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| 19-1759; Rev 0; 7/00 L MANUA ION KIT ALUAT DATA SHEET EV WS FOLLO 3.4GHz to 3.8GHz SiGe Low-Noise Amplifier/PA Predriver Features o 3.4GHz to 3.8GHz Frequency Range o LNA Performance (High/Low-Gain Modes) Gain: +14.4dB/-9.7dB NF: 2.3dB/15.5dB Input IP3: +4dBm/+13dBm Supply Current: 9.2mA/2.7mA o Highly Versatile Application Receive Path 1st and 2nd Stage LNA Transmit PA Predriver LO Buffer o Adjustable IP3 and Supply Current o 0.1A Supply Current in Shutdown Mode o +3.0V to +5.5V Single-Supply Operation o 10-Pin MAX-EP Package (5.0mm x 3.0mm) General Description The MAX2645 is a versatile, high-linearity, low-noise amplifier designed for 3.4GHz to 3.8GHz wireless local loop (WLL), wireless broadband access, and digital microwave radio applications. The device features an externally adjustable bias control, set with a single resistor, that allows the user to meet minimum linearity requirements while minimizing current consumption. The amplifier's high-gain, low-noise performance and adjustable input third-order intercept (IP3) allow it to be used as a low-noise amplifier (LNA) in the receive path, a PA predriver in the transmit path, or as an LO buffer. The MAX2645 features a logic-level gain control that provides a 25dB step reduction in gain, which improves IP3 performance for operation during high input signal level conditions. Supply current is reduced from 9mA in highgain mode to 3mA in low-gain mode. The device also includes a logic-controlled shutdown mode, which reduces supply current to 0.1A. The MAX2645 operates from a +3V to +5.5V supply and is offered in the miniature 10-pin MAX package (5mm 3mm) with an exposed paddle. Its performance has been optimized for use with the MAX2683/MAX2684 3.5GHz SiGe mixers to provide a complete high-performance, front-end solution for 3.5GHz applications. MAX2645 Ordering Information PART MAX2645EUB TEMP. RANGE -40C to +85C PIN-PACKAGE 10 MAX-EP* Applications Wireless Local Loop Wireless Broadband Access Digital Microwave Radios *Exposed paddle Pin Configuration appears at end of data sheet. Typical Operating Circuit RADIAL STUB VCC APPLICATION CIRCUIT LNA, LOW NF LNA, HIGH IP3 PA PREDRIVER GAIN (dB) 14.4/-9.7 14.9/-10.7 15.2/-9.7 NF (dB) 2.3/15.5 2.6/16 2.6/16 IIP3 (dBm) +4/+13 +10/+15.5 +11.8/+16.2 LOGIC INPUTS GAIN STEP SHUTDOWN RBIAS BIAS AND POWER MANAGEMENT TLINE MAX2645 RF INPUT 3.5GHz Z1 C1 RFIN HIGH GAIN LOW GAIN RF OUTPUT GND ________________________________________________________________ Maxim Integrated Products 1 For free samples and the latest literature, visit www.maxim-ic.com or phone 1-800-998-8800. For small orders, phone 1-800-835-8769. 3.4GHz to 3.8GHz SiGe Low-Noise Amplifier/PA Predriver MAX2645 ABSOLUTE MAXIMUM RATINGS VCC to GND ...........................................................