Keysight E4990A Impedance Analyzer: Setting Performance Benchmarks for Precision Component and Material Testing

In the fields of electronic component design, materials science research and semiconductor device characterization, the accuracy of impedance measurement directly determines the success or failure of product R&D. The E4990A impedance analyzer launched by Keysight Technologies features industry-leading accuracy of ±0.045% (typical), frequency coverage up to 120 MHz, and a complete accessory ecosystem, making it the trusted choice for engineers and researchers worldwide.

1. Product Overview: Deeper Insights Beyond LCR Measurement

The E4990A belongs to the Keysight ZA5 class impedance analyzer series. It goes beyond the measurement scope of general-purpose LCR bridges to deliver in-depth insights for demanding applications such as equivalent circuit modeling, high-frequency characterization and material verification. Whether you work in component R&D, materials science experiments, or quality inspection, the E4990A enables you to accurately characterize and test electronic components, semiconductor devices and various materials.

Five Main Application Scenarios:

·Passive component testing (basic parameter and high-frequency characteristic analysis for capacitors, inductors and resistors)

·Permittivity and loss tangent measurement for dielectric materials

·Permeability analysis for magnetic materials

·C-V characteristic characterization for semiconductor devices (MIS devices, pn junctions, etc.)

·Impedance analysis and verification for high-frequency circuits and PCB traces

2. Core Parameters and Technical Specifications

All core technical specifications of the E4990A are sourced from Keysight's official datasheet, and the complete parameter summary is as follows:

Frequency Characteristics

·Frequency range: 20 Hz to 120 MHz (5 upgradeable frequency options: 10 MHz / 20 MHz / 30 MHz / 50 MHz / 120 MHz)

·Frequency resolution: 1 mHz

·Frequency accuracy: ±7 ppm ± 1 mHz (without 1E5 option)

Measurement Accuracy

·Basic impedance measurement accuracy: ±0.08% (±0.045% typical)

·Impedance measurement range (within 10% accuracy): 25 mΩ to 40 MΩ

Signal Source Characteristics

·Voltage signal range: 5 mVrms to 1 Vrms, with 1 mV resolution

·Current signal range: 200 μArms to 20 mArms, with 20 μA resolution

·Output impedance: 25 Ω (nominal)

DC Bias Source

·Voltage range: 0 V to ±40 V

·Current range: 0 A to ±100 mA

·Supports C-V characteristic testing and impedance characteristic analysis under variable bias

Measurement Parameters

·Basic parameters: |Z|, |Y|, θ, R, X, G, B

·Component parameters: L (inductance), C (capacitance), D (dissipation factor), Q (quality factor)

·Complex impedance/Complex admittance: Complex Z, Complex Y

·Level monitoring: Vac, Iac, Vdc, Idc

Display and Operation

·Display: 10.4-inch color LCD touchscreen, XGA resolution (1024 × 768), supports simultaneous display of 4 channels and 4 traces

·Trigger types: continuous, single, average; trigger sources include internal (free run), external (BNC input), GPIB/USB/LAN, manual (front panel key)

Environmental and Physical Specifications

·Operating temperature: +5 °C to +40 °C

·Power supply: 100–240 VAC, 47–63 Hz, typical power consumption 160 W

·Dimensions: 432 mm (W) × 222 mm (H) × 297 mm (D)

·Weight: 14 kg 

⚠️ Specification Note: All technical specifications are measured under the conditions of ambient temperature 23 °C ± 5 °C, after 90 minutes of instrument warm-up; the specification values include guard bands to account for expected statistical performance distribution and environmental variations. Typical (typ) values reflect the expected performance of average units, do not include guard bands, and are not covered under product warranty.

3. Frequency Options and Upgrade Path

The E4990A features modular frequency option design, which allows users to select the appropriate specification based on current budget requirements, and enables future hardware frequency upgrades (for example, from 10 MHz to 120 MHz) to protect your initial investment.

4. Software Options and Optional Accessories

Software and Performance Options 

·Option 001 — Enhanced Measurement Speed: Only available for 10M/20M/30M/50M frequency options, this option boosts the measurement speed of lower-frequency models to match that of the 120 MHz flagship model, significantly reducing the overall test cost for multi-point measurements.

·Option 1E5 — High-Stability Frequency Reference: Improves frequency accuracy and stability.

·Equivalent Circuit Analysis: Supports 7 multi-parameter models (such as series RLC, parallel RLC, etc.), automatically fits measurement data and displays equivalent parameter values including R, L, C, D, Q.

·Limit Line Testing: Allows setting upper and lower test limits, facilitating quality inspection and production screening.

·Firmware Update: Supports user-initiated online updates, no need to return the instrument to the factory. The current latest version is B.06.01 (released in October 2025), which already supports the Windows 11 operating system.

·Software option activation: After purchasing the software option upgrade kit, you need to obtain a 12-character license key, and enter it to activate under menu System > Service Menu > Enable Options on the instrument; the license key file (.lic) is stored in the Factory(E:)LICENSE directory, please back it up when replacing the storage device

Physical Accessories (Optional)

·Rack Mount Kit (E4990A-1CM): Fits for standard rack installation

·Front Handle Kit (E4990A-1CN): Improves convenience for instrument handling and transportation

·Handle/Rack Kit (E4990A-1CP)

·Keyboard (E4990A-810) and external mouse (E4990A-820): optional external input devices

5. Basic Operation Guide

1. Hardware Connection

·Power Connection: Use the original power cable and connect to a 100–240 V AC power supply.

