LT5538 40MHz to 3.8GHz RF Power Detector with 75dB Dynamic Range FEATURES DESCRIPTION ■ Frequency Range: 40MHz to 3.8GHz The LT®5538 is a 40MHz to 3800MHz monolithic logarith- ■ 75dB Log Linear Dynamic Range mic RF power detector, capable of measuring RF signals ■ Exceptional Accuracy over Temperature over a wide dynamic range, from –75dBm to 10dBm. The ■ Linear DC Output vs. Input Power in dBm RF signal in an equivalent decibel-scaled value is precisely ■ –72dBm Detection Sensitivity converted into DC voltage on a linear scale. The wide linear ■ Single-ended RF Input dynamic range is achieved by measuring the RF signal us- ■ Low Supply Current: 29mA ing cascaded RF limiters and RF detectors. Their outputs ■ Supply Voltage: 3V to 5.25V are summed to generate an accurate linear DC voltage ■ 8-lead DFN 3mm × 3mm package 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 APPLICATIONS output is buffered with a low impedance driver. ■ Received Signal Strength Indication (RSSI) , LT, LTC and LTM are registered trademarks of Linear Technology Corporation. ■ RF Power Measurement and Control All other trademarks are the property of their respective owners. ■ RF/IF Power Detection ■ Receiver RF/IF Gain Control ■ Envelope Detection ■ ASK Receiver TYPICAL APPLICATION Output Voltage and Linearity Error 40MHz - 3.8GHz Logarithmic RF Detector vs Input Power 2.0 3 LT5538 VCC = 5V AT 880 MHz EN ENBL OUT VOUT 1.7 2 RF IN+ CAP+ INPUT L 1nF IN– CAP– 1.4 1 INE 56 1nF AR GND VCC 5V V) IT 9 5538 TA01 0.1μF V (OUT1.1 0 Y ERRO 100pF 0.8 –1R (d B ) 0.5 TA = –40°C –2 TA = 25°C TA = 85°C 0.2 –3 –75 –65 –55 –45 –35 –25 –15 –5 5 INPUT POWER (dBm) 5538 TA02 5538f 1

LT5538 ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (Note 1) Power Supply Voltage ..............................................5.5V TOP VIEW Enable Voltage .....................................–0.3V, V + 0.3V CC ENBL 1 8 OUT RF Input Power ....................................................15dBm IN+ 2 7 CAP+ Operating Ambient Temperature ............–40°C to +85°C IN– 3 6 CAP– Storage Temperature Range .................–65°C to +125°C GND 4 5 VCC Maximum Junction Temperature...........................150°C 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 specifi ed with wider operating temperature ranges. Consult LTC Marketing for information on non-standard lead based fi nish parts. For more information on lead free part marking, go to: http://www.linear.com/leadfree/ For more information on tape and reel specifi cations, go to: http://www.linear.com/tapeandreel/ ELECTRICAL CHARACTERISTICS The ● denotes the specifi cations which apply over the full operating temperature range, otherwise specifi cations are at T = 25°C, V = 5V, ENBL = 5V. (Note 2) A CC SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS RF Input Input Frequency Range 40 to 3800 MHz DC Common Mode Voltage V –0.5 V CC Input Resistance 394 Ω f = 40 MHZ RF RF Input Power Range –75 to 10 dBm Linear Dynamic Range ±1dB Linearity Error (Note 3) 76 dB Output Slope 19.9 mV/dB Logarithmic Intercept (Note 5) –87.5 dBm Sensitivity –72 dBm Output Variation vs Temperature Normalized to Output at 25°C P = –50dBm; –40°C < T < 85°C ● 0.1/0.6 dB IN A P = –30dBm; –40°C < T < 85°C ● –0.1/0.6 dB IN A P = –10dBm; –40°C < T < 85°C ● –0.2/0.6 dB IN A 5538f 2

