19-3123; Rev 3; 10/05 KIT ATION EVALU E L B A AVAIL Complete SDARS Receiver The MAX2140 complete receiver is designed for satellite digital audio radio services (SDARS). The device includes a fully monolithic VCO and only needs a SAW at the IF and a crystal to generate the reference frequency. To form a complete SDARS radio, the MAX2140 requires only a low-noise amplifier (LNA), which can be controlled by a baseband controller. The small number of external components needed makes the MAX2140based platform the lowest cost and the smallest solution for SDARS. The receiver includes a self-contained RF AGC loop and baseband-controlled IF AGC loop, effectively providing a total dynamic range of over 92dB. Channel selectivity is ensured by the SAW filter and by on-chip monolithic lowpass filters. The fractional-N PLL allows a very small frequency step, making possible the implementation of an AFC loop. Additionally, the reference is provided by an external XTAL and on-chip oscillator. A reference buffer output is also provided. A 2-wire interface (I2C-bus compatible) programs the circuit for a wide variety of conditions, providing features such as: •Programmable gains Features ♦ Integrated Receiver, Requires Only One SAW Filter ♦ Self-Contained RF AGC Loop ♦ Differential I/Q Interface ♦ Complete Integrated Frequency Generation ♦ Bias Supply for External LNAs ♦ Overcurrent Protection ♦ Low-Power Standby Mode ♦ Very Small 44-Pin Thin QFN Package Ordering Information PART TEMP RANGE PIN-PACKAGE MAX2140ETH -40°C to +85°C 44 Thin QFN-EP* MAX2140ETH+ -40°C to +85°C 44 Thin QFN-EP* *EP = Exposed paddle. +Denotes lead-free package. Block Diagram/Pin Configuration I CA1 2 I2CA2 VCC_BE4 IF2QO- IF2QI- IF2QO+ IF2QI+ QOUT- QOUT+ The MAX2140 minimizes the requirement on the baseband controller. No compensation or calibration procedures are required. The device is available in a 7mm ✕ 7mm 44-pin thin QFN package. SCL •Individual functional block shutdown SDA •Lowpass filters tuning 44 43 42 41 40 39 38 37 36 35 34 XM TUNER VCC_FE0 1 33 VTUNE RFIN+ 2 32 VCCREG RFIN- 3 Applications Satellite Digital Audio Radio Services (SDARS) 2.4GHz ISM Radios 31 VCC_VCO MAX2140 VCC_FE1 4 IFOUT+ 5 30 VCC_FE3 1/N RF AGC Σ ∆ - MOD PFD CHP 1/R IFOUT- 6 28 LOCK RFAGC_C 7 27 VCC_A LPF VCC_FE2 8 HPF 26 VCC_D /4/8 QUAD AGCPWM 9 25 REFOUT IFIN+ 10 24 XTAL LPF HPF IFIN- 11 13 14 15 16 17 18 19 20 21 22 VCC_BE2 VCC_BE3 VINANT VOUTANT IF2IO- IF2II- IF2IO+ IF2II+ IOUT- IOUT+ 23 VCC_XTAL 12 VCC_BE1 Purchase of I2C components from Maxim Integrated Products, Inc., or one of its sublicensed Associated Companies, conveys a license under the Philips I2C Patent Rights to use these components in an I2C system, provided that the system conforms to the I2C Standard Specification as defined by Philips. 29 CPOUT ACTUAL SIZE 7mm x 7mm ________________________________________________________________ Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. 1 MAX2140 General Description MAX2140 Complete SDARS Receiver ABSOLUTE MAXIMUM RATINGS VCC_XX to GND..................................................... -0.3V to +4.3V VINANT to GND.................................................... -0.3V to +5.6V AGCPWM to GND ................................................ -0.3V to +3.0V Digital Input Current ........................................................ ±10mA Maximum VSWR Without Damage ........................................ 4:1 Maximum VSWR Without Oscillations ................................... 4:1 All Other Pins ............................................... -0.3V to VCC + 0.3V Continuous Power Dissipation (TA = +70°C) 44-Pin TQFN (derate 26.31mW/°C above +70°C) ... 2105mW Operating Temperature Range ..........................