A8586KLJTR-T - 3.5A 40V Buck Converter with PFM/Dither | Allegro
料号： A8586KLJTR-T ✓ 量产中| 数量 | 单价 | 小计 |
|---|---|---|
| 1 | $2.85 | $2.85 |
| 10 | $2.62 | $26.20 |
| 100 | $2.28 | $228.00 |
| 500 | $1.95 | $975.00 |
| 1,000 | $1.71 | $1,710.00 |
A8586KLJTR-T 概述
A buck converter (also called a step-down switching regulator) is a DC-DC topology that uses a power switch, an inductor, and a synchronous rectifier (or freewheeling diode) to deliver a lower regulated voltage at high efficiency. Buck converters sit within the broader hierarchy of voltage regulators → power management ICs → mixed-signal semiconductors, and are preferred over linear regulators whenever the input-to-output differential is large, because switching topologies dissipate far less power. The A8586 family specifically targets the mid-current (sub-5 A) point-of-load (POL) segment.
Key features of the A8586KLJTR-T include current-mode control for fast transient response, simple external compensation, an internal high-side MOSFET, and an adjustable switching frequency set by a single external resistor. It also provides enable, power-good, soft-start, and thermal-shutdown functions. The exposed-pad SOIC-8 (LJ-8) package provides a low thermal resistance path, important when the converter operates near the 3.5 A limit at high input voltage.
Architecturally, the A8586 uses current-mode PWM with PFM at light load, so efficiency stays high across the full load range. The integrated high-side MOSFET eliminates the need for an external switch, reducing BOM cost and PCB area. Frequency dither spreads the switching spectrum, lowering peak EMI and easing CISPR 25 / FCC compliance for automotive infotainment and industrial subsystems.
Typical applications include 12 V/24 V automotive infotainment and body-electronics rails, industrial PLC and sensor 24 V power, distributed POL converters in telecom and networking cards, general-purpose 5 V/3.3 V/2.5 V rails from a wide-input source, and battery-powered equipment requiring high efficiency across load.
A key design tip is to keep the high-current loop (input cap, high-side FET, inductor, output cap, and PGND) as small as possible to minimize EMI and ringing. The exposed pad must be soldered to a sufficiently large copper pour for thermal dissipation.
This page synthesizes distributor pricing, datasheet parameters, drop-in alternatives, and practical PCB/thermal design notes not found in the manufacturer datasheet alone, helping engineers select and qualify the A8586KLJTR-T for production.
直接替换替代料： A8586KLJTR-T ——相同封装，引脚兼容。需要 PCB 改动的不同封装料号已排除。
本系列中的变体
可与以下型号直接替换的同系列型号： A8586KLJTR-T （相同外形与封装尺寸） ——差异在于 Control Mode, Input Voltage Range, Output Voltage Range, Package, RoHS Status.
快速对比工具——选择替代料号进行并排对比：
A8586KLJTR-T-1
✅ 直接替换📋 参考替代料（不在目录中）
A8586KLJTR-T-2
✅ 直接替换✓ 有现货
$0.82 / 个
查看数据手册 →A8586KLJTR-T
✅ 直接替换 ⚠️ 规格未核验✓ 有现货
$1.71 / 个
查看数据手册 →LMR16006XDDCR
✅ 直接替换📋 参考替代料（不在目录中）
TPS54331DDA
✅ 直接替换📋 参考替代料（不在目录中）
A8586KLJTR-T 最大额定值与电气特性
| 拓扑 | Step-down (buck) switching regulator |
| 输入电压范围 | 4.0 V to 36 V (40 V transient) |
| 输出电压范围 | 0.8 V to 30 V (adjustable) |
| 最大输出电流 | 3.5 A |
| 输出类型 | Adjustable (external resistor divider) |
| Integrated Switch | Internal high-side power MOSFET |
| Control Mode | Current-mode PWM with PFM at light load |
| 开关频率 | Adjustable (set by external resistor) |
| Light-Load Mode | PFM enabled; frequency dither enabled (KLJTR-T variant) |
| 使能引脚 | Yes |
| Power Good | Yes |
| 软启动 | Yes (programmable) |
| 热关断 | Yes |
| 工作温度 | -40 C to +125 C (automotive AEC-Q100 grade) |
| 封装 | 8-SOIC (0.154", 3.90 mm width) with Exposed Pad (LJ-8) |
| 安装类型 | Surface Mount |
| AEC-Q100 | Qualified (automotive grade) |
| RoHS 状态 | Compliant |
A8586KLJTR-T 引脚配置
| 引脚 1 | BOOT — Bootstrap capacitor for high-side gate driver |
| 引脚 2 | EN — Enable input (active high); UVLO and enable threshold |
| 引脚 3 | VIN — Input supply voltage (4.0 V to 36 V) |
| 引脚 4 | SW — Switch node to external inductor |
| 引脚 5 | SW — Switch node (second pin for high-current path) |
| 引脚 6 | FB — Feedback input (0.8 V reference, external resistor divider sets VOUT) |
| 引脚 7 | PGND — Power ground return for high-current switching loop |
| 引脚 8 | AGND — Analog ground for reference and control circuits |
典型应用
A8586KLJTR-T 适用于 6 应用s: Automotive Infotainment and Body Electronics, Industrial 24 V Sensor and PLC Power, Distributed Point-of-Load Converters, Battery-Powered Equipment, General-Purpose 5 V / 3.3 V / 2.5 V Rails, HVAC and Building Automation.
