19-1759; Rev 1; 8/03 KIT ATION EVALU E L B A IL AVA 3.4GHz to 3.8GHz SiGe Low-Noise Amplifier/PA Predriver Applications Features ♦ 3.4GHz to 3.8GHz Frequency Range ♦ 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 ♦ Highly Versatile Application Receive Path 1st and 2nd Stage LNA Transmit PA Predriver LO Buffer ♦ Adjustable IP3 and Supply Current ♦ 0.1µA Supply Current in Shutdown Mode ♦ +3.0V to +5.5V Single-Supply Operation ♦ 10-Pin µMAX-EP Package (5.0mm x 3.0mm) Ordering Information PART TEMP RANGE PIN-PACKAGE MAX2645EUB -40°C to +85°C 10 µMAX-EP* *EP = exposed paddle. Wireless Local Loop Pin Configuration appears at end of data sheet. Wireless Broadband Access Digital Microwave Radios Typical Operating Circuit RADIAL STUB APPLICATION CIRCUIT LNA, LOW NF LNA, HIGH IP3 PA PREDRIVER VCC LOGIC INPUTS GAIN STEP SHUTDOWN 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 BIAS AND POWER MANAGEMENT TLINE RBIAS MAX2645 C1 RF INPUT 3.5GHz RF OUTPUT HIGH GAIN RFIN Z1 LOW GAIN GND ________________________________________________________________ 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 MAX2645 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 0.1µA. The MAX2645 operates from a +3V to +5.5V supply and is offered in the miniature 10-pin µMAX 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 3.4GHz to 3.8GHz SiGe Low-Noise Amplifier/PA Predriver 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 (50Ω source)........................................16dBm Minimum RBIAS ....................................................................10kΩ Continuous Power Dissipation (TA = +70°C) 10-Pin µMAX-EP (derate 10.3mW/°C above TA = +70°C) ....................825mW Operating Temperature Range ...........................-40°C to +85°C Junction Temperature ......................................................+150°C 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 = +3.0V to +5.5V, GAIN = SHDN = VCC, RBIAS = 20kΩ, no RF signals applied, TA = -40°C to +85°C. Typical values are at VCC = +3.3V, TA = +25°C, unless otherwise indicated.) (Note 1) PARAMETER CONDITIONS Supply Voltage Operating Supply Current 2 TYP MAX UNITS 5.5 V 10.9 3.0 RBIAS = 20kΩ, TA = +25°C GAIN = VCC 9.2 GAIN = GND 2.7 RBIAS = 20kΩ, TA = -40°C to +85°C GAIN = VCC 11.6 GAIN = GND 4.0 RBIAS = 15kΩ, TA = +25°C GAIN = VCC 12 GAIN = GND 3.6 Shutdown Supply Current SHDN = GND Input Logic Voltage High GAIN, SHDN Input Logic Voltage Low GAIN, SHDN Input Logic Bias Current MIN 0.1 µA 0.6 V V 1 -10 _______________________________________________________________________________________ mA 2 2.0 GAIN = SHDN = VCC GAIN = SHDN = GND 3.9 µA 3.4GHz to 3.8GHz SiGe Low-Noise Amplifier/PA Predriver (MAX2645 EV kit, V CC = GAIN = SHDN = +3.3V,R BIAS = 20kΩ ±1%, P RFIN = -20dBm, f RFIN = 3550MHz, Z o = 50Ω, TA = +25°C, unless otherwise noted.) PARAMETER Frequency Range Gain (Note 3) Gain Variation over Temperature CONDITIONS MIN TYP MAX UNITS 3800 MHz (Note 2) 3400 GAIN = VCC 12.9 14.4 15.4 GAIN = GND -11.8 -9.7 -8.0 ±0.3 ±0.7 TA = -40°C to +85°C, GAIN = VCC or GND (Note 4) ±24.1 Gain Step Input Third-Order Intercept Input 1dB Compression Point GAIN = VCC (Note 5) +4 GAIN = GND (Note 6) +13 GAIN = VCC -5 GAIN = GND 0 dB dB dB dBm dBm GAIN = VCC (Notes 4, 7) 2.3 GAIN = GND 15.5 GAIN = VCC 25 GAIN = GND 19 Gain Step Transition Time (Note 8) 1 µs Turn-On/Turn-Off Time (Note 9) 0.5 µs Noise Figure Reverse Isolation 3.0 dB dB AC ELECTRICAL SPECIFICATIONS—LNA (High-Input IP3 Application Circuit) (MAX2645 EV kit, V CC = GAIN = SHDN = +3.3V,R BIAS = 20kΩ ±1%, P RFIN = -20dBm, f RFIN = 3550MHz, Z o = 50Ω, TA = +25°C, unless otherwise noted.) PARAMETER Frequency Range CONDITIONS (Note 2) Gain Gain Variation over Temperature Input 1dB Compression Point Noise Figure Reverse Isolation TYP MAX UNITS 3800 MHz GAIN = VCC 14.9 GAIN = GND -10.7 TA = -40°C to +85°C, GAIN = VCC or GND ±0.3 dB 25.6 +10.0 +15.5 -4 0 2.6 16 25 19 dB GAIN = VCC (Note 6) GAIN = GND (Note 7) GAIN = VCC GAIN = GND GAIN = VCC GAIN = GND GAIN = VCC GAIN = GND Gain Step Input Third-Order Intercept MIN 3400 dB dBm dBm dB dB _______________________________________________________________________________________ 3 MAX2645 AC ELECTRICAL CHARACTERISTICS—LNA (Low-Noise Figure Application Circuit) AC ELECTRICAL SPECIFICATIONS—PA Predriver Application Circuit (MAX2645 EV kit, V CC = GAIN = SHDN = +3.3V,R BIAS = 20kΩ ±1%, P RFIN = -20dBm, f RFIN = 3550MHz, Z o = 50Ω, TA = +25°C, unless otherwise noted.) PARAMETER CONDITIONS Frequency Range MIN (Note 2) Gain Gain Variation over Temperature Input Third-Order Intercept Input 1dB Compression Point Noise Figure Reverse Isolation TYP 3400 MAX UNITS 3800 MHz GAIN = VCC 15.2 GAIN = GND -9.7 TA = -40°C to +85°C, GAIN = VCC or GND ±0.3 dB 24.9 dB Gain Step GAIN = VCC (Note 6) +11.8 GAIN = GND (Note 7) GAIN = VCC GAIN = GND GAIN = VCC GAIN = GND GAIN = VCC GAIN = GND +16.2 -1.8 0 2.6 16 25 19 dB dBm dBm dB dB Note 1: Limits over temperature guaranteed by correlation to worst-case temperature testing. Note 2: 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 3: Specifications are corrected for board losses (0.25dB at input, 0.25dB at output). Note 4: Guaranteed by design and characterization. Note 5: Input IP3 measured with two tones, f1 = 3550MHz and f2 = 3551MHz, at -20dBm per tone. Note 6: Input IP3 measured with two tones, f1 = 3550MHz and f2 = 3551MHz, at -12dBm per tone. Note 7: Specifications are corrected for board losses (0.25dB at input). Note 8: Time from when GAIN changes state to when output power reaches 1dB of its final value. Note 9: 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 = 20kΩ, fRFIN = 3550MHz, TA = +25°C, unless otherwise noted.) SUPPLY CURRENT vs. SUPPLY VOLTAGE (HIGH-GAIN MODE) 12 TA = +85°C 11 TA = -40°C TA = +25°C 10 9 TA = -40°C 8 RBIAS = 15kΩ 4.0 TA = +85°C TA = +25°C 3.5 TA = +85°C TA = -40°C TA = +25°C 3.0 2.5 RBIAS = 20kΩ 7 TA = -40°C 3.5 4.0 4.5 SUPPLY VOLTAGE (V) 5.0 5.5 MAX2645-03 15 VCC = 5V 10 HIGH GAIN VCC = 3.3V V = 5V CC 5 LOW GAIN RBIAS = 20kΩ VCC = 3.3V 2.0 3.0 4 4.5 SUPPLY CURRENT (mA) TA = +25°C SUPPLY CURRENT vs. RBIAS 20 SUPPLY CURRENT (mA) TA = +85°C RBIAS = 15kΩ 13 5.0 MAX2645-02 14 SUPPLY CURRENT vs. SUPPLY VOLTAGE (LOW-GAIN MODE) MAX2645-01 15 SUPPLY CURRENT (mA) MAX2645 3.4GHz to 3.8GHz SiGe Low-Noise Amplifier/PA Predriver 0 3.0 3.5 4.0 4.5 SUPPLY VOLTAGE (V) 5.0 5.5 15 20 RBIAS (kΩ) _______________________________________________________________________________________ 25 3.4GHz to 3.8GHz SiGe Low-Noise Amplifier/PA Predriver GAIN vs. FREQUENCY (LOW-GAIN MODE) 15 -6 TA = +85°C 9 8 -14 3.5 -15 3.6 3.7 TA = +85°C TA = +85°C 13.8 13.6 13.2 LOW-NOISE FIGURE CIRCUIT 3.5 3.6 13.0 3.7 3.8 LOW-NOISE FIGURE CIRCUIT 3.0 4.0 3.5 4.5 5.0 FREQUENCY (GHz) SUPPLY VOLTAGE (V) GAIN vs. SUPPLY VOLTAGE (LOW-GAIN MODE) GAIN STEP vs. SUPPLY VOLTAGE GAIN vs. RBIAS (HIGH-GAIN MODE) GAIN STEP (dB) -8.5 TA = +25°C -9.0 -9.5 TA = +85°C -10.0 14.8 25.0 TA = -40°C 5.5 MAX2645-09 25.5 24.5 GAIN (dB) -8.0 15.0 MAX2645-08 26.0 MAX2645-07 -7.5 TA = +25°C 24.0 23.5 VCC = 5V 14.6 14.4 TA = +85°C VCC = 3.3V 23.0 TA = -40°C 14.2 22.5 -10.5 LOW-NOISE FIGURE CIRCUIT 3.5 4.0 LOW-NOISE FIGURE CIRCUIT 22.0 4.5 5.0 3.0 5.5 3.5 4.0 4.5 14.0 5.0 5.5 LOW-NOISE FIGURE CIRCUIT 15.0 17.5 20.0 22.5 SUPPLY VOLTAGE (V) SUPPLY VOLTAGE (V) RBIAS (kΩ) GAIN vs. RBIAS (LOW-GAIN MODE) NOISE FIGURE vs. FREQUENCY (HIGH-GAIN MODE) NOISE FIGURE vs. FREQUENCY (LOW-GAIN MODE) 19 18 4 NOISE FIGURE (dB) -10.6 -10.8 -11.0 -11.2 20 VCC = 3.3V -11.4 -11.6 25.0 MAX2645-12 VCC = 5V -10.4 5 NOISE FIGURE (dB) -10.2 MAX2645-11 -10.0 MAX2645-10 3.0 3 2 17 16 15 14 13 12 1 -11.8 -12.0 14.0 13.4 3.4 3.8 TA = +25°C 14.2 FREQUENCY (GHz) -7.0 -11.0 TA = +25°C -11 -13 3.4 GAIN (dB) -10 -12 LOW-NOISE FIGURE CIRCUIT 14.4 -9 10 7 GAIN (dB) GAIN (dB) GAIN (dB) 12 11 14.6 TA = -40°C -8 TA = +25°C TA = -40°C 14.8 -7 TA = -40°C 14 13 15.0 GAIN (dB) 16 MAX2645-05 -5 MAX2645-04 17 GAIN vs. SUPPLY VOLTAGE (HIGH-GAIN MODE) MAX2645-06 GAIN vs. FREQUENCY (HIGH-GAIN MODE) 11 LOW-NOISE FIGURE