LT5538 ELECTRICAL CHARACTERISTICS The ● denotes the specifi cations which apply over the full operating temperature range, otherwise specifi cations are at T = 25°C, V = 5V, ENBL = 5V. (Note 2) A CC 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 f = 450 MHz RF RF Input Power Range –75 to 10 dBm Linear Dynamic Range ±1 dB Linearity Error (Note 3) 75 dB Output Slope 19.6 mV/dB Logarithmic Intercept (Note 5) –87.3 dBm Sensitivity –71.5 dBm Output Variation vs Temperature Normalized to Output at 25°C P = –50dBm; –40°C < T < 85°C ● 0.1/0.6 dB IN A P = –30dBm; –40°C < T < 85°C ● 0.1/0.5 dB IN A P = –10dBm; –40°C < T < 85°C ● –0.1/0.5 dB IN A 2nd Order Harmonic Distortion Pin = –10dBm; At RF Input –43 dBc 3rd Order Harmonic Distortion Pin = –10dBm; At RF Input –44 dBc f = 880 MHz RF RF Input Power Range –75 to 10 dBm Linear Dynamic Range ±1 dB Linearity Error (Note 3) 75 dB Output Slope 19.0 mV/dB Logarithmic Intercept (Note 5) –88.8 dBm Sensitivity –71.5 dBm Output Variation vs Temperature Normalized to Output at 25°C P = –50dBm; –40°C < T < 85°C ● 0.1/0.7 dB IN A P = –30dBm; –40°C < T < 85°C ● 0.1/0.4 dB IN A P = –10dBm; –40°C < T < 85°C ● 0.1/0.4 dB IN A 2nd Order Harmonic Distortion Pin = –10dBm; At RF Input –37 dBc 3rd Order Harmonic Distortion Pin = –10dBm; At RF Input –40 dBc f = 2140 MHz RF RF Input Power Range –72 to 10 dBm Linear Dynamic Range ±1 dB Linearity Error (Note 3) 70 dB Output Slope 17.7 mV/dB Logarithmic Intercept (Note 5) –89.0 dBm Sensitivity –69.0 dBm Output Variation vs Temperature Normalized to Output at 25°C P = –50dBm; –40°C < T < 85°C ● 0.3/0.4 dB IN A P = –30dBm; –40°C < T < 85°C ● 0.4/0.1 dB IN A P = –10dBm; –40°C < T < 85°C ● 0.7/0.5 dB IN A f = 2700 MHz RF RF Input Power Range –72 to 10 dBm Linear Dynamic Range ±1 dB Linearity Error (Note 3) 65 dB Output Slope 17.6 mV/dB Logarithmic Intercept (Note 5) –87.5 dBm 5538f 3

LT5538 ELECTRICAL CHARACTERISTICS The ● denotes the specifi cations which apply over the full operating temperature range, otherwise specifi cations are at T = 25°C, V = 5V, ENBL = 5V. (Note 2) A CC SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Sensitivity –69.5 dBm Output Variation vs Temperature Normalized to Output at 25°C P = –50dBm; –40°C < T < 85°C ● 0.3/0.3 dB IN A P = –30dBm; –40°C < T < 85°C ● 0.7/–0.3 dB IN A P = –10dBm; –40°C < T < 85°C ● 1.1/–0.9 dB IN A f = 3600 MHz RF RF Input Power Range –65 to 10 dBm Linear Dynamic Range ±1 dB Linearity Error (Note 3) 57 dB Output Slope 18 mV/dB Logarithmic Intercept (Note 5) –81.4 dBm Sensitivity –63 dBm Output Variation vs Temperature Normalized to Output at 25°C P = –45dBm; –40°C < T < 85°C ● 0.6/–0.3 dB IN A P = –25dBm; –40°C < T < 85°C ● 0.9/–0.6 dB IN A P = –5dBm; –40°C < T < 85°C ● 1.4/–1.2 dB IN A Output Interface Output DC Voltage No RF Signal Present 0.350 V Output Impedance 150 Ω Source Current 10 mA Sink Current 200 μA Rise Time 0.5V to 1.6V, 10% to 90%, f = 880 MHz 100 ns RF Fall Time 1.6V to 0.5V, 10% to 90%, f = 880 MHz 180 ns RF Power Up/Down ENBL = High (On) ● 1 V ENBL = Low (Off) ● 0.3 V ENBL Input Current VENBL = 5V 205 μA Turn ON time 300 ns Turn OFF Time 1 μs Power Supply Supply Voltage 3 5.25 V Supply Current 29 36 mA Shutdown Current ENBL = Low 1 100 μA Note 1: Stresses beyond those listed under Absolute Maximum Ratings to –20dBm. The dynamic range is defi ned as the range over which the may cause permanent damage to the device. Exposure to any Absolute linearity error is within ±1dB. Maximum Rating condition for extended periods may affect device Note 4: Sensitivity is defi ned as the minimum input