Automotive Infotainment and Body Electronics
The A8586KLJTR-T's 4.0-36 V (40 V transient) input and AEC-Q100 qualification make it ideal for 12 V automotive rails that must survive load-dump transients. In infotainment head units, instrument clusters, and body controllers, it generates 5 V, 3.3 V, and 1.8 V rails for processors, memory, and display backlight drivers. Frequency dither on the KLJTR-T variant lowers peak EMI by spreading the switching spectrum, easing CISPR 25 compliance. The 3.5 A capability supports multi-rail subsystems from a single buck. Compared to an LDO, the A8586KLJTR-T dissipates roughly 2-3 W instead of 30+ W at 24 V to 5 V/3.5 A, dramatically easing thermal design in sealed enclosures.
推荐
Industrial 24 V Sensor and PLC Power
Industrial PLCs, sensors, and process-control equipment commonly run on 24 V rails with significant noise and voltage variation. The A8586KLJTR-T operates directly from 24 V without a preregulator, regulating down to 5 V or 3.3 V for microcontrollers and analog front-ends. Its -40 C to +125 C operating range suits cabinet and field-deployed equipment. The current-mode control provides fast transient response to step loads from relays and motor drivers. PFM at light load keeps efficiency above 80 percent even at 50 mA standby, important for energy-conscious industrial designs. The exposed-pad SOIC-8 (LJ-8) package enables compact PCB layouts with adequate thermal performance.
推荐
Distributed Point-of-Load Converters
In telecom, networking, and server cards, the A8586KLJTR-T serves as a distributed POL converter stepping 12 V or 24 V intermediate bus voltages down to 1.0-3.3 V for ASICs, FPGAs, and processors. The 3.5 A current handles moderate-load digital rails with headroom, and the small LJ-8 package allows placement close to the load to minimize trace inductance. The enable pin supports sequencing across multiple rails. Frequency dither reduces EMI coupling into adjacent analog/digital traces, important in dense multi-rail designs. Compared to larger 20-pin buck controllers, the A8586KLJTR-T integrates the high-side MOSFET and requires minimal external components.
推荐
Battery-Powered Equipment
Portable and battery-powered devices benefit from the A8586KLJTR-T's high efficiency at light load, thanks to its PFM mode on the KLJTR-T variant. When the load drops below the PWM/PFM threshold, the regulator switches to pulse-frequency modulation, reducing switching losses and gate-driver losses. Efficiency stays above 80 percent from 50 mA to 3.5 A. This extends battery runtime in handheld instruments, e-bike displays, and battery-backed industrial sensors. The wide 4.0-36 V input also accepts multi-cell battery packs and unregulated adapters directly. The enable pin supports low-quiescent standby modes.
推荐
General-Purpose 5 V / 3.3 V / 2.5 V Rails
The A8586KLJTR-T is a versatile general-purpose buck for any 12 V or 24 V input that needs 5 V, 3.3 V, 2.5 V, 1.8 V, or 1.2 V outputs up to 3.5 A. The 0.8 V reference and external resistor divider set the output precisely, with a tolerance of ±1 percent typical. Current-mode control with simple external compensation means designers do not need to calculate Type-III loop components - just an RC network per the datasheet. This shortens design cycles for prototypes and production. The LJ-8 package with exposed pad fits on almost any 2-layer or 4-layer PCB, making it a strong default choice for mixed-signal boards.
推荐
HVAC and Building Automation
HVAC controllers, building-automation gateways, and thermostat equipment often use 24 VAC rectified rails with significant ripple and voltage variation. The A8586KLJTR-T handles these inputs directly thanks to its 4.0-36 V range. Its AEC-Q100 automotive-grade qualification provides extra margin for the temperature extremes and humidity of mechanical equipment rooms. The 3.5 A output drives multiple subsystems including Wi-Fi modules, relays, and sensor arrays. The exposed-pad SOIC package supports both reflow and selective soldering common in HVAC controller manufacturing.
