LT5538 40MHz to 3.8GHz RF Power Detector with 75dB Dynamic Range FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ DESCRIPTION The LT®5538 is a 40MHz to 3800MHz monolithic logarithmic RF power detector, capable of measuring RF signals over a wide dynamic range, from –75dBm to 10dBm. The RF signal in an equivalent decibel-scaled value is precisely converted into DC voltage on a linear scale. The wide linear dynamic range is achieved by measuring the RF signal using cascaded RF limiters and RF detectors. Their outputs are summed to generate an accurate linear DC voltage proportional to the input RF signal in dBm. The LT5538 delivers superior temperature stable output (within ±1dB over full temperature range) from 40MHz to 3.8GHz. The output is buffered with a low impedance driver. Frequency Range: 40MHz to 3.8GHz 75dB Log Linear Dynamic Range Exceptional Accuracy over Temperature Linear DC Output vs. Input Power in dBm –72dBm Detection Sensitivity Single-ended RF Input Low Supply Current: 29mA Supply Voltage: 3V to 5.25V 8-lead DFN 3mm × 3mm package APPLICATIONS ■ ■ ■ ■ ■ ■ Received Signal Strength Indication (RSSI) RF Power Measurement and Control RF/IF Power Detection Receiver RF/IF Gain Control Envelope Detection ASK Receiver , LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. TYPICAL APPLICATION Output Voltage and Linearity Error vs Input Power 40MHz - 3.8GHz Logarithmic RF Detector 2.0 1nF 1nF OUT CAP+ IN– CAP– GND VCC 9 VOUT 5V 5538 TA01 0.1μF 100pF 3 VCC = 5V AT 880 MHz 1.7 2 1.4 1 1.1 0 0.8 –1 0.5 TA = –40°C TA = 25°C TA = 85°C 0.2 –75 –65 –55 –45 –35 –25 –15 INPUT POWER (dBm) –5 LINEARITY ERROR (dB) 56 ENBL IN+ VOUT (V) EN RF INPUT LT5538 –2 5 –3 5538 TA02 5538f 1 LT5538 ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (Note 1) TOP VIEW Power Supply Voltage ..............................................5.5V Enable Voltage .....................................–0.3V, VCC + 0.3V RF Input Power ....................................................15dBm Operating Ambient Temperature ............ –40°C to +85°C Storage Temperature Range................. –65°C to +125°C Maximum Junction Temperature........................... 150°C ENBL 1 8 OUT IN+ 2 7 CAP+ IN– 3 6 CAP– GND 4 5 VCC DD PACKAGE 8-LEAD (3mm × 3mm) PLASTIC DFN θJA = 43°C/W EXPOSED PAD (PIN 9) SHOULD BE SOLDERED TO PCB ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE LT5538IDD#PBF LT5538IDD#TRPBF LCVG 8-Lead (3mm × 3mm) Plastic DFN –40°C to 85°C Consult LTC Marketing for parts specified with wider operating temperature ranges. Consult LTC Marketing for information on non-standard lead based finish parts. For more information on lead free part marking, go to: http://www.linear.com/leadfree/ For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/ ELECTRICAL CHARACTERISTICS The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C, VCC = 5V, ENBL = 5V. (Note 2) SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS RF Input Input Frequency Range 40 to 3800 DC Common Mode Voltage Input Resistance MHz VCC –0.5 V 394 Ω fRF = 40 MHZ RF Input Power Range Linear Dynamic Range –75 to 10 ±1dB Linearity Error (Note 3) 76 Output Slope Logarithmic