HT45F8640 - 8-bit BMS Flash MCU, 3-7 Cell Li-ion | Holtek
Référence : HT45F8640 ⚠ Dernier achat| Qté | Prix unitaire | Total |
|---|---|---|
| 1 | $1.85 | $1,85 |
| 10 | $1.66 | $16,60 |
| 100 | $1.42 | $142,00 |
| 500 | $1.2 | $600,00 |
| 1 000 | $1.05 | $1 050,00 |
HT45F8640 Présentation
A BMS microcontroller is a specialized type of 8-bit microcontroller unit within the power management IC hierarchy, combining an MCU core with dedicated battery-monitoring analog front-end circuitry. Unlike general-purpose MCUs, BMS devices such as the HT45F8640 integrate cell voltage monitoring, protection FET gate drivers, and high-voltage tolerant front ends, reducing external component count in battery pack designs.
Key features include the accumulative cell voltage monitor, which measures an accumulative voltage from cell 1 to cell N and outputs a divide-by-N voltage through an analog multiplexer with ±0.5% accuracy. Integrated discharge and charge N-type MOSFET gate drivers eliminate external gate-drive ICs, while a high accuracy voltage regulator powers the core from the high-voltage pack rail. The device also provides a multi-channel ADC (up to 5 channels) and true EEPROM for storing calibration data and serial numbers.
Architecturally, the HT45F8640 is based on Holtek's high-performance 8-bit RISC core with Flash multi-programming capability, enabling field firmware updates. The dedicated analog modules are tightly coupled to the core, allowing fast protection loops for overcharge and overdischarge conditions.
Typical applications include 3S to 7S Li-ion battery packs for power tools, e-bikes, portable medical devices, and backup power systems, where integrated cell monitoring and FET drive reduce BOM cost.
Design consideration: plan your end-of-life strategy now - Holtek has issued a formal EOL notification for the HT45F8640/HT45F8650, with the last purchase date of October 07, 2026.
This page synthesizes the EOL notification, drop-in family alternatives, and design guidance not found on standard distributor pages.
Alternatives de remplacement direct pour HT45F8640 — même boîtier, compatible broche à broche. Les références à boîtier différent nécessitant une retouche du PCB sont exclues.
Outil de comparaison rapide — sélectionnez des références alternatives pour une comparaison côte à côte :
Aucune alternative de remplacement direct disponible pour ce produit.
Demander des alternativesHT45F8640 Valeurs maximales et caractéristiques électriques
| Core Architecture | 8-bit high performance RISC |
| Product Type | BMS Flash MCU with accumulative cell voltage monitor |
| Flash Program Memory | 4 KB |
| RAM Data Memory | 256 B |
| EEPROM | Yes, true EEPROM for calibration data and serial numbers |
| Battery Cell Count | 3 to 7 cell Li-ion |
| Maximum Input Voltage | 36 V |
| Cell Voltage Monitor Accuracy | ±0.5% |
| Voltage Monitor Topology | Accumulative 1-to-N monitor with divide-by-N analog multiplexer |
| Gate Drivers | Discharge N-type MOSFET gate driver, charge N-type MOSFET gate driver |
| On-chip Voltage Regulator | High accuracy voltage regulator |
| ADC Channels | Up to 5 channels |
| Boîtier | 28 SSOP-A |
| Type de montage | Surface Mount |
| Flash Programming | Multi-programming (reprogrammable) |
Guide de configuration des broches du HT45F8640 28 ssop-a
Configuration des broches du HT45F8640 (boîtier 28 ssop-a). Ce circuit intégré numérique comprend des GPIO, des interfaces de communication (UART, SPI, I2C) et des broches d'alimentation. Consultez la fiche technique du fabricant pour les fonctions alternatives des broches et les options de configuration. Indispensable pour la conception de systèmes embarqués et la conception de circuits imprimés.
Aucune donnée de brochage détaillée disponible pour HT45F8640.
Consultez la fiche technique pour la configuration complète des broches.
Applications typiques
HT45F8640 convient pour 6 applications: 3S-7S Li-ion Battery Pack Protection, Power Tool Battery Packs, E-bike and Light Electric Vehicle Batteries, Portable Medical Device Batteries, UPS and Backup Power Systems, Smart Battery Authentication and Fuel Gauging.
3S-7S Li-ion Battery Pack Protection
The HT45F8640's core application is protection and management of 3 to 7 cell Li-ion rechargeable packs. Its accumulative cell voltage monitor resolves individual cell voltages with ±0.5% accuracy through a divide-by-N analog multiplexer, enabling precise overcharge (typically above 4.2V per cell) and overdischarge threshold enforcement in firmware. The integrated discharge and charge N-type MOSFET gate drivers directly control the pack's protection FETs without external gate-driver ICs, cutting BOM cost and board area. The 36V maximum input rating comfortably covers 7S packs at about 29.4V full charge, with margin for transient conditions during charge termination.
Recommandé
Power Tool Battery Packs
Cordless power tool packs are typically 4S to 7S Li-ion configurations subject to high discharge currents and mechanical abuse. The HT45F8640 fits this environment because its dual N-type MOSFET gate drivers switch large protection FETs directly, and firmware in the 4KB Flash implements short-circuit, overcurrent, and thermal protection loops with fast response. The true EEPROM stores pack serial numbers, cycle counts, and calibration data for brand authentication and field service. Because the analog front end and MCU are on one die in a compact 28 SSOP-A package, protection PCBs can be folded into tight cylindrical pack enclosures typical of drill and impact-driver batteries.
