20260922-1707-air-ti-platform-touch-battery-evaluation Evaluate TI 2.4 GHz SoCs, capacitive touch input and battery formats for Air

status: completed
createdAt: 2026-09-22 17:07
approvedAt: 2026-09-22 20:16
relatedTask: 20260922-0818-air-ti-platform-touch-battery-evaluation

Context

The owner asked to continue the Air (P05, Air 2 / Air 4) wireless-platform research with the Texas Instruments SimpleLink family, which is expected to have lower standby and radio current than the current recommendation, to look at capacitive-touch input, and to revisit the battery choice. The request says "802.11"; Air is a battery key with a BLE link to Air Hub and Wi-Fi has never been a candidate, so this plan reads it as the 2.4 GHz Air platform (BLE and 802.15.4). The TI Wi-Fi 6 companion (CC3301) is recorded in one row as an Air Hub / Mate candidate only. If Wi-Fi on Air itself was meant, the conclusion changes and this plan must be re-scoped.

Current state of the Air package

bizplan/product/switch/air/P05-air.md R0.4 (spec): 2×AAA Li-FeS2 in series with a buck-boost, thickness ≤14 mm (relaxed from ≤12 mm on 2026-09-11 for the AAA compartment), 750 mAh usable budget, three-year target = 28.54 µA average, AIR-04 gesture-to-result P50 ≤150 ms, AIR-06 100 000 mechanical operations, IP54 cabin, −20…+60 °C.
P05-air-design.md R0.1 §2: first-version recommendation ESP32-H2-MINI-1-H4S (deep sleep 7 µA, RX 25 mA, TX 55 mA at 7 dBm, 3.0–3.6 V, 0.35 A peak), nRF54L15 as the only NFC alternative, ESP32-C6 rejected. §2.2 estimates 90–105 mAh/year for the normal duty cycle, of which deep sleep is about 61 mAh and converter quiescent 9–26 mAh.
evaluations/esp32h2.md: the CR2450 rejection rests on three blockers (supply window, 0.35 A peak, average current); all three are properties of the H2, not of the coin cell.
No page in the repository mentions capacitive touch; Air, Key and the line spec all assume mechanical keys.
Only CR2450 and 2×AAA Li-FeS2 have been compared as battery formats.

Findings (all figures checked against vendor datasheets on 2026-09-22)

Why CC2652R7 and CC2674R10 were missing from the first draft. The first pass took only the TI parts with the lowest standby figure (CC2340) and the newest security block (CC2755), plus CC2674P10 as the +20 dBm variant. That dropped CC2652R7 and CC2674R10, which are the TI parts that matter for the touch question: both carry the autonomous Sensor Controller whose datasheet lists "software defined peripherals; capacitive touch" and which scans while the main CPU stays in Standby. The 2026-09-22 revision below adds them and splits the SoC comparison into two tables by whether a capacitive-touch peripheral is on the die.