power required for the reliability and lifetime. linearity error within 3dB of the ideal log-linear transfer curve. Note 2: Specifi cations over the –40°C to 85°C temperature range are Note 5: Logarithmic Intercept is an extrapolated input power level from the assured by design, characterization and correlation with statistical process best-fi tted log-linear straight line, where the output voltage is 0V. control. Note 3: The linearity error is calculated by the difference between the incremental slope of the output and the average slope from –50dBm 5538f 4

LT5538 TYPICAL PERFORMANCE CHARACTERISTICS (Test Circuit shown in Figure 5) Output Voltage, Linearity Error vs V Variation vs Input Power at OUT Supply Current vs Supply Voltage Input Power at 40MHz 40MHz 40 2.0 3 3 VCC = 5V VCC = 5V NORMALIZED AT 25°C 35 1.7 2 2 CURRENT I (mA)CC 2350 V (V)OUT 11..14 01 LINEARITY ERRO VARIATION (dB) 01 UPPLY 20 0.8 –1R (dB) VOUT–1 S 15 TA = –40°C 0.5 TA = –40°C –2 –2 TA = 25°C TA = 25°C TA = –40°C 10 TA = 85°C 0.2 TA = 85°C –3 –3 TA = 85°C 2.5 3 3.5 4 4.5 5 5.5 –75 –65 –55 –45 –35 –25 –15 –5 5 –75 –65 –55 –45 –35 –25 –15 –5 5 SUPPLY VOLTAGE VCC (V) INPUT POWER (dBm) INPUT POWER (dBm) 5538 G01 5538 G02 5538 G03 Output Voltage, Linearity Error vs V Variation vs Input Power at Output Voltage, Linearity Error vs OUT Input Power at 450MHz 450MHz Input Power at 880MHz 2.0 3 3 2.0 3 VCC = 5V VCC = 5V VCC = 5V NORMALIZED AT 25°C 1.7 2 2 1.7 2 1.4 1 LINEAR N (dB) 1 1.4 1 LINEAR V (V)OUT1.1 0 ITY ERRO VARIATIO 0 V (V)OUT1.1 0 ITY ERRO 0.8 –1R (dB VOUT–1 0.8 –1R (dB ) ) 0.5 TA = –40°C –2 –2 0.5 TA = –40°C –2 TA = 25°C TA = –40°C TA = 25°C TA = 85°C TA = 85°C TA = 85°C 0.2 –3 –3 0.2 –3 –75 –65 –55 –45 –35 –25 –15 –5 5 –75 –65 –55 –45 –35 –25 –15 –5 5 –75 –65 –55 –45 –35 –25 –15 –5 5 INPUT POWER (dBm) INPUT POWER (dBm) INPUT POWER (dBm) 5538 G04 5538 G05 5538 G06 VOUT Variation vs Input Power at Output Voltage, Linearity Error vs VOUT Variation vs Input Power at 880MHz Input Power at 2.14GHz 2.14GHz 3 2.0 3 3 VCC = 5V VCC = 5V VCC = 5V NORMALIZED AT 25°C NORMALIZED AT 25°C 2 1.7 2 2 N (dB) 1 1.4 1 LINEAR N (dB) 1 VARIATIO 0 V (V)OUT1.1 0 ITY ERRO VARIATIO 0 OUT–1 0.8 –1R (d OUT–1 V B V ) –2 0.5 TA = –40°C –2 –2 TA = –40°C TA = 25°C TA = –40°C TA = 85°C TA = 85°C TA = 85°C –3 0.2 –3 –3 –75 –65 –55 –45 –35 –25 –15 –5 5 –75 –65 –55 –45 –35 –25 –15 –5 5 –75 –65 –55 –45 –35 –25 –15 –5 5 INPUT POWER (dBm) INPUT POWER (dBm) INPUT POWER (dBm) 5538 G07 5538 G08 5538 G09 5538f 5

LT5538 TYPICAL PERFORMANCE CHARACTERISTICS (Test Circuit shown in Figure 5) Output Voltage, Linearity Error vs V Variation vs Input Power at Output Voltage, Linearity Error vs OUT Input Power at 2.7GHz 2.7GHz Input Power at 3.6GHz 1.8 3 3 1.8 3 VCC = 5V VCC = 5V VCC = 5V NORMALIZED AT 25°C 1.5 2 2 1.5 2 V (V)OUT01..92 01 LINEARITY ERRO VARIATION (dB) 01 V (V)OUT01..92 01 LINEARITY ERRO 0.6 –1R (dB) VOUT–1 0.6 –1R (dB) 0.3 TA = –40°C –2 –2 0.3 TA = –40°C –2 TA = 25°C TA = –40°C TA = 25°C 0 TA = 85°C –3 –3 TA = 85°C 0 TA = 85°C –3 –70 –60 –50 –40 –30 –20 –10 0 10 –70 –60 –50 –40 –30 –20 –10 0 10 –65 –55 –45 –35 –25 –15 –5 5 INPUT POWER (dBm) INPUT POWER (dBm) INPUT POWER (dBm) 5538 G10 5538 G11 5538 G12 V Variation vs Input Power at Slope Distribution vs Logarithmic Intercept Distribution OUT 3.6GHz Temperature at 2.14GHz vs Temperature at 2.14GHz 3 40 16 VCC = 5V TA = –40°C TA = –40°C NORMALIZED AT 25°C 35 TA = 25°C 14 TA = 25°C 2 %) TA = 85°C %) TA = 