Intercept (Note 5) Sensitivity Output Variation vs Temperature Normalized to Output at 25°C PIN = –50dBm; –40°C < TA < 85°C PIN = –30dBm; –40°C < TA < 85°C PIN = –10dBm; –40°C < TA < 85°C ● ● ● dBm dB 19.9 mV/dB –87.5 dBm –72 dBm 0.1/0.6 –0.1/0.6 –0.2/0.6 dB dB dB 5538f 2 LT5538 ELECTRICAL CHARACTERISTICS The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C, VCC = 5V, ENBL = 5V. (Note 2) SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS 2nd Order Harmonic Distortion Pin = –10dBm; At RF Input –62 dBc 3rd Order Harmonic Distortion Pin = –10dBm; At RF Input –61 dBc –75 to 10 dBm fRF = 450 MHz RF Input Power Range Linear Dynamic Range ±1 dB Linearity Error (Note 3) 75 Output Slope Logarithmic Intercept (Note 5) Sensitivity Output Variation vs Temperature Normalized to Output at 25°C PIN = –50dBm; –40°C < TA < 85°C PIN = –30dBm; –40°C < TA < 85°C PIN = –10dBm; –40°C < TA < 85°C ● ● ● dB 19.6 mV/dB –87.3 dBm –71.5 dBm 0.1/0.6 0.1/0.5 –0.1/0.5 dB dB dB 2nd Order Harmonic Distortion Pin = –10dBm; At RF Input –43 dBc 3rd Order Harmonic Distortion Pin = –10dBm; At RF Input –44 dBc –75 to 10 dBm fRF = 880 MHz RF Input Power Range Linear Dynamic Range ±1 dB Linearity Error (Note 3) 75 Output Slope Logarithmic Intercept 19.0 (Note 5) Sensitivity Output Variation vs Temperature Normalized to Output at 25°C PIN = –50dBm; –40°C < TA < 85°C PIN = –30dBm; –40°C < TA < 85°C PIN = –10dBm; –40°C < TA < 85°C ● ● ● dB mV/dB –88.8 dBm –71.5 dBm 0.1/0.7 0.1/0.4 0.1/0.4 dB dB dB 2nd Order Harmonic Distortion Pin = –10dBm; At RF Input –37 dBc 3rd Order Harmonic Distortion Pin = –10dBm; At RF Input –40 dBc –72 to 10 dBm fRF = 2140 MHz RF Input Power Range Linear Dynamic Range ±1 dB Linearity Error (Note 3) 70 Output Slope Logarithmic Intercept 17.7 (Note 5) Sensitivity Output Variation vs Temperature Normalized to Output at 25°C PIN = –50dBm; –40°C < TA < 85°C PIN = –30dBm; –40°C < TA < 85°C PIN = –10dBm; –40°C < TA < 85°C ● ● ● dB mV/dB –89.0 dBm –69.0 dBm 0.3/0.4 0.4/0.1 0.7/0.5 dB dB dB fRF = 2700 MHz RF Input Power Range Linear Dynamic Range –72 to 10 ±1 dB Linearity Error (Note 3) Output Slope Logarithmic Intercept (Note 5) 65 dBm dB 17.6 mV/dB –87.5 dBm 5538f 3 LT5538 ELECTRICAL CHARACTERISTICS The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C, VCC = 5V, ENBL = 5V. (Note 2) SYMBOL PARAMETER CONDITIONS MIN Sensitivity Output Variation vs Temperature TYP MAX –69.5 Normalized to Output at 25°C PIN = –50dBm; –40°C < TA < 85°C PIN = –30dBm; –40°C < TA < 85°C PIN = –10dBm; –40°C < TA < 85°C ● ● ● UNITS dBm 0.3/0.3 0.7/–0.3 1.1/–0.9 dB dB dB –65 to 10 dBm fRF = 3600 MHz RF Input Power Range Linear Dynamic Range ±1 dB Linearity Error (Note 3) Output Slope Logarithmic Intercept (Note 5) Sensitivity Output Variation vs Temperature Normalized to Output at 25°C PIN = –45dBm; –40°C < TA < 85°C PIN = –25dBm; –40°C < TA < 85°C PIN = –5dBm; –40°C < TA < 85°C ● ● ● 57 dB 18 mV/dB –81.4 dBm –63 dBm 0.6/–0.3 0.9/–0.6 1.4/–1.2 dB dB dB 0.350 V Output Impedance 150 Ω Source Current 10 mA Output Interface Output DC Voltage No RF Signal Present Sink Current 200 μA Rise Time 0.5V to 1.6V, 10% to 90%, fRF = 880 MHz 100 ns Fall Time 1.6V to 0.5V, 