MIC2558BM - PCMCIA Dual Card Socket VPP Switch Matrix | Micrel
料号： MIC2558BM ✗ 停产| 数量 | 单价 | 小计 |
|---|---|---|
| 1 | $1 | $1.00 |
MIC2558BM 概述
A VPP switching matrix, sometimes called a card-socket power switch, is a specialized power management IC in the broader family of load switches and power-distribution switches. In PC Card (PCMCIA) hosts, the VPP pins of a card socket must present 0V (grounded), 12V (programming voltage for flash cards), or the card's VCC voltage (3.3V or 5V read/write operation), and the switching matrix routes the correct voltage to each socket pin under host controller command. This function sits between the system power rails and the card socket in the notebook or embedded host power architecture.
Key features of the MIC2558 include dual-channel operation covering both VPP1 and VPP2 pins of a PCMCIA socket, selectable 12.0V programming voltage output, low on-resistance switching paths to minimize voltage drop during card flash programming, and logic-level control inputs compatible with standard PCMCIA host controller GPIO outputs. The B grade suffix denotes the commercial operating temperature grade, and the M suffix denotes the SOIC surface-mount package.
Architecturally, the device uses MOSFET switch segments arranged in a matrix so that any one of the available input voltages can be connected to either VPP output, with break-before-make switching behavior preventing momentary shorts between supply rails. Internal gate-drive circuitry ensures the external MOSFET switches are driven fully on for low drop-out, eliminating the need for discrete level shifters or drivers in the host design.
Typical applications include notebook and laptop PCMCIA card slots, industrial embedded hosts with PC Card interfaces, flash-card programming fixtures, and legacy CardBus development systems where 12V VPP flash programming voltage must be supplied to memory cards.
When designing with the MIC2558, ensure the 12V programming rail can deliver the card VPP programming current and observe datasheet logic-input timing to guarantee break-before-make switching between voltage states.
This page synthesizes distributor sourcing data, drop-in alternative guidance, and practical design notes not found in the manufacturer datasheet.
直接替换替代料： MIC2558BM ——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：
MIC2558YM
✅ 直接替换 ⚠️ 规格未核验📋 参考替代料（不在目录中）
MIC2558BMT
✅ 直接替换 ⚠️ 规格未核验📋 参考替代料（不在目录中）
MIC2558BM 最大额定值与电气特性
| 功能 | PCMCIA Dual Card Socket VPP Switching Matrix |
| Switching Channels | 2 (VPP1 and VPP2) |
| Selectable Output Voltages | 12.0 V programming voltage plus card VCC voltages (3.3 V / 5 V per PCMCIA standard) |
| Control Inputs | Logic-level switching control inputs |
| 封装 | SOIC |
| 安装类型 | Surface Mount |
| Switching Configuration | Matrix - routes one of multiple input voltages to either VPP output |
| Manufacturer Status | Obsolete / last-time-buy (part no longer in active production) |
MIC2558BM soic 引脚配置指南
MIC2558BM（soic 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： MIC2558BM.
请参阅 数据手册 以查看完整引脚配置。
典型应用
MIC2558BM 适用于 6 应用s: Notebook PCMCIA Card Slots, Embedded PC Card Hosts, Flash Card Programming Fixtures, CardBus Development Systems, Retro Computing Repair and Legacy Maintenance, Point-of-Sale and Rugged Terminals with PC Card Slots.
Notebook PCMCIA Card Slots
The MIC2558BM was designed primarily for notebook and laptop PCMCIA card slots, where the host must present 0V, the card VCC rail, or a 12.0V programming voltage to the socket VPP1 and VPP2 pins depending on card type and operating mode. Its dual-channel matrix covers both VPP pins with a single IC, saving board area and discrete MOSFET count in the tight power-routing region around the card cage. The selectable 12.0V output supports flash-memory card programming per the PCMCIA specification, while low voltage drop in the switch paths preserves VPP accuracy during programming current bursts. Designers place the MIC2558 directly between the 12V/VCC rails and the socket pins, with logic inputs tied to the host controller VPP control signals.
推荐
Embedded PC Card Hosts
Industrial embedded systems that retained PC Card/CardBus interfaces for expansion used the MIC2558BM to implement the VPP switching function without discrete level-shifting circuitry. In these hosts, the device sits in the power path between the 12V auxiliary rail, the 3.3V/5V VCC rail, and the card socket, switching states under command from an embedded controller or FPGA GPIO. The matrix architecture with internal MOSFET gate drive simplifies the design compared to a discrete four-switch network per socket, and break-before-make switching protects against rail-to-rail shorts during state transitions. Engineers should budget the 12V rail for flash-programming current and verify logic thresholds against the controller output levels in the extended temperature environment typical of industrial enclosures.
推荐
Flash Card Programming Fixtures
Production programming fixtures and lab programmers for PCMCIA flash cards require a stable, accurate 12.0V VPP supply switched onto the card socket only during programming cycles. The MIC2558BM provides exactly this function: the 12.0V selectable output is connected to VPP1 and VPP2 only when the host asserts the programming state, and the socket VPP pins are grounded or floated at all other times, protecting unprogrammed cards. The switching matrix isolates the programming voltage from the VCC rail, preventing 12V exposure that would damage cards in normal read/write mode. Fixture designs benefit from the SOIC surface-mount package and the ability to serve both socket VPP pins from one device.
