HT79171 - 500kHz Sync Boost Converter 2A | Holtek
料号： HT79171 ✗ 停产| 数量 | 单价 | 小计 |
|---|---|---|
| 1 | $0.42 | $0.42 |
| 10 | $0.36 | $3.60 |
| 100 | $0.28 | $28.00 |
| 500 | $0.22 | $110.00 |
| 1,000 | $0.18 | $180.00 |
HT79171 概述
A synchronous step-up (boost) converter is a class of switching voltage regulator that raises a lower input voltage to a higher regulated output voltage. Unlike non-synchronous boost topologies that use a Schottky diode as the rectifying element, a synchronous boost replaces the diode with an integrated MOSFET, reducing conduction losses and significantly improving conversion efficiency, which is critical in battery-powered systems. Boost converters sit within the broader power management IC hierarchy, alongside buck (step-down), buck-boost, and charge-pump regulators.
Key differentiating features of the HT79171 include its 500kHz fixed switching frequency, which permits the use of small inductors and ceramic capacitors for a compact bill of materials, its wide 2.2V to 5.0V input span that covers single-cell lithium-ion battery discharge curves (typically 2.5V to 4.2V), and its adjustable current limit. According to the Holtek datasheet, connecting a resistor of 20kOhm to 100kOhm on the OC pin scales the default 5A peak current limit down to as low as 1A, allowing designers to trade peak capability against inductor saturation margin.
Architecturally, the HT79171 uses a PWM control scheme with integrated power switches optimized for low RDSON to maximize efficiency at multi-amp load currents. The synchronous rectification stage avoids the large diode-drop losses that would otherwise dominate at low output voltages, improving light-load behavior and overall conversion efficiency. Internal protection features include cycle-by-cycle peak current limiting and fault handling suitable for battery-powered designs.
Typical applications include portable power banks (the primary documented use case), lithium-battery-powered portable equipment, and any 2.2V to 5.0V input boost regulation rail up to 2A continuous output. The 500kHz switching frequency supports small-footprint USB power bank PCBs.
A key design consideration is inductor selection: the inductor saturation current must exceed the configured peak current limit with margin, since the OC pin setting directly determines peak inductor current.
This page synthesizes distributor availability data, the official Holtek datasheet, and end-of-life cross-reference information into a single engineering resource not found on any single source page.
直接替换替代料： HT79171 ——相同封装，引脚兼容。需要 PCB 改动的不同封装料号已排除。
快速对比工具——选择替代料号进行并排对比：
HT79181
✅ 直接替换📋 参考替代料（不在目录中）
HT79171 最大额定值与电气特性
| 拓扑 | Synchronous Step-Up (Boost) PWM Converter |
| 开关频率 | 500 kHz |
| 输入电压范围 | 2.2 V to 5.0 V |
| Continuous Output Current | 2 A |
| Peak Current Limit (OC floating) | 5 A |
| Adjustable Current Limit Range | 1 A to 5 A (OC resistor 20 kOhm to 100 kOhm) |
| Main FET RDSON | 25 mOhm |
| Synchronous FET RDSON | 45 mOhm |
| Control Scheme | PWM |
| 封装 | ESOP-8 |
| 安装类型 | Surface Mount |
| Application | Portable Li-battery devices, power banks |
| Current Limit Pin | OC pin with external resistor setting |
HT79171 esop-8 引脚配置指南
HT79171（esop-8 封装）的引脚配置。 该功率器件具有栅极、漏极和源极端子。对于无极性封装，请参阅制造商数据手册以了解确切的引脚 1 方向和封装尺寸细节。常见应用包括电源设计、电机驱动和负载开关。
暂无详细引脚数据： HT79171.
请参阅 数据手册 以查看完整引脚配置。
典型应用
HT79171 适用于 6 应用s: Portable Power Banks, Single-Cell Li-Ion Battery Boost Rails, USB Output Power Stage, Portable LED Lighting / Torch Drivers, Handheld Instrument Power Supplies, Li-Ion Backup and Emergency Power Modules.
Portable Power Banks
The HT79171 is purpose-built for power banks: Holtek's datasheet General Description names portable li-battery applications such as power banks as the primary use case. Its 2.2V to 5.0V input range tracks the full single-cell Li-ion discharge curve, while 2A continuous output and integrated 25mOhm/45mOhm RDSON switches deliver USB-class output power without an external rectifier device. The 500kHz switching frequency keeps the inductor small enough for a power bank PCB. The OC-pin resistor (20kOhm-100kOhm) lets designers reduce the 5A peak limit to match the chosen inductor, trimming cost and volume. Note the part is EOL as of 2026/08/12; new power bank designs should apply Holtek's designated replacement.
推荐
Single-Cell Li-Ion Battery Boost Rails
Any product powered by one lithium-ion cell - handheld instruments, portable lights, emergency devices - needs to raise the 2.5V-4.2V battery voltage to a 5V or higher system rail. The HT79171 covers exactly this job: its input span covers deep discharge to full charge, and the synchronous topology preserves efficiency at the low-input, high-current end of the discharge curve where diode-rectified boost converters suffer the largest conduction losses. With 2A continuous capability and a 5A default peak limit adjustable down to 1A, the part spans a wide output power range. The EOL status (Holtek notification effective 2026/08/12) makes lifetime-buy or replacement planning essential for long-lived portable products.
