Analog Devices Inc. 105786-HMC438MS8G

Overview

HMC438MS8G from Analog Devices is a GaAs HBT MMIC divide-by-5 static frequency divider operating from DC (square-wave input) to 7 GHz with -1 dBm output power, -153 dBc/Hz SSB phase noise at 100 kHz offset, and +5 V / 80 mA supply. It serves as a prescaler in C-band PLL systems for UNII radios, 802.11a WLAN, fiber optic links, and cellular infrastructure.

For engineers reviewing the HMC438MS8G datasheet, HMC438MS8G pinout, HMC438MS8G application, or HMC438MS8G equivalent, key selection criteria include its DC–7 GHz input bandwidth, differential RF I/O capability, low additive phase noise, 8-lead Mini-SO-EP package, and compatibility with high-frequency PLL feedback paths requiring stable division ratio and minimal jitter contribution.

Technical Context

The HMC438MS8G implements a static CMOS-compatible divide-by-5 logic core using InGaP GaAs HBT technology, enabling operation down to DC with square-wave inputs and supporting sine-wave inputs from 100 MHz to 7 GHz. Its dual differential outputs (pins 6 and 7) provide complementary 882 MHz signals when driven at 4.41 GHz, with 100 ps transition time and < −50 dBm reverse leakage under terminated conditions.

It requires external DC blocking capacitors on all RF ports and operates within −40 °C to +85 °C ambient, with thermal resistance of 88.5 °C/W (junction-to-ground paddle). The device is ESD-sensitive (HBM Class 1A) and rated for 1 million hour MTTF at 122 °C junction temperature.

Key Specifications

Pinout & Package

Package: 8-Lead Mini Small Outline Package with Exposed Pad (RH-8-1), JEDEC MO-187-AA-T compliant, 3.0 × 3.0 × 0.94 mm body size, exposed thermal paddle on underside.

Key Features

Applications

Equivalent & Alternatives

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

Compared with HMC438MS8G, HMC363S8G offers wider input bandwidth but no DC operation, while HMC492LP5E extends frequency coverage to 13 GHz at the cost of increased package complexity and thermal management requirements-making HMC438MS8G optimal for C-band infrastructure where DC-coupled flexibility and compact thermal design are critical.

Availability

HMC438MS8G is available at Aetrix Electronics and suitable for UNII radios, 802.11a WLAN equipment, and fiber optic transceivers requiring stable component supply, consistent parametric performance across production lots, and long-term lifecycle availability for industrial deployments.

Supply support for HMC438MS8G 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, Inc. is a global leader in high-performance analog, mixed-signal, and RF ICs, serving precision instrumentation, communications, and industrial markets since 1965.

The HMC438MS8G belongs to Analog Devices' Hittite Microwave MMIC product line, engineered specifically for high-frequency wireless infrastructure applications demanding low phase noise, wide bandwidth, and robust RF performance in compact surface-mount packages.

FAQ

What is the minimum input frequency supported by the HMC438MS8G?

The HMC438MS8G supports DC input for square-wave signals, meaning it can operate with zero-Hz fundamental frequency when driven by a clean digital waveform. For sine-wave inputs, the minimum specified frequency is 100 MHz per the datasheet's "Minimum Input Frequency" parameter. This dual-mode capability makes the HMC438MS8G uniquely suited for hybrid digital/analog PLL architectures where clock sources may originate from either logic gates or RF oscillators.

Does the HMC438MS8G require external DC blocking capacitors?

Yes, the HMC438MS8G requires external DC blocking capacitors on both RF input (pins 2 and 3) and RF output (pins 6 and 7) ports. The datasheet explicitly states this in the "Application Circuit" and "Evaluation PCB" sections, specifying 100 pF 0402 capacitors for RF paths. Omitting these capacitors risks bias disruption, degraded matching, and potential damage due to unintended DC paths through the GaAs HBT core.

What is the thermal resistance and maximum junction temperature rating for the HMC438MS8G?

The HMC438MS8G has a thermal resistance of 88.5 °C/W (junction-to-ground paddle) and is rated for 1 million hour MTTF at 122 °C junction temperature. Its absolute maximum junction temperature is 135 °C. These values assume proper soldering of all ground leads and the exposed paddle to a thermally optimized PCB layout with adequate via density-critical for sustained operation in base station or outdoor radio applications where ambient temperatures exceed 70 °C.

Can the HMC438MS8G be used in differential mode?

Yes, the HMC438MS8G supports true differential operation: pin 3 is the 180° out-of-phase complement to pin 2 (IN), and pins 6 and 7 provide complementary divided outputs. The datasheet's "Pin Description" and "Interface Schematic" confirm this configuration. When used differentially, common-mode noise rejection improves, and output skew is minimized-key advantages in high-speed PLL feedback paths where timing integrity directly impacts loop stability and spurious performance.

Is the HMC438MS8G RoHS-compliant?

The HMC438MS8G is not RoHS-compliant; it uses Sn/Pb solder finish and low-stress injection-molded plastic packaging. Its RoHS-compliant variant is the HMC438MS8GE, which substitutes 100% matte tin lead finish and RoHS-compliant body material. Both share identical electrical specifications and pinout, but reflow profiles differ: HMC438MS8G max peak temperature is 235 °C, while HMC438MS8GE supports 260 °C. System designers must select based on assembly process requirements and regulatory compliance targets.