10% to 90%, fRF = 880 MHz 180 ns Power Up/Down ENBL = High (On) ● ENBL = Low (Off) ● ENBL Input Current 1 V 0.3 VENBL = 5V V 205 μA Turn ON time 300 ns Turn OFF Time 1 μs Power Supply Supply Voltage 3 Supply Current Shutdown Current ENBL = Low Note 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliability and lifetime. Note 2: Specifications over the –40°C to 85°C temperature range are assured by design, characterization and correlation with statistical process control. Note 3: The linearity error is calculated by the difference between the incremental slope of the output and the average slope from –50dBm 5.25 V 29 36 mA 1 100 μA to –20dBm. The dynamic range is defined as the range over which the linearity error is within ±1dB. Note 4: Sensitivity is defined as the minimum input power required for the linearity error within 3dB of the ideal log-linear transfer curve. Note 5: Logarithmic Intercept is an extrapolated input power level from the best-fitted log-linear straight line, where the output voltage is 0V. 5538f 4 LT5538 TYPICAL PERFORMANCE CHARACTERISTICS 2 2 30 1.4 1 1.1 0 0.8 –1 25 20 0.5 TA = –40°C TA = 25°C TA = 85°C 2.5 3 5 3.5 4 4.5 SUPPLY VOLTAGE VCC (V) 0.2 –75 –65 –55 –45 –35 –25 –15 INPUT POWER (dBm) 5.5 –5 3 1.1 0 0.8 –1 0.2 –75 –65 –55 –45 –35 –25 –15 INPUT POWER (dBm) –5 5538 G03 Output Voltage, Linearity Error vs Input Power at 880MHz 2.0 1 1.4 1 1.1 0 0.8 –1 0 –1 –5 0.2 –75 –65 –55 –45 –35 –25 –15 –5 INPUT POWER (dBm) 5 5538 G05 3 3 2 1 1.4 1 1.1 0 0.8 –1 VOUT (V) 2 –3 –75 –65 –55 –45 –35 –25 –15 INPUT POWER (dBm) –5 5 5538 G07 TA = –40°C TA = 25°C TA = 85°C 0.2 –75 –65 –55 –45 –35 –25 –15 INPUT POWER (dBm) –5 –2 5 5538 G08 –3 LINEARITY ERROR (dB) 1.7 0.5 –3 5 VOUT Variation vs Input Power at 2.14GHz Output Voltage, Linearity Error vs Input Power at 2.14GHz VCC = 5V –2 5538 G06 2 TA = –40°C TA = 85°C TA = –40°C TA = 25°C TA = 85°C 0.5 –3 –75 –65 –55 –45 –35 –25 –15 INPUT POWER (dBm) 2.0 –2 3 VCC = 5V 2 TA = –40°C TA = 85°C –3 5 1.7 VCC = 5V NORMALIZED AT 25°C –1 –5 2 VOUT Variation vs Input Power at 880MHz 0 –3 –75 –65 –55 –45 –35 –25 –15 INPUT POWER (dBm) VCC = 5V NORMALIZED AT 25°C 5538 G04 3 TA = –40°C TA = 85°C –3 –2 –2 5 –1 –2 VOUT (V) 1 TA = –40°C TA = 25°C TA = 85°C 0 LINEARITY ERROR (dB) 1.4 LINEARITY ERROR (dB) 2 VOUT VARIATION (dB) 3 1.7 0.5 1 VOUT Variation vs Input Power at 450MHz Output Voltage, Linearity Error vs Input Power at 450MHz VCC = 5V 5 VCC = 5V NORMALIZED AT 25°C 5538 G02 5538 G01 2.0 –2 TA = –40°C TA = 25°C TA = 85°C VOUT VARIATION (dB) 10 VCC = 5V VOUT VARIATION (dB) 35 1.7 VOUT (V) SUPPLY CURRENT ICC (mA) 3 2.0 LINEARITY ERROR (dB) 3 40 15 VOUT (V) VOUT Variation vs Input Power at 40MHz Output Voltage, Linearity Error vs Input Power at 40MHz Supply Current vs Supply Voltage VOUT VARIATION (dB) (Test Circuit shown in Figure 5) VCC = 5V NORMALIZED AT 25°C 1 0 –1 –2 TA = –40°C TA = 85°C –3 –75 –65 –55 –45 –35 –25 –15 –5 INPUT POWER (dBm) 5 5538 G09 5538f 5 LT5538 TYPICAL PERFORMANCE CHARACTERISTICS Output Voltage, Linearity Error vs Input Power at 2.7GHz VOUT Variation vs Input Power at 2.7GHz 1.2 1 0.9 0 0.6 –1 –2 0 –70 –60 –50 –40 –30 –20 –10 INPUT POWER (dBm) 2 1 