CIRCUIT 15.0 17.5 20.0 RBIAS (kΩ) 0 22.5 25.0 LOW-NOISE FIGURE CIRCUIT 3.4 3.5 3.6 FREQUENCY (GHz) 10 3.7 3.8 LOW-NOISE FIGURE CIRCUIT 3.4 3.5 3.6 3.7 3.8 FREQUENCY (GHz) _______________________________________________________________________________________ 5 MAX2645 Typical Operating Characteristics (continued) (MAX2645 EV kit, VCC = +3.3V, RBIAS = 20kΩ, fRFIN = 3550MHz, TA = +25°C, unless otherwise noted.) Typical Operating Characteristics (continued) (MAX2645 EV kit, VCC = +3.3V, RBIAS = 20kΩ, fRFIN = 3550MHz, TA = +25°C, unless otherwise noted.) INPUT IP3 vs. SUPPLY VOLTAGE (LOW-GAIN MODE) TA = -40°C 5.5 TA = +85°C 5.0 15.0 4.0 3.5 TA = +25°C 3.0 2.5 17.5 20.0 22.5 25.0 3.0 RBIAS (kΩ) INPUT IP3 vs. RBIAS (HIGH-GAIN MODE) 3.5 4.5 5.0 INPUT IP3 (dBm) 5 3 VCC = 3.3V 3.0 -3.5 MAX2645-17 13.5 13.0 11.5 17.5 20.0 22.5 25.0 15.0 17.5 20.0 MAX2645-19 TA = -40°C -15 VCC = 5V LOW-NOISE FIGURE CIRCUIT 6 -5.0 0 INPUT POWER (dBm) 4.5 5.0 2.50 LOW GAIN 2.25 5.5 1.75 -5 HIGH GAIN 1.50 -7 5.0 4.0 3.5 2.00 -4 VCC = 3.3V -6 -10.0 LOW-NOISE FIGURE CIRCUIT 3.0 INPUT VSWR vs. FREQUENCY 1.25 -20 -25 -7.0 25.0 VSWR INPUT P1dB (dBm) TA = +25°C -10 TA = +85°C -6.5 SUPPLY VOLTAGE (V) -2 -3 TA = +85°C TA = +25°C -6.0 -8.5 22.5 INPUT P1dB vs. RBIAS (HIGH-GAIN MODE) -5 -5.5 -8.0 LOW-NOISE FIGURE CIRCUIT OUTPUT POWER vs. INPUT POWER (LOW-GAIN MODE) 0 -5.0 -7.5 RBIAS (kΩ) 5 5.5 -4.5 VCC = 3.3V RBIAS (kΩ) 10 TA = -40°C -4.0 MAX2645-20 15.0 5.0 INPUT P1dB vs. SUPPLY VOLTAGE (HIGH-GAIN MODE) 14.0 LOW-NOISE FIGURE CIRCUIT 4.5 INPUT IP3 vs. RBIAS (LOW-GAIN MODE) 12.0 -1 4.0 3.5 SUPPLY VOLTAGE (V) VCC = 5V 12.5 1 5.5 SUPPLY VOLTAGE (V) 14.5 VCC = 5V LOW-NOISE FIGURE CIRCUIT 10.5 15.0 7 INPUT IP3 (dBm) 4.0 15.5 MAX2645-16 9 TA = +85°C 11.0 LOW-NOISE FIGURE CIRCUIT INPUT P1dB (dBm) 15.0 1.0 12.5 11.5 1.5 LOW-NOISE FIGURE CIRCUIT 0 13.0 12.0 2.0 1 13.5 MAX2645-18 2 TA = +25°C 14.0 INPUT IP3 (dBm) INPUT IP3 (dBm) NOISE FIGURE (dB) 4.5 3 TA = -40°C 14.5 MAX2645-21 4 15.5 MAX2645-14 6.0 MAX2645-13 5 INPUT IP3 vs. SUPPLY VOLTAGE (HIGH-GAIN MODE) MAX2645-15 NOISE FIGURE vs. RBIAS (HIGH-GAIN MODE) OUTPUT POWER (dBm) MAX2645 3.4GHz to 3.8GHz SiGe Low-Noise Amplifier/PA Predriver LOW-NOISE FIGURE CIRCUIT 15.0 17.5 20.0 RBIAS (kΩ) 1.00 22.5 25.0 LOW-NOISE FIGURE CIRCUIT 3.4 3.5 3.6 FREQUENCY (GHz) _______________________________________________________________________________________ 3.7 3.8 3.4GHz to 3.8GHz SiGe Low-Noise Amplifier/PA Predriver REVERSE ISOLATION (dB) 3.5 3.0 HIGH GAIN 2.5 15.5 -15 LOW GAIN -20 HIGH GAIN 3.5 3.6 3.7 3.8 3.5 3.6 3.7 FREQUENCY (GHz) -11.0 HIGH-INPUT IP3 CIRCUIT 4.5 -13.0 19 3.0 LOW GAIN 2.5 2.0 -14.0 HIGH GAIN HIGH-INPUT IP3 CIRCUIT 15 14 TA = +25°C 