MAX705ESA+T - 4.65V Threshold μP Supervisor, 8-SOIC | Maxim Integrated
料号： MAX705ESA+T ✓ 量产中| 数量 | 单价 | 小计 |
|---|---|---|
| 1 | $0.57 | $0.57 |
| 10 | $0.51 | $5.10 |
| 100 | $0.46 | $46.00 |
| 500 | $0.41 | $205.00 |
| 1,000 | $0.37 | $370.00 |
| 2,500 | $0.33 | $825.00 |
MAX705ESA+T 概述
A microprocessor supervisor is a specialized power-management IC that watches the host system's VCC rail and asserts a clean reset signal to the MCU/MPU whenever that rail drops below a safe operating threshold or when the MCU is stuck and needs a fresh start. This product category sits inside the broader power-management hierarchy and reduces the number of discrete comparators, RC delays, and FET switches that older designs needed. Supervisors are widely used in embedded, industrial, and IoT systems where deterministic startup behavior is critical.
Key features of the MAX705ESA+T include a 4.65 V ±2.5% reset threshold, a 200 ms minimum reset pulse width, an active-low push-pull RESET output, a manual-reset input (MR), and a power-fail comparator (PFI/PFO) for early warning of an impending supply collapse. The device operates over a 1.2 V to 5.5 V supply range and consumes roughly 200 μA of quiescent current, making it suitable for battery-backed designs.
Internally, the part combines a precision bandgap reference, a comparator string, and timing logic that generates the guaranteed reset pulse. The MAX705 family shares the same 8-pin SOIC footprint as the MAX706/MAX707/MAX708/MAX813L parts, allowing PCB layout reuse across threshold and reset-polarity variants. The push-pull (totem-pole) output stage drives CMOS/TTL loads directly without a pull-up resistor.
Typical applications include MCU reset supervision in industrial controllers, battery-backed SRAM/RTC switching, point-of-sale terminals, IoT edge nodes, embedded Linux boards, and any design requiring a clean, deterministic power-on reset. Designers also use the power-fail comparator to detect a low-battery condition before the rail collapses.
When designing with this part, place the 0.1 μF bypass capacitor within 5 mm of the VCC pin, and verify that the chosen reset threshold sits below the MCU's minimum operating voltage. The MAX705ESA+T is pin-compatible with most MAX706/MAX707/MAX708/MAX813L variants in the same package.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes that are not consolidated in the manufacturer datasheet, helping engineers select between same-family and cross-brand supervisory ICs.
直接替换替代料： MAX705ESA+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： MAX705ESA+T （相同外形与封装尺寸） ——差异在于 MSL Level, Packaging, Reset Output Type.
快速对比工具——选择替代料号进行并排对比：
MAX705ESA+
✅ 直接替换📋 参考替代料（不在目录中）
MAX706ESA+T
✅ 直接替换📋 参考替代料（不在目录中）
MAX707ESA+T
✅ 直接替换📋 参考替代料（不在目录中）
MAX813LESA+T
✅ 直接替换📋 参考替代料（不在目录中）
STM705M6F
✅ 直接替换📋 参考替代料（不在目录中）
ADM705ARZ-REEL
✅ 直接替换✓ 有现货
$2.18 / 个
查看数据手册 →SP705EN
✅ 直接替换📋 参考替代料（不在目录中）
MAX705ESA+T 规格参数
| 功能 | Microprocessor Supervisory Circuit |
| Reset Threshold Voltage | 4.65 V |
| Supply Voltage Range | 1.2 V to 5.5 V |
| Reset Output Type | Active-Low, Push-Pull (Totem-Pole) |
| Number of Supervisors | 1 |
| Minimum Reset Pulse Width | 200 ms |
| Manual Reset Input | Yes (MR, active-low) |
| Power-Fail Comparator | Yes (PFI/PFO, 1.25 V threshold) |
| Watchdog Timer | No |
| 工作温度范围 | -40 °C to +85 °C (E suffix = extended) |
| 封装 | 8-pin NSOIC (SOIC-8) |
| 安装类型 | Surface Mount |
| Packaging | Tape & Reel (+T) |
| RoHS 状态 | Compliant |
| MSL 等级 | 1 (per SOIC-8 JEDEC J-STD-020) |
MAX705ESA+T 引脚配置
| 引脚 1 | VCC — Supply voltage input (1.2 V to 5.5 V); bypass with 0.1 μF to GND |
| 引脚 2 | GND — Ground reference |
| 引脚 3 | PFI — Power-Fail Input (comparator; 1.25 V threshold for early warning) |
| 引脚 4 | PFO — Power-Fail Output (active-low, goes low when PFI < 1.25 V) |
| 引脚 5 | MR — Manual Reset input (active-low; tie to VCC through 10 kΩ if unused) |
| 引脚 6 | RESET — Active-low reset output (push-pull/totem-pole); asserts when VCC < 4.65 V |
| 引脚 7 | NC — Not connected internally (per datasheet) |
| 引脚 8 | NC — Not connected internally (per datasheet) |
典型应用
MAX705ESA+T 适用于 6 应用s: MCU Reset Supervision in 5V Embedded Systems, Battery-Backed SRAM/RTC Power Switching, Point-of-Sale Terminal Reset Management, IoT Edge Node Brownout Protection, Industrial PLC and Motor Controller Reset, Automotive Telematics Infotainment Module.