1.2 1 0.9 0 0.6 –1 0 –1 TA = –40°C TA = 85°C –3 –70 –60 –50 –40 –30 –20 –10 INPUT POWER (dBm) 0 5538 G10 40 PERCENTAGE DISTRIBUTION (%) VOUT VARIATION (dB) 2 1 0 –1 –2 30 25 20 15 10 0 0 10 12 10 8 6 4 16 16.8 17.6 18.4 19.2 SLOPE (mV/dB) 20 0 –98 –96 –94 –92 –90 –88 –86 –84 –82 –80 –78 LOGARITHMIC INTERCEPT (dBm) 20.8 5538 G15 5538 G14 Output Voltage, Linearity Error vs VCC @3600MHz Output Voltage, Linearity Error vs VCC @2140MHz Output Voltage, Linearity Error vs VCC @40MHz 2.0 TA = –40°C TA = 25°C TA = 85°C 14 2 5538 G13 3 2.0 NORMALIZED AT 5V 1.8 3 1 1.1 0 0.8 –1 –2 0.5 VCC = 5V VCC = 3V –5 5 5538 G16 –3 VOUT (V) 1.4 1.7 2 1.4 1 1.1 0 0.8 –1 0.5 –2 VCC = 5V VCC = 3V 0.2 –75 –65 –55 –45 –35 –25 –15 INPUT POWER (dBm) –5 5 5538 G17 –3 1.5 2 1.2 1 0.9 0 0.6 –1 0.3 0 –65 LINEARITY ERROR (dB) 2 LINEARITY ERROR (dB) 1.7 3 VCC = 5V NORMALIZED AT 5V LINEARITY ERROR (dB) VOUT (V) 16 TA = –40°C TA = 25°C TA = 85°C 35 –3 5 Logarithmic Intercept Distribution vs Temperature at 2.14GHz 5 TA = –40°C TA = 85°C –3 –70 –60 –50 –40 –30 –20 –10 INPUT POWER (dBm) –45 –35 –25 –15 –5 INPUT POWER (dBm) –2 5538 G12 Slope Distribution vs Temperature at 2.14GHz VCC = 5V NORMALIZED AT 25°C 0.2 –75 –65 –55 –45 –35 –25 –15 INPUT POWER (dBm) 0 –65 –55 10 5538 G11 VOUT Variation vs Input Power at 3.6GHz 3 TA = –40°C TA = 25°C TA = 85°C 0.3 –2 –3 10 0 1.5 PERCENTAGE DISTRIBUTION (%) TA = –40°C TA = 25°C TA = 85°C 3 VCC = 5V 2 VOUT (V) 0.3 VOUT VARIATION (dB) 2 1.8 VCC = 5V NORMALIZED AT 25°C LINEARITY ERROR (dB) 1.5 3 Output Voltage, Linearity Error vs Input Power at 3.6GHz VOUT (V) 3 VCC = 5V LINEARITY ERROR (dB) VOUT (V) 1.8 (Test Circuit shown in Figure 5) –2 VCC = 5V VCC = 3V –55 –45 –35 –25 –15 –5 INPUT POWER (dBm) –3 5 5538 G18 5538f 6 LT5538 PIN FUNCTIONS ENBL (Pin 1): Enable Pin. An applied voltage above 1V will activate the bias for the IC. For an applied voltage below 0.3V, the circuits will be shut down (disabled) with a corresponding reduction in power supply current. If the enable function is not required, then this pin can be connected to VCC. Typical enable pin input currents are 100μA for EN = 3V and 200μA for EN = 5V, respectively. Note that at no time should the ENBL pin voltage be allowed to exceed VCC by more than 0.3V. This pin should be connected to ground with an external ac-decoupling capacitor for low frequency operation. GND (Pin 4, Exposed Pad Pin 9): Circuit Ground Return for the entire IC. This pin must be soldered to the printed circuit board ground plane. VCC (Pin 5): Power Supply Pin. This pin should be decoupled using 100pF and 0.1μF capacitors. CAP–, CAP+ (Pins 6, 7): Optional Filter Capacitor Pins. These pins are internally connected to the detector outputs in front of the output buffer amplifier. An external low-pass filtering can be formed by connecting a capacitor to Vcc from each pin for filtering a low frequency modulation signal. See the Applications Information section for detail. IN+ (Pin 2): RF Input Pin. The pin is internally biased to VCC –0.5V and should be DC blocked externally. The input is connected via internal 394Ω resistor to the IN– pin which should be connected to ground with an ac-decoupling