3.5 3.6 3.7 10 3.4 3.8 3.5 3.6 3.7 3.8 PA PREDRIVER CIRCUIT 3.4 3.5 3.6 3.7 FREQUENCY (GHz) FREQUENCY (GHz) GAIN vs. FREQUENCY (LOW-GAIN MODE) GAIN vs. SUPPLY VOLTAGE (HIGH-GAIN MODE) GAIN vs. SUPPLY VOLTAGE (LOW-GAIN MODE) VCC = 5V TA = -40°C 16.0 -7 GAIN (dB) TA = +85°C -10 TA = -40°C TA = +25°C 15.0 14.5 TA = +25°C TA = -40°C -9.5 GAIN (dB) -9 VCC = 5V -9.0 TA = +25°C 15.5 -8 -8.5 MAX2645-29 MAX2645-28 16.5 3.8 MAX2645-30 FREQUENCY (GHz) VCC = 5V -11 TA = +85°C 11 1.0 -5 GAIN (dB) TA = -40°C 16 12 1.5 -14.5 -6 VCC = 5V 13 3.4 3.8 17 -13.5 -15.0 MAX2645-24 20 GAIN (dB) VSWR -12.5 3.7 18 3.5 TA = -40°C 3.6 GAIN vs. FREQUENCY (HIGH-GAIN MODE) TA = +25°C -12.0 3.5 FREQUENCY (GHz) 4.0 -11.5 GAIN (dB) 5.0 MAX2645-25 TA = +85°C 3.4 3.8 INPUT VSWR vs. FREQUENCY GAIN vs. FREQUENCY (LOW-GAIN MODE) -10.5 TA = +85°C 12.0 3.4 FREQUENCY (GHz) -10.0 TA = +25°C 14.0 12.5 -35 3.4 14.5 13.0 -30 1.0 TA = -40°C 15.0 13.5 -25 2.0 1.5 HIGH-INPUT IP3 CIRCUIT 16.0 -10 GAIN (dB) LOW GAIN 4.0 16.5 MAX2645-26 VSWR 4.5 LOW-NOISE FIGURE CIRCUIT -5 5.0 17.0 MAX2645-23 LOW-NOISE FIGURE CIRCUIT 5.5 0 MAX2645-22 6.0 GAIN vs. FREQUENCY (HIGH-GAIN MODE) REVERSE ISOLATION vs. FREQUENCY MAX2645-27 OUTPUT VSWR vs. FREQUENCY TA = +85°C -10.0 -10.5 14.0 -11.0 13.5 -11.5 TA = +85°C -12 -13 13.0 -14 -15 PA PREDRIVER CIRCUIT 3.4 3.5 3.6 FREQUENCY (GHz) 12.5 3.7 3.8 -12.0 PA PREDRIVER CIRCUIT 3.0 3.5 4.0 -12.5 4.5 SUPPLY VOLTAGE (V) 5.0 5.5 PA PREDRIVER CIRCUIT 3.0 3.5 4.0 4.5 5.0 5.5 SUPPLY VOLTAGE (V) _______________________________________________________________________________________ 7 MAX2645 Typical Operating Characteristics (continued) (MAX2645 EV kit, VCC = +3.3V, RBIAS = 20kΩ, fRFIN = 3550MHz, TA = +25°C, unless otherwise noted.) Typical Operating Characteristics (continued) (MAX2645 EV kit, VCC = +3.3V, RBIAS = 20kΩ, fRFIN = 3550MHz, TA = +25°C, unless otherwise noted.) OUTPUT POWER vs. INPUT POWER (LOW-GAIN MODE) 12 TA = +25°C 10 TA = -40°C INPUT VSWR vs. FREQUENCY PA PREDRIVER CIRCUIT 3.5 4.0 -5 SUPPLY VOLTAGE (V) 5.0 5.5 PA PREDRIVER CIRCUIT VCC = 5V 3.5 TA = +25°C -10 3.0 LOW GAIN 2.5 -15 -25 4.5 4.5 TA = -40°C 2.0 HIGH GAIN -20 3.0 5.0 4.0 0 TA = +85°C 8 7 VCC = 5V 5 OUTPUT POWER (dBm) TA = +85°C 11 9 10 MAX2645-33 VCC = 5V VSWR 13 MAX2645-32 OUTPUT P1dB POINT vs. SUPPLY VOLTAGE (HIGH-GAIN MODE) MAX2645-31 MAX2645 3.4GHz to 3.8GHz SiGe Low-Noise Amplifier/PA Predriver 1.5 PA PREDRIVER CIRCUIT -10.0 -5.0 1.0 0 5.0 INPUT POWER (dBm) 3.4 3.5 3.6 3.7 3.8 FREQUENCY (GHz) Pin Description 8 PIN NAME FUNCTION 1, 2, 4, 7, EP GND Ground. Connect to ground plane with a low-inductance connection. Solder exposed paddle evenly to the board ground plane. 