Analog Devices Inc. 124842-HMC794LP3E

Overview

HMC794LP3E from Analog Devices (formerly Hittite Microwave) is a SiGe BiCMOS programmable RF frequency divider IC operating from 200 MHz to 2 GHz input, supporting division ratios N = 1–4 with differential outputs, −163 dBc/Hz SSB phase noise at 10 MHz offset, and up to +10 dBm output power - ideal for low-noise LO generation in radar and test equipment.

For engineers reviewing the HMC794LP3E datasheet, HMC794LP3E pinout, HMC794LP3E application, or HMC794LP3E equivalent, key selection criteria include its 3×3 mm LCC package, programmable bias control for power optimization, sleep mode (<1 µA), and differential 50% duty cycle outputs requiring external 100 Ω pull-ups.

Technical Context

The HMC794LP3E implements a high-gain SiGe BiCMOS divider core with configurable digital control (B0/B1) for N = 1–4, plus independent CTRL and BIAS0 pins to optimize output power and phase noise performance across temperature and supply voltage. Its internal feedback architecture requires RF input presence or EN disable to prevent oscillation in divide-by-2/3/4 modes.

It features DC-coupled differential RF inputs (RFINP/RFINN) mandating external DC blocking capacitors, open-drain differential outputs (IOUTP/IOUTN) requiring external 100 Ω pull-up resistors to Vcc, and a precision CBIAS reference pin measured only with ≥10 GΩ impedance meters.

Key Specifications

Pinout & Package

16-lead 3×3 mm leadless ceramic chip carrier (LCC) package with exposed ground paddle; RoHS-compliant, MSL1, matte Sn finish; requires soldering all ground leads and paddle to PCB RF ground per Hittite land pattern guidelines.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar programmable RF divider applications.

Compared with HMC794LP3E, HMC363LP3E offers wider bandwidth but lacks programmability, while LMX2594 provides full synthesis capability at the cost of increased complexity, power, and phase noise floor - making HMC794LP3E optimal for dedicated, low-noise, low-power division tasks.

Availability

HMC794LP3E is available at Aetrix Electronics and suitable for radar LO generation, test equipment clock synthesis, military communications transceivers, and sensor signal conditioning requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for HMC794LP3E 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

Analog Devices acquired Hittite Microwave in 2014 and maintains its high-performance RF portfolio, specializing in microwave, millimeter-wave, and high-speed signal processing components.

The HMC794LP3E belongs to Hittite's legacy Frequency Dividers & Detectors product line, designed specifically for low-noise, high-frequency RF signal conditioning in defense, aerospace, and instrumentation systems.

FAQ

What is the maximum input frequency supported by the HMC794LP3E?

The HMC794LP3E supports an RF input frequency range from 200 MHz to 2 GHz. Operation above 2 GHz is not specified and may result in degraded phase noise, reduced output power, or instability. The device is optimized for reliable performance within this band under recommended bias and termination conditions.

Does the HMC794LP3E require external DC blocking on its RF inputs?

Yes, the HMC794LP3E has DC-coupled RF inputs (RFINP and RFINN), so external DC blocking capacitors are mandatory to prevent damage or bias disruption from input signal DC offsets. Typical values used on evaluation boards are 1 nF in 0402 package.

How does the BIAS0 pin affect HMC794LP3E performance?

The BIAS0 pin configures the digital core bias level: 0 V minimizes current consumption (up to 20% reduction), while 5 V maximizes phase noise performance (e.g., −160 dBc/Hz @ 100 kHz). It does not alter division ratio or output frequency - only noise and power trade-offs.

Can the HMC794LP3E operate without an RF input signal?

No - the HMC794LP3E will oscillate in divide-by-2, -3, or -4 modes if no RF input is applied. It remains stable only in divide-by-1 mode without input. To avoid spurious emissions, either apply minimum input power (>−2 dBm) or assert EN = low to enter sleep mode (<1 µA).

What is the purpose of the CBIAS pin on the HMC794LP3E?

The CBIAS pin provides a precision internal bias reference voltage (~3.8 V) for low-noise operation. It must be measured only with a ≥10 GΩ voltmeter (e.g., Agilent 34410A); connecting any load or standard DMM will cause erroneous readings and potential performance degradation.