capacitor. IN– (Pin 3): AC Ground Pin. The pin is internally biased to VCC –0.5V and coupled to ground via internal 20pF capacitor. OUT (Pin 8): Detector DC Output Pin. BLOCK DIAGRAM 5 VCC DC OFFSET CANCELLATION 1 ENBL IN+ 2 RF LIMITER IN– RF LIMITER RF LIMITER RF LIMITER RF LIMITER 3 8 OUT RF DETECTOR CELLS 4 9 GND 6 7 5538 BD01 CAP– CAP+ 5538f 7 LT5538 APPLICATIONS INFORMATION The LT5538 is a 40MHz to 3.8 GHz logarithmic RF power detector. It consists of cascaded limiting amplifiers and RF detectors. The output currents from every RF detector are combined and low-pass filtered before applied to the output buffer amplifier. As a result, the final DC output voltage approximates the logarithm of the amplitude of the input signal. The LT5538 is able to accurately measure an RF signal over a 70dB dynamic range (–68dBm to 2dBm at 2.1GHz) with 50Ω single-ended input impedance. The slope of linear to log transfer function is about 17.7mV/dB at 2.1GHz. Within the linear dynamic range, very stable output is achieved over the full temperature range from –40°C to 85°C and over the full operating frequency range from 40MHz to 3.8GHz. The absolute variation over temperature is typically within ±1dB over 65dB dynamic range at 2.1GHz. RF INPUT The simplified schematic of the input circuit is shown in Figure 1. The IN+ and IN– pins are internally biased to VCC –0.5V. The IN– pin is internally coupled to ground via 20pF capacitor. An external capacitor of 1nF is needed to connect this pin to ground for low frequency operation. The impedance between IN+ and IN– is about 394Ω. The RF input pin IN+ should be DC blocked when connected to ground or other matching components. A 56Ω resistor (R1) connected to ground will provide better than 10dB input return loss over the operating frequency range up to 1.5GHz. At higher operating frequency, additional LC matching elements are needed for a proper impedance matching to a 50Ω source as shown in Figure 2. Refer to Figure 6 for the circuit schematic of the input matching network. The input impedance vs frequency of the RF input port IN+ is detailed in Table 1. Table 1. RF Input Impedance FREQUENCY (MHz) RF INPUT IMPEDANCE (Ω) MAG ANGLE(°) 40 47.3 + j129.7 0.800 38.5 100 246.6 + j210.7 0.790 11.5 200 408.7 – j37.8 0.785 –1.5 400 192.9 – j190.9 0.772 –14.9 600 105.6 – j158.4 0.756 –25.3 800 69.3 – j127.4 0.737 –34.4 1000 51.8 – j106.2 0.720 –42.7 1200 41.5 – j90.9 0.707 –50.6 1400 34.2 – j78.7 0.697 –58.2 1600 29.2 – j60.0 0.687 –65.6 1800 25.4 – j60.7 0.678 –73.1 2000 22.6 – j53.8 0.669 –80.4 2200 20.5 – j47.7 0.659 –87.7 2400 18.9 – j42.4 0.649 –94.6 2600 17.9 – j37.6 0.638 –101.5 2800 17.1 – j33.4 0.627 –108.2 3000 16.4 – j29.5 0.615 –114.7 3200 16.1 – j26.0 0.602 –121.0 3400 15.9 – j22.8 0.589 –127.0 3600 15.9 – j20.0 0.574 –132.8 3800 15.9 – j17.5 0.560 –137.9 0 VCC –5 5.3k INPUT RETURN LOSS (dB) 5.3k S11 IN+ 394 IN– 20p + – 5538 F01 –10 –15 –20 –25 –30 W/O L1 AND C8 L1 = 1.5nH, C8 = 1pF C4, C11 = 12pF, C8 = 0.7pF 0 0.4 0.8 1.2 1.6 2 2.4 2.8 3.2 3.6 4.0 FREQUENCY (GHz) 5538 F02 Figure 1. Simplified Schematic of the Input Circuit Figure 2. Input Return Loss with Additional LC Matching Network 