·Four-terminal pair (4TP) measurement (recommended for high-precision applications): Connect Hc, Hp, Lc, Lp terminals to the test fixture or DUT, suitable for low-impedance measurement (e.g. mΩ-level resistance).

·2-port measurement (common mode): Connect the DUT to the excitation port and detection port, use a shielded cable to reduce noise interference.

·Port description: The rear panel of E4990A is equipped with four-terminal pair (4TP) test ports, compatible with a variety of test accessories (adapters, test fixtures or cables) to achieve more accurate measurement with wide dynamic range.

2. Power-on and Initialization

·Press the power button on the front panel to turn on the instrument, wait for system startup (approx. 30 seconds).

·Recommendation: Before starting a new measurement session, press the Preset key to initialize the instrument to ensure it does not inherit parameter settings from the previous measurement.

3. Calibration and Compensation (Critical Step)

Calibration is a critical step to eliminate the impact of parasitic parameters from test fixtures, connecting cables and other components. The Keysight E4990A provides three calibration types: User Calibration, Port Extension Compensation, and Fixture Compensation.

Standard three-step calibration (Open/Short/Load):

     ·Open calibration: Disconnect all connections, separate the high and low electrodes with a spacing equal to the DUT width, and perform open compensation to eliminate the effect of stray admittance.

     ·Short calibration: Use a shorting block to bring the high and low electrodes into contact, and perform short compensation to eliminate the effect of residual impedance.

     ·Load calibration: Connect a standard resistor with a known impedance value (such as 50 Ω or 100 Ω) for load compensation, which is especially important for high-frequency measurements (above 3 MHz).

     ·Save: After completion, press Save to store the calibration data to the specified location (e.g. Cal Set 1).

Fixture compensation: When using a test fixture such as the Keysight 16047E, navigate to the Cal > Fixture Compensation menu and perform open, short, and load compensation in sequence (requires fixture matching accessories).

Calibration frequency point selection: Navigate to Cal > Compen Point to select:

·Fixed freq: Acquire calibration data at the instrument's predefined fixed frequency points (over 200 distributed points covering 20 Hz–120 MHz), and apply it to each measurement point via interpolation. This setting always assumes an OSC Level of 0.5 V, even if another level is configured. Re-acquisition of calibration data is not required after changing scan settings.

·User freq: Acquire calibration/compensation data at the frequency points used for actual measurement, which is suitable for tests with a specific OSC Level; if you change the scan settings (widen or narrow the frequency sweep span), the calibration data may become invalid.

Adapter selection and calibration requirements for each connection method:

4. Basic Measurement Procedure

Step 1 — Set test conditions:

·Press Freq to set the start and stop frequency (e.g. 1 kHz – 10 MHz). 

·Set the excitation voltage via Level (default is 1 Vrms, which can be reduced to 0.1 V for sensitive devices).

·Select measurement parameters via Meas (e.g. |Z|, C, L, D, Q).

Step 2 — Connect the device under test:

·For capacitance/inductance measurement: connect the component directly to the test port, and select series or parallel measurement mode as required.

·For material measurement: use fixtures such as 16451B or 16453A to fix the sample between the electrodes and ensure flat contact.

·For PCB trace testing: use probes to contact the trace under test and ensure good grounding.

Step 3 — Perform measurement and data analysis:

·Start measurement by pressing Single (single measurement) or Continuous (continuous sweep).

·View results: The main interface displays impedance magnitude, phase and equivalent circuit model values.

·Select a multi-parameter model via Equivalent Circuit, and the instrument will automatically fit the values of R, L, C, D, Q.

·In Sweep Setup, select logarithmic/linear sweep type and number of points (2 to 1601 points, maximum 1601 points).

·Data saving: Press Save/Recall to store data in CSV or image format, and export via USB flash drive is supported.

6. Optional Test Accessories/Fixtures

The Keysight E4990A is compatible with a wide range of test accessories, covering various measurement scenarios from DC to 120 MHz. Users can select the appropriate combination of accessories based on the type, size and measurement frequency of the device under test. Below is the complete accessory list compiled from the original manufacturer's official English technical documentation.

Classification by DUT Type

1. Axial/Radial Lead Components

2. SMD Surface-mounted Components

    Note: 16192A, 16194A, 16196A/B/C/D, 16197A, 16198A require the 42942A terminal adapter (which converts 4TP to 7 mm port) to work with E4990A (with option E4990A-120 installed).

3. Kelvin Test Leads (for other components)

4. Port/Cable Extension

5. Probes

·42941A Impedance Probe Kit: for in-circuit measurement with E4990A-120 (20 Hz–120 MHz). It is equipped with pin probes, clip leads and BNC adapters, supporting measurements of PCB trace impedance, input/output impedance, and more.

6. DC Bias Accessories

·16065A: 200 Vdc External Voltage Bias Fixture (for E4980A/AL, E4981A, E4990A) 

·16065C: 40 Vdc External Voltage Bias Adapter (Exclusive for E4981A, E4980AL)

·16200B: External DC Bias Adapter (7 mm port, max ±5 Adc / 40 V)

7. Dedicated Accessories for Material Measurement

8. Performance Verification Kit (Calibration and Verification)

Operating Guide for Dielectric Material Measurement (16451B)

Model 16451B dielectric test fixture uses the parallel plate method, which clamps a solid dielectric material between two electrodes to form a capacitor. The E4990A from Keysight measures the capacitance, and the relative permittivity is then calculated via a formula.

Measurement method options: