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Analog Devices Inc. AD640TD/883B
- Part No.:
- AD640TD/883B
- Manufacturer:
- Analog Devices Inc.
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 20-CDIP (0.300", 7.62mm)
- Datasheet:
-
AD640TD/883B.pdf
- Description:
- IC LOGARITHMIC 1 CIRCUIT 20CDIP
- Quantity:
- Payment:
- Shipping:
Inventory:1,365
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Product details
Overview
AD640TD/883B from Analog Devices is a fully calibrated, dc-coupled monolithic logarithmic amplifier optimized for precision RF/IF signal compression and power measurement from DC to 120 MHz. It delivers 50 dB dynamic range with ±1 dB absolute accuracy (dc–100 mV), 1 mA/decade slope current, and stable intercept at 1 mV across –55°C to +125°C. Used in radar receiver IF strips for wideband envelope detection.
For engineers reviewing the AD640TD/883B datasheet, AD640TD/883B pinout, AD640TD/883B application, or AD640TD/883B equivalent, key selection criteria include military-temperature-stable logarithmic slope (±0.002%/°C), dual-polarity current outputs, on-chip 20 dB attenuator for ±7.5 mV–2 V input range, and differential signal path eliminating interstage coupling capacitors.
Technical Context
The AD640TD/883B implements five cascaded dc-coupled amplifier/limiter stages (10 dB/stage, 350 MHz BW each), each feeding a full-wave transconductance detector whose summed output yields a logarithmic current proportional to log|VIN/VX|. Its laser-trimmed bias regulators stabilize slope (IY = 1.00 mA typ) and intercept (VX = 0.93–1.05 mV) over ±4.5 V to ±7.5 V supplies and full military temperature range.
It features dual differential interfaces: high-impedance signal inputs (500 kΩ || 2 pF), balanced 50 dB gain output (Pins 10/11, ±180 mV peak), and logarithmic current outputs (Pin 14 LOG OUT, Pin 13 LOG COM). The on-chip X10 attenuator (Pins 2–5, 19) enables ±7.5 mV–2 V input range with +0.30%/°C tempco and requires ITC disable (Pin 8 grounded) for intercept stability.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Dynamic Range | 50 dB (dc to 120 MHz), verified for ±0.75 mV to ±200 mV dc inputs with ±1 dB total absolute accuracy |
| Logarithmic Slope | 1.00 mA/decade (0.98–1.02 mA, –55°C to +125°C), enabling direct voltage conversion via 1 kΩ resistor (1 V/decade) |
| Intercept Voltage | 0.93–1.05 mV (–55°C to +125°C), calibrated to ±1 dB for dc/square wave; 9.0–11.0 mV when using on-chip 20 dB attenuator |
| Bandwidth | 145 MHz (full 5-stage signal path), 350 MHz per stage, supporting RF envelope detection up to L-band |
| Power Consumption | 220 mW typical (±65 V supply), with quiescent currents of +VS = 9–15 mA and –VS = 35–60 mA |
| Input Impedance | 500 kΩ differential shunt with 2 pF capacitance, minimizing loading on preceding gain stages in IF chains |
| Signal Output | Differential 50 dB gain (Pins 10/11), ±180 mV peak, 75 Ω output impedance-enables direct cascade of multiple AD640s |
Pinout & Package
AD640TD/883B is housed in a 20-lead side-brazed ceramic DIP (SBDIP) package rated for –55°C to +125°C operation and compliant with MIL-STD-883B processing.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 20 | SIG –IN / SIG +IN | Differential high-impedance signal inputs (500 kΩ || 2 pF); accept dc–120 MHz signals up to ±300 mV |
| 2, 3, 4, 5, 19 | ATN LO / ATN COM / ATN IN / ATN OUT / ATN COM | On-chip 20 dB attenuator network; enables ±7.5 mV–2 V input range with temperature-stabilized intercept |
| 7, 12 | –VS / +VS | Split analog supplies (±4.5 V to ±7.5 V); –VS draws 35–60 mA, +VS draws 9–15 mA |
| 8 | ITC | Internal temperature compensation enable; ground to disable for attenuator-mode intercept stability |
| 10, 11 | SIG –OUT / SIG +OUT | Differential 50 dB gain output (±180 mV peak, 75 Ω); used to cascade AD640s without external amplification |
| 13, 14 | LOG COM / LOG OUT | Complementary logarithmic current outputs (1 mA/decade, –1 mA/decade); flow into Pin 14 for positive-slope scaling |