5538f 8 LT5538 APPLICATIONS INFORMATION OUTPUT INTERFACE The output interface of the LT5538 is shown in Figure 3. This output buffer circuit can source 10mA current to the load and sink 200 μA current from the load. The smallsignal output bandwidth is approximately 4MHz when the output is resistively terminated or open. The full-scaled 10% to 90% rise and fall times are 100nS and 180nS, respectively. The output transient responses at varied input power levels are shown in Figure 4. VCC 200 C6 200 100μA 20p + – C9 OUT CAP+ + – CAP– OUTPUT CURRENTS FROM RF DETECTORS 150 200μA + – LT5538 5538 F03 Figure 3. Simplified Schematic of the Output Interface 3.0 2.5 VOUT (V) 1.5 1.0 RF PULSE ON RF PULSE OFF EXTERNAL FILTERING AT CAP+, CAP– The CAP+ and CAP– Pins are internally biased at VCC –0.36V via a 200Ω resistor from voltage supply VCC as shown in Figure 3. These two pins are connected to the differential outputs of the internal RF detector cells. In combination with the 20pF in parallel, a low-pass filter is formed with –3dB corner frequency of 20MHz. The high frequency rectified signals (particularly second-order harmonic of the RF signal) from the detector cells are filtered and then the DC output is amplified by the output buffer amplifier. In some applications, the LT5538 may be used to measure a modulated RF signal with low frequency AM content (lower than 20MHz), a large modulation signal may be present at these two pins due to insufficient low-pass filtering, resulting in output voltage fluctuation at the LT5538’s output. Its DC content may also vary depending upon the modulation frequency. To assure stable DC output of the LT5538, external capacitors C6 and C9 can be connected from CAP+ and CAP– to VCC to filter out this low frequency AM modulation signal. Assume the modulation frequency of the RF signal is fMOD, the capacitor value in Farads of C6 and C9 can be chosen by the following formula: 6 2 RF PULSE OFF –2 PIN = 0dBm PIN = 10dBm PIN = 20dBm –6 PIN = 30dBm PIN = 40dBm –10 PIN = 50dBm 0.5 –14 0 –18 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 TIME (μs) RF PULSE ENABLE (V) 2.0 AT 880MHZ When the part is enabled, the output impedance is about 150Ω. When it is disabled, the output impedance is about 29.5kΩ referenced to ground. C6 (or C9) ≥ 10/(2π • 200 • fMOD) Do not connect these two filtering capacitors to ground or any other low voltage reference at any time to avoid an abnormal start-up condition. 5538 F04 Figure 4. Simplified Circuit Schematic of the Output Interface 5538f 9 LT5538 APPLICATIONS INFORMATION μA. To disable or turn off the chip, this voltage should be below 0.3V. It is important that the voltage applied to the ENBL pin should never exceed VCC by more than 0.3V. Otherwise, the supply current may be sourced through the upper ESD protection diode connected at the ENBL pin. Under no circumstances should voltage be applied to the ENBL Pin before the supply voltage is applied to the VCC pin. If this occurs, damage to the IC may result. ENBL (ENABLE) PIN OPERATION A simplified circuit schematic of the ENBL Pin is shown in Figure 5. The enable voltage necessary to turn on the LT5538 is 1V. The