AD8312

AD8312 (Rev.C)

Document overview

• Manufacturer or author: Analog Devices, Inc.
• PDF pages: 19

Technical content

50 MHz to 3.5 GHz, 45 dB RF Detector Rev. C DOCUMENT FEEDBACK TECHNICAL SUPPORT

FEATURES

►Complete RF detector function ►Typical range: −45 dBm to 0 dBm, referencing 50 Ω ►Frequency response from 50 MHz to 3.5 GHz ►Temperature stable linear in dB response ►Accurate to 3.5 GHz ►Rapid response: 85/120 ns (rise/fall) ►Low power: 12 mW at 2.7 V

APPLICATIONS

►Cellular handsets (GSM, CDMA, WCDMA) ►RSSI and TSSI for wireless terminal devices ►Transmitter power measurement GENERAL DESCRIPTION The AD8312 is a complete, low cost subsystem for the measure- ment of radio frequency (RF) signals in the frequency range of 50 MHz to 3.5 GHz. It has a typical dynamic range of 45 dB and is intended for use in a wide variety of cellular handsets and other wireless devices. It provides a wider dynamic range and better accuracy than possible using discrete diode detectors. In particular, its temperature stability is excellent over the full operating range of −40°C to +85°C. Its high sensitivity allows measurement at low power levels, thus reducing the amount of power that needs to be coupled to the detector. It is essentially a voltage responding device, with a typical signal range of 1.25 mV to 224 mV rms or −45 dBm to 0 dBm, referencing 50 Ω. For convenience, the signal is internally ac-coupled, using a 5 pF capacitor to a load of 3 kΩ in shunt with 1.3 pF. This high-pass cou- pling, with a corner at approximately 16 MHz, determines the lowest operating frequency. Therefore, the source may be dc grounded. The AD8312 output, VOUT, increases from close to ground to about 1.2 V because the input signal level increases from 1.25 mV to 224 mV. A capacitor may be connected between the VOUT and CFLT pins when it is desirable to increase the time interval over which averaging of the input waveform occurs. The AD8312 is available in a 6-ball, 1.0 mm × 1.5 mm, wafer level chip scale package and consumes 4.2 mA from a 2.7 V to 5.5 V supply. FUNCTIONAL BLOCK DIAGRAM Figure 1.

analog.com Rev. C | 2 of 19 Transfer Function in Terms of Slope and

REVISION HISTORY

2/2026—Rev. B to Rev. C

analog.com Rev. C | 3 of 19 VS = 3 V, CFLT = open, TA = 25°C, light condition = 600 LUX, 52.3 Ω termination resistor at RFIN, unless otherwise noted. Table 1. Parameter Test Conditions/Comments Min Typ Max Unit SIGNAL INPUT INTERFACE RFIN (Pin 6) Specified Frequency Range 0.05 3.5 GHz Input Voltage Range Internally ac-coupled 1.25 224 mV rms Equivalent Power Range 52.3 Ω external termination −45 0 dBm DC Resistance to COMM 100 kΩ MEASUREMENT MODE VOUT (Pin 2) shorted to VSET (Pin 3), sinusoidal input signal f = 50 MHz Input Impedance 3050 || 1.4 Ω || pF ±1 dB Dynamic Range TA = 25°C 50 dB −40°C < TA < +85°C 42 dB Maximum Input Level ±1 dB error 3 dBm Minimum Input Level ±1 dB error −47 dBm Slope 20.25 mV/dB Intercept −51.5 dBm Output Voltage—High Power In PIN = −10 dBm 0.841 V Output Voltage—Low Power In PIN = −40 dBm 0.232 V Temperature Sensitivity PIN = −10 dBm f = 100 MHz Input Impedance 2900 || 1.3 Ω || pF ±1 dB Dynamic Range TA = 25°C 48 dB −40°C < TA < +85°C 40 dB Maximum Input Level ±1 dB error 2 dBm Minimum Input Level ±1 dB error −46 dBm Slope 19.0 21.0 23.0 mV/dB Intercept −56.0 −50.5 −47.0 dBm Output Voltage—High Power In PIN = −10 dBm 0.850 V Output Voltage—Low Power In PIN = −40 dBm 0.222 V Temperature Sensitivity PIN = −10 dBm f = 900 MHz Input Impedance 890 || 1.15 Ω || pF ±1 dB Dynamic Range TA = 25°C 49 dB −40°C < TA < +85°C 42 dB Maximum Input Level ±1 dB error 1 dBm Minimum Input Level ±1 dB error −48.0 dBm Slope 20.25 mV/dB Intercept −51.9 dBm Output Voltage—High Power In PIN = −10 dBm 0.847 V Output Voltage—Low Power In PIN = −40 dBm 0.237 V Temperature Sensitivity PIN = −10 dBm 25°C ≤ TA ≤ 85°C 0.0019 dB/°C

Table 1. (Continued)

1 Increased output is possible when using an attenuator between VOUT and VSET to raise the slope.

analog.com Rev. C | 6 of 19 Table 2. Parameter Value Supply Voltage VPOS 5.5 V VOUT, VSET 0 V, VPOS Input Voltage 1.6 V rms Equivalent Power 17 dBm Internal Power Dissipation 200 mW θJA (WLCSP) 200°C/W Maximum Junction Temperature 125°C Operating Temperature Range −40°C to +85°C Storage Temperature Range −65°C to +150°C Stresses at or above those listed under Absolute Maximum Ratings may cause permanent damage to the product. This is a stress rating only; functional operation of the product at these or any other conditions above those indicated in the operational section of this specification is not implied. Operation beyond the maximum operat- ing conditions for extended periods may affect product reliability. ESD CAUTION ESD (electrostatic discharge) sensitive device. Charged devices and circuit boards can discharge without detection. Although this product features patented or proprietary protec- tion circuitry, damage may occur on devices subjected to high energy ESD. Therefore, proper ESD precautions should be taken to avoid performance degradation or loss of functionality.

Figure 2. Pin Configuration Table 3. Pin Function Descriptions 1 VPOS Positive Supply Voltage (VS), 2.7 V to 5.5 V. 2 VOUT Logarithmic Output. Output voltage increases with increasing input amplitude. arbitrarily high value by attenuating the signal between VOUT and VSET (see the Increasing the Logarithmic Slope section). 4 CFLT Connection for an External Capacitor to Slow the Response of the Output. Capacitor is connected between CFLT and VOUT. 5 COMM Device Common (Ground).

Table 4. Typical Specifications at Selected Frequencies at 25°C (Mean and Σ)

shows the main features of the AD8312 in block schematic form. with temperature and frequency. the minimum error, straight line fit to the actual graph of VOUT vs. input power. The quoted values assume a sinusoidal (CW) signal. by supply voltages of 2.7 V to 5.5 V. Figure 21. Block Schematic

Table 6. Evaluation Board Configuration Options input impedance of around 50 Ω. Logarithmic Slope section for more details.

Legal Terms and Conditions Information furnished by Analog Devices is believed to be accurate and reliable "as is". However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Specifications subject to change without notice. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Trademarks and registered trademarks are the property of their respective owners. All Analog Devices products contained herein are subject to release and availability. analog.com Rev. C | 19 of 19 Package Drawing (Option) Package Type Package Description CB-6-2 WLCSP 6-Ball Wafer-Level Chip Scale Package For the latest package outline information and land patterns (footprints), go to Package Index. ORDERING GUIDE Model1 Temperature Range Package Description Packing Quantity Package Option Marking Code AD8312ACBZ-R7 –40°C to +85°C 6-Ball Wafer Level Chip Scale Package [WLCSP]7” Reel, 3000 CB-6-2 Q00 AD8312ACBZ-P7 –40°C to +85°C 6-Ball Wafer Level Chip Scale Package [WLCSP]7” Pocket Tape and Reel, 3000CB-6-2 Q00 AD8312ACBZ-P2 –40°C to +85°C 6-Ball Wafer Level Chip Scale Package [WLCSP]2” Pocket Tape and Reel, 250CB-6-2 Q00 1 Z = RoHS Compliant Part. EVALUATION BOARDS Model1 Description AD8312-EVALZ Evaluation Board 1 Z = RoHS Compliant Part.