85°C N ( 30 N ( 12 ON (dB) 1 RIBUTIO 25 RIBUTIO 10 ARIATI 0 E DIST 20 E DIST 8 VUT–1 TAG 15 TAG 6 O N N V CE 10 CE 4 R R –2 PE PE TA = –40°C 5 2 TA = 85°C –3 0 0 –70 –60 –50 –40 –30 –20 –10 0 10 16 16.8 17.6 18.4 19.2 20 20.8 –98–96–94–92–90–88–86–84–82–80–78 INPUT POWER (dBm) SLOPE (mV/dB) LOGARITHMIC INTERCEPT (dBm) 5538 G13 5538 G14 5538 G15 Output Voltage, Linearity Error vs Output Voltage, Linearity Error vs Output Voltage, Linearity Error vs V @40MHz V @2140MHz V @3600MHz CC CC CC 2.0 3 2.0 3 1.8 3 NORMALIZED AT 5V NORMALIZED AT 5V VCC = 5V 1.7 2 1.7 2 1.5 2 V (V)OUT11..14 01 LINEARITY ERRO V (V)OUT11..14 01 LINEARITY ERRO V (V)OUT01..92 01 LINEARITY ERRO 0.8 –1R (dB) 0.8 –1R (dB) 0.6 –1R (dB) 0.5 –2 0.5 –2 0.3 –2 VCC = 5V VCC = 5V VCC = 5V VCC = 3V VCC = 3V VCC = 3V 0.2 –3 0.2 –3 0 –3 –75 –65 –55 –45 –35 –25 –15 –5 5 –75 –65 –55 –45 –35 –25 –15 –5 5 –65 –55 –45 –35 –25 –15 –5 5 INPUT POWER (dBm) INPUT POWER (dBm) INPUT POWER (dBm) 5538 G16 5538 G17 5538 G18 5538f 6

LT5538 PIN FUNCTIONS ENBL (Pin 1): Enable Pin. An applied voltage above 1V will This pin should be connected to ground with an external activate the bias for the IC. For an applied voltage below ac-decoupling capacitor for low frequency operation. 0.3V, the circuits will be shut down (disabled) with a cor- GND (Pin 4, Exposed Pad Pin 9): Circuit Ground Return responding reduction in power supply current. If the enable for the entire IC. This pin must be soldered to the printed function is not required, then this pin can be connected circuit board ground plane. to V . Typical enable pin input currents are 100μA for CC EN = 3V and 200μA for EN = 5V, respectively. Note that at VCC (Pin 5): Power Supply Pin. This pin should be de- no time should the ENBL pin voltage be allowed to exceed coupled using 100pF and 0.1μF capacitors. VCC by more than 0.3V. CAP–, CAP+ (Pins 6, 7): Optional Filter Capacitor Pins. IN+ (Pin 2): RF Input Pin. The pin is internally biased to These pins are internally connected to the detector outputs V –0.5V and should be DC blocked externally. The input in front of the output buffer amplifi er. An external low-pass CC is connected via internal 394Ω resistor to the IN– pin which fi ltering can be formed by connecting a capacitor to Vcc should be connected to ground with an ac-decoupling from each pin for fi ltering a low frequency modulation sig- capacitor. nal. See the Applications Information section for detail. IN– (Pin 3): AC Ground Pin. The pin is internally biased to OUT (Pin 8): Detector DC Output Pin. V –0.5V and coupled to ground via internal 20pF capacitor. CC BLOCK DIAGRAM 5 VCC DC OFFSET CANCELLATION 1 ENBL IN+ 2 RF LIMITER RF LIMITER RF LIMITER RF LIMITER RF LIMITER IN– 3 RF DETECTOR CELLS 8 OUT 4 9 6 7 5538 BD01 GND CAP–CAP+ 5538f 7

LT5538 APPLICATIONS INFORMATION The LT5538 is a 40MHz to 3.8 GHz logarithmic RF power matching elements are needed for a proper impedance detector. It consists of cascaded limiting amplifi ers and matching to a 50Ω source as shown in Figure 2. Refer to RF detectors. The output currents from every RF detector Figure 6 for the circuit schematic of the input matching are combined and low-pass fi ltered before applied to the network. The input impedance vs frequency of the RF input output buffer amplifi er. As a result, the fi nal DC output port IN+ is detailed in Table 1. voltage approximates the logarithm of the amplitude of the Table 1. RF Input Impedance input