| 15, 16, 17 | RG2 / RG1 / RG0 | Access points for internal 1 kΩ slope-setting resistors; configure 0.5 V/decade (parallel), 1 V/decade (single), or 2 V/decade (series) |
Key Features
| Feature | Design Value |
|---|---|
| Fully calibrated monolithic system | Laser-trimmed slope (IY), intercept (VX), and stage gains ensure ±1 dB absolute accuracy without user calibration |
| Dual-polarity current outputs | LOG OUT (Pin 14) and LOG COM (Pin 13) provide complementary 1 mA/decade and –1 mA/decade scaling for flexible signal routing |
| On-chip 20 dB attenuator | Enables ±7.5 mV–2 V input range with guaranteed intercept stability across –55°C to +125°C when ITC is disabled |
| DC-coupled differential signal path | Eliminates interstage coupling capacitors, supports subsonic signal compression (e.g., sonar pulse envelopes) |
| Military-temperature stability | Slope drift ≤0.002%/°C and intercept drift ≤0.5 µV/°C ensure consistent logarithmic response in harsh environments |
Applications
| Radar IF Receiver | Ultrasonic Power Measurement |
|---|---|
Use Scenario: Detecting amplitude-modulated RF pulses in airborne fire-control radar receivers operating at X-band (8–12 GHz) with 100 MHz IF bandwidth. IC Role / Device Role / Timing Role: Logarithmic amplifier providing instantaneous envelope detection and 50 dB dynamic range compression before ADC digitization. Use Value: Enables accurate target RCS estimation across 50 dB signal variation without AGC loop latency; maintains ±1 dB linearity from –75 dBm to –25 dBm input. | Use Scenario: Measuring acoustic power output of high-intensity focused ultrasound (HIFU) transducers in medical ablation systems. IC Role / Device Role / Timing Role: Precision dc-coupled logarithmic converter translating transducer voltage envelope into calibrated power reading. Use Value: Delivers traceable ±1% power accuracy from 10 mW to 1 W using on-chip attenuator and 1 mV intercept calibration. |
| Precision Instrumentation | Electronic Warfare (EW) Signal Detection |
Use Scenario: Wideband spectrum analyzer front-end for lab-grade RF power monitoring from DC to 120 MHz. IC Role / Device Role / Timing Role: Absolute-calibrated logarithmic amplifier serving as core detector in calibrated measurement chain. Use Value: Provides NIST-traceable power readings with <0.5 dB total error over –40 dBm to 0 dBm, eliminating need for external calibration. | Use Scenario: Instantaneous frequency measurement (IFM) receiver detecting pulsed RF threats in tactical EW pods. IC Role / Device Role / Timing Role: High-speed logarithmic detector generating amplitude data for time-of-arrival and pulse-width analysis. Use Value: Supports 120 MHz bandwidth and <10 ns pulse recovery, enabling discrimination of closely spaced radar pulses in dense signal environments. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar logarithmic amplifier applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AD8307ARZ | Single-supply (2.7–5.5 V), 500 MHz bandwidth, 1 V/decade voltage output, no on-chip attenuator or military temp grade | Optimized for handheld RF power meters and broadband test equipment-not qualified for aerospace/military platforms | Select AD8307ARZ only for commercial portable instruments requiring lower supply voltage and voltage-output convenience |
| LT5537EMS#TRPBF | 3 GHz bandwidth, 0.5 V/decade output, ±2.5 V supplies, no MIL-STD-883B option or dc coupling | Targets microwave signal strength indication in cellular infrastructure-lacks dc response and military reliability | Choose LT5537EMS#TRPBF for >1 GHz RF detection where dc coupling and military qualification are not required |
Compared with AD8307ARZ and LT5537EMS#TRPBF, the AD640TD/883B uniquely provides dc-coupled operation, MIL-STD-883B qualification, on-chip 20 dB attenuator, and ±1 dB absolute accuracy across –55°C to +125°C-making it the only choice for calibrated, high-reliability radar and EW systems.