-40°C to +85°C Junction Temperature .....................................................+150°C Theta JC ..........................................................................12°C/W Storage Temperature Range ............................-65°C to +150°C Lead Temperature (soldering, 10s) ................................+300°C Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. CAUTION! ESD SENSITIVE DEVICE DC ELECTRICAL CHARACTERISTICS (VCC = 3.1V to 3.6V; VINANT ≥ VCC, VOUTANT in open circuit, TA = -40°C to +85°C. Typical values are at VCC = 3.3V, VINANT = 3.3V, and TA = +25°C, unless otherwise noted.) (Note 1) PARAMETER Supply Voltage Range (Note 2) Operating Supply Current SYMBOL MIN TYP MAX VCC 3.1 3.3 3.6 VINANT 3.1 3.3 5.3 180 ICC All blocks on 150 ISHDN All blocks off 30 Lock Indicator High (Locked) VIH_LK Lock Indicator Low (Unlocked) VIL_LK Digital Input-Logic High VIH Digital Input-Logic Low VIL Input Current for Digital Control Pins IDIG IAGCPWM Input Current for AGCPWM Voltage Drop VINANT to VOUTANT in Normal Operating Mode CONDITIONS Current Sink at VOUTANT to Flag Bit ACP = 1 IANTDC_H VOUTANT shorted to ground (Note 4) Current Sink at VOUTANT to Flag Bit AND = 1 IANTDC_L 2 mA V 0.5 V 0.5 V -1 +1 µA -10 +290 µA 0.35 V 500 mA 30 mA VCC - 0.5 Maximum current sink at VOUTANT is 150mA V µA VCC - 0.5 DROP VANTDC- UNITS V 195 12 20 _______________________________________________________________________________________ Complete SDARS Receiver (MAX2140 EV kit, current drawn at VOUTANT, IVOUTANT = 150mA max, VCC = 3.1V to 3.6V, VINANT = 3.1V to 5.3V, fRF = 2320MHz to 2345MHz, fLO = 2076MHz, TA = -40°C to +85°C. Typical values are at VCC = VINANT = 3.3V, fRF = 2338MHz, TA = +25°C, unless otherwise noted.) (Note 2) Interstage (IF) 259MHz SAW filter specification: insertion loss = 19dB max, 9.3MHz to 12MHz from center attenuation = 24dB min, beyond 12MHz from center attenuation = 40dB min. PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS -84 dBm GENERAL RECEIVER Minimum Input RF Power to Produce 20mVP-P (Differential) at I and Q Baseband Outputs PMIN IF AGC is set at maximum gain, bit HPF = 0 (Note 4) -91 Maximum Input RF Power to Produce 400mVP-P (Differential) at I and Q Baseband Outputs PMAX RF AGC threshold: RF_AGC_TRIP = -17dBm; IF AGC is set at minimum gain, bit HPF = 0 +3 PLK_H LO-related spurious > 2GHz -66 PLK_L LO-related spurious < 2GHz -38 RF AGC is at maximum gain, IF AGC is at reference gain 8.5 10.4 RF AGC is at maximum gain, IF AGC is at reference gain -10dB 9.3 11.7 RF AGC is at maximum gain -5dB, IF AGC is at reference gain 13.3 15.5 RF AGC is at maximum gain -10dB, IF AGC is at reference gain 17.8 21.5 RF AGC is at maximum gain, IF AGC is at reference gain -32 RF AGC is at maximum gain, IF AGC is at reference gain -5dB -27 LO to RF Input Leakage Noise Figure (Notes 3, 5) In-Band Input IP3 (Notes 5, 6) Out-of-Band Input IP3 (Notes 5, 7) dBm dBm dB NF I_IIP3 O_IIP3 dBm RF AGC is at maximum gain -30dB, IF AGC is at reference gain -43dB +9 RF AGC is at maximum gain -20dB, IF AGC is at reference gain -53dB +6 RF AGC is at maximum gain, IF AGC is at reference gain -9 RF AGC is at maximum gain -7dB, IF AGC is at reference gain -3 RF AGC is at maximum gain -25dB, IF AGC is at reference gain +12 dBm _______________________________________________________________________________________ 3 MAX2140 AC ELECTRICAL CHARACTERISTICS MAX2140 Complete SDARS Receiver AC ELECTRICAL CHARACTERISTICS (continued) (MAX2140 EV kit, current drawn at VOUTANT, IVOUTANT = 150mA max, VCC = 3.1V to 3.6V, VINANT = 3.1V to 5.3V, fRF = 2320MHz to 2345MHz, fLO = 2076MHz, TA = -40°C to +85°C. Typical values are at VCC = VINANT = 3.3V, fRF = 2338MHz, TA = +25°C, unless otherwise noted.) (Note 2) Interstage (IF) 259MHz SAW filter specification: insertion loss = 19dB max, 9.3MHz to 12MHz from center attenuation = 24dB min, beyond 12MHz from center attenuation = 40dB min. PARAMETER In-Band Input IP2 (Notes 5, 6) Out-of-Band Input IP2 (Notes 5, 7) Opposite Sideband Rejection SYMBOL I_IIP2 O_IIP2 OSR CONDITIONS MIN TYP RF AGC is at maximum gain, IF AGC is at reference gain +1 RF AGC is at maximum gain, IF AGC is at reference gain -5dB +6 RF AGC is at maximum gain, IF AGC is at reference gain -25dB +27 RF AGC is at maximum gain, IF AGC is at reference gain +38 RF AGC is at maximum gain -7dB, IF AGC is at reference gain +45 RF AGC is at maximum gain -25dB, IF AGC is at reference gain +60 Baseband frequencies = 100kHz (Note 4) 32 MAX UNITS dBm dBm 39 dB Image Rejection IRej At fLO - fIF 54 dB Half IF Rejection HRej At fLO + 0.5 x fIF 53 dB 42 dB RF AGC LOOP LNA Gain Reduction RFAGC_ Range (Note 4) Minimum RF AGC Trip Point RFAGC_min Bits RF4/3/2/1/0 = 00000 (BIN) RF AGC Trip Point RFAGC_int Maximum RF AGC Trip Point Bits RF4/3/2/1/0 = 00010 (BIN) (Note 4) 30 -35 -37 RFAGC_max Bits RF4/3/2/1/0 = 10100 (BIN) -33 dBm -29 -15 dBm dBm FRONT-END (FE) PROGRAMMABLE GAIN FE Programmable Gain Range FE_Rge FE Programmable Gain Step FE_Step (Note 4) 19 22 26 dB 2 dB IF FILTER INTERFACE IF Output Differential Admittance Input Differential Impedance Presented by the IC to the IF Filter Output Yout, IF Between pins IFOUT+, IFOUT-, fIF = 259MHz and 467MHz 1/900 + j0 S Zin, IF Between pins IFOUT+, IFOUT-, fIF = 259MHz and 467MHz 150 + j0 Ω IF AGC LOOP IF AGC Control Voltage for Max Gain IFAGC_VM Applied at pin AGCPWM 0.2 V IF AGC Control Voltage for Min Gain IFAGC_Vm Applied at pin AGCPWM 2.5 V 4 _______________________________________________________________________________________ Complete SDARS Receiver (MAX2140 EV kit, current drawn at VOUTANT, IVOUTANT = 150mA max, VCC = 3.1V to 3.6V, VINANT = 3.1V to 5.3V, fRF = 2320MHz to 2345MHz, fLO = 2076MHz, TA = -40°C to +85°C. Typical values are at VCC = VINANT = 3.3V, fRF = 2338MHz, TA = +25°C, unless otherwise noted.) (Note 2) Interstage (IF) 259MHz SAW filter specification: insertion loss = 19dB max, 9.3MHz to 12MHz from center attenuation = 24dB min, beyond 12MHz from center attenuation = 40dB min. PARAMETER IF AGC Gain-Control Range SYMBOL IFAGC_ Rge CONDITIONS (Note 4) MIN TYP 47 MAX UNITS 64 dB INTERNAL BASEBAND LOWPASS FILTERS LPF In-Band Ripple LPFA_rip From 0 to 6.3MHz with respect to the amplitude at 100kHz 0.7 LPFrej At 10.25MHz with respect to the amplitude at 2MHz 14 21 LPFrej At 16MHz with respect to the amplitude at 2MHz 47 51 LPF Out-of-Band Rejection (Note 4) dB dB INTERNAL OUTPUT STAGE Gain Increase BB_DG From bit HPF = 0 to HPF = 1 Maximum I/QOUT± Pin Loading IQ_load Per each of the four pins 4 dB 10//10 kΩ//pF FREQUENCY GENERATION: VCO AND PLL VCO Frequency Range VCO Tuning Gain VCO_ Range VCO_Gain Over VCHP range (Note 4) 1861 (Note 4) At 1kHz within PLL band Synthesized VCO Phase Noise Synthesized VCO Phase-Noise Jitter Charge-Pump Voltage Range Charge-Pump Current Pin CHP Leakage Current PLL Reference Division Ratio Synthesized VCO Smallest Fractional Step VCO_PN VCO_jit ICHP CHP_leak -80 At 100kHz outside PLL band -101 Integrated from 100Hz to 100kHz, LO frequency = 2079MHz PLLstep 0.40 MHz/V dBc/Hz Bit CHP = 1 1.2 Across VCHP range DegRMS 2.75 0.6 V mA 5 1 Programmable through I2C 240 1.2 Bit CHP = 0 PLLref MHz -79 At 10kHz outside PLL band VCHP 2079 nA 2 23 Hz _______________________________________________________________________________________ 5 MAX2140 AC ELECTRICAL CHARACTERISTICS (continued) MAX2140 Complete SDARS Receiver AC ELECTRICAL CHARACTERISTICS (continued) (MAX2140 EV kit, current drawn at VOUTANT, IVOUTANT = 150mA max, VCC = 3.1V to 3.6V, VINANT = 3.1V to 5.3V, fRF = 2320MHz