Analog Devices Inc./Maxim Integrated DS1090U-2/V+

Overview

The DS1090U-2/V+ from Maxim Integrated is a resistor-programmed, center-dithered spread-spectrum oscillator designed as an external clock source for switched-mode power supplies. It delivers 2MHz–4MHz output frequency with factory-set prescaler ÷2, 0–8% programmable dither amplitude via J0/J1 pins, and dither rate selectable as f_MOSC/512, /1024, /2048, or /4096 via JC0/JC1 pins. Its primary role is EMI reduction in DC-DC converter timing circuits.

For engineers reviewing the DS1090U-2/V+ datasheet, DS1090U-2/V+ pinout, DS1090U-2/V+ application, or DS1090U-2/V+ equivalent, key selection criteria include verified dither amplitude control range (0–8%), confirmed prescaler value (÷2), RSET resistor tolerance impact on frequency stability (±3% total), CMOS/TTL-compatible output drive capability (±4mA), and operation across industrial temperature range (–40°C to +85°C).

Technical Context

The DS1090U-2/V+ integrates a voltage-controlled master oscillator (4–8MHz) biased by external RSET (45kΩ–91kΩ), a fixed ÷2 factory-programmed prescaler, and a dual-stage dither generator. The triangle-wave modulator uses JC0/JC1 to select one of four dither rates (f_MOSC/512 to /4096), while J0/J1 set discrete dither amplitudes (0%, 2%, 4%, or 8%) by adjusting bias current into the VCO.

Its architecture enables deterministic center-frequency spreading without PLL or crystal reference. Output duty cycle remains stable (45–55% at 4–8MHz, 50% below 4MHz), and supply current scales linearly with VCC (1.4mA typ @ 3.3V, 1.7mA typ @ 5.5V) and RSET value - critical for low-power SMPS clocking where load capacitance is limited to 30pF.

Key Specifications

Pinout & Package

DS1090U-2/V+ is housed in an 8-pin µSOP package (2.0mm × 2.5mm, 0.5mm pitch), thermally enhanced with exposed pad connected to GND per Maxim package drawing 21-0132.

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 ICS8430AM-01LFT, the DS1090U-2/V+ uniquely balances low-cost, resistor-based frequency setting, discrete dither amplitude/rate control, and industrial-grade reliability - making it optimal for cost-sensitive, EMI-constrained SMPS designs requiring field-tunable spread-spectrum behavior.

Availability

DS1090U-2/V+ is available at Aetrix Electronics and suitable for switched-mode power supplies, server power modules, and industrial control systems requiring stable component supply with guaranteed long-term availability.

Supply support for DS1090U-2/V+ 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 markets.

The DS1090U-2/V+ belongs to Maxim's EconOscillator™ family - engineered specifically for EMI reduction in DC-DC converter clocking, emphasizing low cost, minimal external components, and deterministic spread-spectrum control without microcontroller dependency.

FAQ

What is the exact output frequency range of the DS1090U-2/V+?

The DS1090U-2/V+ provides a guaranteed output frequency range of 2MHz to 4MHz. This is achieved by combining its factory-programmed ÷2 prescaler with a master oscillator tuned between 4MHz and 8MHz via the external RSET resistor (45kΩ–91kΩ). Frequency tolerance is ±3.0% over temperature and supply voltage, as specified in the DC Electrical Characteristics table.

How do I configure dither amplitude and rate on the DS1090U-2/V+?

Dither amplitude (0%, 2%, 4%, or 8%) is set using logic levels on J0 and J1 pins per Table 2 in the datasheet; dither rate (f_MOSC/512, /1024, /2048, or /4096) is configured via JC0 and JC1 per Table 1. All four control pins must be hard-wired to VCC or GND - floating inputs are undefined and may cause erratic dither behavior in the DS1090U-2/V+.

What is the recommended RSET resistor tolerance for the DS1090U-2/V+?

Maxim recommends using a minimum 1% tolerance, 1/16W resistor for RSET in the DS1090U-2/V+. This ensures frequency accuracy remains within the ±3.0% total tolerance specification, accounting for initial resistor error, temperature coefficient, and device variation. Tighter tolerance improves repeatability across production batches.

Does the DS1090U-2/V+ require external decoupling capacitors?

Yes - the DS1090U-2/V+ requires local decoupling on the VCC pin. Maxim specifies using both a 0.01µF and 0.1µF high-quality ceramic capacitor placed as close as possible to pins 3 (VCC) and 4 (GND). This suppresses supply noise coupling into the oscillator core, preventing jitter increase and maintaining dither fidelity in the DS1090U-2/V+.

What is the power-up behavior of the DS1090U-2/V+?

The DS1090U-2/V+ exhibits a total power-up stabilization time (t_POR + t_STAB) of 0.1ms to 0.5ms. During this period, the internal master oscillator stabilizes (~500 cycles at programmed frequency) before the OUT pin begins toggling. This delay is intentional and ensures reliable start-up without false triggering in downstream PWM controllers driven by the DS1090U-2/V+.