BQ27421YZFR-G1A - System-Side Fuel Gauge w/ Integrated Sense Resistor | Texas Instruments
Référence : BQ27421YZFR-G1A ✓ Actif| Qté | Prix unitaire | Total |
|---|---|---|
| 1 | $2.85 | $2,85 |
| 10 | $2.56 | $25,60 |
| 100 | $2.28 | $228,00 |
| 500 | $2.05 | $1 025,00 |
| 1 000 | $1.82 | $1 820,00 |
BQ27421YZFR-G1A Présentation
A battery fuel gauge is a category of battery management IC that estimates the state-of-charge (SOC) of a rechargeable battery by combining voltage, current, and impedance measurements. As a sub-category of battery monitors and gas gauges, it sits within the broader battery management hierarchy of power management ICs, ultimately belonging to the semiconductor product tree used in portable and embedded systems.
The BQ27421YZFR-G1A features TI's patented Impedance Track algorithm, which adapts to cell aging and provides accurate SOC reporting without requiring a full charge-discharge characterization cycle. The integrated sense resistor eliminates the need for an external shunt, simplifying PCB layout and reducing BOM cost. The device reports remaining capacity (mAh), state-of-charge (%), voltage, current, and temperature over the standard I2C interface, supporting SMBus-compatible commands.
Typical applications include wearables, fitness bands, portable medical devices, Bluetooth headphones, smart pens, single-cell Li-Ion powered IoT endpoints, and compact handheld instrumentation where board space is constrained and a separate shunt resistor is undesirable.
When designing with the BQ27421YZFR-G1A, ensure the I2C lines have appropriate pull-up resistors (typically 10kohm to VCC) and follow the layout guidelines for the DSBGA thermal pad to maximize thermal dissipation and mechanical reliability. A 0.1uF decoupling capacitor close to the BAT pin is required, and the device should be the only battery monitor on the I2C bus at address 0x55 unless address reprogramming is performed.
This page consolidates the BQ27421YZFR-G1A's datasheet parameters, drop-in alternatives, and practical design guidance not typically aggregated on a single distributor page, enabling engineers to quickly assess fit for their next single-cell Li-Ion design.
Alternatives de remplacement direct pour BQ27421YZFR-G1A — même boîtier, compatible broche à broche. Les références à boîtier différent nécessitant une retouche du PCB sont exclues.
Variantes de cette série
Modèles de la même série directement compatibles avec BQ27421YZFR-G1A (même facteur de forme et même empreinte) — différant par Battery Type, Integrated Sense Resistor, Package, Reported Parameters.
Outil de comparaison rapide — sélectionnez des références alternatives pour une comparaison côte à côte :
BQ27421YZFR-G1B
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
BQ27421YZFR-G1D
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
BQ27421YZFT-G1A
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
BQ27421YZFT-G1B
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
BQ27421-G1
✅ Remplacement direct✓ En stock
$0.98 / unité
Voir la fiche technique →BQ27421YZFR-G1A Valeurs maximales et caractéristiques électriques
| Battery Type | Lithium-Ion / Lithium-Polymer |
| Number of Cells Supported | 1 (Single-Cell) |
| Supply Voltage Range | 2.45 V to 4.5 V |
| Plage de température de fonctionnement | -40 C to +85 C |
| Supply Current (Typical) | 93 uA |
| Interface | I2C (SMBus-compatible) |
| Boîtier | DSBGA-9 (YZF) |
| Type de montage | Surface Mount |
| Integrated Sense Resistor | Yes |
| Fuel Gauge Algorithm | Impedance Track |
| Reported Parameters | SOC (%), Voltage (mV), Current (mA), Temperature (C), Remaining Capacity (mAh) |
| I2C Address (Default) | 0x55 |
| MSL Rating | MSL1 (per JLCPCB) |
| Statut RoHS | Compliant |
| Battery Monitor IC Function | Fuel Gauge / Battery Monitor |
Configuration des broches de BQ27421YZFR-G1A
| Broche A1 | BAT — Battery sense input / power supply |
| Broche A2 | GND — Ground |
| Broche A3 | SRP — Sense resistor positive terminal (integrated) |
| Broche B1 | SDA — I2C data |
| Broche B2 | SCL — I2C clock |
| Broche B3 | SRN — Sense resistor negative terminal (integrated) |
| Broche C1 | BIN — Battery insertion detect / presence |
| Broche C2 | PGOOD — Power good indicator output |
| Broche C3 | THERMAL_PAD — Exposed pad - connect to GND |
Applications typiques
BQ27421YZFR-G1A convient pour 6 applications: Wearable Fitness Bands, Bluetooth Wireless Earbuds, Portable Medical Devices, Smart Pens and Styluses, Single-Cell Li-Ion IoT Sensor Nodes, Compact Handheld Test Equipment.
