RF Switch Testing via On-Chip Voltage Comparators
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Solution Overview
Problem
Conventional methods for testing RF switches in mobile phones fail to detect defects in switching transistors and voltage boosting circuits, which can lead to distortion and performance degradation under normal operating conditions, especially due to the increasing complexity of multiple frequency bands and standards.
Innovation Solution
A method involving on-chip comparators and analog-to-digital converters to measure internal voltages and currents without dedicated test pins, using a serial interface to monitor and control supply voltages, and performing go-no-go tests by ramping input reference voltages, allowing precise parameter measurement and detection of substrate voltage, current, and leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If DC functionality testing is performed on RF switches, then basic operational verification is achieved, but defects in switching transistors and voltage boosting circuits that degrade RF performance under normal operating conditions cannot be detected
Solution Approach 1:
The patent applies parameter changes by transitioning from DC voltage levels to RF frequency voltage levels during testing. The test system applies RF signals at the operating frequency of the switch, enabling detection of defects that only manifest under normal RF operating conditions. This frequency parameter change allows detection of transistor and voltage boosting circuit defects that DC testing cannot reveal.
Solution Approach 2:
The patent implements preliminary action by performing RF-level functionality testing before the device is deployed to field conditions. By conducting comprehensive RF performance testing including insertion loss, return loss, and switching functionality at operating frequencies during manufacturing, defects are detected and filtered out before the device reaches the customer, preventing field failures.
2Adaptability or versatility
If multiple frequency bands and standards are implemented in mobile phones, then communication versatility is improved, but distortion products and jamming issues increase due to circuitry and antenna switch complexity
Solution Approach 1:
The patent applies feedback by implementing comprehensive RF performance testing that measures insertion loss, return loss, and switching functionality across multiple frequency bands. This feedback mechanism identifies devices with distortion products or jamming issues caused by the complex multi-band circuitry and antenna switches, allowing defective devices to be filtered out before deployment, ensuring only high-performance devices reach the market.
3Ease of manufacture
If conventional DC testing methods are used for RF switches, then test simplicity is maintained, but test coverage is insufficient to detect RF performance degradation
Solution Approach 1:
The patent replaces the mechanical/electrical DC testing system with an RF signal-based testing system. Instead of using DC voltage sources and simple continuity checks, the system employs RF signal generators, vector network analyzers, and specialized test fixtures that apply RF signals at operating frequencies. This substitution enables comprehensive RF performance characterization while maintaining test automation and efficiency through computer-controlled test sequences.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables effective detection of defects and performance issues in RF switches, reducing the risk of field failures and performance degradation, while minimizing test time and costs by eliminating the need for additional test-support reference voltage generators.
Implementation Method 1
comparing the supply voltage to an internally generated voltage, generating a digital output value based on the comparing
Data Source
AI summary
In accordance with an embodiment, a method of testing an integrated circuit, includes receiving a supply voltage on the integrated circuit via a first input pin, providing power to circuits disposed on the integrated circuit via the first input pin, comparing the supply voltage to an internally generated voltage, generating a digital output value based on the comparing, and applying the digital output value to a pin of the integrated circuit.