-0.3V to +6.0V GAIN, SHDN, RFOUT to GND .....................0.3V to (VCC + 0.3V) RFIN Input Power (50 source)........................................16dBm Minimum RBIAS ....................................................................10k Continuous Power Dissipation (TA = +70C) 10-Pin MAX-EP (derate 10.3mW/C above TA = +70C) ....................825mW Operating Temperature Range ...........................-40C to +85C Junction Temperature ......................................................+150C Storage Temperature Range .............................-65C to +150C Lead Temperature (soldering, 10s) .................................+300C 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. DC ELECTRICAL CHARACTERISTICS (VCC = +3.0V to +5.5V, GAIN = SHDN = VCC, RBIAS = 20k, no RF signals applied, TA = -40C to +85C. Typical values are at VCC = +3.3V, TA = +25C, unless otherwise indicated.) PARAMETER Supply Voltage RBIAS = 20k, TA = +25C Operating Supply Current RBIAS = 20k, TA = -40C to +85C RBIAS = 15k, TA = +25C Shutdown Supply Current Input Logic Voltage High Input Logic Voltage Low Input Logic Bias Current SHDN = GND GAIN, SHDN GAIN, SHDN GAIN = SHDN = VCC GAIN = SHDN = GND -10 2.0 0.6 1 GAIN = VCC GAIN = GND GAIN = VCC GAIN = GND GAIN = VCC GAIN = GND 12 3.6 0.1 2 A V V A CONDITIONS MIN 3.0 9.2 2.7 TYP MAX 5.5 10.9 3.9 11.6 4.0 mA UNITS V 2 _______________________________________________________________________________________ 3.4GHz to 3.8GHz SiGe Low-Noise Amplifier/PA Predriver MAX2645 AC ELECTRICAL CHARACTERISTICS--LNA (Low-Noise Figure Application Circuit) (MAX2645 EV kit, V CC = GAIN = SHDN = +3.3V,R BIAS = 20k 1%, P RFIN = -20dBm, f RFIN = 3550MHz, Z o = 50, TA = +25C, unless otherwise noted.) PARAMETER Frequency Range Gain (Note 2) Gain Variation over Temperature Gain Step Input Third-Order Intercept Input 1dB Compression Point Noise Figure Reverse Isolation Gain Step Transition Time Turn-On/Turn-Off Time GAIN = VCC (Note 4) GAIN = GND (Note 5) GAIN = VCC GAIN = GND GAIN = VCC (Notes 3, 6) GAIN = GND GAIN = VCC GAIN = GND (Note 7) (Note 8) (Note 1) GAIN = VCC GAIN = GND TA = -40C to +85C, GAIN = VCC or GND (Note 3) CONDITIONS MIN 3400 12.9 -11.8 14.4 -9.7 0.3 24.1 +4 +13 -5 0 2.3 15.5 25 19 1 0.5 3.0 TYP MAX 3800 15.4 -8.0 0.7 UNITS MHz dB dB dB dBm dBm dB dB s s AC ELECTRICAL SPECIFICATIONS--LNA (High-Input IP3 Application Circuit) (MAX2645 EV kit, V CC = GAIN = SHDN = +3.3V,R BIAS = 20k 1%, P RFIN = -20dBm, f RFIN = 3550MHz, Z o = 50, TA = +25C, unless otherwise noted.) PARAMETER Frequency Range Gain Gain Variation over Temperature Gain Step Input Third-Order Intercept Input 1dB Compression Point Noise Figure Reverse Isolation GAIN = VCC (Note 5) GAIN = GND (Note 6) GAIN = VCC GAIN = GND GAIN = VCC GAIN = GND GAIN = VCC GAIN = GND (Note 1) GAIN = VCC GAIN = GND TA = -40C to +85C, GAIN = VCC or GND CONDITIONS MIN 3400 14.9 -10.7 0.3 25.6 +10.0 +15.5 -4 0 2.6 16 25 19 TYP MAX 3800 UNITS MHz dB dB dB dBm dBm dB dB _______________________________________________________________________________________ 