to 2345MHz, fLO = 2076MHz, TA = -40°C to +85°C. Typical values are at VCC = VINANT = 3.3V, fRF = 2338MHz, TA = +25°C, unless otherwise noted.) (Note 2) Interstage (IF) 259MHz SAW filter specification: insertion loss = 19dB max, 9.3MHz to 12MHz from center attenuation = 24dB min, beyond 12MHz from center attenuation = 40dB min. PARAMETER Synthesized VCO Spurs XTAL Oscillator Frequency Range SYMBOL VCOspur CONDITIONS 10kHz < foffset < 1MHz (Note 9) 1MHz < foffset < 10MHz -47 XTALrge 24 XTALerror XTAL Oscillator Input Voltage XTALswing Using an external TCXO Reference Buffer Output Voltage Reference Buffer Output Duty Cycle Maximum REFOUT Pin Loading XTALduty REFV REFduty REFOUT_1d TYP (Note 9) XTAL Oscillator Frequency Error XTAL Oscillator Input Duty Cycle MIN 0Hz < foffset < 10kHz Using an external XTAL (Note 8) Using an external TCXO Using the REFOUT pin loading specified below (Note 4) Using an external XTAL, not overdriven; bit RFD = 0, using the REFOUT pin loading specified below MAX UNITS dBc 49 MHz -16 +16 ppm 0.8 VCC VP-P 53 % 47 50 0.95 1.10 45 50 REFOUT pin frequency = 24MHz 20 REFOUT pin frequency = 48MHz 8 VP-P 55 % pF TIMING CHARACTERISTICS PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS SERIAL INTERFACE (Note 2) Serial Clock Frequency Note 1: Note 2: Note 3: Note 4: Note 5: Note 6: Note 7: Note 8: Note 9: 6 fSCL 200 kHz At TA = -40°C, minimum and maximum values are guaranteed by design and characterization. Minimum and maximum values are guaranteed by design and characterization, unless otherwise noted. At TA = +25°C, minimum and maximum values are guaranteed by design and characterization. At TA = +25°C and TA = +85°C, parameters are production tested. IF AGC reference level is defined as being the required voltage applied on pin AGCPWM, and the corresponding receiver IF gain, to measure 20mVP-P at each I/Q differential output when the RF input power is -91dBm. If even for zero volts applied on pin AGCPWM the I/Q differential outputs are below 20mVP-P when the RF input power is -91dBm, then the reference level is defined as zero volts. In-band IP2 and IP3 are measured with two CW tones at RF input: f1 = 2339.55MHz, f2 = 2339.75MHz. Out-of-band IP2 and IP3 are measured with two CW tones at RF input: f1 = 2326.25MHz, f2 = 2330.25MHz. Error computed using a crystal with no error. No spur in the offset frequency range. _______________________________________________________________________________________ Complete SDARS Receiver INPUT RETURN LOSS vs. FREQUENCY -15 MAXIMUM RF AGC -20 -25 MINIMUM RF AGC -30 -20 -25 -30 DIVIDER: /8 50 -35 2.3 2.4 2.5 40 TA = +25°C TA = -40°C 30 TA = +85°C 20 10 -40 0 0 4 8 12 20 16 0 0.6 1.2 1.8 2.4 FREQUENCY (GHz) RF AGC ENGAGEMENT SETTING CONTROL VOLTAGE (V) RF AGC SETTLING TIME WITH 20dB STEP IF AGC ATTENUATION vs. CONTROL VOLTAGE IF AGC ATTENUATION vs. CONTROL VOLTAGE RF AGC DECAY TIME 5dB/div 60 50 TA = -40°C 40 50 30 TA = +85°C 20 TA = +25°C R4 = 5000Ω C32 = 0.22µF 40 30 TA = -40°C 20 TA = +85°C 10 TA = +25°C 10 -50dBm 0 0 0 START TIME: 0µs STOP TIME: 200µs 3.0 MAX2140 toc06 R4 = 100Ω C32 = 0.1µF IF AGC ATTENUATION (dB) RF AGC ATTACK TIME 70 IF AGC ATTENUATION (dB) 0dBm MAX2140 toc04 2.2 MAX2140 toc03 MAX2140 toc02 DIVIDER: /4 RF AGC ATTENUATION (dB) -10 -15 60 MAX2140 toc05 INPUT RETURN LOSS (dB) -5 -10 RF AGC ENGAGEMENT THRESHOLD (dBm) MAX2140 toc01 0 RF AGC ATTENUATION vs. CONTROL VOLTAGE RF AGC ENGAGEMENT THRESHOLD 0.6 1.2 1.8 3.0 2.4 CONTROL VOLTAGE (V) 0 0.6 1.2 1.8 2.4 3.0 CONTROL VOLTAGE (V) 10.250000MHz -27.278dB -100dB 1MHz MAX2140 toc07 LPF FREQUENCY RESPONSE 0dB 16MHz _______________________________________________________________________________________ 7 MAX2140 Typical Operating Characteristics (TA = +25°C, unless otherwise noted.) Typical Operating Characteristics (continued) (TA = +25°C, unless otherwise noted.) VCO PHASE NOISE vs. OFFSET FREQUENCY LPF GROUP DELAY vs. FREQUENCY REF 80ns 100ns/div REFOUT WAVEFORM (REF = 0, RFD = 0) MAX2140 toc10 -50dBc/Hz MAX2140 toc09 MAX2140 toc08 MAX2140 Complete SDARS Receiver 6.250000MHz 113.8ns 500mV/div -150dBc/Hz 1MHz 16MHz 10 REFOUT WAVEFORM (REF = 1, RFD = 0) FREQUENCY OFFSET (Hz) 20ns/div 1M REFOUT WAVEFORM (REF = 1, RFD = 1) MAX2140 toc12 MAX2140 toc11 200mV/div 500mV/div 10ns/div 8 20ns/div _______________________________________________________________________________________ Complete SDARS Receiver PIN NAME 1, 4, 8, 12–15, 23, 26, 27, 30, 31, 40 VCC_FE0, VCC_FE1, VCC_FE2, VCC_BE1, VCC_BE2, VCC_BE3, VINANT, VCC_XTAL, VCC_D, VCC_A, VCC_FE3, VCC_VCO, VCC_BE4 2, 3 RFIN+, RFIN- 5, 6 IFOUT+, IFOUT- 7 RFAGC_C RF AGC Power-Detector Output. Set the RF AGC attack and decay response times. 9 AGCPWM IF AGC Control Voltage Input. Input from the filtered PWM AGC control signal from the SDARS channel-decoder IC. 10, 11 IFIN+, IFIN- Differential First IF Input 16 VOUTANT Overcurrent-Protected Unregulated DC Supply Output. Provides DC power supply to the antenna module. 17, 19, 37, 39 IF2IO-, IF2IO+, IF2QO+, IF2QO- 18, 20, 36, 38 IF2II-, IF2II+, IF2QI+, IF2QI- 21, 22, 34, 35 IOUT-, IOUT+, QOUT+, QOUT- 24 XTAL 25 REFOUT 28 LOCK 29 CPOUT 32 VCCREG 33 VTUNE 41, 42 I2CA2, I2CA1 43, 44 SCL, SDA — Exposed Pad FUNCTION Power Supplies. Bypass to ground with capacitors as close to the pins as possible. Differential RF Inputs. Accept RF input signal from the SDARS cabled antenna with a 50Ω to 100Ω balun. Differential First IF Output. Connect an external SAW filter to the IF output. Differential Baseband DC Blocking Outputs. IF2IO- = Inverting in-phase baseband output. AC couple to pin 18. IF2IO+ = Noninverting in-phase baseband output. AC couple to pin 20. IF2QO+ = Noninverting quadrature baseband output. AC couple to pin 36. IF2QO- = Inverting quadrature baseband output. AC couple to pin 38. Differential Baseband DC Blocking Inputs. IF2II- = Inverting in-phase baseband input. AC couple to pin 16. IF2II+ = Noninverting in-phase baseband input. AC couple to pin 19. IF2QI+ = Noninverting quadrature baseband input. AC couple to pin 37. IF2QI- = Inverting quadrature baseband input. AC couple to pin 39. Differential I/Q Baseband Outputs. IOUT- = Inverting in-phase baseband output. IOUT+ = Noninverting in-phase baseband output. QOUT+ = Noninverting quadrature baseband output. QOUT- = Inverting quadrature baseband output. Crystal Reference Input Buffered System Clock Output. Provides clock signal to the SDARS channel-decoder IC. Digital Logic Output to the System Controller. Indicates the lock status of the internal PLL. VCO Charge-Pump Output Regulated Supply Voltage for the VCO High-Impedance VCO Tuning Input I2C Input Signals. Define the MAX2140 I2C device address. I2C-Compatible Programming Input. Connect to an I2C-compatible bus. Exposed Paddle. Connect to ground. _______________________________________________________________________________________ 9 MAX2140 Pin Description MAX2140 Complete SDARS Receiver Detailed Description Front End The front end of the MAX2140, which downconverts the RF signal to IF, is defined from the differential RF inputs (pins RFIN+ and RFIN-) to the output (pins IFOUT+ and IFOUT-) to the SAW filter. The front end includes a self-contained analog RF AGC loop. The engagement threshold of the loop can be programmed from -35dBm to -15dBm referred to the RF input in 1dB steps using the RF4–RF0 programming bits. The time constant of the loop is set externally by the capacitor connected to RFAGC_C. The image reject first mixer ensures a good image and half IF rejection. The front-end