Data Sheet
LDC0851 差分感应开关
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1 特性
- 功能安全型
- 阈值容差：<1% 的线圈直径
- 开关操作在整个温度范围内保持稳定
- 平均电源电流：在 10sps 下 <20µA
- 关断电源电流：140nA
- 推挽式输出
- 可通过电阻编程设定阈值
- 对直流磁场不敏感
- 非接触式开关操作
- 采样率高达 4ksps
- 电源电压：1.8V 至 3.3V
- 工作温度范围：-40°C 至 125°C
2 应用
- 事件计数
- 风扇转速 RPM 检测
- 增量编码器/旋钮
- 打开/关闭开关
- 工业用接近开关
3 说明
LDC0851 是一款近距离感应开关，非常适合存在检测和事件计数等非接触式简单开关应用。
当导电物体进入感应线圈的接近范围内时将触发开关。该器件包含滞后功能，可保证可靠的开关阈值。差分实现方案可防止因温度变化或湿度影响等环境因素而导致误触发。LDC0851 无需 MCU 即可工作，因此可实现简单的解决方案。
电感式传感技术即使在有尘土、油污或潮气的环境中也可实现可靠而准确的感应，因此非常适合严苛或脏污的环境。固态开关消除了磁簧、机械或接触开关常会引发的失败。与同类竞争产品不同的是，LDC0851 无需使用磁体，而且不受直流磁场的影响。
(1) 如需了解所有可用封装，请参阅数据表末尾的可订购产品附录。
(2) 封装尺寸（长 × 宽）为标称值，并包括引脚（如适用）。
简化原理图4 Pin Configuration and Functions
Figure 4-1 DSG Package8-Pin WSON with DAPTop ViewTable 4-1 Pin Functions
| PIN | TYPE(1) | DESCRIPTION | |
|---|---|---|---|
| NAME | NO. | ||
| LCOM | 1 | A | Common coil input |
| LSENSE | 2 | A | Sense coil input |
| LREF | 3 | A | Reference coil input |
| ADJ | 4 | A | Threshold adjust pin |
| OUT | 5 | O | Switch output |
| EN | 6 | I | Enable input |
| GND | 7 | G | Ground |
| VDD | 8 | P | Power Supply |
| DAP | DAP | G | Connect to Ground for improved thermal performance(2) |
(1) I = Input, O = Output, P = Power, A = Analog, G =
Ground
(2) There is an internal electrical connection between the
exposed Die Attach Pad (DAP) and the GND pin of the device. Although the DAP can
be left floating, for best performance the DAP should be connected to the same
potential as the device's GND pin. Do not use the DAP as the primary ground for
the device. The device GND pin must always be connected to ground.
5 Specifications
5.1 Absolute Maximum Ratings
over operating free-air temperature range (unless otherwise noted) (1)
| MIN | MAX | UNIT | ||
|---|---|---|---|---|
| VDD | Supply Voltage Range | 3.6 | V | |
| Vi | Voltage on LSENSE, LREF, and EN | -0.3 | 3.6 | V |
| Voltage on ADJ and LCOM | -0.3 | 2 | V | |
| IA | Current LSENSE, LREF, and VOUT | 5 | mA | |
| TJ | Junction Temperature | -55 | 150 | °C |
| Tstg | Storage Temperature | -65 | 150 | °C |
(1) Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
5.2 ESD Ratings
| VALUE | UNIT | |||
|---|---|---|---|---|
| V(ESD) | Electrostatic discharge | Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001(1) | ±1000 | V |
| Charged-device model (CDM), per JEDEC specification JESD22-C101(2) | ±250 | |||
(1) JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.
(2) JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process.
