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

In electronic component design, materials science research, and semiconductor device characterization, the accuracy of impedance measurement directly determines the success or failure of product development. With its industry-leading accuracy of ±0.045% (typical), frequency coverage up to 120 MHz, and a comprehensive accessory ecosystem, the E4990A Impedance Analyzer from Keysight Technologies has become the trusted choice of engineers and researchers worldwide.

1. Product Overview: Deeper Insight Beyond LCR Measurement

The E4990A belongs to the Keysight ZA5-class impedance analyzer family, going beyond the measurement scope of general-purpose LCR bridges to provide deep insight for demanding applications such as equivalent circuit modeling, high-frequency characterization, and material verification. Whether you are engaged in component R&D, materials science experiments, or quality inspection work, the E4990A helps you precisely characterize and test electronic components, semiconductor devices, and various materials.

Five Major Application Scenarios:

·Passive component testing (basic parameters and high-frequency characteristics analysis of capacitors, inductors, and resistors)

·Permittivity and dissipation factor (loss tangent) measurement of dielectric materials

·Permeability analysis of magnetic materials

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

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

2. Core Parameters and Technical Specifications

The core technical specifications of the E4990A are all sourced from the official Keysight datasheet. Below is a complete summary of the parameters:

Frequency Characteristics

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

·Frequency resolution: 1 mHz

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

Measurement Accuracy

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

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

Signal Source Characteristics

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

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

·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 varying 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/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, Averaging; trigger sources include Internal (free run), External (BNC input), GPIB/USB/LAN, and 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 an ambient temperature of 23 °C ± 5 °C after the instrument has warmed up for 90 minutes; specification values include guard bands to cover the expected statistical performance distribution and environmental variation factors. Typical values (typ) reflect the expected performance of an average unit, do not include guard bands, and are not covered by the product warranty.

3. Frequency Options and Upgrade Path

The E4990A features a modular frequency option design. Users can select the appropriate configuration based on their current budget, and hardware frequency upgrades are possible in the future (e.g., from 10 MHz to 120 MHz), protecting the initial investment.

4. Software Options and Available Accessories

Software and Performance Options 

·Option 001 — Enhanced measurement speed: Only applicable to the 10M/20M/30M/50M frequency options, it boosts the measurement speed of low-frequency models to a level comparable to the 120 MHz flagship model, significantly reducing the total test cost of multi-point measurements

·Option 1E5 — High-stability frequency reference: Improves frequency accuracy and stability

·Equivalent circuit analysis function: Supports 7 multi-parameter models (such as series RLC, parallel RLC, etc.), automatically fitting the data and displaying equivalent parameter values such as R, L, C, D, and Q

·Limit line testing: Supports setting test upper and lower limits, facilitating quality inspection and production screening

·Firmware updates: Users can perform online upgrades themselves without returning to the factory; the latest version is B.06.01 (released October 2025), which already supports the Windows 11 operating system

·Software option activation: After purchasing a software option upgrade kit, you need to obtain a license key (12 characters) and enter it in the instrument's System > Service Menu > Enable Options menu to activate it; the license key file (.lic) is stored in the Factory(E:)LICENSE directory, so it must be backed up when replacing the storage device

Physical Accessories (Optional)

·Rack mount kit (E4990A-1CM): For installation in standard equipment cabinets

·Front handle kit (E4990A-1CN): Enhances convenience when moving and transporting the instrument

·Handle/Rack kit (E4990A-1CP)

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

5. Basic User Guide

1. Hardware Connections

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

·Four-terminal pair (4TP) measurement (recommended for high-accuracy applications): Connect the Hc, Hp, Lc, and Lp terminals to the test fixture or DUT; suitable for low-impedance measurements (such as mΩ-level resistors).

·2-terminal measurement (common mode): Connect the DUT to the stimulus and detection terminals, using shielded cables to reduce noise interference.

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

2. Powering On and Initialization

·Press the power button on the front panel to turn on the instrument and wait for the system to start (approximately 30 seconds).

·Recommendation: Before each new measurement session, press the Preset key to initialize the instrument, ensuring that parameter settings from the previous measurement are not carried over.

3. Calibration and Compensation (Critical Steps)

Calibration is a key step in eliminating the effects of parasitic parameters from test fixtures, connecting cables, etc. The E4990A offers three calibration types: User Calibration, Port Extension Compensation, and Fixture Compensation.

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

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

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

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

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

Fixture compensation: When using test fixtures such as the 16047E, go to the Cal > Fixture Compensation menu and perform open, short, and load compensation in sequence (dedicated fixture tools required).

Calibration frequency point selection: Press Cal > Compen Point to choose:

·Fixed freq: Calibration data is acquired at the instrument's predefined fixed frequency points (over 200 distributed points covering 20 Hz–120 MHz) and applied to each measurement point via interpolation. This setting always assumes the OSC Level is 0.5 V, even if a different level is set. Changing the sweep settings does not require re-acquisition of calibration data.

·User freq: Calibration/compensation data is acquired at the actual frequency points used for measurement, suitable for tests at a specific OSC Level; if the sweep settings are changed (widening or narrowing the 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 frequencies (e.g., 1 kHz – 10 MHz). 

·Press Level to set the stimulus voltage (default 1 Vrms; can be reduced to 0.1 V for sensitive devices).

·Press Meas to select the measurement parameters (e.g., |Z|, C, L, D, Q).

Step 2 — Connect the device under test:

·Capacitor/inductor measurement: Connect the component directly to the test port; series or parallel measurement mode can be selected.

·Material measurement: Use fixtures such as the 16451B or 16453A to clamp the sample between the electrodes, ensuring flat contact.

·PCB trace testing: Use probes to contact the trace under test, ensuring good grounding.

Step 3 — Perform measurement and data analysis:

·Press Single (single measurement) or Continuous (continuous sweep) to perform the measurement.

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

·Press Equivalent Circuit to select a multi-parameter model; the instrument will automatically fit the R, L, C, D, and Q values.

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

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

6. Test Accessories/Fixture Options

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

Classified by DUT Type

1. Leaded Components (Axial/Radial Lead Components)

2. SMD Components

    Note: The 16192A, 16194A, 16196A/B/C/D, 16197A, and 16198A require the 42942A terminal adapter (converting the 4TP port to a 7 mm port) in order to be used with the E4990A (with Option E4990A-120 installed).

3. Kelvin Clip Leads (Other Components)

4. Port/Cable Extensions