Microchip Technology U2793B-MFSG3

Overview

U2793B-MFSG3 from Atmel is a 300-MHz single-ended quadrature modulator IC designed for RF up-conversion in digital radio systems. It delivers 90° phase-shift accuracy (<1° error), 45 dB typical LO suppression, and -143 dBm/Hz noise floor at 5 V supply, with low-power 15 mA operation and -15 dBm LO input sensitivity. Used in GSM, PCN, JDC, and WLAN transmitters as the final I/Q modulation stage before power amplification.

For engineers reviewing the U2793B-MFSG3 datasheet, U2793B-MFSG3 pinout, U2793B-MFSG3 application, or U2793B-MFSG3 equivalent, key selection criteria include its SSO20 package, 30–300 MHz LO range, differential baseband inputs (0–50 MHz), RF output level adjustability via LP1/LP2 pins, and duty-cycle-regenerated LO path enabling excellent sideband suppression without external tuning.

Technical Context

The U2793B-MFSG3 integrates a frequency doubler, duty-cycle regenerator, and precision 90° control loop to generate orthogonal LO signals internally-eliminating external phase-shifting networks. Its architecture supports direct AC- or DC-coupled baseband inputs (1.0 Vpp differential typical) and features dual low-pass/power-control terminals (LP1/LP2) for spurious optimization and output-level tailoring.

It operates with single-ended 50-Ω LO and RF ports, accepts -15 dBm LO drive across 30–300 MHz, and maintains <±0.25 dB amplitude error and <1° phase error over temperature (-40°C to +85°C). Power-down mode reduces supply current to 1 µA via PU pin, while VREF pin provides a stable 2.5 V reference for biasing.

Key Specifications

Pinout & Package

U2793B-MFSG3 is housed in a 20-pin SSO20 (Shrink Small Outline) package with exposed thermal pad, optimized for RF signal integrity and thermal management in compact transmitter modules.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar quadrature modulator applications.

Compared with ADL5375-05 and TRF3705, the U2793B-MFSG3 delivers best-in-class LO and sideband suppression with ultra-low 15 mA supply current and built-in VREF-making it uniquely suited for cost- and power-sensitive 30–300 MHz digital radio transmitters where external calibration is prohibited.

Availability

U2793B-MFSG3 is available at Aetrix Electronics and suitable for GSM handset design, WLAN up-converter development, and portable digital radio production requiring stable component supply and long-term lifecycle support.

Supply support for U2793B-MFSG3 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

Atmel Corporation (now part of Microchip Technology) is a semiconductor innovator known for RF, microcontroller, and wireless SoC solutions targeting communications, automotive, and industrial markets.

The U2793B-MFSG3 belongs to Atmel's UHF quadrature modulator product line, engineered specifically for low-power, high-fidelity digital radio transmitters in cellular, PCN, and WLAN applications where adjustment-free operation and spectral purity are mandatory.

FAQ

What is the recommended LO input configuration for U2793B-MFSG3?

The U2793B-MFSG3 requires a single-ended LO signal applied to Pin 14 (LOI), while Pin 15 (LOI) is typically grounded. The LO input presents a 50 Ω + 15 pF impedance, and the device operates optimally with -15 dBm drive across 30–300 MHz. External matching is unnecessary due to integrated impedance design, and the duty-cycle regenerator ensures consistent 90° phase splitting regardless of LO waveform distortion.

How does the U2793B-MFSG3 achieve adjustment-free operation?

The U2793B-MFSG3 achieves adjustment-free operation through an on-chip 90° control loop and duty-cycle regenerator that actively correct LO signal asymmetry and maintain precise quadrature phase alignment. This eliminates the need for external phase shifters, trimmer capacitors, or factory calibration-reducing BOM count, test time, and field drift in production GSM and WLAN radios.

Can U2793B-MFSG3 be used with DC-coupled baseband inputs?

Yes, U2793B-MFSG3 supports both AC- and DC-coupled baseband inputs. For DC coupling, the application circuit uses resistive bias networks (e.g., R1 = 2.5 kΩ, R2 ≤ 10 kΩ) to set common-mode voltage at 2.5 V via the internal VREF pin. This configuration maintains ≥35 dB LO suppression and avoids input offset-induced distortion in continuous transmission modes.

What is the function of Pins LP1 and LP2 on U2793B-MFSG3?

Pins LP1 and LP2 on U2793B-MFSG3 provide external low-pass filtering and output power control. Adding a chip capacitor between them improves spurious performance-especially below 100 MHz-while adding a parallel resistor adjusts RF output level to match the next-stage mixer without compromising LO suppression or noise floor. This tunability is unique to the U2793B-MFSG3 among fixed-gain modulators.

Is U2793B-MFSG3 RoHS-compliant and lead-free?

Yes, U2793B-MFSG3 is supplied in a lead-free SSO20 package (per ordering code MFSG3H suffix) and complies with RoHS Directive 2011/65/EU. The "G3" in the part number explicitly denotes lead-free, halogen-free, and green-material compliance-verified by Atmel's material declarations and certified by third-party lab testing.