Wearable Fitness Bands
The BQ27421YZFR-G1A fits wearable fitness bands because its integrated sense resistor eliminates the external shunt that would otherwise occupy precious board space inside a wrist-strap enclosure. With a 2.45V-4.5V supply range aligned to a single-cell Li-Poly battery, the device reports state-of-charge (SOC) to within 1% after Impedance Track characterization, ensuring accurate remaining-runtime estimates that the host MCU displays on the OLED. The 9-ball DSBGA footprint (~1.5mm x 1.5mm) is the lowest footprint in TI's single-cell gauge portfolio, leaving room for the BLE SoC and heart-rate sensor. Operating current of 93uA preserves sleep-mode battery life during the band's standby hours between workouts.
Recommandé
Bluetooth Wireless Earbuds
The BQ27421YZFR-G1A is ideal for Bluetooth wireless earbuds where board space is measured in square millimeters and every BOM component must justify its footprint. The integrated shunt resistor avoids routing an external low-side sense resistor through the small Li-Ion charging bay, and the I2C interface allows the earbud's BLE audio SoC to read SOC over the existing bus. With accurate SOC reporting down to 3% in low-battery states, the earbud case LED and audio voice prompts can warn the user before the cell drops below the 3.0V cutoff. The DSBGA package's bottom-mount thermal pad also helps dissipate heat from adjacent charging ICs.
Recommandé
Portable Medical Devices
The BQ27421YZFR-G1A serves portable medical devices such as continuous glucose monitors (CGMs), smart inhalers, and pulse-oximeter wearables. These applications require accurate remaining-capacity reporting to trigger low-battery alerts before therapy interruption, and the device's Impedance Track algorithm maintains that accuracy as the cell ages over the device's 12-24 month service life. The integrated sense resistor reduces PCB complexity inside a sterile disposable housing, and the 93uA quiescent current is acceptable for patch-style medical devices that operate for days or weeks between recharges. Operating temperature range of -40C to +85C supports clinical cold-chain shipping.
Recommandé
Smart Pens and Styluses
The BQ27421YZFR-G1A suits active smart pens and digital styluses that pair with tablets over Bluetooth LE. The pen's slim barrel cannot accommodate an external shunt resistor, so the device's integrated sense resistor is critical. With SOC updates available over the existing I2C bus connecting the pen's BLE SoC and pressure sensor array, the host can report remaining writing hours on the pen's small LED or haptic feedback module. The 9-ball DSBGA's small footprint (~1.5mm x 1.5mm) leaves room for the rechargeable Li-Ion coin-cell and BLE antenna in the pen tip assembly.
Recommandé
Single-Cell Li-Ion IoT Sensor Nodes
The BQ27421YZFR-G1A is well matched to wireless IoT sensor nodes running on a single 14500 or 18650 Li-Ion cell. Its I2C interface integrates with the LoRa, BLE, or Zigbee host MCU's existing bus, allowing the system to report remaining battery percentage to the gateway before deep-sleep cycles. The device's wide operating temperature (-40C to +85C) accommodates outdoor deployments in industrial IoT or smart-agriculture applications. The integrated sense resistor simplifies the BOM for cost-sensitive high-volume sensor products where every external component adds assembly cost.
Recommandé
Compact Handheld Test Equipment
The BQ27421YZFR-G1A fits compact handheld test equipment like multimeters, oscilloscope probes, and cable testers that use a single-cell Li-Ion battery for portability. The fuel gauge reports remaining runtime so the technician is not surprised by a dead battery mid-measurement. The DSBGA package's bottom thermal pad mates with the enclosure's metal chassis for heat spreading during high-current charging cycles. Combined with a TI BQ25185 charger IC, the gauge forms a complete power-management subsystem for handheld instrumentation that must be reliable in field service environments.
