Texas Instruments BQ27Z561YPHT

Overview

BQ27Z561YPHT from Texas Instruments is a flash-programmable, Impedance Track™ battery gas gauge IC for 1-series Li-ion/Li-polymer battery packs, featuring dual independent ADCs (coulomb counter + general-purpose), SHA-256 authentication, and support for 1 mΩ sense resistors. It operates down to 2 V and delivers <1 µV typical input offset error in coulomb counting - enabling accurate state-of-charge estimation in deeply discharged portable health devices.

For engineers reviewing the BQ27Z561YPHT datasheet, BQ27Z561YPHT pinout, BQ27Z561YPHT application, or BQ27Z561YPHT equivalent, key selection considerations include its dual-ADC architecture for simultaneous current/voltage sampling, 400 kHz I²C + HDQ one-wire interface flexibility, ultra-low-power SLEEP/DEEP SLEEP modes (<11 µA / <9 µA), integrated 1.8 V LDO, and Kelvin-sense BAT/BAT_SNS configuration for high-accuracy pack-side gauging.

Technical Context

The BQ27Z561YPHT implements a Harvard-architecture RISC CPU running up to 4.2 MHz with 32 kB program flash and 4 kB data flash, executing TI's Impedance Track™ algorithm to compute real-time state-of-charge, full-charge capacity, and state-of-health. Its coulomb counter uses a delta-sigma integrating ADC with 3.74 µV LSB resolution and <1 µV offset error, while the second 16-bit delta-sigma ADC supports 14–15 effective bits across BAT, TS, BAT_SNS, and internal references.

It integrates two oscillators - a 65.536 kHz low-frequency oscillator (LFO) and a 16.78 MHz high-frequency oscillator (HFO) - with HFO locked to LFO for timing stability. Power management includes four functional modes (NORMAL, SLEEP, DEEP SLEEP, OFF), where SLEEP and DEEP SLEEP maintain coulomb counting at <11 µA and <9 µA respectively, enabled by the internal 1.8 V REG18 LDO and dual voltage references (REF1 = 1.21 V ±80 ppm/°C for CC/LDO; REF2 = 1.21 V ±20 ppm/°C for ADC).

Key Specifications

Pinout & Package

Package: 12-pin DSBGA (YPH), 1.69 mm × 2.07 mm, ball pitch 0.4 mm - optimized for ultra-compact battery pack integration with minimal PCB footprint.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar battery fuel gauging applications.

Compared with BQ27Z561DYYR, the BQ27Z561YPHT offers superior thermal performance and 40% smaller area for ultra-compact battery modules; compared with BQ28Z610RTWR, it provides HDQ compatibility and lower-voltage optimization essential for 1S consumer electronics - making it the only choice for thin-profile, single-wire, 1-series Li-ion gauging.

Availability

BQ27Z561YPHT is available at Aetrix Electronics and suitable for smartphones, tablet computing, and wearable health devices requiring stable component supply, long-lifecycle support, and consistent manufacturing traceability.

Supply support for BQ27Z561YPHT includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and power management technologies, with decades of leadership in battery management ICs.

The BQ27Z561YPHT belongs to TI's Impedance Track™ gas gauge product line, engineered specifically for high-accuracy, low-power, pack-integrated fuel gauging in space-constrained 1-series Li-ion applications - emphasizing security, longevity, and real-time impedance-based state estimation.

FAQ

What is the minimum sense resistor value supported by the BQ27Z561YPHT?

The BQ27Z561YPHT supports sense resistors as low as 1 mΩ, enabled by its coulomb counter's <1 µV typical input offset error and ±100 mV differential input range. This allows accurate current measurement even at high discharge rates while minimizing power loss and heat generation in compact battery packs - a key requirement for smartphones and wearables where thermal headroom is limited. The BQ27Z561YPHT achieves this using an integrating delta-sigma ADC with factory-calibrated offset compensation.

Does the BQ27Z561YPHT support both I²C and HDQ communication simultaneously?

No, the BQ27Z561YPHT does not support I²C and HDQ simultaneously. The SDA/HDQ pin is shared and configurable: once switched to HDQ mode via firmware command, the change is irreversible and I²C functionality is disabled. I²C remains active by default at power-up. Engineers must select the interface early in design - I²C for high-speed host access, HDQ for pin-constrained systems requiring single-wire communication. The BQ27Z561YPHT datasheet specifies strict HDQ timing parameters including tRST (2.2 s reset) and tCYCD (190–250 µs device-to-host cycle).

How does the BQ27Z561YPHT handle temperature measurement?

The BQ27Z561YPHT supports dual temperature sensing: an integrated internal sensor (±0.19 mV/°C drift) for rapid pack-level thermal estimation, and an external NTC thermistor interface on the TS pin with internal 18 kΩ pull-up for precise cell-level monitoring. Both inputs route through the ADC multiplexer, allowing software-selectable sampling. The BQ27Z561YPHT uses these measurements in Impedance Track™ modeling and JEITA-compliant charge control - for example, scaling charging current based on real-time TS readings. Calibration data is stored in flash and applied automatically during conversion.

What are the power consumption differences between SLEEP and DEEP SLEEP modes in the BQ27Z561YPHT?

In SLEEP mode, the BQ27Z561YPHT consumes <11 µA (typical) while maintaining periodic coulomb counting and data updates at user-defined intervals. In DEEP SLEEP mode, current drops further to <9 µA (typical), with longer intervals between measurements and reduced internal activity - ideal for extended storage or low-duty-cycle applications. Both modes retain RAM contents and flash state; only OFF mode (<1.9 µA) disables the REG18 LDO and requires CE low assertion. The BQ27Z561YPHT transitions between these states via firmware commands, with timing controlled by the internal LFO (65.536 kHz).

Is the BQ27Z561YPHT pin-compatible with other members of the BQ27Zxx family?

The BQ27Z561YPHT is not pin-compatible with other BQ27Zxx variants such as BQ27Z561DYYR (WSON package) or BQ27Z561YFPT (different ball map). While functionally identical, the YPHT variant uses a 12-ball DSBGA (YPH) layout with specific pin assignments (e.g., BAT at D2, CE at D3, TS at B1) defined in the mechanical drawing SLUSCY0C. Substituting packages requires PCB redesign due to differing ball pitch (0.4 mm), footprint (1.69 × 2.07 mm), and thermal pad configuration. Always verify package drawings before migration - the BQ27Z561YPHT's compact size is intentional for ultra-thin battery modules.