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Analog Devices Inc. AD641ANZ
- Part No.:
- AD641ANZ
- Manufacturer:
- Analog Devices Inc.
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 20-DIP (0.300", 7.62mm)
- Datasheet:
-
AD641ANZ.pdf
- Description:
- IC LOGARITHMIC 1 CIRCUIT 20DIP
- Quantity:
- Payment:
- Shipping:
Inventory:2,031
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Product details
Overview
AD641ANZ from Analog Devices is a 250 MHz demodulating logarithmic amplifier in 20-lead plastic DIP (N) package, delivering ±2.0 dB log conformance over 44 dB dynamic range with 1 mA/decade slope current and –40.51 dBm intercept at 250 MHz. It performs wideband RF/IF signal compression and power measurement in radar ECM and RSSI systems.
For engineers reviewing the AD641ANZ datasheet, AD641ANZ pinout, AD641ANZ application, or AD641ANZ equivalent, this page provides verified specifications, validated pin functions, confirmed military-grade temperature performance (–40°C to +85°C), and real-world alternatives for high-speed logarithmic signal processing in RF front-ends.
Technical Context
The AD641ANZ implements a five-stage successive detection architecture with direct-coupled differential limiting amplifiers (10 dB/stage, 350 MHz –3 dB bandwidth per stage) and full-wave transconductance rectifiers. Its output current (IOUT = IY log|VIN/VX|) is calibrated to 1.00 mA/decade slope and –40.51 dBm intercept at 250 MHz, with on-chip 10× attenuator enabling ±10 mV to ±2 V input range.
Internal bias regulators stabilize slope and intercept against supply (±4.5 V to ±7.5 V) and temperature (–40°C to +85°C), while integrated 1 kΩ application resistors (RG0/RG1/RG2) support voltage conversion at 0.5 V/decade, 1 V/decade, or 2 V/decade. The ITC pin (Pin 8) enables/disables internal temperature compensation for intercept stability.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Bandwidth | 250 MHz - supports RF/IF signal processing up to L-band without external filtering |
| Dynamic Range | 44 dB single-device - measures input signals from –44 dBm to 0 dBm with <±2.0 dB error |
| Slope Current | 1.00 mA/decade - enables precise 1 V/decade voltage output using onboard 1 kΩ resistor |
| Log Conformance | ±2.0 dB at 250 MHz - ensures accurate RSSI and spectrum analysis across full temp range |
| Input Noise | 2.0 nV/√Hz - preserves SNR in low-level RF detection applications |
| Supply Current | +VS: 9 mA, –VS: 35 mA - enables low-power operation in battery-backed RF monitoring |
| Intercept Voltage | 1 mV (dc/square wave) - defines zero-reference point for logarithmic scaling |
Pinout & Package
AD641ANZ uses a 20-lead plastic DIP (N) package with 2.54 mm lead pitch, rated for industrial temperature range (–40°C to +85°C). Thermal resistance θJA = 61°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 20 | Differential Signal Input | Direct-coupled RF/IF input path; 500 kΩ differential impedance, ±2 V common-mode range |
| 2, 3, 4, 5, 19 | Attenuator Interface | Configures 20 dB on-chip attenuation; pins 5–19 set 20 dB ratio trimmed to calibrate intercept |
| 7 | –VS Supply | Negative supply rail (–4.5 V to –7.5 V); sinks 35 mA quiescent current |
| 8 | ITC (Internal Temp Comp) | Grounding disables intercept temperature compensation when attenuator is active |
| 10, 11 | Differential Limiter Output | ±180 mV square-wave output; 75 Ω output impedance per pin for cascading |
| 12 | +VS Supply | Positive supply rail (+4.5 V to +7.5 V); draws 9 mA quiescent current |
| 13 | LOG COM | Complementary logarithmic current output (–1 mA/decade slope); used for differential current summing |
| 14 | LOG OUT | Main logarithmic current output (1 mA/decade slope); converts to voltage via RG0/RG1/RG2 |
| 15, 16, 17 | RG0/RG1/RG2 | On-chip 1 kΩ resistors; configure 0.5 V/decade (parallel), 1 V/decade (single), or 2 V/decade (series) |
Key Features
| Feature | Design Value |
|---|---|
| Five-stage limiting architecture | Delivers 250 MHz bandwidth with stable 10 dB/stage gain and minimal interstage coupling capacitors |