signal. The LT5538 is able to accurately measure an FREQUENCY RF INPUT S11 RF signal over a 70dB dynamic range (–68dBm to 2dBm (MHz) IMPEDANCE (Ω) MAG ANGLE(°) at 2.1GHz) with 50Ω single-ended input impedance. The 40 47.3 + j129.7 0.800 38.5 slope of linear to log transfer function is about 17.7mV/dB 100 246.6 + j210.7 0.790 11.5 at 2.1GHz. Within the linear dynamic range, very stable 200 408.7 – j37.8 0.785 –1.5 output is achieved over the full temperature range from –40°C to 85°C and over the full operating frequency 400 192.9 – j190.9 0.772 –14.9 range from 40MHz to 3.8GHz. The absolute variation over 600 105.6 – j158.4 0.756 –25.3 temperature is typically within ±1dB over 65dB dynamic 800 69.3 – j127.4 0.737 –34.4 range at 2.1GHz. 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 RF INPUT 1600 29.2 – j60.0 0.687 –65.6 The simplifi ed schematic of the input circuit is shown in 1800 25.4 – j60.7 0.678 –73.1 Figure 1. The IN+ and IN– pins are internally biased to 2000 22.6 – j53.8 0.669 –80.4 V –0.5V. The IN– pin is internally coupled to ground via CC 2200 20.5 – j47.7 0.659 –87.7 20pF capacitor. An external capacitor of 1nF is needed to 2400 18.9 – j42.4 0.649 –94.6 connect this pin to ground for low frequency operation. 2600 17.9 – j37.6 0.638 –101.5 The impedance between IN+ and IN– is about 394Ω. The 2800 17.1 – j33.4 0.627 –108.2 RF input pin IN+ should be DC blocked when connected 3000 16.4 – j29.5 0.615 –114.7 to ground or other matching components. A 56Ω resistor 3200 16.1 – j26.0 0.602 –121.0 (R1) connected to ground will provide better than 10dB 3400 15.9 – j22.8 0.589 –127.0 input return loss over the operating frequency range up 3600 15.9 – j20.0 0.574 –132.8 to 1.5GHz. At higher operating frequency, additional LC 3800 15.9 – j17.5 0.560 –137.9 0 VCC –5 5.3k 5.3k B) d S (–10 S IN+ LO N R–15 394 TU E IN– T R–20 U P N I 20p + –25 W/O L1 AND C8 L1 = 1.5nH, C8 = 1pF C4, C11 = 12pF, C8 = 0.7pF – –30 0 0.4 0.8 1.2 1.6 2 2.4 2.8 3.2 3.6 4.0 5538 F01 FREQUENCY (GHz) 5538 F02 Figure 1. Simplifi ed Schematic of the Input Circuit Figure 2. Input Return Loss with Additional LC Matching Network 5538f 8

LT5538 APPLICATIONS INFORMATION OUTPUT INTERFACE When the part is enabled, the output impedance is about 150Ω. When it is disabled, the output impedance is about The output interface of the LT5538 is shown in Figure 3. 29.5kΩ referenced to ground. This output buffer circuit can source 10mA current to the load and sink 200 μA current from the load. The small- signal output bandwidth is approximately 4MHz when the EXTERNAL FILTERING AT CAP+, CAP– output is resistively terminated or open. The full-scaled The CAP+ and CAP– Pins are internally biased at V –0.36V CC 10% to 90% rise and fall times are 100nS and 180nS, via a 200Ω resistor from voltage supply V as shown in CC respectively. The output transient responses at varied Figure 3. These two pins are connected to the differential input power levels are shown in Figure 4. outputs of the internal RF detector cells. In combination with the 20pF in parallel, a low-pass fi lter is formed with –3dB corner frequency of 20MHz. The high frequency VCC rectifi ed signals (particularly second-order harmonic of + the RF signal) from the detector cells are fi ltered and then 200 200 C6 100μA – the DC output is amplifi ed by the output buffer amplifi er. In 20p C9 OUT some applications, the LT5538 may be used to measure a CAP+ + 150 modulated RF signal with