推荐
CardBus Development Systems
CardBus and legacy 16-bit PC Card development platforms use the MIC2558BM to exercise all PCMCIA-defined VPP states during card validation and driver development. The dual-channel matrix lets a test host independently control VPP1 and VPP2 - useful for verifying card behavior with asymmetric VPP conditions and for margining the 12.0V programming voltage. Because the device handles the voltage routing internally, developers can toggle states from software via the host controller without rewiring. The commercial B temperature grade suits bench environments, while the Y-grade variant covers extended testing. Verify the device's switching timing against the controller's VPP change sequences to guarantee clean transitions during automated test runs.
推荐
Retro Computing Repair and Legacy Maintenance
Repair of vintage laptops, field-data terminals, and industrial PDAs that used PCMCIA sockets frequently traces socket faults to failed VPP switching circuitry. The MIC2558BM remains the correct replacement in these repairs because it matches the original Micrel-specified matrix function, pinout, and 12.0V programming behavior, restoring full card-flash programming capability. Technicians should confirm the failed device marking and package before ordering, since multiple Micrel socket-power parts share similar naming. Given the part's obsolete status, sourcing from excess stock is the practical path, and XAIPART quote-based sourcing covers small repair quantities where broker stock is the only supply option.
推荐
Point-of-Sale and Rugged Terminals with PC Card Slots
Older point-of-sale terminals, rugged handheld data collectors, and mobile payment devices commonly carried a single PCMCIA slot for memory or modem cards, with the MIC2558BM providing socket VPP power management in a compact SOIC footprint. The dual-matrix function mattered less in single-slot designs but was retained because the same device served the full VPP1/VPP2 requirement with margin. The 12.0V selectable rail enables in-field firmware or data updates on flash PC Cards, a key serviceability feature for deployed terminals. Designers in these applications should ensure the terminal's DC-DC stage reliably generates the 12V programming rail only during update cycles to limit quiescent dissipation in battery-powered operation.
推荐
推荐产品汇总
工程参考数据： MIC2558BM ——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 | MIC2558YM | MIC2558BMT |
|---|---|---|---|
| Package | SOIC | SOIC - same | SOIC - same |
| Brand | Micrel Semiconductor (now Microchip Technology) | Micrel Semiconductor (now Microchip Technology) | Micrel Semiconductor (now Microchip Technology) |
| Function | PCMCIA dual card socket VPP switching matrix | PCMCIA dual card socket VPP switching matrix | PCMCIA dual card socket VPP switching matrix |
| Selectable Programming Voltage | 12.0 V | 12.0 V | 12.0 V |
| Switching Channels | 2 (VPP1 + VPP2) | 2 (VPP1 + VPP2) | 2 (VPP1 + VPP2) |
| Temperature Grade | B (commercial) | Y (extended) | B (commercial) |
| Lifecycle Status | Obsolete | Obsolete | Obsolete |
关键差异点
- Integrated dual-channel VPP matrix （对比 Discrete MOSFET switch network)
- Selectable 12.0V programming voltage （对比 MIC2558YM (same function))
- Trade-off: no modern continuation path （对比 Discrete MOSFET switch network)
设计说明
Estimated: the 12V VPP rail must supply flash-programming current for the card being programmed. Size the upstream 12V source for the programming current specified by your card vendor plus margin, and decouple the MIC2558 12V input with a bulk capacitor (10 uF or more) close to the device to hold up during programming current bursts. Voltage sag on the 12V rail below the PCMCIA VPP tolerance is a common cause of flash-programming failures in card sockets.
Drive the MIC2558 control inputs with a break-before-make sequence when changing VPP states. Connecting the 12.0V programming rail and the card VCC rail to the same VPP output simultaneously, even momentarily, can short two supply rails and damage the switches or the card. Tie unused states to ground per the PCMCIA specification, and verify your host controller's VPP control timing against the MIC2558 datasheet truth table before production.
Place the MIC2558 close to the card socket VPP pins to minimize trace inductance on the switched 12V path, which carries pulsed programming current. Use short, wide traces (at least 20 mil on 1 oz copper for typical programming currents) for the VPP outputs, and ground unused matrix inputs at the device rather than at a remote ground point. Add a small ceramic capacitor (0.1 uF) at each matrix input for high-frequency bypass alongside the bulk 12V reservoir.
The MIC2558BM is obsolete - Micrel was acquired by Microchip Technology and this PCMCIA-focused family is no longer manufactured. For any new design or volume production, qualify a discrete MOSFET switching matrix or a modern card-power interface device instead of committing to broker-stock MIC2558 supply, which has no factory lead time and no continuation plan. Use the same-family MIC2558YM only for repairs and legacy sustaining builds.
合规信息
Compliance data is not stated in the archived Micrel listings reviewed. This is a legacy Micrel part predating uniform RoHS reporting; original MIC2558BM stock may be non-RoHS (tin-lead plating). Verify with the supplier for any RoHS-sensitive application.