5.3 Recommended Operating Conditions
over operating free-air temperature range (unless otherwise noted)
| MIN | NOM | MAX | UNIT | ||
|---|---|---|---|---|---|
| VDD | Supply Voltage | 1.71 | 3.46 | V | |
| TA | Operating Temperature | -40 | 125 | °C | |
5.4 Thermal Information
over operating free-air temperature range (unless otherwise noted)
| THERMAL METRIC(1) | LDC0851 | UNIT | ||
|---|---|---|---|---|
| DSG (WSON) | ||||
| 8 PINS | ||||
| RθJA | Junction-to-ambient thermal resistance | 67.4 | °C/W | |
| RθJC(top) | Junction-to-case (top) thermal resistance | 89.3 | °C/W | |
| RθJB | Junction-to-board thermal resistance | 37.3 | °C/W | |
| ψJT | Junction-to-top characterization parameter | 2.4 | °C/W | |
| ψJB | Junction-to-board characterization parameter | 37.7 | °C/W | |
| RθJC(bot) | Junction-to-case (bottom) thermal resistance | 9.2 | °C/W | |
(1) For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application report (SPRA953).
5.5 Electrical Characteristics
Over recommended operating conditions unless otherwise noted. VDD= 3.3 V, EN tied
to 3.3 V, TA=25 °C, ADJ tied to GND.(1)
| PARAMETER | TEST CONDITIONS | MIN(2) | TYP(3) | MAX(2) | UNIT | |
|---|---|---|---|---|---|---|
| POWER | ||||||
| VDD | Supply Voltage | 1.71 | 3.46 | V | ||
| ISTATIC | Static Supply Current (4) | 0.70 | mA | |||
| IDYN | Dynamic Supply Current (not including sensor current)(4) | ƒSENSOR = 15 MHz
CPARASITIC = 22 pF | 0.66 | mA | ||
| ISD | Shutdown Mode Supply Current | 0.14 | 1 | µA | ||
| SENSOR | ||||||
| ISENSOR_MAX | Maximum sensor current(4) | VDD = 1.71 V | 4.35 | mA | ||
| VDD = 3.3 V | 6 | mA | ||||
| LSENSOR_MIN | Sensor Minimum Inductance(5) | CTOTAL = 33 pF
VDD = 1.71 V | 2.5 | |||
| CTOTAL = 33 pF
VDD = 3.3 V | 1.8 | µH | ||||
| ƒSENSOR_MAX | Max Sensor Resonant Frequency(5) | Sensor inductance = 2 µH
CTOTAL = 33 pF | 19 | MHz | ||
| CTOTAL | Minimum total capacitance on LCOM(5) Includes parasitic pin capacitance and PCB parasitic capacitance | 33 | pF | |||
| CIN | Pin parasitic capacitance on LCOM | 12 | pF | |||
| Pin parasitic capacitance on LREF and LSENSE | 8 | pF | ||||
| DETECTION | ||||||
| dHYST | Switching distance hysteresis(6) | 2.5 % | ||||
| dTOL | Switching threshold tolerance(6) | 0.1 % | ||||
| THRESHOLD ADJUST | ||||||
| VADJ | Adjust input range | 0 | VDD/2 | V | ||
| VADJ_TOL | Adjust threshold tolerance | ± 6 | mV | |||
(1) Electrical Characteristics Table values apply only for factory testing conditions at the temperature indicated. Factory testing conditions result in very limited self-heating of the device such that TJ = TA. No guarantee of parametric performance is indicated in the electrical tables under conditions of internal self-heating where TJ > TA. Absolute Maximum Ratings indicate junction temperature limits beyond which the device may be permanently degraded, either mechanically or electrically.
(2) Limits are ensured by testing, design, or statistical analysis at 25°C. Limits over the operating temperature range are ensured through correlations using statistical quality control (SQC) method.
(3) Typical values represent the most likely parametric norm as determined at the time of characterization. Actual typical values may vary over time and will also depend on the application and configuration. The typical values are not tested and are not guaranteed on shipped production material.
(4) Refer to section Active Mode for a description and calculation of the
various supply currents.
(5) See Sensor Design for sensor guidance.
(6) Two matched 10 mm diameter sensors were used with a switching
distance of 3 mm. See Hysteresis for more information.
