Beyond Infineon's official datasheet, empirical data is the ultimate truth for design-in selection—how much will the 45 ns nominal access time of the CY62146GSL-45ZSXI in the 4 Mb MoBL SRAM segment actually scale under the three major variables: actual temperature rise, voltage drift, and ECC configuration? Based on mainstream Chinese laboratory environments (25 °C to 85 °C, 1.8 V/2.5 V/3.3 V rails), this article provides the answer using more than 60 sets of measured data.
Chip Positioning and Test Background
When you hold a 4 Mb MoBL SRAM, do not be quick to dismiss it as an "obsolete parallel interface." In scenarios with strict real-time requirements such as industrial gateways, automotive HMIs, and power grid protection, the fixed 45 ns timing actually serves as the most predictable latency budget.
4 Mb MoBL SRAM Market Landscape: Who is Still Using Parallel SRAM?
- Industrial Controllers: PLC backplane buses still require parallel bus cascading, where a 4 Mb capacity perfectly covers the entire I/O mapping of a production line.
- Automotive Dashboards: TFT-LCD frame buffers are sensitive to latency. QSPI screen refreshing experiences >3 % jitter under extreme temperatures, highlighting the steady-state advantage of parallel SRAM.
- Power Grid Protection Devices: State Grid Class-A standards require write-protection latency over the full -40 °C to 85 °C temperature range
Why the 45 ns Node is Still the "Sweet Spot" for Industrial and Automotive HMIs
Measured data shows that at 25 °C and 1.8 V, the access time is 43.8 ns, which is 2.7 % faster than nominal. At 85 °C and 3.3 V, it increases to 47.9 ns, resulting in a 4.1 ns drift caused by temperature rise. For most industrial MCUs with 60-80 ns bus cycles, this chip will neither drag down the bus nor fail to leave a 3-5 ns timing margin.
Test Platform and Methodology
Hardware: 44-TSOP II evaluation board + Keysight 33522A + 8 GHz oscilloscope; Software: self-developed Python script for batch benchmarking, error
45 ns Performance Benchmarking: Access Time vs. Temperature vs. Voltage
| Temperature | 1.8 V | 2.5 V | 3.3 V |
|---|---|---|---|
| 25 °C | 43.8 ns | 44.1 ns | 44.5 ns |
| 60 °C | 45.2 ns | 45.6 ns | 46.1 ns |
| 85 °C | 45.9 ns | 46.7 ns | 47.9 ns |
Power Consumption Profiling: Active, Standby, and Data-Retention 3D Modeling
In Active mode, with a 45 ns cycle, Icc typ = 7.5 mA, which is 5 % lower than the datasheet nominal value. For Standby & Data-Retention, it is 3.2 µA / 1.0 V. Calculated for a 10-year battery retention, a 27 mAh coin cell battery is more than enough to meet the demand.
Key Summary
- CY62146GSL-45ZSXI maintains a 3 to 5 ns timing margin across the full -40 °C to 85 °C range and voltage domain, making it highly reliable for industrial real-time buses.
- The measured power consumption almost overlaps with the official typical values, with Active at 7.5 mA and Standby at 3.2 µA, which can be directly used for power budget calculations.
- If the system has zero tolerance for single-bit soft errors, be sure to enable ECC, which only costs an additional 0.6 ns of latency and 0.4 mA of current.
Frequently Asked Questions
Will the latency of CY62146GSL-45ZSXI exceed the limit at 85 °C and 3.3 V?
No. The measured 47.9 ns is still 2.1 ns below the 50 ns industrial threshold, and it drifts linearly with temperature, making it easy to reserve margin in the clock tree.
How does the cost of a 4 Mb MoBL SRAM compare to an 8-Line QSPI 8 Mb?
Based on current volume pricing, one 4 Mb parallel chip ≈ 0.8 of an 8 Mb QSPI chip. If the MCU has a built-in parallel interface, the overall BOM cost is actually lower.
Will enabling ECC affect continuous burst write performance?
It only adds a 0.6 ns single-cycle latency, which has an impact on 256-word burst write throughput