gain can be reduced by programming bits PM3–PM0 over a 22dB range, with a step of 2dB. This allows the selections of SAW filters with different insertion loss. The IF output is nominally 900Ω differentially and requires pullup inductors to VCC, which can be used as part of the matching network to the SAW filter impedance. Back End The back end, which downconverts the IF signal to quadrature baseband, is defined from the SAW filter inputs (pins IFIN+ and IFIN-) to the baseband outputs (pins IOUT+, IOUT-, QOUT+, QOUT-). The back end contains an IF AGC loop, which is closed by the baseband controller. The IF AGC control voltage is applied at the AGCPWM pin. The gain can be reduced over 53dB (typ) and exhibits a log-linear characteristic. The back end also contains individual lowpass filters on each channel. The lowpass-filter bandwidth is the useful SDARS downconverted bandwidth (6.25MHz). The lowpass-filter performance is factory trimmed. The bit IOT switches between the factory-trimmed set and the control through the I 2 C-compatible bus using bits B4–B1. Even when using the factory-trimmed set, the user can still slightly modify the cutoff frequency (by ±250kHz) by varying bits LP1/LP0. Highpass filters are also inserted in the back-end signal paths. Their purpose is to remove the DC offset. They are designed for a low corner frequency so as not to degrade the SDARS content. Their exact cutoff frequency is set by the external capacitors connected between 10 IF2 access pins, given by the following equation: fcutoff = 1/(2 x π x R x C) [Hz] where R = 8000Ω, C = external capacitor to be connected. Finally, the HPF bit allows an increase to the back-end gain by 4dB at the slight expense of a degraded inband linearity. Frequency Generation An on-chip VCO and a low-step fractional-N PLL ensure the necessary frequency generation. The 1st mixer’s LO is at the VCO frequency itself, while the 2nd mixer’s LO is the VCO frequency divided by 4 or by 8 (bit D48). Hence, the two possible IF frequencies for SDARS are 467MHz and 259MHz. Typical applications are based on 259MHz IF frequency. The reference divider path in the PLL can either use an external crystal and the on-chip crystal oscillator or an external TCXO that can overdrive the on-chip crystal oscillator. A reference division ratio of 1 or 2 is set by the REF bit. The crystal oscillator (or TCXO) signal is available at pin REFOUT. The output is either at the same frequency as the reference signal, or divided by two, based on the setting of bit RFD. The VCO main division ratio is set by bits N6–N0 (for the integer part) and bits F19–F00 (for the fractional part). The minimum step is below 30Hz, small enough for effective AFC to be implemented by the baseband. The charge-pump (pin CPOUT) is to be connected to the VCO tuning input (pin VTUNE) through an appropriate loop filter. Overcurrent Protection This DC function allows external circuitry consuming up to 150mA and connected to the pin VOUTANT to sink current from a VCC line (pin VINANT) through overcurrent-protection circuitry. When no overcurrent is present, a low dropout voltage exists between pins VINANT and VOUTANT. In overcurrent conditions (including short-circuit from VOUTANT to GND), the current is limited to approximately 300mA and bit ACP in the READ byte status goes high. This circuit also senses if the current drawn at the pin VOUTANT is typically larger than 20mA, in which case the bit AND from the READ byte status goes high (the purpose is to inform the baseband controller if there is any device drawing current from VOUTANT). ______________________________________________________________________________________ Complete SDARS Receiver Serial Interface and Control Registers I 2C Bit Description