BQ40Z557RSMR

Texas Instruments BQ40Z557RSMR multicell battery fuel gauge IC (variant confirmation recommended)

A practical sourcing and design guide for engineers and buyers evaluating the Texas Instruments BQ40Z557RSMR. The submitted orderable code appears to map to TI’s bq40z5x family in the 32‑pin VQFN (RSM) package on tape‑and‑reel; however, this exact string “BQ40Z557RSMR” could not be conclusively verified. It most closely matches BQ40Z55RSMR. Please confirm the intended MPN prior to purchase and design-in.

Quick summary

• Brand / Manufacturer: Texas Instruments (TI)
• Category: Battery Management ICs > Fuel Gauges / Pack Managers
• Candidate MPN under review: BQ40Z557RSMR (exact variant unverified)
• Closest verified match: BQ40Z55RSMR (bq40z55, VQFN‑32 RSM, tape‑and‑reel)
• Family: bq40z5x (multicell Li‑ion/LiPo fuel gauge / pack manager)
• Package: VQFN‑32 (TI package code RSM)
• Mounting: Surface‑mount (SMT)
• Pin count: 32
• Inventory (user‑provided): 0 units on hand

Links for confirmation and technical details:

• TI product page (bq40z55): https://www.ti.com/product/BQ40Z55
• TI datasheet (bq40z55): https://www.ti.com/lit/ds/symlink/bq40z55.pdf

Overview

The Texas Instruments BQ40Z557RSMR, as provided, aligns with TI’s bq40z5x family of multicell Li‑ion/LiPo battery fuel gauge and pack manager ICs. While the exact orderable code is not confirmed in public listings, the nearest commonly available part is BQ40Z55RSMR, a 2–4 series‑cell fuel gauge that leverages TI’s Impedance Track algorithm and communicates over SMBus/I2C. It is offered in the compact 32‑pin VQFN (RSM) package, well‑suited for slim battery packs and space‑constrained portable or industrial systems.

If your program depends on precise feature sets, revision codes, or firmware behaviors, please verify whether your intended part number is BQ40Z55RSMR or another bq40z5x variant before committing to a PCB or a production buy.

Key specifications and attributes

The following reflect attributes explicitly available for the bq40z5x family and the submitted part context. Where device‑specific values are not confirmed for BQ40Z557RSMR, they are indicated accordingly.

• Architecture/function: Multicell Li‑ion/LiPo battery fuel gauge / pack manager
• Supported cells in series (family): 2–4S (typical for bq40z5x)
• Fuel‑gauge algorithm: Impedance Track (family characteristic)
• Host interface: SMBus/I2C (typical for family)
• Package: VQFN‑32 (TI “RSM” package code)
• Packaging: Tape & Reel (suffix “R” indicates TR)
• Mounting: Surface‑mount
• Pin count: 32
• RoHS / Environmental: Not specified in provided data; confirm with TI
• Lifecycle status: Not specified in provided data; confirm with TI
• Exact variant “BQ40Z557RSMR” verification: Not confirmed; closest match BQ40Z55RSMR

Notes on unlisted parameters:

• Electrical ratings (voltage/current limits, quiescent current, temperature range), protection feature set, authentication options, memory size, and calibration details are not specified here. Refer to the TI datasheet and product page once the exact part number is confirmed.

Where this device fits best

Applications that commonly leverage the bq40z5x family:

• Rechargeable battery packs (2S to 4S) for portable or industrial equipment
• E‑bikes and light EV battery modules
• Medical and instrumentation battery packs
• UPS/backup battery systems and field equipment

Why engineers choose this class of device:

• Accurate state‑of‑charge (SoC) estimation across load/temperature via Impedance Track
• SMBus/I2C host communication simplifies integration with embedded controllers
• Compact VQFN‑32 helps achieve high energy density in the pack

(Verify all device‑specific features against the selected, confirmed orderable MPN.)

Package, layout, and hardware integration notes

Although detailed pin functions and electrical limits depend on the confirmed variant and datasheet, the following general practices apply broadly to multicell fuel gauges in the bq40z5x family:

• Thermal pad and grounding: Solder the exposed thermal pad to a solid ground region with ample vias. This aids both thermal performance and analog measurement stability.
• Cell sense routing: Keep cell sense lines short, matched, and routed away from noisy high‑di/dt paths. Use RC filtering where the datasheet recommends.
• High‑current paths: Separate charger/discharger FET currents and gate‑drive traces from sensitive measurement nodes.
• Kelvin connections: Use Kelvin sense for pack voltage and current‑shunt measurements per TI guidance.
• Decoupling and filtering: Place recommended decoupling capacitors as close as possible to the device pins; implement any input filtering per TI’s reference schematics once the exact variant is confirmed.
• Programming/communication: Reserve access to SMBus/I2C lines for configuration, calibration, and in‑system updates.

Always conform to the specific reference design and layout guidance in the official TI datasheet for the exact MPN.

Ordering code decoding and what to confirm

TI package code “RSM” denotes the 32‑pin VQFN. The trailing “R” typically indicates tape‑and‑reel packaging. Because the provided code includes an extra digit (“BQ40Z557RSMR”), take the following steps before ordering:

1) Check the TI product page

• Compare against TI’s official orderable part numbers. For bq40z55, look for BQ40Z55RSMR (and any temperature/grade variants if applicable).

