Surface mounted piezoelectric devices for frequency control and selection - Standard outlines and terminal lead connections - Part 2: Ceramic enclosures
1Key Takeaways
This part of IEC 61837 is based on IEC 61240:2016 and describes standard package dimensions and terminals as they apply to surface mountable devices (SMDs) for frequency stabilization and selection in ceramic packages.
2Expert Interpretation
An in-depth analysis of the DIN EN IEC 61837-2:2018 standard for ceramic housings for surface-mount piezoelectric devices, covering 45 standard housing sizes, terminal connection specifications, a comparison of new and legacy models, and implementation requirements. This expertly analyzes the standard's technical evolution, dimensional tolerance requirements, and application implementation recommendations.
Standard Overview and Technical Background
DIN EN IEC 61837-2:2018 is a key standard for surface-mount piezoelectric devices. Developed based on IEC 61240:2016, it specifically specifies the standard dimensions and terminal connection requirements for surface-mount devices (SMDs) in ceramic housings for frequency control and selection. The standard was adopted as a European standard by CENELEC on June 12, 2018, and officially implemented in Germany on February 1, 2019.
Main Technical Content of the Standard
This standard specifies 45 different types of ceramic housing configurations, including two primary structural types: dual-chip carrier (DCC) and quad-chip carrier (QCC). All housings are manufactured from ceramic materials and feature leadless terminals, with metallization used as the connection terminals.
Analysis of Shell Naming System
The standard establishes a systematic shell naming system, which consists of four parts:
| Components | Meaning | Example description |
|---|---|---|
| A | Shell configuration symbol | DCC (dual chip carrier), QCC (quad chip carrier) |
| B | Terminal structure | No lead structure, no special identification |
| C | Number of terminals | 2, 4, 6, 8, 10, 12, 18 terminals, etc. |
| D | Serial number | Corresponding drawing number |
| E | Terminal arrangement | A (width direction), B (length direction), C (corner) |
Major technical changes and updates
Compared with the 2014 edition of the standard, this update mainly includes the following important changes:
- Comprehensive revision and optimization of all drawings
- Seven new housing types have been added: DCC-6/5032A, DCC-6/3225A, DCC-4/3215C, DCC-6/2016A, DCC-2/2012C, DCC-2/1610C, DCC-4/1210C
- Improved terminal connection specifications and recommendations
- Updated dimensional tolerance requirements
Detailed comparison and analysis of housing types
| Serial number | New model | Old model | Number of terminals | Dimensions (mm) | Application characteristics |
|---|---|---|---|---|---|
| 1 | QCC-18/1809A | QCC-18/01 | 18 | 18.0×9.0 | High Frequency Multi-Terminal Applications |
| 3 | DCC-4/1206A | DCC-4/01 | 4 | 12.0×6.0 | General-Purpose Crystal Resonator |
| 30 | DCC-6/3225A | - | 6 | 3.2×2.5 | New Miniaturized Package |
| 32 | DCC-4/3215C | - | 4 | 3.2×1.5 | Ultra-thin design |
| 39 | DCC-6/2016A | - | 6 | 2.0×1.6 | Miniaturized high-frequency applications |
Terminal Connection Specifications and Recommendations
The standard provides detailed terminal connection recommendations and gives corresponding terminal assignment schemes for different types of piezoelectric devices (crystal resonators, crystal oscillators, crystal filters, SAW devices):
Typical Connection Configuration Examples
| Terminal Number | Crystal Resonator | Crystal Oscillator | Crystal Filter | SAW Device |
|---|---|---|---|---|
| 1 | Terminal 1 | Control Voltage | Ground | Ground |
| 2 | Optional | Ground | Output/Input | Output/Input |
| 3 | Terminal 2 | Output | Ground | Input/Output |
| 4 | Optional | Power Supply | Input/Output | Grounding |
Dimensional Tolerances and Mechanical Requirements
The standard sets clear requirements for the dimensional tolerances of various types of housings, especially for the maximum allowable value of the direction mark dimension LB:
- QCC-18/1809A: The maximum LB of terminal 1 can be increased to 2.10mm
- DCC-4/5032A: The maximum LB of terminal 1 can be increased to 2.00mm
- QCC-8/5050A: The maximum LB of terminal 8 can be increased to 1.90mm
- DCC-6/6035A: The maximum LB of terminal 1 can be increased to 1.60mm
Implementation Recommendations and Transition Arrangements
Transition Arrangements
According to the standard, the transition period for DIN EN 61837-2:2014-10 version is until June 12, 2021. Before this date, the old and new versions of the standard can be used in parallel, but new designs are recommended to adopt the 2018 version of the standard.
Design Implementation Recommendations
- Model Migration: For existing designs, a comparison table of old and new models should be established to ensure a smooth transition
- PCB Layout: Re-evaluate pad design based on the dimensional requirements of the new standard
- Soldering Process: Optimize the reflow soldering temperature profile for new miniaturized housings
- Inspection Standards: Update automated optical inspection (AOI) procedures and acceptance criteria
Key Points for Quality Control
- Strictly monitor the dimensional tolerances of ceramic housings, especially the height tolerances
- Strengthen terminal plating quality inspection to ensure soldering reliability
- Establish handling and installation specifications for new miniaturized housings
- Improve temperature cycling and mechanical shock test procedures
Technology Development Trend Analysis
The development trend of piezoelectric device packaging technology can be seen from the updated standard content:
| Technical Direction | Typical Models | Size Reduction | Performance Improvement |
|---|---|---|---|
| Miniaturization | DCC-2/1610C | 1.6×1.0mm | Suitable for wearable devices |
| High Density | QCC-18/1809A | 18.0×9.0mm | Multi-terminal Complex Functions |
| Thinness | DCC-4/3215C | 3.2×1.5mm | Ultra-thin device applications |
Coordination with related standards
This standard is coordinated with multiple international standards. The main related standards include:
- IEC 61240:2016 General rules for preparation of outline drawings of surface mount piezoelectric devices
- IEC 60122-3:2010 Crystal units for quality assessment - Part 3: Standard outline and lead connections
- IEC 60679-3:2012 Crystal oscillators for quality assessment - Part 3: Standard outline and lead connections
- ISO 1101:2017 Geometrical Product Specifications (GPS) - Geometrical Tolerances
Application Cases and Best Practices
5G Communication Equipment Applications
In 5G base station equipment, the DCC-6/3225A housing is widely used due to its excellent high-frequency performance and compact size. Typical Configuration:
- Terminal 1: Control voltage (for VCXO applications)
- Terminal 2: Ground
- Terminal 3: RF output
- Terminal 4: Power supply
- Terminals 5/6: NC or auxiliary function
IoT Device Applications
To meet the low power requirements of IoT devices, the DCC-2/1610C housing offers ultimate size optimization:
- Measuring only 1.6×1.0mm, it is suitable for space-constrained designs
- Low parasitic parameters improve frequency stability
- Optimized thermal performance adapts to temperature changes
Summary and Outlook
The release and implementation of the DIN EN IEC 61837-2:2018 standard provides the latest technical specifications for the design and manufacture of surface-mount piezoelectric devices. By adding seven new housing types and refining technical details, the standard better meets the needs of modern electronic devices for miniaturized, high-performance piezoelectric devices. Manufacturers and designers should make full use of the transition period to complete technology upgrades and ensure that their products meet the latest standard requirements.
With the rapid development of applications such as 5G, the Internet of Things, and automotive electronics, piezoelectric device packaging technology will continue to develop towards smaller size, higher performance, and better reliability. It is expected that future standards will further incorporate more innovative packaging forms to meet the technical requirements of emerging applications.