Diodes Incorporated ZNBG4001Q16TC

Overview

ZNBG4001Q16TC from Zetex plc is a quad-channel GaAs/HEMT FET bias controller in QSOP16 package, generating regulated -3 V negative rail and 2.0 V drain voltage per stage from a single 5–12 V supply. It sets individual drain currents (0–15 mA per FET) via two external resistors (RCAL1/RCAL2), provides dynamic gate protection (-3.5 V to +0.7 V output range), and ensures unconditional RF stability with recommended 4.7 nF gate and 10 nF drain capacitors. Used in satellite LNB front-ends for low-noise amplifier biasing.

For engineers reviewing the ZNBG4001Q16TC datasheet, ZNBG4001Q16TC pinout, ZNBG4001Q16TC application, or ZNBG4001Q16TC equivalent, key selection criteria include drain voltage tolerance (±0.2 V), temperature coefficient of drain voltage (50 ppm/°C), gate output current capability (-30 µA to +2000 µA), negative rail regulation under load (up to -200 µA), and FET-stage independence for noise/gain optimization.

Technical Context

The ZNBG4001 integrates four independent bias stages sharing a common on-chip oscillator-based negative rail generator (200–800 kHz). Each stage regulates drain voltage to 2.0 V (typ.) and controls FET drain current via feedback from an external sense resistor network tied to RCAL1/RCAL2 pins.

Gate drive outputs are clamped to -3.5 V to +0.7 V across all operating conditions including power-up/down transients; drain supply shuts down automatically if the -3 V rail fails due to overload or short circuit - protecting connected GaAs FETs without external supervision.

Key Specifications

Pinout & Package

Package: QSOP16 (4.85 mm × 3.90 mm × 1.40 mm body, 0.635 mm pitch). Pin 1 marked by recessed corner.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ZNBG4000Q16TC, the ZNBG4001Q16TC's lower 2.0 V drain voltage better optimizes noise in first-stage LNB amplifiers, while MAX2640 trades flexibility and rail integration for monolithic simplicity in low-channel-count systems.

Availability

ZNBG4001Q16TC is available at Aetrix Electronics and suitable for satellite receiver LNBs, private mobile radio (PMR) transceivers, and cellular base station receivers requiring stable component supply, temperature-resilient bias control, and long-lifecycle availability.

Supply support for ZNBG4001Q16TC 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

Zetex plc (now part of Diodes Incorporated) is a UK-based analog semiconductor company specializing in high-performance discrete and analog ICs for RF, power management, and precision bias applications.

The ZNBG series was designed specifically for GaAs/HEMT FET biasing in satellite and wireless infrastructure, emphasizing RF stability, fault resilience, and minimal external component count.

FAQ

What external components are mandatory for ZNBG4001Q16TC operation?

Four mandatory components: two 47 nF capacitors (CNB and CSUB) for the internal negative rail generator; two gate bypass capacitors (4.7 nF each, CG) from G1–G4 to GND; and two drain bypass capacitors (10 nF each, CD) from D1–D4 to GND. RCAL1 and RCAL2 resistors are required to set drain current but may be omitted only if zero bias is acceptable.

Can unused bias channels be left unconnected without affecting others?

Yes. Unused drain (Dx) and gate (Gx) pins may be left open-circuit with no impact on remaining active channels. However, RCAL1 and RCAL2 must still be connected to ground (via resistors or short) even if only one pair of FETs is used - otherwise bias regulation fails across all stages.

How does the ZNBG4001Q16TC protect external FETs during power-up?

It enforces strict gate voltage limits (-3.5 V to +0.7 V) at every stage during all transients, including power-on ramp and brownout. If the internal -3 V rail fails (e.g., CSUB short), the device disables all D1–D4 outputs within microseconds, preventing uncontrolled FET conduction and thermal damage.

Is the -3 V rail on CSUB usable for other circuitry?

Yes - the CSUB pin delivers up to -200 µA of regulated -3 V current and is explicitly intended to power auxiliary circuits such as LNA enable logic or level-shifting interfaces. Operation beyond -200 µA is not guaranteed and may degrade regulation or trigger shutdown.