AD8314 Analog Devices, AD8314 Datasheet
AD8314
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AD8314 Summary of contents
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... RSSI and TSSI for wireless terminal devices Transmitter power measurement and control GENERAL DESCRIPTION The AD8314 is a complete low cost subsystem for the measurement and control of RF signals in the frequency range of 100 MHz to 2.7 GHz, with a typical dynamic range of 45 dB, intended for use in a wide variety of cellular handsets and other wireless devices ...
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... AD8314 TABLE OF CONTENTS Features .............................................................................................. 1 Applications....................................................................................... 1 General Description ......................................................................... 1 Functional Block Diagram .............................................................. 1 Revision History ............................................................................... 2 Specifications..................................................................................... 3 Absolute Maximum Ratings............................................................ 4 ESD Caution.................................................................................. 4 Pin Configurations and Function Descriptions............................ 5 Typical Performance Characteristics ............................................. 6 Theory of Operation ...................................................................... 10 Inverted Output .......................................................................... 11 Applications..................................................................................... 12 Basic Connections ...................................................................... 12 Transfer Function in Terms of Slope and Intercept ............... 12 REVISION HISTORY 5/06— ...
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... A 2 ENBL, −40°C ≤ T ≤ +85° condition, −40°C ≤ T ≤ +85°C A Pin VPOS −40°C ≤ T ≤ +85°C A −40°C ≤ T ≤ +85°C A Rev Page AD8314 Min Typ Max Unit 0.1 2.5 GHz 1.25 224 mV rms −45 0 dBm 18.85 21.3 23 ...
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... AD8314 ABSOLUTE MAXIMUM RATINGS Table 2. Parameter Supply Voltage VPOS V_UP, V_DN, VSET, ENBL Input Voltage Equivalent Power Internal Power Dissipation θ (MSOP) JA θ (LFCSP, Paddle Soldered) JA θ (LFCSP, Paddle Not Soldered) JA Maximum Junction Temperature Operating Temperature Range Storage Temperature Range Lead Temperature (Soldering 60 sec) ...
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... COMM 4 5 Figure 2. RM-8 Pin Configuration RFIN 1 8 VPOS AD8314 ENBL 2 7 V_DN TOP VIEW VSET 3 5 V_UP (Not to Scale) FLTR 4 5 COMM Figure 3. CP-8-1 Pin Configuration for Normal Operation. Connect pin to ground for disable mode 2 5 Rev Page AD8314 ...
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... AD8314 TYPICAL PERFORMANCE CHARACTERISTICS 1.2 1.0 0.8 0.6 0.4 0.2 0 –75 –65 –55 –45 –35 (–52dBm) INPUT AMPLITUDE (dBV) Figure 4. V vs. Input Amplitude UP 1.2 1.0 +25°C 0.8 –40°C +85°C 0.6 +25°C 0.4 SLOPE AND INTERCEPT 0.2 NORMALIZED AT +25°C AND APPLIED TO –40°C AND +85°C 0 –70 –60 –50 –40 –30 (–47dBm) INPUT AMPLITUDE (dBV) Figure 5 ...
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... FREQUENCY (GHz) Intercept vs. Frequency; −40°C, +25°C, and +85°C UP 0.1GHz 2.5GHz 0.9GHz 1.9GHz 3.0 3.5 4.0 4.5 2.5 V (V) S Figure 14. V Intercept vs. Supply Voltage DECREASING 3 V ENBL INCREASING V 2 ENBL 1 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 V (V) ENBL Figure 15. Supply Current vs. ENBL Voltage, V AD8314 –40°C +25°C 2.5 5.0 5.5 2.2 2.4 2 ...
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... PULSE MODE IN OUT GENERATOR RF OUT –3dB TEK P6204 FET PROBE 0.1µF 1 RFIN VPOS 8 TEK P6204 3.0V 2 ENBL V_DN 7 FET PROBE AD8314 TEK P6204 V_UP 3 6 VSET FET PROBE FLTR COMM CONNECT Figure 20. Text Setup for Pulse Response 10 –50dBm –60dBm – ...