2) Validate against the datasheet

• Ensure the confirmed orderable matches the package code, pin count, and any revision identifiers in the datasheet orderable table.

3) Match electrical/feature needs

• Confirm the cell count (2–4S), protection features, authentication options (if needed), and supported chemistries align with your pack requirements.

4) Align programming and production flow

• Plan for configuration, calibration, and golden image processes appropriate to the confirmed variant. Coordinate with your CM for programming fixtures and test.

5) Record PCNs and revision control

• Capture TI product change notifications (PCNs) and lock the exact orderable code in your BOM to avoid unintended substitutions.

Lifecycle, compliance, and supply chain

• Lifecycle status: Not specified in the provided data. Check TI’s product page for current status and recommended replacements, if any.
• RoHS/REACH: Not specified in the provided data. TI typically publishes material compliance documents per orderable part number; verify after confirming the exact MPN.
• MSL/handling: Not specified. Follow TI’s packaging/handling guidance for VQFN devices.
• Availability: User-provided on-hand inventory is 0. Check authorized distributors and TI direct after confirming the MPN.

Environmental and regulatory note: IC‑level RoHS/REACH compliance does not constitute pack‑level safety or transport certification. Battery packs must meet applicable standards (for example, UN 38.3, IEC 62133) independent of the gauge IC.

Approved alternates and replacements

Policy guidance (pending confirmation of the exact variant):

• Stay within the TI bq40z5x family to preserve pin/package compatibility and firmware workflows.
• Prioritize orderables in the RSM (VQFN‑32) package to minimize PCB changes.
• The most likely intended part is Texas Instruments BQ40Z55RSMR; verify this match against your design requirements and documentation.

When choosing alternates, confirm at minimum:

• Identical package/pinout
• Same supported cell count (2–4S)
• Interface compatibility (SMBus/I2C)
• Algorithm/feature equivalence (Impedance Track and any required protection/authentication)

Sourcing checklist

To reduce back‑and‑forth and de‑risk procurement, confirm these items before placing an order:

• Exact MPN spelling (Texas Instruments BQ40Z55RSMR vs. BQ40Z557RSMR)
• Package and suffix codes: RSM (VQFN‑32), “R” for tape‑and‑reel
• Family and capabilities: bq40z5x; 2–4S support; SMBus/I2C; Impedance Track
• Temperature grade and any revision or firmware identifiers listed by TI
• RoHS/REACH documentation for the confirmed orderable
• Lead time and allocation status from authorized channels
• Programming/calibration plan (golden image, production tools) appropriate to the confirmed device

Frequently asked questions (FAQs)

Q: Is Texas Instruments BQ40Z557RSMR a valid TI ordering code?
A: We could not conclusively verify this exact code in public catalogs. It most closely matches BQ40Z55RSMR (bq40z55 in RSM VQFN‑32 package, tape‑and‑reel). Please confirm the intended MPN.

Q: What does the “RSMR” suffix indicate for TI parts like the BQ40Z55RSMR?
A: “RSM” denotes TI’s 32‑pin VQFN package code. The trailing “R” typically indicates tape‑and‑reel packaging.

Q: How many cells does the TI bq40z5x family support?
A: Typically 2–4 series Li‑ion/LiPo cells. Verify the exact range for your chosen variant in the TI datasheet.

Q: What host interface does the TI BQ40Z55/BQ40Z557 family use?
A: SMBus/I2C is standard for this family.

Q: Does the device include protection FET control, authentication, or cell balancing?
A: Not specified in the provided data. Some functions are common within the family, but confirm the exact capabilities for your final MPN in the official TI datasheet.

Q: Is there any on‑hand stock of Texas Instruments BQ40Z557RSMR?
A: The provided inventory indicates 0 units on hand. Check TI’s site and authorized distributors after confirming the exact orderable code.

Q: Where can I find authoritative specifications and orderable part numbers?
A: Use the TI product page and datasheet for the closest verified match:

• Product page: https://www.ti.com/product/BQ40Z55
• Datasheet: https://www.ti.com/lit/ds/symlink/bq40z55.pdf

Practical next steps

1) Confirm the intended MPN: Texas Instruments BQ40Z55RSMR vs. BQ40Z557RSMR.
2) Lock the verified orderable into your BOM and procurement systems.
3) Review the TI datasheet for electrical limits, register maps, and layout guidance specific to that part number.
4) Plan configuration/calibration using TI’s recommended workflow for the chosen bq40z5x device.
5) Gather compliance statements (RoHS/REACH) and evaluate supply availability.

Resources

• TI product page (bq40z55): https://www.ti.com/product/BQ40Z55
• TI datasheet (bq40z55): https://www.ti.com/lit/ds/symlink/bq40z55.pdf

If you confirm that your target is indeed the Texas Instruments BQ40Z55RSMR (or another specific bq40z5x variant), you can revisit key sections—specifications, lifecycle, and compliance—to populate exact values from the official datasheet and material content reports. Until then, treat BQ40Z557RSMR as an unverified code and proceed with the checks above to ensure a smooth sourcing and design‑in process.