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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Battery Management

Texas Instruments BQ20Z40PW

Name: BQ20Z40PW
Brand: Texas Instruments
SKU: BQ20Z40PW
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BQ20Z40PW

Manufacturer:: Texas Instruments

Category:: Battery Management

Package:: 20-TSSOP (0.173", 4.40mm Width)

Datasheet:: BQ20Z40PW.pdf

Description:: IC GAS GAUGE W/IMP TRACK 20TSSOP

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Product details

Overview

BQ20Z40PW from Texas Instruments is an SBS 1.1-compliant gas gauge IC with Impedance Track™ technology, designed for Li-ion/Li-polymer battery packs with 2–4 series cells. It integrates an 8-bit RISC CPU, dual delta-sigma ADCs (for current, voltage, and temperature), SMBus v1.1 interface, SHA-1 authentication, and full programmable protection logic-including primary/secondary overvoltage, overcurrent, and overtemperature detection. It operates in –40°C to +85°C and delivers <1% gas-gauge error over battery lifetime in notebook PC battery management systems.

For engineers reviewing the BQ20Z40PW datasheet, BQ20Z40PW pinout, BQ20Z40PW application, or BQ20Z40PW equivalent, key selection considerations include its 20-pin TSSOP (PW) package, 2.4–2.6 V supply range, 400 mA typical operating current (with bq29330), integrated coulomb counter with ±0.2 V SRP–SRN input range, and dual thermistor support for JEITA-compliant charging control.

Technical Context

The BQ20Z40PW implements a closed-loop gas-gauging architecture using patented Impedance Track™ technology that continuously models battery impedance to compute remaining capacity under varying discharge rates, temperatures, and aging states-without requiring full-charge/full-discharge learning cycles. Its integrating delta-sigma ADC measures current via SRP/SRN with 0.65 nVh fundamental resolution and supports auto-calibration of sense-resistor offset.

It functions as a system-level safety co-processor alongside the bq29330 analog front-end: the BQ20Z40PW handles digital computation, SMBus communication, and decision logic, while delegating high-speed analog monitoring (cell balancing, FET drive, fast overcurrent) to the AFE. Protection decisions are executed across two tiers-primary (reversible) and secondary (SAFE pin-triggered fuse blow)-enabling fail-safe battery pack shutdown.

Key Specifications

Parameter	Value and Actual Design Meaning
Supply Voltage	2.4 V to 2.6 V - fixed low-voltage rail enabling direct connection to regulated LDO output of battery pack; excludes higher-voltage cell monitoring paths.
Operating Current	400 mA typical (with bq29330) - total active-mode current draw for full gas-gauging, protection, and SMBus communication.
Coulomb Counter Input Range	±0.2 V across SRP–SRN - supports 5 mΩ to 20 mΩ sense resistors for charge/discharge current measurement up to ±40 A at 20 mΩ.
Temperature Sensing	Two external NTC inputs (TS1/TS2) + internal sensor - enables independent thermal monitoring of cell stack and PCB for JEITA profile enforcement.
SMBus Interface	v1.1 compliant with PEC, 10–100 kHz clock - ensures interoperability with host controllers implementing Smart Battery System specification.
Gas-Gauging Accuracy	Better than 1% error over battery lifetime - achieved via real-time impedance modeling, eliminating need for periodic recalibration or learning cycles.
Data Retention	10 years in flash memory - preserves lifetime logging data (max/min voltage, temperature, current, power) for warranty analysis and field failure diagnostics.

Pinout & Package

20-pin TSSOP (PW) package, 6.4 mm × 4.4 mm × 1.2 mm max height, RoHS-compliant NiPdAu lead finish, MSL Level-1 (260°C peak reflow).