Table A. Radio + MCU SoCs without a capacitive-touch peripheral

Device (datasheet rev.)	Standby, RTC + RAM retention	RX / TX 0 dBm	Supply	Radio	Security listed	Notes
Espressif ESP32-H2 (current recommendation)	7 µA	25 mA / 55 mA at 7 dBm	3.0–3.6 V, 0.35 A peak	BLE 5.3 + 802.15.4	Secure Boot v2, flash encryption, eFuse	needs buck-boost on 2×AAA
TI CC2340R5 / R53 (SWRS272F, 2026-05)	0.71 µA (R52 figure)	5.3 / 5.1 mA (+8 dBm 10.7 mA)	1.71–3.8 V	BLE 5.4, Zigbee, Thread	AES-128, RNG, SHA-256 in ROM; no secure boot / debug lock listed	CC2340R5MODA 7×10 mm module, BLE-only pre-certified (2026-06); 512 KB / 36–64 KB
TI CC2755R10 (SWRS306E, 2026-09)	0.9 µA	6.1 / 7.7 mA	1.71–3.8 V	BLE 6.0 + Channel Sounding, Zigbee 3.0, Thread, Matter	HSM, secure boot RoT, TrustZone-M, DPA countermeasures	1 MB / 162 KB; QFN40 6×6
Nordic nRF54L15 (datasheet v1.0)	0.6–0.8 µA	3.2 / 5.0 mA	1.7–3.6 V	BLE 5.4 + 802.15.4	TrustZone, KMU	NFC-A; 1.5 MB / 256 KB
Silicon Labs EFR32BG22 (Rev 1.3)	1.40 µA (32 KB, LFXO)	3.6 / 4.1 mA (6 dBm 8.2 mA)	1.71–3.8 V	BLE 5.x only	Secure Vault Mid, secure boot RTSL	512 KB / 32 KB; no 802.15.4
Silicon Labs EFR32BG27 (search excerpt)	1.6 µA (64 KB)	3.6 / 4.1 mA	1.71–3.8 V	BLE only	Secure Vault Mid/High	to be re-read from datasheet
ST STM32WB05xN (DS14620 Rev 2, 2024-06)	0.8 µA Deepstop (LSE), 1.0 µA (LSI)	3.4 / 4.3 mA	1.7–3.6 V	BLE 5.4 only	not listed on front page	Cortex-M0+; xN is the network-coprocessor variant, xZ the standalone MCU
onsemi RSL15 (Rev 4, 2023-04)	36 nA GPIO wake, 57 nA with RTC	2.7 / 4.3 mA	1.2–3.6 V, direct coin or silver-oxide cell	BLE 5.2 only	Arm CryptoCell-312, secure boot, TrustZone	284/512 KB flash, 80 KB RAM; lowest sleep of the set
Infineon AIROC CYW20829 (Rev *L, 2025-08)	4.5 µA (64 KB)	5.6 / 5.2 mA	1.7–3.6 V	BLE 5.4 only	secure boot, eFuse	datasheet lists no CAPSENSE; external QSPI flash
NXP MCX W71 (product page; AN14389 measurements)	not obtained (datasheet behind login)	6.9 / 6.9 mA measured, buck	1.8–3.6 V	BLE 5.3 + 802.15.4, Matter	EdgeLock secure enclave, secure boot and debug	optional CAN FD; 1 MB / 128 KB
Telink TLSR9218 (search excerpt)	0.7 µA no retention, 1.7 µA 32 KB	6.1 / 6.6 mA	—	BLE 5.2 + Zigbee/Thread/Matter	—	datasheet not retrieved; treat as unverified
TI CC3301 (SWRS294F, 2025-10)	—	Wi-Fi RX 62 mA; DTIM=3 idle 355 µA	1.8 V + 3.3 V PA	Wi-Fi 6 + BLE 5.4 companion	firmware authentication, anti-rollback	needs a Linux/RTOS host over SDIO/SPI; Air Hub / Mate only

