U3770M CT2 I/Q Modulator and Clock Circuitry Description The U3770M is a quadrature modulator realized using Atmel Wireless & Microcontrollers’ advanced 0.8 micron CMOS process. The IC is especially designed for CT2 applications in conjunction with Atmel Wireless & Microcontrollers’ RF/IF signal processor U2760B and a CT2 baseband controller (i.e., AMD PhoXTM controller Am79C4xx). Together with Atmel Wireless & Microcontrollers’ PLL IC U2783B and the GaAs front end U7001BG, a complete CT2 chip set is available. Electrostatic sensitive device. Observe precautions for handling. Features D Programmable 0.8/1.6-MHz quadrature-modulated carrier generation D More than 26 dB LO and sideband suppression D 18.432 MHz CMOS level clock generation D Supply-voltage range 2.7 V to 3.3 V D Low power consumption, typically 12 mW D SO16 package or die form Block Diagram RRef in 12.8 MHz LF 2 DIV / 25 Phase 512 kHz comparator Amp. VDD DGND AGND PROG TST Qin QBin Iin IBin 95 9881 11 VCO 512 kHz DIV / 36 14 CLK out 9 MOD out 18.432 MHz 3 4 13 DIV / 2 or DIV / 4 12 10 6.4 MHz 3.2 MHz Dual DFF 6 5 8 7 1, 15, 16 DNC Figure 1. Block diagram Ordering Information Extended Type Number Package U3770M-MFP SO16 Tube U3770M-MFPG3 SO16 Taped and reeled Rev. A3, 07-Sep-00 Remarks 1 (6) U3770M Functional Description The U3770M has been designed to reduce power consumption and cost of CT2 devices. An innovative CMOS I/Q modulator with extremely low current provides all the advantages of I/Q modulation: – No requirement for FM deviation tuning – Eliminates the Gaussian filter – Simplifies the power ramping control The modulated output carrier can be programmed to be 0.8 MHz or 1.6 MHz by the PROG control pin. The typical supply voltage is 3 V @ 4 mA. To reduce overall system cost, an internal PLL generates an 18.432-MHz clock signal from the system’s 12.8-MHz reference oscillator. This way, only one crystal oscillator is needed in the complete CT2 device. Internally, the 12.8-MHz reference signal is fed into a shaping amplifier and then into two logic dividers, to generate a 512-kHz and a programmable 3.2-MHz or 6.4-MHz clock. This clock is divided by 4 by two D flipflops. The flip-flop outputs drive the four analog switches in quadrature. The local oscillator (LO) supression mixer consists of a pair of analog switches. make a local oscillator (LO) suppression mixer. By summing the other pair outputs the suppression (both LO and side tone) is <–26 dBc. The 512-kHz clock drives a frequency synthesizer. The VCO runs at a fixed frequency of 18.432 MHz. The VCO control voltage (LF pin) controls the VCO frequency. Pin Description Pin Symbol n.c. 1 16 n.c. 2 FRef in External 12.8-MHz reference frequency input FRef in 2 15 n.c. 3 VDD Supply voltage 4 DGND Digital ground 5 QBin Analog switch input 6 Qin Analog switch input 7 IBin Analog switch input 8 Iin Analog switch input 9 MODout 10 TST 11 LF 12 PROG PROG = 0, 1.6-MHz mode PROG = 1, 0.8-MHz mode 13 AGND Analog ground 14 CLKout Digital CMOS clock output 18.432 MHz 1, 15, 16 n.c. VDD 3 14 CLKout DGND 4 13 AGND QB 5 12 PROG Q 6 IB I 11 LF 10 TST 7 9 MODout 8 95 9930 Figure 2. Pinning 2 (6) Function Modulator output signal Test input, must be connected to GND (only factory use) PLL loop filter Not connected Rev. A3, 07-Sep-00 U3770M Absolute Maximum Ratings Stresses at or above those listed 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 this data sheet is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Parameters Symbol Value Unit VDD 6 V Modulator input voltages I, IB, Q, QB –0.5 to VDD V Reference frequency input FRef in –0.5 to VDD V Ambient temperature Tamb –40 to +85 °C Storage temperature Tstg –65 to +150 °C Junction temperature Tj Tj < Tamb +10 °C Symbol Value Unit Supply voltage VDD 3 " 10% V Ambient temperature Tamb –5 to +70 °C Junction temperature Tj Tj < Tamb +5 °C Storage temperature Tstg –40 to +125 °C Supply voltage Operating Range Parameters Electrical Characteristics Test conditions (unless otherwise specified) related to test circuit VS = 3 V, VBIi, VBIi and VBQi, VBQi = 1 VPP single ended, oscillator frequency FRef in = 12.8 MHz, Tamb = –5 to +70°C Parameters Test Conditions / Pins Symbol Min. Typ. Max. Unit 2.7 3 3.3 V Supply-voltage range Pin 3 VDD Supply current Pin 3 IDD FRef in Pin 2 4 mA Input voltage VF Ref in 150 mVPP Input impedance ZF Ref in 100 kW I, Q inputs Pins 5, 6, 7 and 8 Input voltage Single ended VIin, Qin 1 VPP Input impedance Single ended ZIin, Qin 20 kW Input frequency FIin, Qin 18 kHz External bias voltage VIB, QB 1.5 V VMod out 70 mVRMS LO sub SB sub ZMod out –26 dBc 5 kW FCLK out 18.432 MHz MODout Output level Pin 9 1) Unloaded LO and sideband suppression Output impedance CLKout Pin 14 Output frequency Output-voltage swing Rev. A3, 07-Sep-00 @ load = 20 pF VCLK out 1.8 V 3 (6) U3770M Note 1) 4 (6) The output signal contains some harmonics to be filtered by an external lowpass filter Rev. A3, 07-Sep-00 U3770M Test Circuit 47 nF 4.7 nF R Ref in 12.8 MHz LF 2 VDD Phase comparator 512 kHz Amp VCO 14 CLK out DIV / 36 512 kHz 18.432 MHz 4 DGND 13 AGND 12 PROG 95 9967 11 DIV / 25 3 22 W DIV / 2 or DIV / 4 6.4 MHz Dual DFF 3.2 MHz 10 TST 9 MOD out 6 5 QB in Q in 1 nF 1 kW 8 I in 1 nF 1 kW 7 IB in 1 nF 1 kW 1 nF 1 kW Figure 3. Test circuit Rev. A3, 07-Sep-00 5 (6) U3770M Package Information Package: SO16 3. We reserve the right to make changes to improve technical design and may do so without further notice. Parameters can vary in different applications. All operating parameters must be validated for each customer application by the customer. Should the buyer use TEMIC Semiconductors products for any unintended or unauthorized application, the buyer shall indemnify TEMIC Semiconductors against all claims, costs, damages, and expenses, arising out of, directly or indirectly, any claim of personal damage, injury or death associated with such unintended or unauthorized use. Data sheets can also be retrieved from the Internet: http://www.temic–semi.com TEMIC Semiconductor GmbH, P.O.B. 3535, D-74025 Heilbronn, Germany Telephone: 49 (0)7131 67 2594, Fax number: 49 (0)7131 67 2423 6 (6) Rev. A3, 07-Sep-00