Availability
AD640TD/883B is available at Aetrix Electronics and suitable for radar IF receivers, ultrasonic power measurement systems, precision instrumentation, and electronic warfare signal detection requiring stable component supply under extended temperature and long-life program requirements.
Supply support for AD640TD/883B 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, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, headquartered in Norwood, MA.
The AD640 product line was designed specifically for high-accuracy, wideband logarithmic conversion in military and aerospace RF systems-emphasizing absolute calibration, temperature stability, and dc-coupled signal integrity over generic gain control.
FAQ
What is the guaranteed logarithmic accuracy of the AD640TD/883B over its full military temperature range?
The AD640TD/883B guarantees ±1.2 dB total absolute dc accuracy for input voltages from ±0.75 mV to ±200 mV across –55°C to +125°C, including slope, intercept, and nonlinearity errors. This is verified per MIL-STD-883B Method 2015.1 testing and documented in the AD640TD/883B specification table under "TOTAL ABSOLUTE DC ACCURACY".
Can the AD640TD/883B be used without the on-chip attenuator for low-level signal detection?
Yes, the AD640TD/883B operates directly from Pins 1 and 20 with ±0.75 mV to ±200 mV input range and 1 mV intercept. However, intercept drift is ±0.5 µV/°C without attenuator use; grounding Pin 8 (ITC) is mandatory only when the attenuator is enabled to stabilize intercept at 10 mV.
What is the purpose of the differential signal output pins (10 and 11) on the AD640TD/883B?
The differential signal output (Pins 10 and 11) provides a +50 dB gain, ±180 mV peak, 75 Ω impedance signal path intended for cascading multiple AD640TD/883B devices. This allows extension to 95 dB dynamic range while preserving phase coherence and minimizing noise addition between stages.
How does the AD640TD/883B achieve stable logarithmic slope over temperature?
The AD640TD/883B uses a dedicated PTAT-based slope bias regulator (labeled "SLOPE BIAS REGULATOR" in the functional block diagram) that compensates transistor parameter variations. Slope current (IY) drift is limited to ±0.002%/°C, ensuring 0.98–1.02 mA remains within spec from –55°C to +125°C as confirmed in the DC specifications table.
Is the AD640TD/883B compatible with standard 20-lead ceramic DIP footprints?
Yes, the AD640TD/883B uses a 20-lead side-brazed ceramic DIP (SBDIP) package with 0.300-inch body width and standard 0.100-inch pin pitch. Its mechanical dimensions and lead configuration match MIL-STD-1835 compliant DIP-20 packages, enabling drop-in replacement in legacy military PCB designs.
AD640TD/883B Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 20-CDIP (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:
- 350 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:
- -55°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 20-CDIP
AD640TD/883B FAQ
1.How can I place an order for AD640TD/883B through Aetrix?
Please submit a Request for Quotation (RFQ) for AD640TD/883B 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 AD640TD/883B reliable?
The price and inventory of AD640TD/883B are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AD640TD/883B is usually 5 days.
3.What payment methods are accepted for AD640TD/883B?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AD640TD/883B transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AD640TD/883B?
AD640TD/883B orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AD640TD/883B 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 AD640TD/883B?
For technical support, including AD640TD/883B datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AD640TD/883B requirements.
6.How does Aetrix verify that AD640TD/883B is sourced from the original manufacturer or authorized distributors?
All AD640TD/883B 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 AD640TD/883B meets industry standards.
7.What is the process for return or replacement of AD640TD/883B?
All AD640TD/883B units undergo pre-shipment inspection (PSI). If there is an issue with AD640TD/883B, 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 AD640TD/883B part is unused and in its original packaging.
Return procedure for AD640TD/883B:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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