3 RFIN 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. 5 BIAS Bias-Setting Resistor Connection. A resistor, RBIAS, placed from BIAS to ground sets the linearity and supply current of the amplifier. 6 RFOUT 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. 8 SHDN 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. 9 GAIN 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. 10 VCC 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. _______________________________________________________________________________________ 3.4GHz to 3.8GHz SiGe Low-Noise Amplifier/PA Predriver 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. 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 0.1µA. 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 0.1µA. Bias Circuitry Applications Information 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 15kΩ to 25kΩ range, with a nominal value of 20kΩ suitable for most applications. See Typical Operating Characteristics for performance variation vs. R BIAS value. Shutdown Control 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) S11 MAG S21 PHASE MAG S12 PHASE MAG S22 PHASE MAG PHASE RBIAS = 20kΩ, VCC = +3.3V, TA = +25°C 3400 0.468 -149.8 5.061 -44.6 0.053 -55.5 0.660 -57.0 3450 0.466 -150.4 4.975 -46.3 0.058 -60.8 0.658 -58.4 3500 3550 0.472 0.469 -151.6 -153.4 5.098 4.883 -49.9 -53.7 0.056 0.054 -64.6 -62.7 0.661 0.658 -60.6 -63.0 3600 0.471 -154.6 4.814 -53.7 0.056 -64.4 0.647 -64.2 3650 0.477 -155.0 5.118 -57.4 0.058 -68.9 0.657 -66.2 3700 3750 0.485 0.484 -156.6 -156.5 4.769 4.780 -63.4 -62.3 0.054 0.058 -70.5 -72.0 0.657 0.654 -69.8 -70.9 3800 0.492 -157.0 4.939 -66.6 0.060 -75.4 0.654 -72.3 RBIAS = 15kΩ, VCC = +5V, TA = +25°C 3400 3450 0.454 0.457 -146.6 -147.4 5.350 5.245 -41.8 -43.5 0.057 0.061 -51.3 -56.7 0.651 0.646 -52.3 -53.7 3500 0.465 -147.9 5.375 -46.6 0.060 -61.2 0.654 -55.6 3550 0.468 -149.7 5.165 -50.3 0.057 -61.0 0.652 -58.3 3600 3650 0.472 0.481 -150.5 -150.5 5.066 5.386 -50.2 -53.4 0.060 0.063 -62.7 -67.6 0.645 0.652 -59.3 -60.7 3700 0.486 -152.2 5.040 -59.4 0.060 -67.8 0.648 -63.9 3750 0.486 -152.4 5.019 -58.3 0.062 -67.0 0.642 -64.8 3800 0.499 -152.6 5.207 -62.0 0.065 -73.3 0.643 -66.2 _______________________________________________________________________________________ 9 MAX2645 Detailed Description MAX2645 3.4GHz to 3.8GHz SiGe Low-Noise Amplifier/PA Predriver Table 2. MAX2645 Noise Parameters |Γopt| Γopt ANGLE RN (Ω) FREQUENCY (MHz) FMIN (dB) 3400 2.098 0.237 144.1 31.1 3450 2.122 0.235 146.1 31.5 3500 2.148 0.235 148.2 32.0 3550 2.173 0.234 150.3 32.5 3600 2.198 0.233 152.4 32.9 3650 2.225 0.232 154.5 33.5 3700 2.251 0.231 156.5 33.9 3750 2.279 0.230 158.6 34.5 3800 2.306 