Pin/Terminal	Circuit Role	Design Meaning
1 XALERT	Input from bq29330	Receives asynchronous fault alert from AFE to trigger immediate safety response without SMBus polling delay.
2 TS2 / 3 TS1	Analog thermistor inputs	High-impedance (8 MΩ) differential-capable inputs for dual NTC thermistors; enable independent charge/discharge thermal thresholds per JEITA.
4 CLKOUT	32.768 kHz output	Drives bq29330's low-frequency oscillator; eliminates need for external crystal and reduces BOM count in smart battery designs.
6 PFIN	Secondary protector status input	Monitors 2nd-level protection output from external hardware (e.g., fuse controller); enables coordinated multi-tier safety escalation.
7 SAFE	Active-high safety output	Asserts to blow in-line fuse during critical faults (e.g., safety overvoltage, cell imbalance, AFE comms failure); irreversible shutdown path.
8 SMBD / 10 SMBC	SMBus bidirectional data/clock	Open-drain I/O pins compliant with SMBus v1.1 timing; support master/slave modes and packet error checking (PEC).
14 SRP / 15 SRN	Current-sense differential inputs	Accept bipolar ±0.2 V signal from sense resistor; integrated auto-calibration cancels offset drift for long-term coulomb counting accuracy.
19 VCELL+ / 20 VCELL−	Scaled cell voltage inputs	Receive multiplexed, scaled cell voltage signals from bq29330; used for impedance calculation and individual cell health assessment.

Key Features

Feature	Design Value
Impedance Track™ gas gauging	Delivers <1% remaining capacity error over battery lifetime by dynamically modeling cell impedance vs. SOC, temperature, and aging-no full-cycle learning required.
Dual-level protection architecture	Separates reversible (PRES-controlled FETs) and irreversible (SAFE-triggered fuse blow) responses, enabling granular safety policy enforcement per UL/IEC 62133.
Lifetime data logging	Stores 12+ parameters (e.g., lifetime min/max cell voltage, discharge current, temperature) in nonvolatile flash for field failure root-cause analysis and warranty validation.
JEITA-compliant charging control	Supports split-temperature-range profiles with independent voltage/current limits per zone, enabling safe fast-charging across wide ambient conditions (–40°C to +85°C).
SHA-1 authentication	Verifies host identity before allowing access to protected registers (e.g., calibration, keys), preventing unauthorized firmware modification or counterfeit battery insertion.

Applications

Notebook PC Battery Packs	Medical Portable Devices
Use Scenario: Integrated into removable Li-ion battery packs for business-class laptops requiring precise runtime prediction and safety compliance. IC Role / Device Role / Timing Role: Primary gas gauge and safety manager; communicates SoC, SoH, and fault status via SMBus to EC/BIOS; triggers SAFE pin on critical overvoltage. Use Value: Enables <1% runtime estimation error across 300+ cycles and satisfies UL 2054/IEC 62133 secondary protection requirements without external comparators.	Use Scenario: Used in sealed, non-removable battery modules for portable ultrasound and infusion pumps where regulatory traceability and failure logging are mandatory. IC Role / Device Role / Timing Role: Lifetime data logger and JEITA-enforcing charger coordinator; stores min/max voltage/temperature for FDA audit trails; controls charge current based on dual thermistor readings. Use Value: Provides 10-year flash-retained diagnostic logs and dual independent thermal zones-meeting IEC 62304 software safety classification and ISO 13485 traceability requirements.
Test & Measurement Equipment	Industrial Handheld Instruments
Use Scenario: Embedded in rechargeable battery packs for portable oscilloscopes and multimeters requiring stable runtime under variable load and temperature. IC Role / Device Role / Timing Role: Real-time coulomb counter and cell-balancing enabler; uses Impedance Track™ to maintain accuracy during pulsed loads (e.g., scope trigger bursts); balances cells during constant-voltage phase. Use Value: Achieves consistent 92–95% depth-of-discharge utilization across 500 cycles, extending usable pack energy by 8% versus conventional gauges.	Use Scenario: Deployed in explosion-proof handheld gas detectors with 2–4S Li-ion packs operating in harsh industrial environments (–20°C to +70°C). IC Role / Device Role / Timing Role: Dual-thermistor safety monitor and SMBus telemetry hub; reports TS1/TS2 temperatures separately to host for zone-specific derating; asserts SAFE on open-thermistor fault. Use Value: Eliminates need for discrete thermal supervisors and provides certified fault reporting for ATEX/IECEx compliance documentation.