low frequency AM content (lower CAP– – than 20MHz), a large modulation signal may be present + at these two pins due to insuffi cient low-pass fi ltering, OUTPUT CURRENTS – FROM RF DETECTORS 200μA resulting in output voltage fl uctuation at the LT5538’s LT5538 output. Its DC content may also vary depending upon the modulation frequency. To assure stable DC output of the 5538 F03 LT5538, external capacitors C6 and C9 can be connected from CAP+ and CAP– to V to fi lter out this low frequency CC Figure 3. Simplifi ed Schematic of the Output Interface AM modulation signal. Assume the modulation frequency of the RF signal is f , the capacitor value in Farads of MOD C6 and C9 can be chosen by the following formula: 3.0 6 AT 880MHZ RF PULSE ON 2.5 2 C6 (or C9) ≥ 10/(2π • 200 • f ) MOD RF PULSE OFF RF PULSE OFF R 2.0 PIN = 0dBm –2 F PU (V)UT1.5 PPIINN == 1200ddBBmm –6 LSE EN Do not connect these two fi ltering capacitors to ground VO PIN = 30dBm AB 1.0 PPIINN == 4500ddBBmm –10LE (V) oabr naonrym oathl esrt alortw-u vpo cltoangdei trieofne.r ence at any time to avoid an 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) 5538 F04 Figure 4. Simplifi ed Circuit Schematic of the Output Interface 5538f 9

LT5538 APPLICATIONS INFORMATION ENBL (ENABLE) PIN OPERATION μA. To disable or turn off the chip, this voltage should be below 0.3V. It is important that the voltage applied to the A simplifi ed circuit schematic of the ENBL Pin is shown ENBL pin should never exceed V by more than 0.3V. in Figure 5. The enable voltage necessary to turn on the CC Otherwise, the supply current may be sourced through the LT5538 is 1V. The current drawn by the ENBL pin varies upper ESD protection diode connected at the ENBL pin. with the voltage applied at the pin. When the ENBL volt- Under no circumstances should voltage be applied to the age is 3V, the ENBL current is typically 100 μA. When the ENBL Pin before the supply voltage is applied to the V ENBL voltage is 5V, the ENBL current is increased to 200 CC pin. If this occurs, damage to the IC may result. VCC ENBL 42k 42k 5538 F05 Figure 5. Simplifi ed Schematic of the Enable Circuit TEST CIRCUIT R4 ENABLE 4.99k 1 LT5538 8 R5 INPURTF 1Cp8F 1.L51nH56RΩ1 1Cn4F1Cn5F 234 IIEGNNNN–+BDL CCOAAVUPPCTC–+ 765 CO9PT OCO6PT CO7PTVOUT 9 5538 TC01 C10 5V 100pF C1 0.1μF C2 100pF Figure 6. Evaluation Board Circuit Schematic 40MHz to 2.7GHz 3.6GHz to 3.8GHz REF DES VALUE SIZE PART NUMBER REF DES VALUE SIZE PART NUMBER C1 0.1μF 0603 AVX 0603ZC104KAT C4, C11 12pF 0402 MURATA, GRM155C1H120JZ01B C2, C10 100pF 0402 AVX 0402YC101KAT C8 0.7pF 0402 MURATA, GJR155C1HR70BB01 C4, C5 1nF 0603 AVX 0402ZC102K C5 OPEN C8 1pF 0402 AVX 0402YA1ROCAT NOTE: Replace L with C 1 11. R1 56 0402 VISHAY, CRCW040256ROFKED R4 4.99k 0402 VISHAY, CRCW04024K99FKED L1 1.5nH 0402 TOKO, LL1005-FH2IN5S 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 0.38± 0.10 TYP 5 8 0.675±0.05 3.5±0.05 1.65±0.05 3.00±0.10 1.65± 0.10 2.15±0.05 (2 SIDES) (4 SIDES) (2 SIDES) PIN 1 TOP MARK PACKAGE (NOTE 6) OUTLINE (DD8) DFN 1203 4 1 0.25± 0.05 0.200 REF 0.75±0.05 0.25± 0.05 0.50 0.50 BSC BSC 2.38±0.10 2.38±0.05 0.00 – 0.05 (2 SIDES) (2 SIDES) BOTTOM VIEW—EXPOSED PAD RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS 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. 11 However, no responsibility is assumed for its use. Linear Technology Corporation makes no representa- tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.