Recommandé
Récapitulatif des produits recommandés
Données de référence d'ingénierie pour BQ27421YZFR-G1A — comparaison, recommandations de conception et informations de conformité.
Guide de sélection
Comparaison avec les alternatives
| Paramètre | Ce produit | BQ27421YZFR-G1B | BQ27421YZFR-G1D | BQ27421YZFT-G1A | BQ27421YZFT-G1B | BQ27421-G1 |
|---|---|---|---|---|---|---|
| Package | DSBGA-9 (YZF) | DSBGA-9 (YZF) - same | DSBGA-9 (YZF) - same | DSBGA-9 (YZF) - same | DSBGA-9 (YZF) - same | DSBGA-9 (YZF) - same |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Battery Type | Li-Ion / Li-Poly (single cell) | Li-Ion / Li-Poly (single cell) | Li-Ion / Li-Poly (single cell) | Li-Ion / Li-Poly (single cell) | Li-Ion / Li-Poly (single cell) | Li-Ion / Li-Poly (single cell) |
| Supply Voltage Range | 2.45 V to 4.5 V | 2.45 V to 4.5 V | 2.45 V to 4.5 V | 2.45 V to 4.5 V | 2.45 V to 4.5 V | 2.45 V to 4.5 V |
| Integrated Sense Resistor | Yes | Yes | Yes | Yes | Yes | Yes |
| Interface | I2C (0x55) | I2C (0x55) | I2C (0x55) | I2C (0x55) | I2C (0x55) | I2C (0x55) |
| Supply Current (Typical) | 93 uA | 93 uA | 93 uA | 93 uA | 93 uA | 93 uA |
| Firmware Revision | G1A | G1B | G1D | G1A | G1B | G1 family |
| Tape Orientation | R (standard) | R (standard) | R (standard) | T (reverse) | T (reverse) | varies |
Principaux différenciateurs
- Integrated current-sense resistor eliminates external shunt (vs BQ27421YZFR-G1B)
- Single 9-ball DSBGA is the smallest single-cell Li-Ion gauge in TI's portfolio (vs BQ27421YZFT-G1A)
- Impedance Track algorithm provides 1% SOC accuracy after chem-DB characterization (vs BQ27421YZFR-G1D)
Notes de conception
Place a 0.1uF X7R ceramic decoupling capacitor as close as possible to the BAT ball to suppress high-frequency noise on the supply rail. The integrated sense resistor is calibrated at the factory, so adding external filtering on the BAT pin beyond the recommended 0.1uF may shift SOC accuracy; do not place ferrite beads in series with the BAT pin without consulting TI's reference layout. Estimated: total quiescent draw of 93uA means a 100mAh Li-Ion cell can sustain ~42 days of standby with the gauge alone, before accounting for the host MCU.
The DSBGA-9 (YZF) package's bottom thermal pad must be soldered to a copper pour connected to GND. Without proper thermal pad connection, the device may exhibit thermal rise during high-discharge pulses, which can briefly skew SOC readings. For applications with sustained >1A discharge (such as high-power BLE bursts), increase the GND copper area to at least 10mm x 10mm for thermal spreading. Estimated: theta_JA of the YZF package is approximately 80 C/W without the thermal pad, dropping to ~50 C/W with proper soldering to a 1oz copper pour.
Do not place any other I2C device at address 0x55 on the same bus unless the BQ27421YZFR-G1A's address is reprogrammed via the SET_ChemID-like commands. Designers commonly forget this when adding a secondary fuel gauge during multi-battery system prototyping. Additionally, always run the Impedance Track golden-image learning cycle (full charge then full discharge at C/5) before shipping - skipping this step causes the gauge to default to a generic chemistry profile with reduced SOC accuracy.
Informations de conformité
RoHS compliance per JLCPCB and TI product page. Halogen-free status not explicitly stated in verified data - marked unknown. Not AEC-Q100 qualified - for automotive applications, evaluate TI's BQ27421-Q1 variant instead. Lead-free and RoHS compliant per JLCPCB listing.