MAX2140 Programming Bits: The MAX2140 conforms to the Philips I2C standard, 400kbps (fast mode), and operates as a slave. The MAX2140 addresses can be selected from three values, which are determined by the logic state of the two address-select pins I2CA1 and I2CA2. In all cases, the MSB is transmitted (and read) first. MAX2140 I2C-Compatible Programming Bit Definition: BYTE PLLint: RFD = reference buffer division: RFD = 0 (/1) and RFD = 1 (/2) N6 to N0 is the binary-written main dividing ratio, integer part. BYTE PLLfrac2: PLS = Reserved: use only PLS = 0 LI1/0 = Reserved: use only LI1 = LI0 = 0 INT = Integer N mode: INT = 1 (fractional) and INT = 0 (integer) Table 1. MAX2140 Write Address Bytes AS1 AS0 MSB Low High High High Low High 1 1 1 ADDRESS BYTE 1 1 1 0 0 0 0 0 0 LSB 0 0 0 0 1 1 1 0 1 0 0 0 Table 2. MAX2140 Read Address Bytes AS1 AS0 MSB Low High 1 1 0 ADDRESS BYTE 0 0 0 1 LSB 1 High Low 1 1 0 0 0 1 0 1 High High 1 1 0 0 0 1 1 1 Table 3. MAX2140 Write Programming Bits WRITE-TO MODE Address PLLint RESET VALUE ADDR (hex) MSB CONTROL BYTE LSB — C2 C4 C6 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 1 1 1 0 1 0 0 0 01010110 00 RFD N6 N5 N4 N3 N2 N1 N0 PLLfrac2 00011110 01 PLS LI1 LI0 INT F19 F18 F17 F16 PLLfrac1 10010000 02 F15 F14 F13 F12 F11 F10 F09 F08 PLLfrac0 01101001 03 F07 F06 F05 F04 F03 F02 F01 F00 Control 01100000 04 REF CHP D48 SDR ANT SDF SDB SDP CustomGain 00000100 05 RF4 RF3 RF2 RF1 RF0 LP1 LP0 HPF PMA_Test 00000000 06 PM3 PM2 PM1 PM0 SDX T2 T1 T0 LPFTrim 00000000 09 0 0 IOT B4 B3 B2A B2 B1 Unused2 00000000 08 0 0 0 0 0 0 0 0 Unused1 00000000 07 0 0 0 0 0 0 0 0 Unused0 00000000 10 0 0 0 0 0 0 0 0 ______________________________________________________________________________________ 11 MAX2140 Applications Information MAX2140 Complete SDARS Receiver F19 to F16 is the upper-part binary-written main dividing ratio, fractional part multiplied by 2 20 = 1,048,576. BYTES PLLfrac1 and PLLfrac0: F15 to F0 is the lower-part binary-written main dividing ratio, fractional part multiplied by 220 = 1,048,576. BYTE Control: REF = reference division ratio: REF = 0 (/1) and REF = 1 (/2) CHP = charge-pump current: CHP = 0 (0.6mA) and CHP = 1 (1.2mA) D48 = LO division ratio: D48 = 0 (/4) and D48 = 1 (/8) SDR = shutdown RF AGC: SDR = 0 (on) and SDR = 1 (shutdown) ANT = antenna overcurrent protection: ANT = 0 (on) and ANT = 1 (shutdown) SDF = shutdown front end: SDF = 0 (on) and SDF = 1 (shutdown) SDB = shutdown back end: SDB = 0 (on) and SDB = 1 (shutdown) SDP = shutdown PLL: SDP = 0 (on) and SDP = 1 (shutdown) T2/T1/T0 = test bits: 000 (normal), 001 (main division), 010 (reference division), 011 (reserved), 100 (CHP low-Z), 101 (CHP source on), 110 (CHP sink on), 111 (CHP high-Z) BYTE LPFTrim: B4/B3/B2/B2A/B1 = Reserved for LPF trim. All = 0 in normal operating mode IOT = LPF corner frequency setup: IOT = 0 (default factory trim) and IOT = 1 (controllable through I2C). IOT = 0 in normal operating mode BYTE Status: RF AGC = RF AGC status: RF AGC = 0 (is not engaged) and RF AGC = 1 (engaged) ACP = antenna current protection: ACP = 0 (no overcurrent) and ACP = 1 (overcurrent) AND = antenna detection: ANT = 0 (current < threshold) and ANT = 1 (current > threshold) LD = lock detect: LD = 0 (out of lock) and LD = 1 (lock) BYTE Reserved: Inactive at this time, all bits are 0 Register configuration for the LO generation when the comparison frequency = 23.92MHz: to generate 2078.893333MHz: BYTE CustomGain: RF4/RF3/RF2/RF1/RF0 = RF AGC engagement threshold (dBm): see the RF AGC Settling Time graph in the Typical Operating Characteristics. LP1/LP0 = change by 250kHz the LPF corner frequency: LP1/LP0 = 10 (nominal), LP1/LP0 = 11 (decrease), LP1/LP0 = 00 (increase) PLLint = 01010110, PLLfrac2 = 