Keysight N4431D DC to 13.5 GHz 4-Port ECal Module

Key Features At A Glance

• Single-connection calibration replaces multi-standard mechanical SOLT routines for faster, more repeatable VNA calibrations
• Five product families spanning DC to 67 GHz coverage, with 2-port and 4-port configurations available
• Solid-state programmable impedance states traceable via the National Metrology Institute (NMI)
• Connector options include Type-N 50 Ω, Type-N 75 Ω, Type-F 75 Ω, 7-16, 4.3-10, 7 mm, 3.5 mm, 2.92 mm, 2.4 mm, and 1.85 mm
• Option 0DC extends calibration frequency range down to DC on N469xD and N443xD Series for broadband and time-domain (TDR) applications
• User-characterization capability allows custom mixed-connector, waveguide, and fixture calibrations to be embedded in module memory
• Direct USB control from supported PNA, ENA, PXI VNA, Streamline USB VNA, and FieldFox analyzers — no external PC required
• Module-specific S-parameter data stored in flash memory and applied automatically during VNA calibration routines

The Keysight Electronic Calibration (ECal) Module portfolio brings single-connection calibration to vector network analyzers across five product families: the N755xA Series 2-port Economy ECal Modules, the 8509xC Series 2-port RF ECal Modules, the N469xD Series 2-port Microwave ECal Modules, the N443xA/B Series 4-port ECal Modules, and the N443xD Series 4-port ECal Modules. These modules are solid-state devices with programmable, highly repeatable impedance states that are traceable via the National Metrology Institute, and they are controlled directly from supported Keysight network analyzers without requiring an external PC.

ECal modules are used to calibrate vector network analyzers in place of traditional mechanical SOLT (Short-Open-Load-Thru) calibration kits. A full VNA calibration can be accomplished with a single connection to the ECal module and minimal operator interaction, which reduces the number of connections required during the calibration process. According to the datasheet, this approach helps users calibrate faster, reduces the chance of operator error for greater repeatability, and reduces wear on connectors — lowering repair costs on both the test port connectors and the calibration standards.

ValueTronics International ships all featured Keysight ECal modules from our 20,000 sq ft secure warehouse at 1675 Cambridge Drive, Elgin, Illinois, where {{CONDITION}} modules are inspected and confirmed against the model and option codes listed in our catalog before they leave the facility. Unlike drop-shippers and pass-through brokers who never physically handle the hardware, our team verifies connector type, frequency option, and accessory completeness on every unit — so the module that arrives at your bench matches the model number on your purchase order.

Brand Heritage

Keysight Technologies was spun off from Agilent Technologies in 2014 and inherited the electronic measurement business that originated with Hewlett-Packard's test and measurement division. The ECal product line traces directly through this corporate lineage, which is why some legacy documentation and historical model references in the user community may carry Agilent or HP branding for predecessor modules.

Compare Other Models in This Series

Keysight's Electronic Calibration portfolio is organized into five product families that share a common architecture — solid-state programmable impedance states, NMI-traceable characterization, single-connection calibration workflow, and direct USB control from the host VNA — but differ in frequency coverage, port count, connector options, and accuracy tier. The N755xA Series is positioned as the economy 2-port option, the 8509xC Series covers traditional RF 2-port calibration to 9 GHz, the N469xD Series provides higher-accuracy 2-port microwave calibration up to 67 GHz, and the N443xA/B and N443xD Series provide 4-port calibration for full multi-port VNA workflows.

Across all five families, the datasheet identifies the same core selling points: efficient single-standard calibration, precision transfer standards with traceability via the National Metrology Institute, broad choice of connector and frequency configurations, frequency coverage down to DC on the D-suffix modules, support from current Keysight VNA platforms, and the ability to create custom characterizations through user-characterization. Selection between families is driven by the host VNA, the maximum frequency required, the port count of the calibration workflow, and the accuracy tier the application demands.

Each new ECal module below is listed as its own product page with condition-matched pricing. The compare models section that follows summarizes the frequency coverage, port count, and connector options for the families covered by this datasheet so the selection that matches your VNA and your DUT connector environment is easy to identify.

The five families differ primarily on three axes. First, port count: the N755xA, 8509xC, and N469xD Series are 2-port modules, while the N443xA/B and N443xD Series are 4-port modules intended for full 4-port VNA calibration. Second, maximum frequency: the N755xA Series tops out at 26.5 GHz (N7555A), the 8509xC Series at 9 GHz, the N469xD Series at 67 GHz (N4694D), the N443xA/B at 20 GHz (N4433A), and the N443xD at 26.5 GHz (N4433D). Third, low-end coverage: D-suffix modules (N469xD and N443xD) support Option 0DC for calibration starting at DC, which the datasheet recommends for enhanced time domain analysis on Keysight VNAs.