3 3.4GHz to 3.8GHz SiGe Low-Noise Amplifier/PA Predriver MAX2645 AC ELECTRICAL SPECIFICATIONS--PA Predriver Application Circuit (MAX2645 EV kit, V CC = GAIN = SHDN = +3.3V,R BIAS = 20k 1%, P RFIN = -20dBm, f RFIN = 3550MHz, Z o = 50, TA = +25C, unless otherwise noted.) PARAMETER Frequency Range Gain Gain Variation over Temperature Gain Step Input Third-Order Intercept Input 1dB Compression Point Noise Figure Reverse Isolation GAIN = VCC (Note 5) GAIN = GND (Note 6) GAIN = VCC GAIN = GND GAIN = VCC GAIN = GND GAIN = VCC GAIN = GND (Note 1) GAIN = VCC GAIN = GND TA = -40C to +85C, GAIN = VCC or GND CONDITIONS MIN 3400 15.2 -9.7 0.3 24.9 +11.8 +16.2 -1.8 0 2.6 16 25 19 TYP MAX 3800 UNITS MHz dB dB dB dBm dBm dB dB Note 1: This is the recommended operating frequency range. Operation outside this frequency range is possible but has not been characterized. The device is characterized and tested at 3550MHz. For optimum performance at a given frequency, the output matching network must be properly designed. See Applications Information section. Note 2: Specifications are corrected for board losses (0.25dB at input, 0.25dB at output). Note 3: Guaranteed by design and characterization. Note 4: Input IP3 measured with two tones, f1 = 3550MHz and f2 = 3551MHz, at -20dBm per tone. Note 5: Input IP3 measured with two tones, f1 = 3550MHz and f2 = 3551MHz, at -12dBm per tone. Note 6: Specifications are corrected for board losses (0.25dB at input). Note 7: Time from when GAIN changes state to when output power reaches 1dB of its final value. Note 8: Time from when SHDN changes state to when output power reaches 1dB of its final value. Typical Operating Characteristics (MAX2645 EV kit, VCC = +3.3V, RBIAS = 20k, fRFIN = 3550MHz, TA = +25C, unless otherwise noted.) SUPPLY CURRENT vs. SUPPLY VOLTAGE (HIGH-GAIN MODE) MAX2645-01 SUPPLY CURRENT vs. SUPPLY VOLTAGE (LOW-GAIN MODE) MAX2645-02 SUPPLY CURRENT vs. RBIAS MAX2645-03 15 14 SUPPLY CURRENT (mA) 13 12 11 10 9 8 7 3.0 3.5 4.0 4.5 5.0 TA = -40C RBIAS = 20k TA = +85C TA = -40C TA = +25C RBIAS = 15k TA = +25C TA = +85C 5.0 4.5 SUPPLY CURRENT (mA) RBIAS = 15k 4.0 3.5 TA = -40C 3.0 2.5 2.0 TA = -40C TA = +25C TA = +25C TA = +85C TA = +85C 20 SUPPLY CURRENT (mA) 15 VCC = 5V 10 VCC = 3.3V V = 5V CC 5 VCC = 3.3V 0 LOW GAIN HIGH GAIN RBIAS = 20k 4.5 5.0 5.5 15 5.5 3.0 3.5 4.0 20 RBIAS (k) 25 SUPPLY VOLTAGE (V) SUPPLY VOLTAGE (V) 4 _______________________________________________________________________________________ 3.4GHz to 3.8GHz SiGe Low-Noise Amplifier/PA Predriver Typical Operating Characteristics (continued) (MAX2645 EV kit, VCC = +3.3V, RBIAS = 20k, fRFIN = 3550MHz, TA = +25C, unless otherwise noted.) MAX2645 GAIN vs. FREQUENCY (HIGH-GAIN MODE) MAX2645-04 GAIN vs. FREQUENCY (LOW-GAIN MODE) MAX2645-05 GAIN vs. SUPPLY VOLTAGE (HIGH-GAIN MODE) 14.8 14.6 TA = -40C MAX2645-06 17 16 15 14 GAIN (dB) TA = -40C -5 -6 -7 -8 GAIN (dB) -9 -10 -11 -12 -13 -14 TA = +25C TA = +85C TA = -40C 15.0 14.4 GAIN (dB) 14.2 14.0 13.8 13.6 13.4 13.2 TA = +25C TA = +85C 13 12 11 10 9 8 7 TA = +25C TA = +85C LOW-NOISE FIGURE CIRCUIT 3.4 3.5 3.6 FREQUENCY (GHz) 3.7 3.8 -15 LOW-NOISE FIGURE CIRCUIT 3.4 3.5 3.6 FREQUENCY (GHz) 3.7 3.8 13.0 LOW-NOISE FIGURE CIRCUIT 3.0 3.5 4.0 4.5 5.0 5.5 SUPPLY VOLTAGE (V) GAIN vs. SUPPLY VOLTAGE (LOW-GAIN MODE) MAX2645-07 GAIN STEP vs. SUPPLY VOLTAGE MAX2645-08 GAIN vs. RBIAS (HIGH-GAIN MODE) MAX2645-09 -7.0 -7.5 -8.0 -8.5 GAIN (dB) -9.0 -9.5 TA = +85C TA = +25C TA = -40C 26.0 25.5 25.0 GAIN STEP (dB) TA = +25C 15.0 14.8 VCC = 5V 24.0 23.5 23.0 22.5 TA = +85C TA = -40C LOW-NOISE FIGURE CIRCUIT 3.0 3.5 4.0 4.5 5.0 5.5 GAIN (dB) 24.5 14.6 14.4 VCC = 3.3V 14.2 LOW-NOISE FIGURE CIRCUIT 15.0 17.5 20.0 RBIAS (k) 22.5 25.0 -10.0 -10.5 -11.0 LOW-NOISE FIGURE CIRCUIT 3.0 3.5 4.0 4.5 22.0 5.0 5.5 14.0 SUPPLY VOLTAGE (V) SUPPLY VOLTAGE (V) GAIN vs. RBIAS (LOW-GAIN MODE) MAX2645-10 NOISE FIGURE vs. FREQUENCY (HIGH-GAIN MODE) MAX2645-11 NOISE FIGURE vs. FREQUENCY (LOW-GAIN MODE) 19 18 NOISE FIGURE (dB) 17 16 15 14 13 12 11 MAX2645-12 -10.0 -10.2 -10.4 -10.6 GAIN (dB) -10.8 -11.0 -11.2 -11.4 -11.6 -11.8 -12.0 LOW-NOISE FIGURE CIRCUIT 15.0 17.5 20.0 RBIAS (k) 22.5 VCC = 3.3V VCC = 5V 5 20 4 NOISE FIGURE (dB) 3 2 1 LOW-NOISE FIGURE CIRCUIT 3.4 3.5 3.6 FREQUENCY (GHz) 3.7 3.8 0 25.0 10 LOW-NOISE FIGURE CIRCUIT 3.4 3.5 3.6 FREQUENCY (GHz) 3.7 3.8 _______________________________________________________________________________________ 5 3.4GHz to 3.8GHz SiGe Low-Noise Amplifier/PA Predriver MAX2645 Typical Operating Characteristics (continued) (MAX2645 EV kit, VCC = +3.3V, RBIAS = 20k, fRFIN = 3550MHz, TA = +25C, unless otherwise noted.) NOISE FIGURE vs. RBIAS (HIGH-GAIN MODE) MAX2645-13 INPUT IP3 vs. SUPPLY VOLTAGE (HIGH-GAIN MODE) MAX2645-14 INPUT IP3 vs. SUPPLY VOLTAGE (LOW-GAIN MODE) 15.0 14.5 14.0 INPUT IP3 (dBm) 13.5 13.0 12.5 12.0 11.5 11.0 TA = +85C MAX2645-15 5 6.0 5.5 5.0 4.5 INPUT IP3 (dBm) TA = -40C TA = +85C 15.5 TA = -40C 4 NOISE FIGURE (dB) TA = +25C 3 4.0 3.5 3.0 2.5 TA = +25C 2 1 LOW-NOISE FIGURE CIRCUIT 15.0 17.5 20.0 RBIAS (k) 22.5 25.0 2.0 1.5 LOW-NOISE FIGURE CIRCUIT 3.0 3.5 4.0 4.5 5.0 5.5 0 1.0 10.5 LOW-NOISE FIGURE CIRCUIT 3.0 3.5 4.0 4.5 5.0 5.5 SUPPLY VOLTAGE (V) SUPPLY VOLTAGE (V) INPUT IP3 vs. RBIAS (HIGH-GAIN MODE) MAX2645-16 INPUT IP3 vs. RBIAS (LOW-GAIN MODE) MAX2645-17 INPUT P1dB vs. SUPPLY VOLTAGE (HIGH-GAIN MODE) -4.0 -4.5 INPUT P1dB (dBm) -5.0 -5.5 -6.0 -6.5 -7.0 -7.5 -8.0 LOW-NOISE FIGURE CIRCUIT 3.0 3.5 4.0 4.5 5.0 5.5 TA = +85C TA = +25C TA = -40C MAX2645-18 9 15.5 15.0 14.5 INPUT IP3 (dBm) 14.0 13.5 13.0 12.5 12.0 VCC = 3.3V VCC = 5V -3.5 7 VCC = 5V INPUT IP3 (dBm) 5 3 VCC = 3.3V 1 LOW-NOISE FIGURE CIRCUIT -1 15.0 17.5 20.0 RBIAS (k) 22.5 25.0 11.5 LOW-NOISE FIGURE CIRCUIT 15.0 17.5 20.0 RBIAS (k) 22.5 25.0 -8.5 SUPPLY VOLTAGE (V) OUTPUT POWER vs. INPUT POWER (LOW-GAIN MODE) MAX2645-19 INPUT P1dB vs. RBIAS (HIGH-GAIN MODE) MAX2645-20 