current drawn by the ENBL pin varies with the voltage applied at the pin. When the ENBL voltage is 3V, the ENBL current is typically 100 μA. When the ENBL voltage is 5V, the ENBL current is increased to 200 VCC ENBL 42k 42k 5538 F05 Figure 5. Simplified Schematic of the Enable Circuit TEST CIRCUIT ENABLE R4 4.99k L1 RF INPUT 1.5nH C8 1pF R1 56Ω 1 C4 1nF C5 1nF LT5538 ENBL OUT 8 R5 O 2 IN+ CAP+ 7 3 IN– CAP– 6 4 GND VCC 9 5 C9 OPT 5538 TC01 C2 100pF C1 0.1μF C7 OPT VOUT C6 OPT C10 100pF 5V Figure 6. Evaluation Board Circuit Schematic 40MHz to 2.7GHz 3.6GHz to 3.8GHz REF DES VALUE SIZE PART NUMBER REF DES C1 0.1μF 0603 AVX 0603ZC104KAT C4, C11 12pF 0402 MURATA, GRM155C1H120JZ01B C2, C10 100pF 0402 AVX 0402YC101KAT C8 0.7pF 0402 MURATA, GJR155C1HR70BB01 C5 OPEN C4, C5 1nF 0603 AVX 0402ZC102K C8 1pF 0402 AVX 0402YA1ROCAT R1 56 0402 VISHAY, CRCW040256ROFKED R4 4.99k 0402 VISHAY, CRCW04024K99FKED L1 1.5nH 0402 TOKO, LL1005-FH2IN5S VALUE SIZE PART NUMBER NOTE: Replace L1 with C11. 5538f 10 LT5538 TEST CIRCUIT 5538 TC02 Figure 7. Component Side of Evalution Board PACKAGE DESCRIPTION DD Package 8-Lead Plastic DFN (3mm × 3mm) (Reference LTC DWG # 05-08-1698) R = 0.115 TYP 5 0.38 ± 0.10 8 0.675 ±0.05 3.5 ±0.05 1.65 ±0.05 2.15 ±0.05 (2 SIDES) 3.00 ±0.10 (4 SIDES) PACKAGE OUTLINE 1.65 ± 0.10 (2 SIDES) PIN 1 TOP MARK (NOTE 6) (DD8) DFN 1203 0.200 REF 0.25 ± 0.05 0.50 BSC 2.38 ±0.05 (2 SIDES) RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS 0.75 ±0.05 0.00 – 0.05 4 0.25 ± 0.05 1 0.50 BSC 2.38 ±0.10 (2 SIDES) BOTTOM VIEW—EXPOSED PAD NOTE: 1. DRAWING TO BE MADE A JEDEC PACKAGE OUTLINE M0-229 VARIATION OF (WEED-1) 2. DRAWING NOT TO SCALE 3. ALL DIMENSIONS ARE IN MILLIMETERS 4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE 5. EXPOSED PAD SHALL BE SOLDER PLATED 6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON TOP AND BOTTOM OF PACKAGE 5538f Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights. 11 LT5538 RELATED PARTS PART NUMBER DESCRIPTION COMMENTS Infrastructure LT5514 Ultralow Distortion, IF Amplifier/ADC Driver with Digitally Controlled Gain 850MHz Bandwidth, 47 dBm OIP3 at 100MHz, 10.5dB to 33dB Gain Control Range LT5515 1.5GHz to 2.5GHz Direct Conversion Quadrature Demodulator 20dBm IIP3, Integrated LO Quadrature Generator LT5516 0.8GHz to 1.5GHz Direct Conversion Quadrature Demodulator 21.5dBm IIP3, Integrated LO Quadrature Generator LT5517 40MHz to 900MHz Quadrature Demodulator 21dBm IIP3, Integrated LO Quadrature Generator LT5518 1.5GHz to 2.4GHz High Linearity Direct Quadrature Modulator 22.8dBm OIP3 at 2GHz, –158.2dBm/Hz Noise Floor, 50Ω Single-Ended RF and LO Ports, 4-Channel W-CDMA ACPR = –64dBc at 2.14GHz LT5519 0.7GHz to 1.4GHz High Linearity Upconverting Mixer 17.1dBm IIP3 at 1GHz, Integrated RF Output Transformer with 50Ω Matching, Single-Ended LO and RF Ports Operation LT5520 1.3GHz to 2.3GHz High Linearity Upconverting Mixer 15.9dBm IIP3 at 1.9GHz, Integrated RF Output Transformer with 50Ω Matching, Single-Ended LO and RF Ports Operation LT5521 10MHz to 3700MHz High Linearity Upconverting Mixer 24.2dBm IIP3 at 1.95GHz, NF = 12.5dB, 3.15V to 5.25V Supply, SingleEnded LO Port Operation LT5522 