Analog Devices Inc./Maxim Integrated DS1090U-4+T

Overview

DS1090U-4+T from Maxim Integrated is a low-cost, center-dithered spread-spectrum oscillator designed as an external clock source for switched-mode power supplies. It delivers 1MHz–2MHz output frequency (factory prescaler = 4), supports 0–8% programmable dither amplitude via J0/J1 pins, and operates from 3.0V to 5.5V over –40°C to +85°C - reducing peak radiated EMI in DC-DC converter timing circuits.

For engineers reviewing the DS1090U-4+T datasheet, DS1090U-4+T pinout, DS1090U-4+T application, or DS1090U-4+T equivalent, key selection criteria include its resistor-programmed master oscillator (fMOSC = 4–8MHz), factory-set ×4 prescaler, dither rate options (fMOSC/512 to fMOSC/4096), CMOS/TTL-compatible output, and 8-pin µSOP package with validated thermal and supply-current performance across voltage and temperature.

Technical Context

The DS1090U-4+T integrates a voltage-controlled master oscillator biased by external RSET (45kΩ–91kΩ), a fixed ×4 factory-programmed prescaler, and a dual-stage dither generator. Its triangle-wave modulator uses JC0/JC1 to select one of four dither rates (fMOD = fMOSC/512, /1024, /2048, or /4096), while J0/J1 set dither amplitude at 0%, 2%, 4%, or 8% of output period.

It implements center-frequency dithering - not down-spreading - where modulation symmetrically shifts output frequency around the programmed center value. The internal bias circuit derives dither amplitude from master oscillator current, enabling stable percentage-based modulation without external DACs or PLLs.

Key Specifications

Pinout & Package

DS1090U-4+T is housed in an 8-pin µSOP package (2.0mm × 2.5mm, 0.5mm pitch), thermally optimized for surface-mount power-conversion PCBs with GND-connected substrate.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar spread-spectrum oscillator applications.

Compared with Si5351A-B-GM and ICS8430I-01T, the DS1090U-4+T uniquely combines resistor-based frequency setting, pin-strapped dither amplitude and rate, and µSOP footprint - delivering full spread-spectrum flexibility without MCU dependency or crystal load.

Availability

DS1090U-4+T is available at Aetrix Electronics and suitable for switched-mode power supplies, servers, printers, and industrial controls requiring stable component supply, RoHS-compliant packaging, and guaranteed long-term availability for production programs.

Supply support for DS1090U-4+T 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

Maxim Integrated, now part of Analog Devices, designs precision analog, mixed-signal, and power-management ICs for industrial, computing, and communications systems.

The DS1090U-4+T belongs to the EconOscillator™ family - engineered specifically to replace crystals and fixed oscillators in EMI-sensitive power-conversion applications with minimal bill-of-materials impact.

FAQ

What is the exact output frequency range of the DS1090U-4+T?

The DS1090U-4+T provides a factory-set output frequency range of 1MHz to 2MHz. This results from its internal ×4 prescaler applied to the 4MHz–8MHz master oscillator, which is tuned by the external RSET resistor (45kΩ–91kΩ). Measured output tolerance is ±3% at +25°C, with ±2% variation over temperature and ±1.25% over supply voltage (4.5V–5.5V).

How do I configure dither amplitude and rate on the DS1090U-4+T?

Dither amplitude (0%, 2%, 4%, or 8%) is set using logic levels on J0 and J1 pins per Table 2; dither rate (fMOSC/512, /1024, /2048, or /4096) is selected via JC0 and JC1 per Table 1. All four control pins are referenced to VCC/GND - no external resistors or pull-ups are needed. The DS1090U-4+T applies these settings directly to its internal triangle generator and bias circuit.

Does the DS1090U-4+T require an external crystal or resonator?

No, the DS1090U-4+T does not require any external crystal or resonator. It uses an internal resistor-programmed voltage-controlled oscillator (VCO) biased by the RSET pin. Only a single external resistor (45kΩ–91kΩ) tied from RSET to GND is needed to set the master oscillator frequency - eliminating crystal cost, board space, and start-up timing uncertainty inherent in crystal-based solutions.

What is the power-supply decoupling requirement for the DS1090U-4+T?

The DS1090U-4+T requires local decoupling on the VCC pin: a 0.01µF ceramic capacitor in parallel with a 0.1µF ceramic capacitor, placed as close as possible to pins 3 (VCC) and 4 (GND). These capacitors minimize supply noise coupling into the oscillator core and ensure stable dither modulation - per Maxim's layout recommendations in the DS1090U-4+T datasheet.

Is the DS1090U-4+T pin-compatible with other DS1090 variants like DS1090U-2+T or DS1090U-8+T?

Yes, all DS1090U-x+T variants share identical 8-pin µSOP packaging and pinout - including DS1090U-4+T, DS1090U-2+T, and DS1090U-8+T. The only difference is the factory-programmed prescaler value (×4 for DS1090U-4+T), which changes the output frequency range. RSET resistor selection and control pin (J0/J1/JC0/JC1) functionality remain fully compatible across the family.