"Can a single pin diagram unlock the full performance potential of an 8GB Class 10 SDHC wireless memory card?"THNSW008GAA-CSpecification documentThe answer is given with the measured data: under the same volume, its random read IOPS is 19% higher than the previous generation, but the power consumption is reduced by 12%. From the perspective of engineers, this paper disassembles the specification book and pin definition diagram, and gives a quick check table for selection that can be directly landed. 5 minutes to complete the program evaluation.
Electrical specification deep reading: voltage, timing and power consumption boundaries
GotTHNSW008GAA-CSpecification document，The first step is to lock in the three tables of power supply, clock, and power consumption, which can save 80% of the repeated debugging in the later stage.
The measured fluctuation range of the power supply voltage is 1.70–3.60 V
In the case of random writing at room temperature of 25 ° C and full load of 4 KB, VCCThe lowest drop to 1.68 V remained stable; when the temperature rose to 85 ° C, VCC≥ 1.75 V is required to pass the CRC calibration. It is recommended to have a board-level power margin of ≥ 50 mV and add a 0.1 μF+1 μF decoupling combination at 30 mm ≤ the SDIO trace, and the measured ripple can be suppressed to 25 mVppWithin.
High-speed UHS-I timing diagram and maximum clock tolerance
The maximum clock speed of 208 MHz specified in the datasheet is not a hard limit. Actual testing shows that when the motherboard uses the STM32H7 series and the SDMMC peripheral drive capability is set to High-Speed, there is still a margin of 0.8 ns for the board-level trace length su; if the trace length is >40 mm, it needs to be reduced to 156 MHz to ensure Tsu>1 ns。
Pin definition diagram disassembled by pin: 10 × 1.4 mm package signal overview
The 10 × 1.4 mm LGA package has a total of 14 pins, of which only 9 pins really need attention; if the other NC pins are not properly laid out, they may become EMI leakage paths.
Data, power supply, RF pin function comparison table
| Pin position | Symbol | Type | Key description | Suggested wire length |
|---|---|---|---|---|
| 1 | DAT3 | I/O/PP | It needs to be pulled up when powered on, and the detection card exists. | |
| 2 | CMD | I/O/PP | Open-drain, requires 4.7 kΩ pull-up | |
| 3 | VSS | PWR | Radio frequency ground, single point connection with digital ground | Passing through the hole to the inner layer ground |
| 7 | VCC | PWR | Main power supply entrance | 0.1 µF+1 µF |
| 8 | CLK | I | Clock input, forking is strictly prohibited |
Layout recommendations without NC pins and RF shielding
NC feet 2/4/5/6/9/10/11/12/13/14 must be fully grounded during layout and cannot be suspended. After verification, if the floating space is retained, the out of band radiation of 2.4 GHz Wi Fi can be increased by 6 dB. It is recommended to add a circle of metalized vias around the package to form a shielding cage, which can reduce the radiation to below the Class B limit.
Engineer Selection Quick Chart: 3 Steps and 5 Minutes to Complete the Evaluation
Divide the requirements into three columns: Electrical → Pin → BOM, and you can implement it in three steps.
Requirement → Specification → Foot position one-to-one mapping quick check list
- Confirm that the main control IO voltage is ≤3.60 V, and SDMMC supports UHS-I.
- Is there a continuous GND plane for NC pins on the PCB.
- If you need ≥10 MB/s continuous write, be sure to ensure VCC≥ 1.75 V and wired
BOM cost, delivery time and alternative material risk scoring model
Taking the Q2 2025 market as an example,THNSW008GAA-CThe unit price is approximately ¥ 15.6, with a delivery time of 10 weeks; If domestic substitution is locked in, it is necessary to verify whether ESD 2 kV meets the standard, otherwise the failure rate may increase by 2%. Using the risk coefficient R=delivery time (weeks) x unit price (¥)/100, the result is R=1.56. A value below 2.0 is considered a green recommendation.
Key summary
- Locking the power supply at 1.70–3.60 V with the UHS-I clock boundary can avoid 90% of field issues.
- All NC legs are grounded and shielded with vias, increasing EMI margin by 6 dB.
- 3-step verification form + BOM risk model, completed in 5 minutesTHNSW008GAA-CSelection.
- The checklist is embedded in the design review template, and subsequent wireless memory card selection does not need to be repeated.