Table B. Radio + MCU SoCs with an on-die capacitive-touch peripheral

Device (datasheet rev.)	Touch block and channels	Scans with CPU asleep?	Standby, RTC + RAM	RX / TX 0 dBm	Supply	Radio	Security listed
TI CC2652R7 (SWRS253B, 2023-03)	Sensor Controller: current source + time-to-digital converter + comparator, up to 8 analog GPIOs; baseline tracking, hysteresis and filtering run on the SCE	Yes: SCE runs in Standby, 29.2 µA while active at 2 MHz, duty-cycled	0.9 µA (144 KB), 0.8 µA (64 KB)	6.4 / 7.3 mA (+5 dBm 9.7 mA)	1.8–3.8 V	BLE 5.2, Zigbee, Thread, Matter	AES, ECC/RSA PKA, SHA-2, TRNG; secure boot not on front page
TI CC2674R10 (SWRS268B, 2024-04) / CC2674P10 (+20 dBm)	same Sensor Controller	Yes, 32 µA at 2 MHz while active	1.19 µA (256 KB), 0.96 µA (128 KB)	6.4 / 7.3 mA (P10: 6.9 mA; +20 dBm 102 mA)	1.8–3.8 V	BLE 5.3, Zigbee, Thread, Matter, Wi-SUN	secure boot, secure key storage, TrustZone, secure debug lock, anti-rollback
ST STM32WBA55 (DS14127 Rev 6, 2024-09)	TSC, up to 20 sensors (charge-transfer, 3 sensors + 1 Cs per group)	No: TSC runs in Run/Sleep; Standby needs an RTC wake per scan	0.9 µA (64 KB), 160 nA without RAM	4.4 / 5.2 mA	1.71–3.6 V	BLE 5.4 + 802.15.4 (Thread, Matter, Zigbee)	TrustZone, RDP, secure boot / RSS, DPA-resistant AES and PKA
ST STM32WB55 (DS11929 Rev 14, 2022-08)	TSC, up to 18 sensors; not available on the QFN48 package	No (as WBA55)	0.6 µA (32 KB SRAM2a + RTC)	4.5 / 5.2 mA	1.71–3.6 V	BLE 5.3 + 802.15.4	PKA, AES, secure boot (RSS)
Silicon Labs EFR32MG24 (Rev 1.2)	ACMP capacitive-sense oscillator mode (not a touch block); KEYSCAN 6×8 matrix for mechanical keys	Partially: ACMP/LETIMER in EM2 via PRS, software-tuned	1.3 µA (16 KB)	4.4 / 5.0 mA (+10 dBm 19.1 mA)	1.71–3.8 V	BLE, Zigbee, Thread, Matter, Channel Sounding	Secure Vault High: PUF, tamper, secure debug
Microchip PIC32CX-BZ3 / WBZ351 module (DS70005541C, preliminary)	CVD touch controller, up to 8 channels on the shared SAR ADC	Not stated; "Sleep Walking" peripherals to be verified	1.7 µA (16 KB), 1.9 µA (32 KB)	RX not extracted; TX 0 dBm 26 mA incl. CPU, MLDO only	1.9–3.6 V	BLE 5.2 + Zigbee 3.0	secure boot ROM, eFuse key storage, debug lock
Renesas RA4W1 (Rev 1.00, 2020-03)	CTSU, 14 TS pins on this package	No: needs CPU or snooze wake	0.9 µA (48 KB) + 0.4–0.5 µA RTC	3.3 / 4.5 mA (DC-DC)	1.8–3.6 V	BLE 5.0 only	AES, TRNG; no secure boot listed
Infineon PSoC 63 BLE (Rev *S, 2026-06)	CAPSENSE CSD block, liquid tolerance claimed	No: CAPSENSE cannot wake from Deep Sleep, CPU must run the scan	7 µA (64 KB)	6.7 / 5.7 mA	1.7–3.6 V	BLE 5.0 only	eFuse, secure boot
Espressif ESP32-H4 (product page; no datasheet yet)	15 touch-sensing GPIOs	unknown	not published	not published	—	BLE 5.4 + 802.15.4, Thread 1.4, Zigbee 3.0	not published; sampling only as of 2026-09
Espressif ESP32-S3 (for completeness)	14 touch pads, touch wake from deep sleep	Yes, ~30 µA with touch wake enabled	7 µA	BLE ~90+ mA	3.0–3.6 V	Wi-Fi + BLE 5.0, no 802.15.4	rejected for the same reason as ESP32-C6

What the tables show:

On power, every part in Table A except the ESP32-H2 and the CYW20829 sits at or below 1.6 µA standby and 3–8 mA radio. TI, Nordic, Silicon Labs and ST are the same order of magnitude; onsemi RSL15 is a further ten times lower in sleep and can be fed from a 1.5 V cell, but it is BLE-only and a smaller vendor.
The touch question is not "does the die have a touch block" but "does the block scan while the CPU sleeps". Only the TI Sensor Controller (CC2652R7, CC2674R10/P10) does this on a BLE + 802.15.4 part with the security features SEC-05 asks for. ST's TSC, Renesas' CTSU and Infineon's CAPSENSE all need the main CPU per scan, so their touch cost is set by wake-up energy rather than by the touch block. External touch ICs (TI CapTIvate MSP430FR2633 3.6 µA for four buttons; Azoteq IQS7222A 5.8–6.7 µA at 150 ms) remain the alternative for any SoC in Table A.
With the TI Sensor Controller the touch cost can be estimated (not measured): four electrodes scanned every 100 ms at about 1 ms per scan and 30 µA gives roughly 0.3 µA average plus baseline-tracking wakes, so on the order of 1–2 µA on top of the 1 µA standby. This is a different regime from the 5–7 µA external controllers, but the AIR-04 latency argument (a scan interval is spent before the gesture is even seen) and the wet-cabin argument are unchanged.
Security separates the TI parts: CC2340R5 and CC2652R7 do not list secure boot or a debug lock; CC2674R10 and CC2755R10 do. If touch is wanted on TI, the candidate is CC2674R10 (or P10 where +20 dBm is useful); if touch is not wanted, CC2755R10 or nRF54L15.