Notebook PC Battery Packs

Medical Portable Devices

Use Scenario: Integrated into removable Li-ion battery packs for business-class laptops requiring precise runtime prediction and safety compliance.

IC Role / Device Role / Timing Role: Primary gas gauge and safety manager; communicates SoC, SoH, and fault status via SMBus to EC/BIOS; triggers SAFE pin on critical overvoltage.

Use Value: Enables <1% runtime estimation error across 300+ cycles and satisfies UL 2054/IEC 62133 secondary protection requirements without external comparators.

Use Scenario: Used in sealed, non-removable battery modules for portable ultrasound and infusion pumps where regulatory traceability and failure logging are mandatory.

IC Role / Device Role / Timing Role: Lifetime data logger and JEITA-enforcing charger coordinator; stores min/max voltage/temperature for FDA audit trails; controls charge current based on dual thermistor readings.

Use Value: Provides 10-year flash-retained diagnostic logs and dual independent thermal zones-meeting IEC 62304 software safety classification and ISO 13485 traceability requirements.

Test & Measurement Equipment

Industrial Handheld Instruments

Use Scenario: Embedded in rechargeable battery packs for portable oscilloscopes and multimeters requiring stable runtime under variable load and temperature.

IC Role / Device Role / Timing Role: Real-time coulomb counter and cell-balancing enabler; uses Impedance Track™ to maintain accuracy during pulsed loads (e.g., scope trigger bursts); balances cells during constant-voltage phase.

Use Value: Achieves consistent 92–95% depth-of-discharge utilization across 500 cycles, extending usable pack energy by 8% versus conventional gauges.

Use Scenario: Deployed in explosion-proof handheld gas detectors with 2–4S Li-ion packs operating in harsh industrial environments (–20°C to +70°C).

IC Role / Device Role / Timing Role: Dual-thermistor safety monitor and SMBus telemetry hub; reports TS1/TS2 temperatures separately to host for zone-specific derating; asserts SAFE on open-thermistor fault.

Use Value: Eliminates need for discrete thermal supervisors and provides certified fault reporting for ATEX/IECEx compliance documentation.

Equivalent & Alternatives

The following parts are listed as comparable options for similar gas gauge and battery protection applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
BQ20Z45DBTR	Same Impedance Track™ core but in 30-pin TSSOP; adds integrated 5-V LDO and enhanced cell balancing drive capability.	Targeted at higher-cell-count (up to 6S) packs requiring internal LDO regulation and stronger FET gate drive.	Select BQ20Z45DBTR only if board layout accommodates larger footprint and design requires on-chip 5-V supply for external circuitry.
BQ20Z65-R1	Successor device with extended temperature range (–40°C to +105°C), improved SMBus robustness, and updated SHA-1 implementation per NIST SP 800-131A.	Required for new designs targeting automotive cabin modules or industrial edge devices needing >85°C operation and modern crypto compliance.	BQ20Z65-R1 is TI's recommended replacement for new designs; BQ20Z40PW remains viable for legacy repair and cost-sensitive consumer applications.

Compared with BQ20Z40PW, BQ20Z45DBTR offers expanded analog integration but increases PCB area and cost, while BQ20Z65-R1 delivers broader environmental tolerance and updated security-making it the preferred choice for next-generation designs despite higher unit price.

Availability

BQ20Z40PW is available at Aetrix Electronics and suitable for notebook PC battery packs, medical portable instrumentation, test equipment, and industrial handheld instruments requiring stable component supply and long-term lifecycle support.

Supply support for BQ20Z40PW 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 BQ20Z40PW belongs to TI's Smart Battery Fuel Gauge product line, engineered specifically for SBS 1.1-compliant Li-ion/Li-polymer battery packs requiring high-accuracy fuel gauging, multi-tier safety, and lifetime data integrity in portable computing and medical applications.

FAQ

What is the primary function of the BQ20Z40PW in a smart battery system?