| On-chip 10× attenuator | Extends input range to ±2 V dc/square wave while maintaining ±2.0 dB conformance and eliminating lateral transfer-function shift over temperature |
| Integrated 1 kΩ application resistors | Enables flexible slope selection (0.5/1/2 V/decade) without external components, reducing BOM count and layout area |
| Laser-trimmed slope & intercept | Guarantees ±0.3 dB calibration accuracy for 2 kHz square-wave inputs (±1 mV to ±100 mV) without user trimming |
| PTAT-stabilized biasing | Maintains ±2.0 dB log conformance across –40°C to +85°C by compensating transistor parameter drift in slope and intercept generators |
Applications
| Radar ECM Front-End | IF Signal Strength Monitoring |
|---|---|
Use Scenario: Wideband RF signal detection in electronic countermeasures systems operating from 100 MHz to 180 MHz. IC Role / Device Role / Timing Role: Demodulating logarithmic amplifier compressing incoming threat signals into linear-in-dB baseband current for ADC digitization. Use Value: 44 dB dynamic range and ±2.0 dB conformance enable accurate amplitude ranking of multiple simultaneous emitters without AGC circuitry. |
Use Scenario: Real-time received signal strength indication in SDR-based communication receivers. IC Role / Device Role / Timing Role: Logarithmic detector converting IF output (e.g., 10.7 MHz) to DC voltage proportional to input power in dBm. Use Value: 250 MHz bandwidth and 37.5 mV/dB output sensitivity allow fast RSSI updates (<1 µs response) for adaptive channel selection. |
| High-Speed Spectrum Analyzer | Radar Pulse Compression |
Use Scenario: Video detector in swept-tuned spectrum analyzers requiring >100 MHz instantaneous bandwidth. IC Role / Device Role / Timing Role: Baseband logarithmic converter generating amplitude-vs-frequency display data from mixer output. Use Value: Dual polarity current outputs (LOG OUT/LOG COM) enable differential current summing to suppress common-mode noise in analog-to-digital conversion paths. |
Use Scenario: Pulse envelope detection in pulsed-Doppler radar receivers processing microsecond-duration RF bursts. IC Role / Device Role / Timing Role: High-speed logarithmic amplifier capturing peak amplitude of short RF pulses (≥10 ns rise time) for target ranging. Use Value: Direct-coupled differential signal path eliminates coupling capacitors, preserving pulse fidelity and enabling sub-100 ns transient response. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar logarithmic amplifier applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AD8307ARZ | 500 MHz bandwidth, 90 dB dynamic range, 2.5 V output voltage (not current), no on-chip attenuator | Better suited for wide-dynamic-range DC-coupled measurements; lacks cascading capability and differential limiter outputs | Select AD8307ARZ when higher bandwidth and voltage output simplify interface with ADCs, but avoid when cascaded log amp configurations or RF pulse fidelity are required. |
| LT5537EMS#TRPBF | 1 GHz bandwidth, 60 dB dynamic range, 2.5 V output, integrated 50 Ω input matching, no internal resistors | Optimized for cellular/WiFi frequency bands; requires external gain-setting resistors and has no ITC control | Choose LT5537EMS#TRPBF for GHz-range LTE/WiFi RSSI where board space is constrained, but verify intercept stability over temperature without on-chip compensation. |
Compared with AD8307ARZ and LT5537EMS#TRPBF, the AD641ANZ uniquely supports cascaded configurations via differential limiter outputs (Pins 10/11), offers selectable slope via integrated resistors, and provides temperature-stable intercept with ITC control-making it optimal for military-grade RF front-ends requiring traceable calibration and multi-stage dynamic range extension.
Availability
AD641ANZ is available at Aetrix Electronics and suitable for radar ECM systems, IF signal strength monitoring, high-speed spectrum analyzers, and pulsed radar receivers requiring stable component supply across extended temperature ranges.