Consequence: the buck-boost and the coin-cell rejection both fall. A 1.71–3.8 V input covers 2×AAA over the whole discharge (3.6 V fresh to 1.8 V at 0.9 V/cell) and a CR2450 over the whole discharge (3.0 V to 2.0 V). TX peaks are ≤11 mA; the CC2340 datasheet only asks for a 10 µF input capacitor with high end-of-life coin-cell source resistance. The three blockers of evaluations/esp32h2.md §4 do not apply, so the ≤12 mm thickness target can be reopened.

Capacitive touch is not recommended for the first version.

The Air architecture is "zero current until pressed". Touch needs periodic scanning: TI CapTIvate MSP430FR2633 wake-on-touch with four buttons 3.6 µA at 3.3 V (LPM3); Azoteq IQS7222A ultra-low-power mode 5.8–6.7 µA at a 150 ms report rate with two channels (datasheet v1.7, 2026-02). Both are five to ten times the SoC standby, +30–60 mAh/year.
AIR-04 requires gesture-to-result P50 ≤150 ms. A 150 ms scan interval alone spends that budget; shortening the IQS7222A to 60 ms raises it to 110–126 µA.
TI's own liquid-tolerant keypad reference design (TIDM-1021 / TIDUE90) uses mutual capacitance with a well-grounded mains supply and states that it "is not optimized for low power consumption" (1.1 mA). Air is a floating battery device in a cabin with wet hands and gloves, the least favourable combination for liquid rejection.
Touch also changes AIR-06 (mechanical life becomes irrelevant, panel and overlay thickness become the constraint) and adds a tuning step to production test.

Battery formats, assuming a 1.71 V-capable SoC fed directly

Cell	Capacity (datasheet)	Temperature	Notes
2×AAA Li-FeS2, Energizer L92	~1250 mAh/cell at low drain to 0.8 V; IR 140–180 mΩ; 1.5 A continuous	−40…60 °C, 25-year shelf	current baseline; ≤14 mm; lithium-metal transport documents
2×AAA alkaline, Energizer E92	1100–1200 mAh; IR 150–300 mΩ	−18…55 °C	users will fit these anyway, so the design must tolerate 1.6→0.9 V/cell; misses the −20 °C target; leakage risk
CR2450 Li-MnO2, Energizer	620 mAh to 2.0 V at 7.5 kΩ; self-discharge ~1 %/year; IR rises from tens of ohms to >100 Ω at end of life	−30…60 °C	5.0 mm thick; at ~10 mAh/year the five-year target has margin; needs 10 µF input capacitor and a low-battery threshold that respects the rising IR
AAA Li-SOCl2, ER10450	800 mAh at 3.6 V (single cell only; two in series exceed 3.8 V)	−60…85 °C, <1 %/year	passivation and voltage delay after months at µA load are exactly this use case's weakness; not recommended without a hybrid capacitor

Wi-Fi row. CC3301 (SWRS294F, 2025-10) is a companion IC that needs a Linux or RTOS host running TCP/IP over SDIO/SPI; DTIM=3 connected idle is 355 µA at 3.3 V. It cannot replace the self-contained ESP32-C6 on Air and is relevant only to the Air Hub / Mate radio choice.

Proposal

Create one evaluation page and list it in the Air package index. No Level 1 value and no design-appendix recommendation changes.

New page bizplan/product/switch/air/evaluations/ti-cc2340-touch-battery.md (kind evaluation, status active, product P05, Chinese, following docs/templates/evaluation.md):