推荐
USB Output Power Stage
Power banks and portable chargers must generate a regulated 5V-class output from a Li-ion cell for USB device charging. The HT79171's boost stage converts the 2.2V-4.2V battery voltage upward while its low RDSON synchronous switches minimize losses at multi-amp charging currents, preserving battery runtime. The 500kHz PWM frequency allows compact magnetics that fit the tight board area of USB connector-adjacent layouts. Designers should configure the OC-pin current limit resistor so peak inductor current stays below inductor saturation across the minimum input voltage condition. Verify USB compliance of the complete output stage, since load-share and signaling circuitry sits outside this converter's scope.
推荐
Portable LED Lighting / Torch Drivers
Portable LED torches and lanterns powered by one Li-ion cell require a boost stage to drive LED strings above the battery voltage. The HT79171 supplies the needed step-up from 2.2V-5.0V input with 2A continuous output, and its low 25mOhm/45mOhm RDSON switches minimize conduction losses during sustained high-current LED operation, extending runtime versus diode-rectified alternatives. The adjustable OC current limit (1A-5A via 20kOhm-100kOhm resistor) can protect the LED string and magnetics. Thermal design in a small torch barrel must account for switch and inductor losses; the exposed pad of the ESOP-8 package aids heat spreading into the PCB copper. Confirm replacement part availability given the 2026 EOL.
推荐
Handheld Instrument Power Supplies
Handheld meters, detectors, and portable instrumentation commonly run from a single 18650 or pouch Li-ion cell and need a stable higher rail for analog front ends, displays, and wireless modules. The HT79171 provides that boost conversion from 2.2V-5.0V input with fixed 500kHz operation, so switching ripple sits well above sensitive analog bands and can be filtered with small LC stages. Synchronous rectification keeps efficiency high at the multi-hundred-milliamp loads typical of backlit displays and RF modules. Its ESOP-8 footprint suits compact handheld PCBs. Because Holtek announced the part's end-of-life (effective 2026/08/12), instrument platforms with long service lifetimes should qualify the EOL-listed replacement device now.
推荐
Li-Ion Backup and Emergency Power Modules
Backup power modules, emergency lamps, and portable routers use a single Li-ion cell charged from mains or USB and discharged through a boost converter during outages. The HT79171 fits this discharge path: the 2.2V minimum input allows extraction of usable energy even when the cell sags under load, maximizing backup runtime, while the synchronous topology limits standby losses that matter in always-on emergency equipment. The 2A continuous output covers router and lamp load classes, and the OC-pin current limit can be sized to the module's worst-case load. As the part is now EOL per Holtek's 2026 notification, spares and replacement qualification should be arranged through the official EOL cross-reference document.
推荐
推荐产品汇总
工程参考数据： HT79171 ——对比、设计指导和合规信息。
选型指南
与替代料对比
| 参数 | 本产品 | HT79181 |
|---|---|---|
| Package | ESOP-8 | ESOP-8 - same |
| Brand | Holtek Semiconductor | Holtek Semiconductor |
| Input Voltage Range | 2.2 V to 5.0 V | 2.2 V to 5.0 V |
| Continuous Output Current | 2 A | 3 A |
| Peak Current Limit (default) | 5 A | 6 A |
| Main FET RDSON | 25 mOhm | 20 mOhm |
| Synchronous FET RDSON | 45 mOhm | 40 mOhm |
| Switching Frequency | 500 kHz | 500 kHz |
| Lifecycle Status | EOL (effective 2026/08/12) | EOL per Holtek notification |
关键差异点
- Lower cost entry point in the Holtek boost family （对比 HT79181)
- Fully synchronous rectification （对比 HT79181)
- Adjustable current limit via single resistor （对比 HT79181)
设计说明
Configure the peak current limit deliberately. With the OC pin floating the HT79171 limits main-FET peak current to 5A; a 20kOhm-100kOhm resistor scales this down to 1A (per the Holtek datasheet). Size the inductor saturation current above the configured peak limit with at least 20% margin, and remember peak inductor current is worst at minimum input voltage (2.2V) for a given output power. Undersized inductors saturating at high battery draw are the most common power bank field failure mode for this converter class.
The ESOP-8 exposed pad is the primary thermal and ground return path. Solder it to a solid ground pour with an array of thermal vias (typically 3x3 or more) to spread heat into inner layers. Keep the high-current loop - input capacitor, main FET, inductor, synchronous FET, output capacitor - as short and tight as possible to reduce switching ringing at 500kHz. Place the input ceramic capacitor within a few millimeters of the VIN pin; long traces there cause input voltage dips that can trip protection or disturb regulation.
Do not connect any other component type than the specified resistor range (20kOhm-100kOhm) to the OC pin - the datasheet explicitly restricts this. Also verify the part's lifecycle before release: Holtek's EOL notification (effective 2026/08/12) ends production of the HT79171 and the ESOP-8 HT79181; the 10-pin QFN variant already reached its last purchase date of January 30, 2026. New designs must adopt the replacement device from the Holtek EOL cross-reference document (EOL_HT79171-V110.pdf) to avoid mid-lifecycle sourcing gaps.
合规信息
Distributor listing (JLCPCB Assembly, part C9900148945) marks the ESOP-8 HT79171 as ROHS. Reach/halogen-free/conflict-minerals status not stated in provided data.