Connector availability also varies by family. The 8509xC Series uniquely offers Type-N 75 Ω (85096C), Type-F 75 Ω (85099C), and 7 mm (85091C) configurations. The N469xD Series spans Type-N, 3.5 mm, 2.92 mm, 2.4 mm, 1.85 mm, and 7 mm — making it the family of choice when test ports use precision microwave connectors. The N4431D within the N443xD Series is the only model in the portfolio to offer a 4.3-10 connector option, addressing the connector standard used in some cellular infrastructure environments.

Model	Frequency Range	Ports	Connector Types
N4431D	DC to 13.5 GHz	4	3.5 mm / Type-N 50 Ω / 7-16 / 4.3-10 / mixed
N7550A	DC to 4 GHz	2	3.5 mm or Type-N 50 Ω
N7551A	DC to 6.5 GHz	2	3.5 mm or Type-N 50 Ω
N7552A	DC to 9 GHz	2	3.5 mm or Type-N 50 Ω

Additional differences in specifications beyond the few shown above are not listed here — see each model's full specifications below.

Product Core & Specifications

Parameter	8509x	N4431B	N4432/3A & N443xD	N755xA	N469x
Typical maximum input power	+9.0 dBm	+7.0 dBm	−7.0 dBm	−15 dBm	−5.0 dBm
Typical maximum DC level applied to test port	± 20 volts	± 3 volts	± 3 volts	0 volts	± 10 volts
Typical damage level	+20.0 dBm	+20.0 dBm	+20.0 dBm	+10.0 dBm	+10.0 dBm
Operating temperature (8509x Series)	+20 to +30 °C
Operating temperature (N443xD Series)	+20 to +26 °C, up to 95% RH at 40 °C, non-condensing
Operating temperature (N443xA/B Series)	+20 to +30 °C
Operating temperature (N469x Series)	+20 to +26 °C
Operating temperature (N755xA Series)	+15 to +35 °C, up to 75% RH

Important: Maximum input power and DC limits vary by family: 8509xC accepts +9.0 dBm typical max input and ±20 V DC; N4431B accepts +7.0 dBm and ±3 V DC; N4432/3A and N443xD accept −7.0 dBm and ±3 V DC; N755xA accepts −15 dBm and 0 V DC; N469xD accepts −5.0 dBm and ±10 V DC. Typical damage level is +20.0 dBm for 8509x and N443x families and +10.0 dBm for N755xA and N469x families. Exceeding the typical maximum input power degrades calibration results from the performance indicated in the datasheet tables.Important: Before performing a calibration, ensure the input power and DC levels do not exceed the maximum values specified for each module series. Exceeding these limits may damage the module.Important: The ECal module must be operated within the specified temperature range to meet operating specifications (varies by series; see specifications).Important: When applied power exceeds the rated maximum input power for the module, calibration results will be degraded from the performance indicated in the characteristic performance tables.Important: Some VNA models require specific minimum firmware revisions to support certain ECal modules. The N9912A FieldFox does not support ECal. The N4693D and N4694D are not supported on the E5071C, E5072A, E5061B, and E5063A. The E5071C, E5072A, E5061B, and E5063A do not support the N4433D 4-port ECal model.Important: The 4.3-10 connector option is only available for the N4431D model.Important: Option 0DC (low frequency starts from DC) is only available for the N469xD and N4432/3D Series ECal modules.Important: Option 003 (low frequency starts from 300 kHz) is only available for the N4690D, N4691D, N4696D, N4432D, and N4433D ECal modules.Important: Option 100 (low frequency starts from 10 MHz) is only available for the N4692D, N4693D, and N4694D ECal modules.Important: Option 00A (male-to-male and female-to-female adapters) is not available for the N755xA Series and for ECal modules with 7 mm connectors (e.g., N4696D).Recommended pairing: select the ECal family that matches your VNA per the datasheet's VNA compatibility list — the N469xD Series is identified as the higher-accuracy choice for PNA and PNA-X up to 67 GHz, the N443xA/B/D Series is recommended for full 4-port calibration on PNA, ENA, and PXI VNA, and the N755xA Series is positioned as the economy option supported across PNA, ENA, Streamline USB VNA, PXI VNA, and FieldFox platforms.

Please review the Manufacturer's Data Sheet to verify published specifications. Feedback on this webpage is always welcome — please reach out to your Test Architect at any time for questions or concerns. Thank you, we truly appreciate you being our customer.