INPUT VSWR vs. FREQUENCY MAX2645-21 10 5 OUTPUT POWER (dBm) 0 TA = +85C -5 TA = +25C -10 -15 -20 -25 LOW-NOISE FIGURE CIRCUIT -10.0 -5.0 0 INPUT POWER (dBm) TA = -40C -2 VCC = 5V 2.50 2.25 2.00 VSWR LOW GAIN -3 INPUT P1dB (dBm) -4 1.75 1.50 HIGH GAIN -5 -6 VCC = 3.3V LOW-NOISE FIGURE CIRCUIT 15.0 17.5 20.0 RBIAS (k) 22.5 25.0 1.25 1.00 LOW-NOISE FIGURE CIRCUIT 3.4 3.5 3.6 FREQUENCY (GHz) 3.7 3.8 -7 5.0 6 _______________________________________________________________________________________ 3.4GHz to 3.8GHz SiGe Low-Noise Amplifier/PA Predriver Typical Operating Characteristics (continued) (MAX2645 EV kit, VCC = +3.3V, RBIAS = 20k, fRFIN = 3550MHz, TA = +25C, unless otherwise noted.) MAX2645 OUTPUT VSWR vs. FREQUENCY MAX2645-22 REVERSE ISOLATION vs. FREQUENCY MAX2645-23 GAIN vs. FREQUENCY (HIGH-GAIN MODE) 16.5 16.0 15.5 TA = -40C HIGH-INPUT IP3 CIRCUIT MAX2645-24 6.0 5.5 5.0 4.5 VSWR 4.0 3.5 3.0 2.5 2.0 1.5 1.0 3.4 3.5 3.6 FREQUENCY (GHz) 3.7 HIGH GAIN LOW GAIN LOW-NOISE FIGURE CIRCUIT 0 -5 REVERSE ISOLATION (dB) -10 -15 -20 -25 17.0 LOW-NOISE FIGURE CIRCUIT LOW GAIN GAIN (dB) 15.0 14.5 14.0 13.5 TA = +25C HIGH GAIN -30 -35 13.0 12.5 12.0 TA = +85C 3.8 3.4 3.5 3.6 3.7 FREQUENCY (GHz) 3.8 3.4 3.5 3.6 FREQUENCY (GHz) 3.7 3.8 GAIN vs. FREQUENCY (LOW-GAIN MODE) MAX2645-25 INPUT VSWR vs. FREQUENCY MAX2645-26 GAIN vs. FREQUENCY (HIGH-GAIN MODE) 19 18 VCC = 5V MAX2645-27 -10.0 -10.5 -11.0 -11.5 GAIN (dB) -12.0 -12.5 -13.0 -13.5 -14.0 -14.5 -15.0 HIGH-INPUT IP3 CIRCUIT 3.4 3.5 3.6 FREQUENCY (GHz) 3.7 TA = +25C TA = +85C 5.0 4.5 4.0 20 HIGH-INPUT IP3 CIRCUIT 17 GAIN (dB) 16 15 14 13 TA = +25C TA = +85C TA = -40C VSWR TA = -40C 3.5 3.0 2.5 2.0 1.5 1.0 3.8 3.4 3.5 3.6 FREQUENCY (GHz) 3.7 3.8 HIGH GAIN LOW GAIN 12 11 10 PA PREDRIVER CIRCUIT 3.4 3.5 3.6 3.7 3.8 FREQUENCY (GHz) GAIN vs. FREQUENCY (LOW-GAIN MODE) MAX2645-28 GAIN vs. SUPPLY VOLTAGE (HIGH-GAIN MODE) MAX2645-29 GAIN vs. SUPPLY VOLTAGE (LOW-GAIN MODE) VCC = 5V TA = -40C TA = +25C -9.0 -9.5 GAIN (dB) -10.0 -10.5 -11.0 -11.5 -12.0 TA = +85C MAX2645-30 -5 -6 -7 -8 GAIN (dB) VCC = 5V 16.5 16.0 15.5 GAIN (dB) VCC = 5V -8.5 TA = -40C TA = +25C -9 -10 -11 -12 -13 -14 -15 PA PREDRIVER CIRCUIT 3.4 3.5 3.6 TA = -40C TA = +25C TA = +85C 15.0 14.5 14.0 13.5 13.0 12.5 PA PREDRIVER CIRCUIT 3.0 3.5 4.0 4.5 5.0 5.5 TA = +85C -12.5 PA PREDRIVER CIRCUIT 3.0 3.5 4.0 4.5 5.0 5.5 3.7 3.8 FREQUENCY (GHz) SUPPLY VOLTAGE (V) SUPPLY VOLTAGE (V) _______________________________________________________________________________________ 7 3.4GHz to 3.8GHz SiGe Low-Noise Amplifier/PA Predriver MAX2645 Typical Operating Characteristics (continued) (MAX2645 EV kit, VCC = +3.3V, RBIAS = 20k, fRFIN = 3550MHz, TA = +25C, unless otherwise noted.) OUTPUT P1dB POINT vs. SUPPLY VOLTAGE (HIGH-GAIN MODE) MAX2645-31 OUTPUT POWER vs. INPUT POWER (LOW-GAIN MODE) MAX2645-32 INPUT VSWR vs. FREQUENCY 4.5 4.0 PA PREDRIVER CIRCUIT VCC = 5V MAX2645-33 13 12 VCC = 5V 10 5 OUTPUT POWER (dBm) 0 -5 -10 -15 VCC = 