Diodes Incorporated ZNBG4003JA16TC

Overview

ZNBG4003JA16TC from Diodes Incorporated is a 4-stage depletion-mode FET bias controller for satellite LNBs, providing regulated −2.5 V gate drive and 2.0 V drain supply per stage, user-selectable drain current (0–15 mA), and integrated switched-capacitor negative supply generation - deployed in twin/quad LNB systems requiring stable multi-stage GaAs/HEMT FET biasing.

For engineers reviewing the ZNBG4003JA16TC datasheet, ZNBG4003JA16TC pinout, ZNBG4003JA16TC application, or ZNBG4003JA16TC equivalent, key selection criteria include stage-paired RCAL-based current programming, temperature-stable 2.0 V drain regulation (±0.2 V), −2.5 V internal negative rail availability at CSUB, and QFN1633 package compatibility with RF-sensitive LNB PCB layouts.

Technical Context

The ZNBG4003JA16TC implements two independent RCAL-controlled current loops (RCAL1 for stages 1 & 3; RCAL2 for stages 2 & 4), enabling optimized noise performance on input stages and gain optimization on amplifier stages. Each stage features individual current limiting and gate voltage clamping to −3 V maximum during power-up/down transients.

Its integrated switched-capacitor DC-DC converter generates a regulated −2.5 V substrate voltage (VCSUB) using external CNB and CSUB capacitors (47 nF each), with the CSUB pin delivering this rail for external use. Drain voltage stability is maintained at 2.0 V ±0.2 V over −40°C to +85°C and 4.75–8.0 V supply range.

Key Specifications

Pinout & Package

Package: 16-pin QFN (3 mm × 3 mm, 0.5 mm pitch), exposed thermal pad (to be left floating or connected to CSUB).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar FET bias controller applications.

Compared with ZNBG4002JA16TC, the ZNBG4003JA16TC adds two more bias stages with independent RCAL pairing - essential for quad LNBs. Versus MAX2641, it integrates the −2.5 V rail and supports four coordinated channels, eliminating external DC-DC components and simplifying thermal management in dense LNB modules.

Availability

ZNBG4003JA16TC is available at Aetrix Electronics and suitable for satellite LNB manufacturing, microwave link development, and PMR radio infrastructure projects requiring stable component supply, long-term lifecycle support, and RoHS-compliant QFN packaging.

Supply support for ZNBG4003JA16TC 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

Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, specializing in high-reliability power management, signal integrity, and precision timing solutions for industrial, automotive, and communications markets.

The ZNBG product line targets satellite receiver LNBs, delivering integrated multi-stage FET bias control with minimal external components - designed specifically to replace discrete resistor-diode-zener networks in GaAs/HEMT front-end amplifiers.

FAQ

What is the function of the CSUB pin on the ZNBG4003JA16TC?

The CSUB pin delivers the internally generated −2.5 V regulated negative supply, usable both for internal gate driver operation and external circuitry such as mixer bias or local oscillator stages. It requires a 47 nF reservoir capacitor (CSUB) connected to ground, and the exposed QFN pad may be tied to this node for improved thermal and electrical performance.

Can unused bias stages be disabled without affecting others?

Yes - unused gate (Gx) and drain (Dx) pins can be left open-circuit with no impact on remaining active stages. If an entire RCAL pair (e.g., stages 1 & 3) is unused, the corresponding RCAL resistor may be omitted. The device maintains full regulation and protection functionality for all powered stages.

How does the ZNBG4003JA16TC protect FETs during power-up?

It enforces hardware-limited gate voltage (≤ −3 V) and per-stage drain current limiting during all supply transients. The internal negative supply ramps under controlled slew rate, and drain supplies remain inactive until regulation is established - preventing gate oxide stress or thermal runaway in depletion-mode GaAs/HEMT devices.

What external capacitors are mandatory for operation?

Four mandatory capacitors: two 10 nF ceramic caps (one each from Gx and Dx to ground per active stage) for RF stability, plus one 47 nF charge-transfer cap (C NB) and one 47 nF reservoir cap (C SUB) for the internal −2.5 V generator. All must be placed per the layout guidelines in DS35007 to ensure noise performance and regulation stability.