推荐
推荐产品汇总
工程参考数据： A8586KLJTR-T ——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 | A8586KLJTR-T-1 | A8586KLJTR-T-2 | LMR16006XDDCR | TPS54331DDA |
|---|---|---|---|---|---|
| Brand | Allegro MicroSystems | Allegro MicroSystems | Allegro MicroSystems | Texas Instruments | Texas Instruments |
| Package | 8-SOIC Exposed Pad (LJ-8) | 8-SOIC Exposed Pad (LJ-8) - same | 8-SOIC Exposed Pad (LJ-8) - same | SO PowerPAD-8 (DDC) - same pin count, different layout | SO PowerPAD-8 (DDA) - same pin count, different layout |
| Input Voltage Range | 4.0 V to 36 V (40 V transient) | 4.0 V to 36 V (40 V transient) | 4.0 V to 36 V (40 V transient) | 4.0 V to 60 V | 3.5 V to 28 V |
| Maximum Output Current | 3.5 A | 3.5 A | 3.5 A | 0.6 A | 3.0 A |
| Output Voltage Range | 0.8 V to 30 V | 0.8 V to 30 V | 0.8 V to 30 V | 0.8 V to 50 V | 0.8 V to 25 V |
| Light-Load PFM | Enabled | Disabled | Disabled | Enabled (Eco-Mode) | Disabled (FPWM option) |
| Frequency Dither | Enabled | Disabled | Enabled | Not specified | Not specified |
| AEC-Q100 | Qualified | Qualified | Qualified | Not automotive grade | Not automotive grade (TPS54331-Q1 exists) |
关键差异点
- PFM at light load plus frequency dither in a single SKU （对比 A8586KLJTR-T-1)
- AEC-Q100 automotive grade on a 3.5 A/40 V part （对比 TPS54331DDA)
- Wide 4.0-36 V input with integrated high-side MOSFET （对比 LMR16006XDDCR)
设计说明
Estimated: At VIN=24 V, VOUT=5 V, IOUT=3.5 A and 90 percent efficiency, the A8586KLJTR-T dissipates approximately 1.9 W internally (3.5 A x (24-5)x(1-0.9)). The LJ-8 SOIC exposed pad has a typical theta_JA of 35-45 C/W on a 1 oz 4-layer PCB with a 1 cm² copper pour, yielding a 70-90 C junction temperature rise at 25 C ambient. To stay below 125 C at 85 C ambient, keep copper pour at least 1 cm² and consider 4-layer thermal vias under the EP. At VIN=24 V to VOUT=3.3 V, dissipation rises to ~7 W and heatsinking or larger copper pours are mandatory.
Minimize the high-current switching loop: keep the input ceramic capacitor, the SW node, the inductor, and the output capacitor on the same PCB side with the smallest possible loop area. Place the bootstrap capacitor close to the BOOT and SW pins. Keep the analog ground (AGND) and power ground (PGND) returns separated and tied at a single point near the IC exposed pad to avoid injecting switching noise into the FB reference. Use 10-22 uF X7R ceramic input and output capacitors for most applications; the Allegro datasheet specifies minimum capacitance for stability.
The KLJTR-T variant enables frequency dither, which spreads the switching spectrum across roughly ±10 percent of the switching frequency, reducing peak EMI by typically 6-10 dB on a CISPR 25 conducted scan. For maximum EMI margin, pair dither with a small RC snubber on the SW node (typically 2-5 ohm + 1-2 nF) and use shielded inductors with flux-closed construction. If the application needs even lower emissions, switch to the -1 or -2 variant and disable dither, then optimize the input filter instead.
Do not exceed 36 V continuous (40 V transient) at VIN - on 24 V industrial buses with surge events, add a 33 V or 36 V TVS across VIN to PGND. Ensure the feedback resistor divider uses 1 percent or better resistors to keep output accuracy within 2 percent. The BOOT capacitor must be a 0.1 uF ceramic rated for at least 10 V. Do not leave the EN pin floating - tie it to VIN through a 100 kohm resistor or drive it directly. Exposed pad must be soldered for thermal dissipation; a dry EP will cause thermal shutdown at moderate loads.
合规信息
RoHS and REACH compliant per Allegro product page. AEC-Q100 qualified for automotive applications per Arrow distributor listing ('Conv DC-DC 3.8V to 36V Step Down Single-Out 0.8V to 30V 3.5A Automotive AEC-Q100'). Lead-free (Pb-free) per Allegro datasheet packaging information. Halogen-free status not explicitly stated in the verified web data.