MCU Reset Supervision in 5V Embedded Systems
The MAX705ESA+T provides deterministic power-on reset for 5 V microcontrollers in industrial controllers and embedded Linux boards. The 4.65 V threshold sits safely below the MCU's minimum operating voltage of 4.75 V, ensuring a valid reset only after VCC has stabilized. The 200 ms minimum reset pulse width prevents the MCU from booting during brownout events. Placed between the 5 V LDO and the MCU's NRST pin with a 0.1 μF bypass on VCC, it eliminates discrete comparator/RESET circuits and reduces BOM count by 4-6 components.
推荐
Battery-Backed SRAM/RTC Power Switching
The MAX705ESA+T is ideal for battery-backed memory and RTC designs that must preserve data on main power loss. The on-chip PFI/PFO power-fail comparator (1.25 V threshold) provides early warning of an impending VCC collapse, while the supervisor asserts reset before the rail falls below the 4.65 V threshold. Combined with an external lithium cell and a few discretes, it replaces a discrete supervisor + RTC + battery-management circuit. Quiescent current of 200 μA preserves battery life in standby. This is the canonical Maxim reference design for the MAX705 family.
推荐
Point-of-Sale Terminal Reset Management
In point-of-sale terminals, a clean reset on power-up is essential to prevent the secure-payment processor from entering an undefined state. The MAX705ESA+T's 200 ms reset pulse guarantees that all peripherals (NFC reader, printer, display) have stabilized VCC before the host CPU begins execution. The active-low push-pull output drives the CPU's NRST input directly without a pull-up resistor. The manual-reset input (MR) connects to the enclosure's reset button, allowing service-mode reboots without power cycling.
推荐
IoT Edge Node Brownout Protection
Battery- and USB-powered IoT edge nodes (wireless sensor modules, BLE beacons) benefit from the MAX705ESA+T's 1.2 V to 5.5 V supply range and 4.65 V threshold, which prevents brownouts during WiFi/BLE transmit bursts that momentarily sag the input rail. The supervisor keeps the MCU in reset until VCC has recovered, eliminating crash-on-transmit failure modes. The 8-SOIC footprint is small enough for sub-2 cm² sensor modules, and the 200 μA quiescent current is negligible against typical battery self-discharge.
推荐
Industrial PLC and Motor Controller Reset
In industrial PLC and stepper/servo motor controllers, the MAX705ESA+T monitors the 24V-to-5V intermediate rail and asserts reset before the MCU or gate driver loses regulation. The 200 ms reset pulse covers the typical gate-driver power-up time, preventing cross-conduction in the H-bridge. The PFI input can monitor a separate analog supply (e.g., the 15 V driver rail) for early fault detection, supporting predictive maintenance signaling through the PFO output to the MCU.
推荐
Automotive Telematics Infotainment Module
In automotive telematics and infotainment modules, the MAX705ESA+T provides clean reset sequencing for the head-unit MCU during cranking events when the 12 V battery rail dips below 6 V. Although the E-grade part is rated -40 °C to +85 °C, automotive designers select the MAX705ESA+T family for under-hood and cabin applications where the temperature range is acceptable. The active-low push-pull output ties directly to the MCU's reset input, simplifying the schematic versus a discrete RC reset circuit.