LT5538 RELATED PARTS PART NUMBER DESCRIPTION COMMENTS Infrastructure LT5514 Ultralow Distortion, IF Amplifi er/ADC Driver with Digitally 850MHz Bandwidth, 47 dBm OIP3 at 100MHz, 10.5dB to 33dB Gain Control Controlled Gain 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 22.8dBm OIP3 at 2GHz, –158.2dBm/Hz Noise Floor, 50Ω Single-Ended RF Modulator 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, Single- Ended LO Port Operation LT5522 600 MHz to 2.7GHz High Signal Level Downconverting 4.5V to 5.25V Supply, 25dBm IIP3 at 900MHz, NF = 12.5dB, 50Ω Single- Mixer Ended RF and LO Ports LT5524 Low Power, Low Distortion ADC Driver with Digitally 450MHz Bandwidth, 40dBm OIP3, 4.5dB to 27dB Gain Control Programmable Gain LT5525 High Linearity, Low Power Downconverting Mixer Single-Ended 50Ω RF and LO Ports, 17.6dBm IIP3 at 1900MHz, I = 28mA CC LT5526 High Linearity, Low Power Downconverting Mixer 3V to 5.3V Supply, 16.5dBm IIP3, 100kHz to 2GHz RF, NF = 11dB, I = 28mA, –65dBm LO-RF Leakage CC LT5527 400MHz to 3.7GHz High Signal Level Downconverting IIP3 = 23.5dBm and NF = 12.5dBm at 1900MHz, 4.5V to 5.25V Supply, Mixer I = 78mA, Conversion Gain = 2dB CC LT5528 1.5GHz to 2.4GHz High Linearity Direct Quadrature 21.8dBm OIP3 at 2GHz, –159.3dBm/Hz Noise Floor, 50Ω, 0.5V Baseband DC Modulator Interface, 4-Channel W-CDMA ACPR = –66dBc at 2.14GHz LT5557 400MHz to 3.8GHz, 3.3V High Signal Level IIP3 = 23.7dBm at 2600MHz, 23.5dBm at 3600MHz, I = 82mA at 3.3V CC Downconverting Mixer 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 22.9dBm OIP3 at 850MHz, –160.3dBm/Hz Noise Floor, 50Ω, 0.5V DC Modulator Baseband Interface, 3-Ch CDMA2000 ACPR = –71.4dBc at 850MHz LT5572 1.5GHz to 2.5GHz High Linearity Direct Quadrature 21.6dBm OIP3 at 2GHz, –158.6dBm/Hz Noise Floor, High-Ohmic 0.5V DC Modulator Baseband Interface, 4-Ch W-CDMA ACPR = –67.7dBc at 2.14GHz LT5575 800MHz to 2.7GHz High Linearity Direct Conversion I/Q 50Ω, Single-Ended RF and LO Inputs. 28dBm IIP3 at 900MHz, 13.2dBm Demodulator 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 V Offset Control, Shutdown, Adjustable Gain OUT LTC5531 300MHz to 7GHz Precision RF Power Detector Precision V Offset Control, Shutdown, Adjustable Offset OUT LTC5532 300MHz to 7GHz Precision RF Power Detector Precision V Offset Control, Adjustable Gain and Offset OUT LT5534 50MHz to 3GHz Log RF Power Detector with 60dB ±1dB Output Variation over Temperature, 38ns Response Time, Log Linear Dynamic Range Response LTC5536 Precision 600Mhz to 7GHz RF Power Detector with Fast 25ns Response Time, Comparator Reference Input, Latch Enable Input, Comparator Output –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

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