Recommandé
E-bike and Light Electric Vehicle Batteries
E-bike packs in the 24V to 29.4V class map directly to the HT45F8640's 7S support and 36V maximum input rating. The ±0.5% cell monitoring accuracy matters because cell imbalance in used packs accelerates capacity fade; firmware can trigger balancing decisions and communicate state-of-charge estimates to the vehicle display. The high accuracy voltage regulator derives low-voltage core power from the pack rail, surviving the wide input range between deep discharge and full charge. Integrated gate drivers handle both charge-path and discharge-path N-MOSFETs used by charger interlock and motor current switching in the battery enclosure.
Recommandé
Portable Medical Device Batteries
Battery-powered medical devices such as infusion pumps, portable monitors, and diagnostic instruments require accurate pack state reporting and tamper-evident authentication. The HT45F8640's ±0.5% monitor accuracy supports conservative runtime estimation, and its EEPROM stores unique pack IDs and calibration constants that host systems verify before enabling critical functions. The reprogrammable 4KB Flash permits firmware updates for regulatory-driven behavior changes without hardware revision. The single-chip integration of monitoring, gate drive, and MCU in 28 SSOP-A simplifies compliance documentation because the protection chain is contained within one documented device rather than several discrete analog parts.
Recommandé
UPS and Backup Power Systems
Small UPS units and backup power supplies built from 3S to 7S Li-ion packs benefit from the HT45F8640's combined cell supervision and FET control. Firmware can implement float-charge management, deep-discharge cutoff, and load-shedding decisions while the ADC tracks pack temperature-dependent behavior. The accumulative monitoring scheme samples cells sequentially, which is acceptable in UPS applications where protection latency of milliseconds is tolerable, unlike high-rate power-tool discharges. EEPROM retention of cycle history enables predictive maintenance reporting to the host system over a serial interface implemented in firmware.
Recommandé
Smart Battery Authentication and Fuel Gauging
Smart battery packs conforming to host-communication requirements need non-volatile identity and fuel-gauge data. The HT45F8640 addresses this with true EEPROM for serial numbers, manufacture dates, and calibration tables, plus the 4KB Flash for gauge algorithms that integrate current-derived estimates with the ±0.5% voltage readings. The multi-programming Flash allows the gauge algorithm to be tuned per customer pack profile without mask ROM commitment. Because cell monitoring, computation, and gate-drive control share one die, the authentication state machine can hard-fail the charge and discharge FETs if a pack identity check fails, protecting OEM revenue on replacement packs.
Recommandé
Récapitulatif des produits recommandés
Données de référence d'ingénierie pour HT45F8640 — comparaison, recommandations de conception et informations de conformité.
Guide de sélection
Comparaison avec les alternatives
| Paramètre | Ce produit | HT45F8650 |
|---|---|---|
| Brand | Holtek Semiconductor | Holtek Semiconductor |
| Core | 8-bit RISC | 8-bit RISC (same family) |
| Battery Cell Count | 3 to 7 cells | 3 to 7 cells |
| Cell Voltage Monitor Accuracy | ±0.5% | ±0.5% |
| Maximum Input Voltage | 36 V | 36 V |
| ADC Channels | Up to 5 | Up to 8 (family xx50/xx62 variants, per Ineltek) |
| MOSFET Gate Drivers | Discharge + charge N-type drivers | 2 discharge MOSFET gate drivers (per Ineltek) |
| Lifecycle Status | EOL - last purchase October 07, 2026 | EOL - last purchase October 07, 2026 |
Principaux différenciateurs
- Single-chip integration of cell monitoring plus dual MOSFET gate drive (vs HT45F8650)
- Lower channel count but smallest solution cost in family (vs HT45F8650)
- True EEPROM for calibration and pack identity (vs HT45F8650)
Notes de conception
Obsolescence planning is the dominant risk for this part. Holtek's official EOL notification (EOL_HT45F8640_50-V120) sets the last purchase date at October 07, 2026. Any design still using the HT45F8640 must either place a lifetime-buy before that date or begin migration to a current-generation Holtek BMS MCU. Do not start new designs with this device; the HT45F8650 sibling shares the same EOL date, so it is not a long-term escape path either.
The HT45F8640 accepts a pack rail up to 36V maximum; a 7S Li-ion pack reaches about 29.4V at full charge, leaving reasonable headroom, but verify charger tolerance windows and load-dump style transients on the high-voltage rail. The internal high accuracy voltage regulator generates core power from this rail, so follow the datasheet decoupling recommendations on the VIN pin and do not back-feed regulated domains from external supplies. Estimated: at 29.4V input the regulator drops roughly 28V to core levels, so keep core current low and check internal power dissipation per the datasheet thermal data.
Place the cell-tap sense routing for the accumulative voltage monitor as short and symmetric as practical, and add the datasheet-recommended series resistors and filtering on each cell tap to protect against pack shorts and to average switching noise from the discharge path. Keep the discharge and charge N-MOSFET gate-drive loops tight, with the gate resistors close to the MCU gate-driver pins and the FETs, because the drivers switch the high-current protection path and gate ringing couples back into the ±0.5% accuracy measurement front end.
Informations de conformité
Compliance data not present in the provided web sources; consult Holtek's official product page and green-package documentation for RoHS/REACH status.
