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Analog Devices Inc. HMC685LP4E
- Part No.:
- HMC685LP4E
- Manufacturer:
- Analog Devices Inc.
- Category:
- RF Mixers
- Package:
- 24-VFQFN Exposed Pad
- Datasheet:
-
HMC685LP4E.pdf
- Description:
- IC MMIC MIXER LO AMP 24-QFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,573
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Product details
Overview
HMC685LP4E from Analog Devices (formerly Hittite Microwave) is a BiCMOS MMIC double-balanced mixer with integrated LO amplifier, operating as a high-linearity downconverter or upconverter in RF front-ends for 1.7–2.2 GHz cellular infrastructure. It delivers +35 dBm input IP3, 8 dB typical conversion loss at 0 dBm LO drive, and DC–500 MHz differential IF bandwidth - enabling robust 3G/4G LTE base station receiver and transmitter signal chains.
For engineers reviewing the HMC685LP4E datasheet, HMC685LP4E pinout, HMC685LP4E application, or HMC685LP4E equivalent, key selection criteria include its 24-pin 4×4 mm QFN package, adjustable G_BIAS and LO_BIAS for linearity–power trade-offs, LO-to-RF isolation ≥30 dB, and compatibility with low-side LO injection in FDD/TDD architectures.
Technical Context
The HMC685LP4E integrates a broadband passive double-balanced mixer core with an on-die LO buffer amplifier, supporting both upconversion and downconversion modes. Its internal RF and LO baluns provide single-ended 50 Ω interfaces, while the differential IF port (IFP/IFN) supports DC-coupled operation up to 500 MHz.
Supply current is actively tunable via external resistors on Vcc1/2/3 (nominal 120 mA at +5 V) and G_BIAS (2.5 V nominal), enabling optimization of conversion loss (−8 dB typ.) versus IP3 (+35 dBm typ.). LO drive range is −6 to +3 dBm, with optimal performance at 0 dBm and low-side injection configuration.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| RF Frequency Range | 1.7–2.2 GHz - covers LTE Band 1/3/7/38/40 and WCDMA UMTS 2100 MHz bands. |
| LO Frequency Range | 1.5–2.2 GHz - supports low-side LO injection for downconversion with ≥30 dB LO-to-RF isolation. |
| IF Bandwidth | DC–500 MHz - enables direct sampling of GSM/CDMA/OFDM baseband signals without external IF filtering. |
| Input IP3 (Typ.) | +35 dBm at 0 dBm LO - ensures minimal intermodulation distortion in multi-carrier 4G base station receivers. |
| Conversion Loss | 8 dB typical at 0 dBm LO - reduces required gain staging and noise figure impact in cascaded receiver chains. |
| LO-to-RF Isolation | 30 dB min - suppresses LO leakage into antenna paths, critical for TDD/FDD duplexing compliance. |
| Supply Current | 70–140 mA (adjustable) - allows dynamic power scaling across operational modes without hardware change. |
Pinout & Package
Package: 24-lead, 4 mm × 4 mm, RoHS-compliant QFN with exposed thermal paddle; MSL1 rating; 100% matte tin plating; max reflow 260 °C.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 6, 7, 11–14, 18, 20, 23 | N/C | No connection; may be tied to RF ground without performance impact. |
| 2, 5, 15, 17 | GND | RF/DC ground reference; must connect to PCB ground plane via multiple vias. |
| 3 | RF | Single-ended 50 Ω RF input/output; internally DC-shortened via balun - no external DC blocking required. |
| 4 | TAP | Center tap of internal RF balun secondary; short to ground with zero-ohm resistor adjacent to IC. |
| 8, 10, 24 | Vcc1, Vcc2, Vcc3 | Independent 5 V supply pins; each requires local 0.1 µF decoupling per datasheet layout guidelines. |
| 9 | LO_BIAS | Adjusts LO buffer current via external R9 (270 Ω nominal); tunes LO drive capability vs. power dissipation. |
| 16 | LO | Single-ended 50 Ω LO input; internally DC-shortened - no external DC blocking needed. |
| 19 | G_BIAS | External bias control (0–5 V); sets mixer conversion loss and IP3 trade-off; 15 kΩ internal pull-down. |
| 21, 22 | IFN, IFP | Differential 50 Ω IF interface; supports DC-coupled operation; use external DC blocking only if DC not required. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated LO amplifier | Eliminates external LO driver stage, reducing BOM count and board area in compact RF modules. |
