VPG unveil PRND HT series of Hermetically Sealed Precision Resistor Network Devices

Custom configured to requested circuit schematics and specifications, VFR's PRND HTs are hermetically sealed networks consisting of multiple Bulk Metal Z1-Foil chip resistors connected by gold-wire bonding inside ceramic packages. The combination of the PRND HT's ceramic package, which has the advantage of electrical isolation on the underside and high heat dissipation capability, with hermetic sealing and the location of the chips within the package, helps to preserve uniform conditions inside the device for maximum environmental protection. The result is improved load-life stability and better performance for high-temperature and high-moisture environments.

The PRND HT series is based on VFR's next-generation Z1-Foil technology, which provides an order of magnitude reduction in the Bulk Metal Foil element's sensitivity to temperature changes — both external and internal — with emphasis on long-term stability in high-temperature environments. The devices' solid element alloy is matched to the substrate, forming a single entity with balanced temperature characteristics for an unusually low and predictable TCR of ±2.5 ppm/°C typical from -55°C to +200°C.

Offered in dual-in-line, flatpack, gull wing, and leadless chip carrier package configurations, the PRND HTs feature a wide resistance range from 5 Ohm, with tolerance matching to ±0.005%. Any resistance value within this range is available at any tolerance with no additional cost or lead time effect. The devices provide a power rating to 1.4 W per package (150 mW per resistor) at +70°C.

The resistor networks feature a rise time of 1.0 ns with effectively no ringing, a thermal stabilization time of <1 s (nominal value achieved within 10 ppm of steady state value), current noise of 0.010 µVrms per volt of applied voltage (<-40 dB), and a voltage coefficient of <0.1 ppm/V. Offered with lead-free gold-plated terminations, the devices provide a non-inductive (<0.08 μH), non-capacitive design.

The precision-matched PRND HT resistors are optimized for a wide variety of high-reliability applications requiring resistors to have a minimal drift from their initial values when operating above +175°C and in humid environments. These include high-performance signal conditioning applications in different amplifiers, precision dividers, and reference and bridge circuits.

The Z1-Foil technology allows VFR to produce customer-oriented products designed to satisfy unique and specific technical requirements. In addition to the special chip stabilization under extreme environment conditions in the production line, additional specially oriented post manufacturing operations are offered for high-temperature applications that require an even higher degree of reliability and stability.

The hermetic networks are based on fabrication from a standing inventory of packages and resistor chips. This permits quick delivery of prototypes because there are no masks to design or trial processing to be made. Further, it allows a large combination of values, tolerances, and circuits. There are normally no engineering or setup charges, and no minimum quantities are required.
Samples and production quantities of the PRND HT resistors are available now, with lead times of eight weeks for standard orders.