Supply support for AD641ANZ includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Analog Devices is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving precision instrumentation, communications, and defense markets since 1965.
The AD641 belongs to Analog Devices' RF logarithmic amplifier product line, designed specifically for wideband signal power measurement and compression in military and aerospace electronic warfare systems where temperature stability and calibrated dynamic range are critical.
FAQ
What is the maximum input frequency supported by the AD641ANZ?
The AD641ANZ supports a guaranteed 3 dB bandwidth of 250 MHz, enabling accurate logarithmic conversion of RF/IF signals up to L-band frequencies. Performance remains within ±2.0 dB log conformance at 250 MHz for input levels from –44 dBm to 0 dBm, making it suitable for radar and ECM applications operating between 100 MHz and 180 MHz.
How does the AD641ANZ achieve temperature-stable logarithmic intercept?
The AD641ANZ achieves temperature-stable intercept through two methods: (1) internal temperature compensation (ITC) activated by leaving Pin 8 open, which injects a PTAT correction current; and (2) use of the on-chip 20 dB attenuator with positive temperature coefficient, which stabilizes the effective input to the first stage. When the attenuator is used, Pin 8 must be grounded to disable ITC and prevent overcompensation.
Can the AD641ANZ be cascaded with another AD641ANZ for extended dynamic range?
Yes, two AD641ANZ devices can be cascaded to achieve 58 dB dynamic range at 250 MHz. The differential limiter outputs (Pins 10/11) provide square-wave signals compatible with direct connection to the next stage's inputs. When cascading, ground Pin 8 on at least one device to disable redundant ITC compensation and maintain intercept accuracy across the combined transfer function.
What is the role of the RG0, RG1, and RG2 pins on the AD641ANZ?
RG0 (Pin 15), RG1 (Pin 16), and RG2 (Pin 17) connect to three laser-trimmed 1 kΩ resistors inside the AD641ANZ. These resistors enable configurable slope conversion: using one resistor yields 1 V/decade, series connection gives 2 V/decade, and parallel yields 0.5 V/decade. This eliminates external components for voltage output generation while maintaining precision slope calibration.
Does the AD641ANZ require external decoupling capacitors?
Yes, the AD641ANZ requires external 0.1 µF ceramic decoupling capacitors placed as close as possible to Pins 7 (–VS) and 12 (+VS), with additional 10 µF bulk capacitance recommended on each supply rail. Proper decoupling is essential to maintain 250 MHz bandwidth and prevent oscillation, especially given the 35 mA quiescent current drawn from –VS and the high-gain limiting stages.
AD641ANZ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 20-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Active
- Amplifier Type:
- Logarithmic
- Number of Circuits:
- 1
- Output Type:
- -
- Slew Rate:
- -
- Gain Bandwidth Product:
- -
- -3db Bandwidth:
- 250 MHz
- Current - Input Bias:
- 7 µA
- Voltage - Input Offset:
- 50 µV
- Current - Supply:
- 35mA
- Current - Output / Channel:
- 2.3 mA
- Voltage - Supply Span (Min):
- 9 V
- Voltage - Supply Span (Max):
- 15 V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 20-PDIP
AD641ANZ FAQ
1.How can I place an order for AD641ANZ through Aetrix?
Please submit a Request for Quotation (RFQ) for AD641ANZ on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for AD641ANZ reliable?
The price and inventory of AD641ANZ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AD641ANZ is usually 5 days.
3.What payment methods are accepted for AD641ANZ?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AD641ANZ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AD641ANZ?
AD641ANZ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AD641ANZ order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for AD641ANZ?
For technical support, including AD641ANZ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AD641ANZ requirements.
6.How does Aetrix verify that AD641ANZ is sourced from the original manufacturer or authorized distributors?
All AD641ANZ products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that AD641ANZ meets industry standards.
7.What is the process for return or replacement of AD641ANZ?
All AD641ANZ units undergo pre-shipment inspection (PSI). If there is an issue with AD641ANZ, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The AD641ANZ part is unused and in its original packaging.
Return procedure for AD641ANZ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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