评估目的与边界 — the three questions, the "802.11 read as 2.4 GHz" assumption, and the rule that this page is cited only from AIR-O-01 / AIR-O-02 and the design appendix.
候选与来源 — the two device-fact tables above (A: no touch peripheral; B: on-die touch peripheral) with datasheet numbers, revision and date; H2 and nRF54L15 figures copied from the existing pages; CC3301 in one row marked "Air Hub / Mate only"; unverified rows (BG27, TLSR9218, MCX W71 standby, ESP32-H4) flagged as such.
对比 — 3.1 power against the 750 mAh / 28.54 µA budget (the per-year table above, marked as order-of-magnitude); 3.2 supply window and peak current, showing which cells each SoC can take directly; 3.3 security against SEC-05 (CC2340 gap, CC2755 coverage); 3.4 NFC and AIR-O-02 (unchanged by TI); 3.5 touch input against AIR-04, AIR-06 and the wet cabin, split into on-die touch blocks (with the "scans while the CPU sleeps" criterion) and external touch ICs, with the scan-rate versus current trade-off; 3.6 battery formats table with the transport and user-substitution notes.
风险与未核实项 — no 1ku price or lifecycle statement obtained; R53 standby not separately listed; CC2340 secure-boot / debug-lock status to be confirmed with TI; module is a 2026-06 part; all mAh/year figures are estimates; CR2450 end-of-life IR and low-battery threshold need measurement; touch figures are datasheet modes, not a tuned design.
建议（供待决项引用）— (a) add CC2340R5/R53, CC2755R10 and CC2674R10 to the D0 comparison next to nRF54L15: CC2755R10 when touch is not wanted, CC2674R10 when it is, and CC2340 only if TI confirms a boot verification that satisfies SEC-05; (b) treat "direct battery supply, no buck-boost" as the design change that makes the difference and re-open the ≤12 mm / CR2450 question under AIR-O-05; (c) keep mechanical keys for the first version and, if touch is still wanted, open AIR-O-10 with mutual-capacitance, guard electrode, wet-hand and glove tests and a separate power and latency budget; (d) keep 2×AAA Li-FeS2 as baseline, make the design tolerate alkaline substitution, and carry CR2450 as the thickness-driven alternative; drop Li-SOCl2.

Index row in bizplan/product/switch/air/index.md, evaluations table: evaluations/ti-cc2340-touch-battery.md | 评估 | 现行 | TI CC2340 / CC2755 与 H2、nRF54L15 对照；触摸输入与电池形态；2026-09-22.

Task file: append the outcome note; changelog entry on completion.

Verification: bun run docs:lint && bun run docs:build && git diff --check; manual check that every figure in the page has a source line and that no requirement or number in the spec or design appendix is altered.

Risks

The CC2340R5 datasheet lists no hardware secure boot or debug lock; if TI cannot confirm a software-verified boot that satisfies SEC-05, the TI candidate is CC2755R10, whose radio current is slightly higher (still an order of magnitude below the H2).
Switching to TI does not close the NFC gap; AIR-O-02 remains open exactly as with the H2. If NFC OOB becomes a hard requirement, nRF54L15 is the only listed option.
Reopening the coin cell reopens the thickness and structure work under AIR-O-05; this plan only records the option, it does not change the ≤14 mm target.
Estimated mAh/year figures could be over-read as measured; the page marks them and repeats the "no chip standby figure may stand in for the product average" rule.
Datasheet revisions dated 2026 may still move; the page records revision codes.

Scope

New: bizplan/product/switch/air/evaluations/ti-cc2340-touch-battery.md (about 150–200 lines).
Edit: bizplan/product/switch/air/index.md (one table row).
Tracking: task 20260922-0818-…, this plan, docs/changelog.md entry.
Not in scope: any change to P05-air.md, P05-air-design.md, P05-air-hub-* or P03-mate-*; these become follow-up tasks once the owner decides on the D0 candidate list.

Alternatives

Extend evaluations/esp32h2.md with a TI section. Smaller diff, but that page is the record of one device and of the 2026-09-11 decision; folding touch and battery topics into it would blur what it evidences.
Change the design appendix directly to list CC2340 as a candidate. Skips the evaluation-before-decision rule of the documentation standard; rejected.
Three separate evaluation pages (platform, touch, battery). Cleaner per topic, but the three questions are coupled by the supply window (touch and coin cell only make sense once the SoC accepts 1.71 V), so one page keeps the reasoning in one place. Can be split later if any topic grows.

Annotations

2026-09-22 (owner): asked why CC2652R and CC2674 were absent, and for a deeper pass over 2.4 GHz radio + MCU parts with and without integrated touch. Answered in Context ("Why CC2652R7 and CC2674R10 were missing") and Tables A/B; proposal items 2, 3.5 and 5(a) updated accordingly. Approved on 2026-09-22 20:16 with the added requirement to verify Zigbee, Matter and BLE support per candidate from vendor SDK or certification sources.