Analog Devices Inc. 118040-HMC311SC70

Overview

HMC311SC70 from Analog Devices is a GaAs InGaP HBT MMIC gain block amplifier operating from DC to 8 GHz, delivering 15 dB small-signal gain, +15 dBm P1dB output power, and +30 dBm output IP3 at 5 V/54 mA. It functions as a cascadable 50 Ω RF gain stage or LO driver for mixers in microwave signal chains.

For engineers reviewing the HMC311SC70 datasheet, HMC311SC70 pinout, HMC311SC70 application, or HMC311SC70 equivalent, key selection criteria include its SC70 package footprint, broadband DC–8 GHz performance, single-supply biasing, thermal stability over –40°C to +85°C, and compatibility with standard RF PCB layout practices.

Technical Context

The HMC311SC70 employs a Darlington-configured InGaP HBT topology, enabling high gain stability across temperature (≤0.022 dB/°C) and reduced process sensitivity. Its 50 Ω matched input/output ports support direct cascading without external matching networks up to 8 GHz.

DC-coupled RFIN and RFOUT pins require external blocking capacitors; RFOUT also serves as the DC bias feed point. Bias is set via a single external resistor (Rbias = 22 Ω typical), drawing 54 mA from a +5 V supply with no need for active regulation or temperature compensation circuitry.

Key Specifications

Pinout & Package

Package: SC70 (6-lead, low-stress injection-molded plastic, Sn/Pb lead finish, MSL1, marking "311"). Dimensions per Analog Devices outline drawing: 2.00 × 1.25 × 0.95 mm (L × W × H).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar RF gain block applications.

Compared with HMC311SC70, HMC441LP3E extends usable bandwidth and output power at the expense of size and current draw, while QPL9057 trades bandwidth and LO drive strength for integration and compliance-making HMC311SC70 optimal for compact, wideband, LO-buffer-critical designs.

Availability

HMC311SC70 is available at Aetrix Electronics and suitable for cellular base stations, WiMAX CPE transmitters, CATV optical nodes, and microwave test equipment requiring stable component supply, consistent RF performance, and long-term obsolescence management.

Supply support for HMC311SC70 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 communications, industrial, automotive, and aerospace markets since 1965.

The HMC311SC70 belongs to Analog Devices' Hittite Microwave RF MMIC product line, engineered specifically for broadband gain blocks, driver amplifiers, and LO buffer applications in wireless infrastructure and instrumentation.

FAQ

What is the recommended external bias resistor value for HMC311SC70?

The datasheet specifies Rbias = 22 Ω as the typical value to achieve 54 mA quiescent current at +5 V supply. This value satisfies Icq = (Vs − 3.8 V)/Rbias. Using 22 Ω ensures stable operation within absolute maximum ratings and matches the characterization conditions for all published specs including gain, P1dB, and IP3. Deviations require recalculating Icq and verifying thermal limits.

Does HMC311SC70 require external DC blocking capacitors?

Yes, HMC311SC70 requires external DC blocking capacitors on both RFIN (Pin 3) and RFOUT (Pin 6) because both ports are DC-coupled. The evaluation board uses 100 pF 0402 capacitors for frequencies above 900 MHz. For DC–50 MHz use, larger values (e.g., 0.01 µF) are recommended per the application table. Failure to include them risks DC level mismatch and potential damage to adjacent stages.

Can HMC311SC70 operate from a 3.3 V supply?

No, HMC311SC70 is characterized and specified only for +5 V operation. The absolute maximum collector bias voltage is +7 V, but the internal Darlington structure requires ~3.8 V minimum across the bias network to maintain proper transistor biasing. At 3.3 V, Icq drops below functional threshold, gain collapses, and P1dB degrades significantly. No performance data exists for 3.3 V, and operation outside Vs = +5 V is not supported.

What is the thermal resistance and maximum junction temperature of HMC311SC70?

HMC311SC70 has a junction-to-lead thermal resistance of 191 °C/W and a maximum junction temperature of 150 °C. At 54 mA and +5 V, power dissipation is ~270 mW. With ambient at +85 °C, junction temperature reaches ~136 °C - within safe limit. To ensure reliability, PCB design must provide low-impedance thermal path via all four ground pins soldered to a solid ground plane with multiple vias.

Is HMC311SC70 pin-compatible with HMC311SC70E?

Yes, HMC311SC70 and HMC311SC70E share identical pinout, electrical specifications, and SC70 package dimensions. The only differences are RoHS compliance (100% matte Sn finish vs. Sn/Pb), MSL1 reflow profile (260 °C peak vs. 235 °C), and marking ("311E" vs. "311"). Both are functionally interchangeable in new designs and legacy replacements where lead-free assembly is required.