5V 5.0 TA = +85C 11 TA = +25C 10 9 8 7 PA PREDRIVER CIRCUIT 3.0 3.5 4.0 4.5 5.0 5.5 TA = -40C TA = +25C VSWR 3.5 3.0 2.5 LOW GAIN TA = -40C TA = +85C -20 -25 PA PREDRIVER CIRCUIT -10.0 -5.0 0 5.0 2.0 HIGH GAIN 1.5 1.0 3.4 3.5 3.6 FREQUENCY (GHz) 3.7 3.8 SUPPLY VOLTAGE (V) INPUT POWER (dBm) Pin Description PIN 1, 2, 4, 7, EP 3 5 NAME GND RFIN BIAS FUNCTION Ground. Connect to ground plane with a low-inductance connection. Solder exposed paddle evenly to the board ground plane. RF Input Port to Amplifier. Requires a matching network and a DC-blocking capacitor that may be part of this network. See Figure 1 for recommended component values. Bias-Setting Resistor Connection. A resistor, RBIAS, placed from BIAS to ground sets the linearity and supply current of the amplifier. RF Open-Collector Output Port of Amplifier. Requires a matching network composed of an inductance to VCC and a DC-blocking capacitor. See Figure 1 for recommended component values. Shutdown Control Logic-Level Input. A logic high enables the device for normal operation. A logic low places the device in low-power shutdown mode. Gain Control Logic-Level Input. A logic high places the device in high-gain mode. A logic low places the device in low-gain mode, reducing the gain by 25dB. Power Supply Input. Bypass directly to ground with a capacitor as close to the supply pin as possible. See Figure 1 for recommended component values. 6 RFOUT 8 9 10 SHDN GAIN VCC 8 _______________________________________________________________________________________ 3.4GHz to 3.8GHz SiGe Low-Noise Amplifier/PA Predriver Detailed Description The MAX2645 is a versatile amplifier with high-gain, high-linearity, and low-noise performance--features that make it suitable for use as an LNA, high-linearity/lownoise amplifier, PA predriver, or LO buffer in the 3.4GHz to 3.8GHz frequency range. See Figure 1, MAX2645 Typical Application Circuit, for recommended component values. A single external bias-setting resistor allows the system designer to trade off linearity for reduced supply current. A logic-level control reduces gain by a 25dB step to further improve input IP3 performance. A low-power shutdown mode disables the device and reduces current consumption to 0.1A. Gain Step Control The MAX2645 features a logic-level gain step control input (GAIN) that places the device in high-gain or lowgain mode. A logic-level high places the device in highgain mode, where the gain is 14.5dB. A logic-level low places the device in low-gain/high-linearity mode, where the gain is reduced to 10dB and the input IP3 performance is increased. MAX2645 Shutdown Control The MAX2645 features a logic-level shutdown control input. A logic high on SHDN enables the device for normal operation. A logic low on SHDN disables all device functions and reduces supply current to 0.1A. Bias Circuitry The linearity and supply current of the MAX2645 are externally programmable with a single resistor (RBIAS) placed from BIAS to GND. Larger resistor values result in lower IP3 performance and lower supply current, while smaller resistor values result in higher IP3 performance and higher supply current. Use resistor values in the 15k to 25k range, with a nominal value of 20k suitable for most applications. See Typical Operating Characteristics for performance variation vs. R BIAS value. Applications Information RF Input The RFIN port is internally biased and requires an external DC-blocking capacitor. A matching network is required for best performance. Figure 1 shows component values optimized for best noise-figure performance, low-noise figure, high-input IP3 performance, and highoutput P1dB performance in the 3.4GHz to 3.8GHz frequency range. For matching to other frequencies, see Tables 1 and 2. Table 1. MAX2645 S-Parameters FREQ (MHz) 3400 3450 3500 3550 3600 3650 3700 3750 3800 3400 3450 3500 3550 3600 3650 3700 3750 3800 S11 MAG 0.468 0.466 0.472 0.469 0.471 0.477 0.485 0.484 0.492 0.454 0.457 0.465 0.468 0.472 0.481 0.486 0.486 0.499 PHASE -149.8 -150.4 -151.6 -153.4 -154.6 -155.0 -156.6 -156.5 -157.0 -146.6 -147.4 -147.9 -149.7 -150.5 -150.5 -152.2 -152.4 -152.6 MAG 5.061 4.975 5.098 4.883 4.814 5.118 4.769 4.780 4.939 5.350 5.245 5.375 5.165 5.066 5.386 5.040 5.019 5.207 S21 PHASE -44.6 -46.3 -49.9 -53.7 -53.7 -57.4 -63.4 -62.3 -66.6 -41.8 -43.5 -46.6 -50.3 -50.2 -53.4 -59.4 -58.3 -62.0 MAG 0.053 0.058 0.056 0.054 0.056 0.058 0.054 0.058 0.060 0.057 0.061 0.060 0.057 0.060 0.063 0.060 0.062 0.065 RBIAS = 20k, VCC = +3.3V, TA = +25C -55.5 -60.8 -64.6 -62.7 -64.4 -68.9 -70.5 -72.0 -75.4 -51.3 -56.7 -61.2 -61.0 -62.7 -67.6 -67.8 -67.0 -73.3 0.660 0.658 0.661 0.658 0.647 0.657 0.657 0.654 0.654 0.651 0.646 0.654 0.652 0.645 0.652 0.648 0.642 0.643 -57.0 -58.4 -60.6 -63.0 -64.2 -66.2 -69.8 -70.9 -72.3 -52.3 -53.7 -55.6 -58.3 -59.3 -60.7 -63.9 -64.8 -66.2 S12 PHASE MAG S22 PHASE RBIAS = 15k, VCC = +5V, TA = +25C _______________________________________________________________________________________ 9 3.4GHz to 3.8GHz SiGe Low-Noise Amplifier/PA Predriver MAX2645 Table 2. MAX2645 Noise Parameters FREQUENCY (MHz) 3400 3450 3500 3550 3600 3650 3700 3750 3800 3400 3450 3500 3550 3600 3650 3700 3750 3800 FMIN (dB) 2.098 2.122 2.148 2.173 2.198 2.225 2.251 2.279 2.306 2.103 2.127 2.152 2.177 2.203 2.229 2.256 2.282 2.310 |opt| 0.237 0.235 0.235 0.234 0.233 0.232 0.231 0.230 0.229 RBIAS = 15k, VCC = +5V, TA = +25C 0.210 0.209 0.208 0.207 0.206 0.206 0.205 0.204 0.204 146.3 148.4 150.5 152.6 154.7 156.8 158.9 161.0 163.1 31.1 31.6 32.1 32.5 33.0 33.5 34.0 34.6 35.1 opt ANGLE 144.1 146.1 148.2 150.3 152.4 154.5 156.5 158.6 160.7 RN () 31.1 31.5 32.0 32.5 32.9 33.5 33.9 34.5 35.0 RBIAS = 20k, VCC = +3.3V, TA = +25C RF Output The RFOUT port is an open-collector output that must be tied to VCC through an inductance for proper biasing. The MAX2645 EV kit uses a length of transmission line equivalent to 1.5nH of