| Adjustable G_BIAS and LO_BIAS | Enables real-time optimization of conversion loss (−6 to −12 dB) and IP3 (32–35 dBm) without hardware revision. |
| DC–500 MHz differential IF | Supports direct-conversion and zero-IF architectures without external IF transformers or filters. |
| High LO-to-RF isolation (30 dB min) | Reduces need for external LO suppression filters in FDD transceivers, lowering system insertion loss. |
| 24-pin 4×4 mm QFN with thermal paddle | Provides low thermal resistance (48.33 °C/W) for stable operation at +85 °C ambient in outdoor base stations. |
Applications
| Cellular Base Station Receiver | 4G LTE FDD Transmitter |
|---|---|
Use Scenario: Downconverting 1.8–2.2 GHz LTE signals to baseband in macrocell BTS receive chains. IC Role / Device Role / Timing Role: Double-balanced mixer with integrated LO amplifier performing RF-to-IF translation. Use Value: +35 dBm IP3 and 8 dB conversion loss maintain EVM < 2.5% under multi-carrier 20 MHz LTE conditions. |
Use Scenario: Upconverting baseband I/Q signals to 1.7–2.2 GHz for LTE Band 1/3/7 transmission. IC Role / Device Role / Timing Role: Active mixer providing high linearity and LO rejection in transmit signal path. Use Value: 33 dB LO-to-RF isolation prevents LO leakage from violating ACLR mask requirements in 4G power amplifiers. |
| GSM/CDMA Repeater System | WiMAX Subscriber Unit |
Use Scenario: Bidirectional signal amplification in in-building repeaters covering 1.7–2.2 GHz spectrum. IC Role / Device Role / Timing Role: Dual-mode mixer supporting simultaneous up/down conversion with shared LO. Use Value: Adjustable supply current (70–140 mA) enables thermal management in fanless repeater enclosures. |
Use Scenario: IF-to-RF upconversion in fixed WiMAX CPE units operating at 2.3–2.7 GHz (using image-reject architecture). IC Role / Device Role / Timing Role: High-dynamic-range mixer with DC–500 MHz IF port enabling complex modulation schemes. Use Value: Differential IF interface simplifies connection to AD9122 or similar dual DACs without balun transformers. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar mixer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| HMC684LP4E | Same 24-pin QFN package and pinout; RF range 0.7–1.0 GHz instead of 1.7–2.2 GHz. | Targeted for 700–900 MHz LTE Band 12/13/17/20/28 systems, not 1.8–2.2 GHz bands. | Select HMC684LP4E only when operating below 1.2 GHz; not a drop-in replacement for HMC685LP4E's frequency band. |
| ADL5802ACPZ-R7 | Active double-balanced mixer; 0.4–6.0 GHz RF range; requires external LO buffer; 32-pin LFCSP. | Broader frequency coverage but higher power (220 mA) and larger footprint; lacks integrated LO amplifier. | Choose ADL5802ACPZ-R7 for wideband lab test equipment; HMC685LP4E preferred for space-constrained 1.7–2.2 GHz infrastructure designs. |
Compared with HMC684LP4E and ADL5802ACPZ-R7, the HMC685LP4E uniquely combines 1.7–2.2 GHz optimization, integrated LO amplification, and 4×4 mm footprint - delivering superior size, power, and integration efficiency for LTE-Advanced macrocell and small cell transceivers.
Availability
HMC685LP4E is available at Aetrix Electronics and suitable for cellular infrastructure, wireless repeaters, and WiMAX subscriber units requiring stable component supply across extended temperature ranges (−40 to +85 °C) and long production lifecycles.
Supply support for HMC685LP4E 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-frequency RF portfolio, specializing in microwave/mmWave ICs for communications, defense, and instrumentation.
The HMC685LP4E belongs to Hittite's legacy BiCMOS MMIC mixer family, engineered specifically for high-dynamic-range, low-power cellular infrastructure signal chains where integration, linearity, and thermal reliability are critical.
FAQ
What is the recommended LO drive level for optimal performance of the HMC685LP4E?