推荐
推荐产品汇总
工程参考数据： MAX705ESA+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 | MAX705ESA+ | MAX706ESA+T | MAX707ESA+T | STM705M6F | ADM705ARZ | SP705EN |
|---|---|---|---|---|---|---|---|
| Brand | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated | STMicroelectronics | Analog Devices | Sipex |
| Package | 8-pin SOIC | 8-pin SOIC - same | 8-pin SOIC - same | 8-pin SOIC - same | 8-pin SOIC - same | 8-pin SOIC - same | 8-pin SOIC - same |
| Reset Threshold | 4.65 V | 4.65 V | 4.40 V | 4.65 V | 4.65 V | 4.65 V | 4.65 V |
| Watchdog Timer | No | No | Yes | No | No | No | No |
| RESET Output Type | Active-Low, Push-Pull | Active-Low, Push-Pull | Active-Low, Push-Pull | Active-Low + Active-High, Push-Pull | Active-Low, Push-Pull | Active-Low, Push-Pull | Active-Low, Push-Pull |
| Manual Reset Input (MR) | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| Power-Fail Comparator | Yes (PFI/PFO, 1.25 V) | Yes (PFI/PFO, 1.25 V) | Yes | No | Yes | Yes | Yes |
| Supply Voltage Range | 1.2 V to 5.5 V | 1.2 V to 5.5 V | 1.2 V to 5.5 V | 1.2 V to 5.5 V | 1.0 V to 5.5 V | 1.2 V to 5.5 V | 1.0 V to 5.5 V |
| Operating Temperature | -40 °C to +85 °C | -40 °C to +85 °C | -40 °C to +85 °C | -40 °C to +85 °C | -40 °C to +85 °C | -40 °C to +85 °C | -40 °C to +85 °C |
关键差异点
- Drop-in 8-SOIC pinout shared with MAX706/MAX707/MAX708/MAX813L family （对比 MAX706ESA+T)
- Wide cross-brand support with pin-compatible equivalents （对比 STM705M6F (STMicroelectronics))
- Active-low push-pull output stage eliminates external pull-up resistor （对比 MAX705ESA (open-drain variant))
设计说明
Place a 0.1 μF ceramic bypass capacitor within 5 mm of the VCC pin (pin 1) and a 1 μF to 10 μF bulk capacitor on the same node to handle VCC droop during transient load steps. The MAX705 datasheet recommends a minimum 0.1 μF decoupling; smaller values risk false reset assertion during high-frequency noise. For battery-backed designs, the PFI/PFO comparator can be used to detect an early warning of VCC collapse: tie PFI to a resistor divider from VCC and use PFO to interrupt the MCU before the rail falls below 4.65 V. This is a typical application circuit from the Maxim MAX705 datasheet.
Route the RESET trace away from high-current switching nodes (DC-DC switch node, gate drivers, motor phases) to avoid capacitive coupling that can cause false reset pulses. Keep the trace shorter than 50 mm and use a ground guard trace if routing near noisy nets. The 8-SOIC exposed pad is not present on this package; thermal performance is sufficient at the supervisor's low quiescent current (~200 μA), so no copper-pour thermal relief is required for the IC itself, although a small VCC pour under the SOIC helps with decoupling.
Do not leave the MR pin floating - it must be tied to VCC through a 10 kΩ resistor if the manual-reset button is not used, otherwise the internal pull-down can assert a spurious reset. The NC pins (7 and 8) must be left open; do not connect them to ground or VCC. Avoid placing large capacitors (>10 μF) directly on the RESET output if driving a CMOS input with high impedance, since the totem-pole output stage can source/sink limited current during the rising edge. If a large RC load is unavoidable, add a series resistor (100 Ω) to limit inrush. Estimated: per the MAX705 datasheet, the RESET pin can sink 20 mA at VCC = 5 V; verify by checking the V_OL specification for your application.
合规信息
RoHS and lead-free status per Maxim Integrated product page. E-grade part is -40 °C to +85 °C, not AEC-Q100 qualified - choose MAX705AESA+T (automotive grade) for AEC-Q100 designs. Halogen-free status not explicitly stated in verified data.
