Figure 18, and tape and reel dimensions are provided in Figure 19. Care must be taken when attaching this product, whether it is done manually or in a production solder reflow environment. Production quantities of this product are shipped in a standard tape and reel format. Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 8 April 7, 2011 • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice • 201371B DATA SHEET • SKY12347-362LF LOW NOISE AMPLIFIER Figure 14. SKY12347-362LF Evaluation Board Assembly Diagram Figure 15. SKY12347-362LF Evaluation Board Schematic Diagram Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 9 201371B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice • April 7, 2011 DATA SHEET • SKY12347-362LF SIX-BIT DIGITAL ATTENUATOR Figure 16. SKY12347-362LF PCB Layout Footprint Figure 17. Typical Part Markings Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 10 April 7, 2011 • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice • 201371B DATA SHEET • SKY12347-362LF SIX-BIT DIGITAL ATTENUATOR Figure 18. SKY12347-362LF 24-Pin QFN Package Dimensions Figure 19. SKY12347-362LF Tape and Reel Dimensions Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 201371B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice • April 7, 2011 11 DATA SHEET • SKY12347-362LF SIX-BIT DIGITAL ATTENUATOR Ordering Information Model Name SKY12347-362LF Digital Attenuator Manufacturing Part Number SKY12347-362LF Evaluation Board Part Numbers SKY12347-362LF-EVB Copyright © 2011 Skyworks Solutions, Inc. All Rights Reserved. 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Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 12 April 7, 2011 • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice • 201371B