inductance. A DC-blocking capacitor is required and can be part of the output matching network. See Figure 1 for component values recommended for operation over the 3.4GHz to 3.8GHz frequency range. See Table 1 for matching to other frequencies. This transmission line is terminated at the VCC node with a radial stub for high-frequency bypassing. This arrangement provides a high-Q, low-loss bias network used to optimize performance. The radial stub can be replaced with an appropriate microwave capacitor. To minimize the amount of noise injected into the bias circuitry and logic inputs, bypass the pins with capacitors located as near to the device pin as possible. For additional isolation on the logic-control pins, place resistors between the logic-control inputs and the bypass capacitors. See Figure 1 for recommended component values; refer to MAX2645 EV kit manual for recommended board layout. Layout Considerations A properly designed PC board is an essential part of any RF/microwave circuit. Keep RF signal lines as short as possible to reduce losses, radiation, and inductance. Use separate, low-inductance vias to the ground plane for each ground pin. For best performance, solder the exposed paddle on the bottom of the device package evenly to the board ground plane. Power-Supply, Bias Circuitry, and LogicInput Bypassing Proper power-supply bypassing is essential for high-frequency circuit stability. Bypass VCC with 10F, 0.1F, and 50pF capacitors located as close to the VCC pin as possible. 10 ______________________________________________________________________________________ 3.4GHz to 3.8GHz SiGe Low-Noise Amplifier/PA Predriver MAX2645 1 VCC GND VCC 47pF 2 GAIN 9 HIGH GAIN LOW GAIN 0.1F GND C1 RF INPUT 3.4GHz to 3.8GHz Z1 MAX2645 3 RFIN SHDN 8 ON OFF 4 GND GND 7 RADIAL STUB* 40 5 220pF BIAS RBIAS RFOUT 8 TLINE LEQUIV = 1.5nH 294 mil s VCC RF OUTPUT 0.75pF 1000pF APPLICATION CIRCUIT LNA, LOW NF LNA, HIGH INPUT IP3 PA PREDRIVER C1 1.5pF 1000pF 0.01F Z1 1.8nH 0.75pF 0.75pF RBIAS (k) VCC (V) 20 3.3 20 15 3.3 5.0 *BOARD MATERIAL = GETek, COPPER THICKNESS = 1 oz BOARD THICKNESS = 0.012in, DIELECTRIC CONSTANT = 3.8 Figure 1. Typical Application Circuit MAX2645 MAX2645 RF IMAGE-REJECT FILTER MAX2683 MAX2684 IF BANDPASS FILTER RECEIVE IF OUTPUT MAX2645 LOW NF LNA HIGH IP3 LNA LO LO BUFFER DUPLEXER MAX2645 MAX2645 PA RF BANDPASS FILTER TRANSMIT IF INPUT MAX2683 MAX2684 LO LO BUFFER PA PREDRIVER Figure 2. Typical System Application Block Diagram ______________________________________________________________________________________ 11 3.4GHz to 3.8GHz SiGe Low-Noise Amplifier/PA Predriver MAX2645 Pin Configuration TRANSISTOR COUNT: 271 TOP VIEW GND 1 GND RFIN GND BIAS 2 3 4 5 10 VCC 9 GAIN SHDN GND RFOUT Chip Information MAX2645 8 7 6 MAX-EP Package Information 10LUMAX.EPS 12 ______________________________________________________________________________________ |
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