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... RFIN TEK P6204 2 ENBL V_DN 7 FET PROBE AD8314 V_UP 0.2 VSET FLTR COMM CONNECT Figure 27. Test Setup for Power-On Response at V_DN Output, Controller Mode with VSET Pin Held Low AD8314 3.4 3.5 TRIG OUT PULSE OUT 49.9Ω TRIG TEK TDS784C SCOPE ...
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... In measurement modes, this output is connected back to a voltage-to-current (V-I) stage, in such a manner that V_UP is a logarithmic measure of the RF input voltage, with a slope and intercept controlled by the design. For a fixed termination resistance at the input of the AD8314, a given voltage corresponds to a certain power level. DET RFIN ...
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... In practice, it usually falls off somewhat at higher frequencies, due to the declining gain of the amplifier stages and other effects in the detector cells. For the AD8314, the slope at low frequencies is nominally 21.3 mV/dB, falling almost linearly with frequency to about 19.2 mV/dB at 2.5 GHz. These values are sensibly independent of temperature (see Figure 10) and almost totally unaffected by the supply voltage from 2 ...
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... Figure 32 shows the transfer function for V_UP at a supply voltage and input frequency of 0.9 GHz. V_DN, which is generally not used when the AD8314 is used in measurement mode, is essentially an inverted version of V_UP. The voltage on V_UP and V_DN are related by ...
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... V amplifier to reduce its output. This restores a balance between the actual power level sensed at the input of the AD8314 and the demanded value determined by the setpoint. This assumes that the gain control sense of the variable gain element is positive, that is, an increasing voltage from V_DN tends to increase gain ...
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... Table 5). The voltage gain is calculated by Voltage Gain dB where R2 is the input impedance of the AD8314, and R1 is the source impedance to which the AD8314 is being matched. Note that this gain is only achieved for a perfect match. Component tolerances and the use of standard values tend to reduce gain. ...
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... Voltage Gain (dB) looks like a vertical shift in the log amp’s transfer function. The logarithmic slope, however, is not affected. For example, 11.8 consider the case of the AD8314 being alternately fed by an 7.8 unmodulated sine wave and by a single CDMA channel of the 2.55 same rms power. The AD8314’s output voltage differs by the equivalent of 3 ...
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... Figure 39. A Dual Mode Power Amplifier Control Circuit The setpoint voltage, in the 1.1 V range, is applied to the VSET pin of the AD8314. This is typically supplied by a DAC. This voltage is compared to the input level of the AD8314. Any imbalance between VSET and the RF input level is corrected by V_DN, which drives the V amplifier ...
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... RFIN V 2 ENBL S V_DN 7 AD8314 V_UP 3 6 VSET FLTR COMM 220pF Figure 41. A Single Mode Power Amplifier Control Circuit –10 –20 –30 –40 –50 0 0.2 0.4 0.6 0.8 VSET (V) Figure 42. POUT vs. VSET at 0.9 GHz for Single Mode Handset AD8314 RF INPUT P IN 0dBm V S 2.7V 1.0 ...
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... AD8314 OPERATION AT 2.7 GHz While the AD8314 is specified to operate at frequencies up to 2.5 GHz, it works at higher frequencies, although it does exhibit slightly higher output voltage temperature drift. Figure 43 shows the transfer function of a typical device at 2.7 GHz, at ambient as well as hot and cold temperatures. Figure 44 shows the transfer function of the AD8314 when driven by both an unmodulated sine wave and a 64 QAM signal ...
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... In Position B, the ENBL pin is grounded, putting the device in power-down mode. R1, R2 Input Interface. The 52.3 Ω resistor in Position R2 combines with the AD8314’s internal input impedance to give a broadband input impedance of around 50 Ω. A reactive match can be implemented by replacing R2 with an inductor and R1 (0 Ω) with a capacitor. Note that the AD8314’ ...
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... AD8314ARMZ-REEL 1 −40°C to +85°C 1 AD8314ARMZ-REEL7 −40°C to +85°C AD8314-EVAL AD8314ACP-REEL −40°C to +85°C AD8314ACP-REEL7 −40°C to +85°C AD8314ACP-WP −40°C to +85°C 1 AD8314ACPZ-REEL −40°C to +85°C 1 AD8314ACPZ-RL7 −40°C to +85°C AD8314ACP-EVAL Pb-free part, # denotes lead-free product may be top or bottom marked ...