The BQ20Z40PW serves as the central gas gauge and safety manager in SBS 1.1-compliant battery packs. It computes remaining capacity using Impedance Track™ technology, monitors cell voltages and temperatures via the bq29330 AFE, enforces primary and secondary protection policies, and communicates all telemetry-including SoC, SoH, and fault status-over SMBus to the host system. Its role is indispensable for accurate runtime prediction and regulatory safety compliance in the BQ20Z40PW-based battery solution.

Does the BQ20Z40PW require an external crystal or oscillator?

No, the BQ20Z40PW integrates both a 4.194 MHz high-frequency oscillator and a 32.768 kHz low-frequency oscillator. The CLKOUT pin (Pin 4) provides the 32.768 kHz signal directly to the bq29330 AFE, eliminating the need for external crystals or oscillators. This integration reduces bill-of-materials cost and PCB area in smart battery designs using the BQ20Z40PW.

How does the BQ20Z40PW handle battery temperature monitoring for JEITA compliance?

The BQ20Z40PW supports two independent external NTC thermistor inputs (TS1 and TS2) plus an internal temperature sensor. It allows separate configuration of charge/discharge thresholds per thermistor, enabling full JEITA profile implementation-such as reducing charge current above 45°C or suspending charge below 0°C. This dual-input capability is essential for meeting JEITA guidelines in the BQ20Z40PW-based battery management system.

What protection features does the BQ20Z40PW provide beyond basic overvoltage and overcurrent?

Beyond standard cell overvoltage and charge/discharge overcurrent, the BQ20Z40PW implements secondary-level safety features including safety overvoltage/undervoltage, safety overtemperature (with independent alarms per thermistor), cell imbalance detection (active and at rest), open thermistor detection, and AFE communication fault monitoring. These are enforced via the SAFE pin (Pin 7) to trigger irreversible fuse blow-ensuring robust compliance with UL 2054 and IEC 62133 in the BQ20Z40PW safety architecture.

Is the BQ20Z40PW still recommended for new designs?

No-Texas Instruments explicitly marks the BQ20Z40PW as "Not Recommended for New Designs" (NRND) in its official documentation and packaging addendum. While fully functional and supported for legacy repair and maintenance, TI recommends migrating to successors like the BQ20Z65-R1 for new projects due to its extended temperature range, updated cryptographic compliance, and enhanced SMBus robustness. The BQ20Z40PW remains available for existing production continuity.

BQ20Z40PW Specifications

Product attributes: Attribute value

Manufacturer:: Texas Instruments

Series:: Impedance Track™

Package/Case:: 20-TSSOP (0.173", 4.40mm Width)

Packaging:: Bulk

Product Status:: Not For New Designs

Function:: Battery Monitor

Battery Chemistry:: Lithium Ion/Polymer

Number of Cells:: 2 ~ 4

Fault Protection:: Over Current, Over Temperature, Over/Under Voltage, Short Circuit

Interface:: -

Operating Temperature:: -40°C ~ 85°C (TA)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 20-TSSOP

BQ20Z40PW FAQ

1.How can I place an order for BQ20Z40PW through Aetrix?

Please submit a Request for Quotation (RFQ) for BQ20Z40PW on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for BQ20Z40PW reliable?

The price and inventory of BQ20Z40PW are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BQ20Z40PW is usually 5 days.

3.What payment methods are accepted for BQ20Z40PW?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BQ20Z40PW transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BQ20Z40PW?

BQ20Z40PW orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BQ20Z40PW order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for BQ20Z40PW?

For technical support, including BQ20Z40PW datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BQ20Z40PW requirements.

6.How does Aetrix verify that BQ20Z40PW is sourced from the original manufacturer or authorized distributors?

All BQ20Z40PW products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that BQ20Z40PW meets industry standards.

7.What is the process for return or replacement of BQ20Z40PW?

All BQ20Z40PW units undergo pre-shipment inspection (PSI). If there is an issue with BQ20Z40PW, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The BQ20Z40PW part is unused and in its original packaging.

Return procedure for BQ20Z40PW:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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