The HMC685LP4E achieves best linearity and conversion loss balance at 0 dBm LO drive, with specified operation from −6 to +3 dBm. At 0 dBm, typical conversion loss is 8 dB and input IP3 reaches +35 dBm. Driving outside this range increases conversion loss or degrades IP3 - for example, −3 dBm yields ~9 dB loss, while +3 dBm raises current draw without significant IP3 improvement. Always verify LO drive with calibrated source in final design.
Can the HMC685LP4E be used in upconversion mode, and what are the key layout considerations?
Yes, the HMC685LP4E supports upconversion with the same pin assignments: RF becomes output, IF becomes input, and LO remains input. Critical layout practices include maintaining 50 Ω controlled impedance on all RF/LO/IF traces, grounding the exposed paddle with ≥8 thermal vias, and placing decoupling capacitors (0.1 µF per Vcc pin) within 2 mm of each supply pin. Avoid routing IF traces near LO or RF paths to prevent coupling-induced spurs.
How does adjusting the G_BIAS voltage affect the HMC685LP4E's RF performance?
Adjusting G_BIAS from 1.0 V to 3.0 V trades conversion loss for linearity: at 1.0 V, conversion loss improves to ~−12 dB but IP3 drops to ~30 dBm; at 3.0 V, loss degrades to ~−6 dB while IP3 rises to ~36 dBm. The nominal 2.5 V setting delivers 8 dB loss and +35 dBm IP3. This adjustment is implemented via external voltage source or resistor divider - the internal 15 kΩ pull-down ensures stable biasing even with open-circuit inputs.
Is the HMC685LP4E pin-compatible with any other Hittite/Analog Devices mixers?
Yes, the HMC685LP4E is pin-for-pin compatible with the HMC684LP4E, differing only in RF frequency range (1.7–2.2 GHz vs. 0.7–1.0 GHz) and internal matching. Both share identical 24-pin 4×4 mm QFN footprints, pin functions, supply requirements, and biasing schemes. This allows reuse of PCB layouts across 700 MHz and 1.8 GHz bands - only RF/LO filter components require redesign.
What is the maximum RF input power the HMC685LP4E can handle without damage?
The absolute maximum RF/IF input power for the HMC685LP4E is +26 dBm (400 mW) when Vcc1/2/3 = +5 V. However, compression and distortion begin well below this limit: the input 1 dB compression point is +25 dBm (typical), and reliable linear operation is maintained up to +20 dBm. Exceeding +26 dBm risks permanent damage to the mixer diodes or LO amplifier, especially under continuous wave conditions at elevated temperatures.
HMC685LP4E Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 24-VFQFN Exposed Pad
- Packaging:
- Strip
- Product Status:
- Obsolete
- RF Type:
- LTE, WiMax
- Frequency:
- 1.7GHz ~ 2.2GHz
- Number of Mixers:
- 1
- Gain:
- -
- Noise Figure:
- 8dB
- Secondary Attributes:
- Up/Down Converter
- Current - Supply:
- 120mA
- Voltage - Supply:
- 4.75V ~ 5.25V
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 24-QFN (4x4)
HMC685LP4E FAQ
1.How can I place an order for HMC685LP4E through Aetrix?
Please submit a Request for Quotation (RFQ) for HMC685LP4E on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for HMC685LP4E reliable?
The price and inventory of HMC685LP4E are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for HMC685LP4E is usually 5 days.
3.What payment methods are accepted for HMC685LP4E?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for HMC685LP4E transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for HMC685LP4E?
HMC685LP4E orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your HMC685LP4E order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for HMC685LP4E?
For technical support, including HMC685LP4E datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your HMC685LP4E requirements.
6.How does Aetrix verify that HMC685LP4E is sourced from the original manufacturer or authorized distributors?
All HMC685LP4E products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that HMC685LP4E meets industry standards.
7.What is the process for return or replacement of HMC685LP4E?
All HMC685LP4E units undergo pre-shipment inspection (PSI). If there is an issue with HMC685LP4E, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The HMC685LP4E part is unused and in its original packaging.
Return procedure for HMC685LP4E:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
HMC685LP4E Tags
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MAX2681EUT+T
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ADE-1ASK+
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ADE-1L+
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