600 MHz to 2.7GHz High Signal Level Downconverting Mixer 4.5V to 5.25V Supply, 25dBm IIP3 at 900MHz, NF = 12.5dB, 50Ω SingleEnded RF and LO Ports LT5524 Low Power, Low Distortion ADC Driver with Digitally Programmable Gain 450MHz Bandwidth, 40dBm OIP3, 4.5dB to 27dB Gain Control LT5525 High Linearity, Low Power Downconverting Mixer Single-Ended 50Ω RF and LO Ports, 17.6dBm IIP3 at 1900MHz, ICC = 28mA LT5526 High Linearity, Low Power Downconverting Mixer 3V to 5.3V Supply, 16.5dBm IIP3, 100kHz to 2GHz RF, NF = 11dB, ICC = 28mA, –65dBm LO-RF Leakage LT5527 400MHz to 3.7GHz High Signal Level Downconverting Mixer IIP3 = 23.5dBm and NF = 12.5dBm at 1900MHz, 4.5V to 5.25V Supply, ICC = 78mA, Conversion Gain = 2dB LT5528 1.5GHz to 2.4GHz High Linearity Direct Quadrature Modulator 21.8dBm OIP3 at 2GHz, –159.3dBm/Hz Noise Floor, 50Ω, 0.5VDC Baseband Interface, 4-Channel W-CDMA ACPR = –66dBc at 2.14GHz LT5557 400MHz to 3.8GHz, 3.3V High Signal Level Downconverting Mixer IIP3 = 23.7dBm at 2600MHz, 23.5dBm at 3600MHz, ICC = 82mA at 3.3V LT5560 Ultra-Low Power Active Mixer 10mA Supply Current, 10dBm IIP3, 10dB NF, Usable as Up- or Down-Converter. LT5568 700MHz to 1050MHz High Linearity Direct Quadrature Modulator 22.9dBm OIP3 at 850MHz, –160.3dBm/Hz Noise Floor, 50Ω, 0.5VDC Baseband Interface, 3-Ch CDMA2000 ACPR = –71.4dBc at 850MHz LT5572 1.5GHz to 2.5GHz High Linearity Direct Quadrature Modulator 21.6dBm OIP3 at 2GHz, –158.6dBm/Hz Noise Floor, High-Ohmic 0.5VDC Baseband Interface, 4-Ch W-CDMA ACPR = –67.7dBc at 2.14GHz LT5575 800MHz to 2.7GHz High Linearity Direct Conversion I/Q Demodulator 50Ω, Single-Ended RF and LO Inputs. 28dBm IIP3 at 900MHz, 13.2dBm P1dB, 0.04dB I/Q Gain Mismatch, 0.4° I/Q Phase Mismatch RF Power Detectors LTC®5505 RF Power Detectors with >40dB Dynamic Range 300MHz to 3GHz, Temperature Compensated, 2.7V to 6V Supply LTC5507 100kHz to 1000MHz RF Power Detector 100kHz to 1GHz, Temperature Compensated, 2.7 to 6V Supply LTC5508 300MHz to 7GHz RF Power Detector 44dB Dynamic Range, Temperature Compensated, SC70 Package LTC5509 300MHz to 3GHz RF Power Detector 36dB Dynamic Range, Low Power Consumption, SC70 Package LTC5530 300MHz to 7GHz Precision RF Power Detector Precision VOUT Offset Control, Shutdown, Adjustable Gain LTC5531 300MHz to 7GHz Precision RF Power Detector Precision VOUT Offset Control, Shutdown, Adjustable Offset LTC5532 300MHz to 7GHz Precision RF Power Detector Precision VOUT Offset Control, Adjustable Gain and Offset LT5534 50MHz to 3GHz Log RF Power Detector with 60dB Dynamic Range ±1dB Output Variation over Temperature, 38ns Response Time, Log Linear Response LTC5536 Precision 600Mhz to 7GHz RF Power Detector with Fast Comparator Output 25ns Response Time, Comparator Reference Input, Latch Enable Input, –26dBm to +12dBm Input Range LT5537 Wide Dynamic Range Log RF/IF Detector Low Frequency to 1GHz, 83dB Log Linear Dynamic Range LT5570 2.7GHz RMS Power Detector Fast Responding, up to 60dB Dynamic Range, ±0.3dB Accuracy Over Temperature and Dynamic Range 5538f 12 Linear Technology Corporation LT 0408 • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com © LINEAR TECHNOLOGY CORPORATION 2008