00011110, PLLfrac1= 10010000, PLLfrac0 = 01101001 to generate 2067.777778MHz: PLLint = 01010110, PLLfrac2 = 00010111, PLLfrac1 = 00100001, PLLfrac0 = 00000010 to generate 1871.004000 MHz: PLLint = 01001110, PLLfrac2 = 00010011, PLLfrac1 = 10000001, PLLfrac0 = 11111000 to generate 1861.000000MHz: PLLint = 01001101, PLLfrac2 = 00011100, PLLfrac1 = 11010000, PLLfrac0 = 11101000 HPF = HPF gain increase by 4dB: HPF = 0 (off) and HPF = 1 (on) BYTE PMA_Test: PM3/PM2/PM1/PM0 = PMA gain cutback (dB): PM3/PM2/PM1/PM0DEC SDX = shutdown reference buffer: SDX = 0 (on) and SDX = 1 (shutdown) Table 4. MAX2140 Read Programming Bits READ-FROM MODE Address RESET VALUE ADDRESS (hex) MSB — C3 C5 C7 1 1 1 CONTROL BYTE 1 1 1 0 0 0 0 0 0 0 0 0 LSB 0 1 1 1 0 1 1 1 1 Reserved 00000000 00 0 0 0 0 0 0 0 0 Status 00000000 01 0 0 0 0 RFAGC ACP AND LD 12 ______________________________________________________________________________________ Complete SDARS Receiver The third byte is written to the internal register directed by the command address byte. The following bytes (if any) are written into successive internal registers. The transfer lasts until stop conditions are encountered. The MAX2140 acknowledges every byte transfer. Read Operation: When either address C3, C5, C7 is sent, the MAX2140 sends back first the status byte then the reserved byte. See Table 5 and Table 6 for read/write register operations. Power-Supply Layout To minimize coupling between different sections of the IC, the ideal power-supply layout is a star configuration, which has a large decoupling capacitor at a central VCC node. The VCC traces branch out from this node, each going to a separate VCC node in the MAX2140 circuit. At the end of each trace is a bypass capacitor with impedance to ground less than 1Ω at the frequency of interest. This arrangement provides local decoupling at each VCC pin. Use at least one via per bypass capacitor for a low-inductance ground connection. Matching Network Layout The layout of a matching network can be very sensitive to parasitic circuit elements. To minimize parasitic inductance, keep all traces short and place components as close to the IC as possible. To minimize parasitic capacitance, a cutout in the ground plane (and any other planes) below the matching network components can be used. On the high-impedance ports (e.g., IF inputs and outputs), keep traces short to minimize shunt capacitance. Chip Information TRANSISTOR COUNT: 22,000 PROCESS: BiCMOS Layout Issues The MAX2140 EV kit can be used as a starting point for layout. For best performance, take into consideration power-supply issues, as well as the RF, LO, and IF layout. Package Information For the latest package outline information, go to www.maxim-ic.com/packages. Table 5. Example: Write Registers 1 to 3 with 0E, D8, 26 Device Address Write (C2, C4, C6) ACK Register Address 00 ACK DATA 0E ACK DATA D8 ACK DATA 26 ACK STOP Table 6. Example: Read from Status Registers (Sending an NACK Terminate Slave Transmit Mode Device Address Write (C2, C4, C6) ACK Register Address 00 ACK DATA 0E ACK DATA D8 ACK DATA 26 ACK STOP Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. 13 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 2005 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products, Inc. MAX2140 I 2C Functional Description I2C Register Map: This is the standard I2C protocol. The first byte is either C6, C4, C2 (hex) dependent on the state of the I2CA_ pins, for a write-to-device operation and either C7, C5, C3 (hex) for a read-from operation (again dependent on the state of pins I2CA_). Write Operation: The first byte is the device address plus the direction bit (R/W = 0). The second byte contains the internal address command of the first address to be accessed.