0.229 160.7 35.0 3400 2.103 0.210 146.3 31.1 3450 2.127 0.209 148.4 31.6 3500 2.152 0.208 150.5 32.1 3550 2.177 0.207 152.6 32.5 3600 2.203 0.206 154.7 33.0 3650 2.229 0.206 156.8 33.5 3700 2.256 0.205 158.9 34.0 3750 2.282 0.204 161.0 34.6 3800 2.310 0.204 163.1 35.1 RBIAS = 20kΩ, VCC = +3.3V, TA = +25°C RBIAS = 15kΩ, VCC = +5V, TA = +25°C 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. Power-Supply, Bias Circuitry, and LogicInput Bypassing 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. Proper power-supply bypassing is essential for high-frequency circuit stability. Bypass VCC with 10µF, 0.1µF, and 50pF capacitors located as close to the VCC pin as possible. 10 ______________________________________________________________________________________ 3.4GHz to 3.8GHz SiGe Low-Noise Amplifier/PA Predriver VCC GND VCC 0.1µF 47pF 2 C1 RF INPUT 3.4GHz to 3.8GHz MAX2645 1 GND GAIN 9 HIGH GAIN LOW GAIN 8 ON OFF MAX2645 3 RFIN SHDN GND GND Z1 4 7 RADIAL STUB * 40° 5 220pF BIAS RFOUT TLINE LEQUIV = 1.5nH 8 294 mil s VCC 1000pF RF OUTPUT RBIAS 0.75pF APPLICATION CIRCUIT LNA, LOW NF LNA, HIGH INPUT IP3 PA PREDRIVER C1 Z1 1.5pF 1000pF 0.01µF 1.8nH 0.75pF 0.75pF RBIAS (kΩ) 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 LOW NF LNA MAX2645 HIGH IP3 LNA LO LO BUFFER DUPLEXER MAX2645 MAX2645 RF BANDPASS FILTER LO LO BUFFER TRANSMIT IF INPUT PA MAX2683 MAX2684 PA PREDRIVER Figure 2. Typical System Application Block Diagram ______________________________________________________________________________________ 11 Pin Configuration Chip Information TRANSISTOR COUNT: 271 TOP VIEW GND 1 10 VCC GND 2 RFIN 3 9 GAIN 8 SHDN GND 4 7 GND BIAS 5 6 RFOUT MAX2645 µMAX-EP Package Information (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information go to www.maxim-ic.com/packages.) e 10LUMAX.EPS MAX2645 3.4GHz to 3.8GHz SiGe Low-Noise Amplifier/PA Predriver 4X S 10 10 INCHES H ÿ 0.50±0.1 0.6±0.1 1 1 0.6±0.1 BOTTOM VIEW TOP VIEW D2 MILLIMETERS MAX DIM MIN A 0.043 A1 0.006 0.002 A2 0.030 0.037 D1 0.116 0.120 D2 0.114 0.118 E1 0.116 0.120 E2 0.114 0.118 H 0.187 0.199 L 0.0157 0.0275 L1 0.037 REF b 0.007 0.0106 e 0.0197 BSC c 0.0035 0.0078 0.0196 REF S α 0∞ 6∞ MAX MIN 1.10 0.15 0.05 0.75 0.95 3.05 2.95 2.89 3.00 3.05 2.95 2.89 3.00 4.75 5.05 0.40 0.70 0.940 REF 0.177 0.270 0.500 BSC 0.090 0.200 0.498 REF 0∞ 6∞ E2 GAGE PLANE A2 c A b A1 α E1 D1 L L1 FRONT VIEW SIDE VIEW PROPRIETARY INFORMATION TITLE: PACKAGE OUTLINE, 10L uMAX/uSOP APPROVAL DOCUMENT CONTROL NO. 21-0061 REV. I 1 1 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. 12 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 2003 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.