LINEAR Hot Swap Solution AMC & MicroTCA Compliance Design Note 437 by Vladimir Ostrerov Hot Swap Instructions User Guide
Summary
The LTC4223 is a professional dual Hot Swap controller built specifically for Advanced Mezzanine Cards in ATCA and MicroTCA industrial computing systems. This device comprehensively monitors 12V load current while managing two independent power supplies. The manual details its critical protective functions, including ultra-fast fault detection (overcurrent/short-circuit), dynamic supply control, card presence sensing, and adjustable analog current limits. It simplifies reliable power management for complex industrial hardware designs.
Page 1 Text Content
Hot Swap Solution Meets AMC and Micro TCA Standards Design Note 437 Vladimir Ostrerov Introduction The LTC4223 monitors 12V load current by sensing
The LTC®4223 is a dual Hot Swap™ controller that meets voltage across an external resistor and outputs a ground- the power requirements of the Micro Telecommunication referenced voltage (at the 12IMON pin) proportional to Computing Architecture (Micro TCA) specifi cation recently the load current. It also provides separate power-good ratifi ed by the PCI Industrial Computer Manufacturers outputs for the two supplies and a single, common fault Group (PICMG). output. Additional features include card detection and independent control of the two supplies. The LTC4223-
The LTC4223 includes an internal pass FET for the 3.3V
1 latches off after a circuit breaker fault timeout expires
auxiliary supply and a driver for an external N-channel
while the LTC4223-2 provides automatic retry after a
pass FET for the 12V payload supply. Inrush current for
fault. A fault on the 12V supply shuts down only the 12V
both supplies is controlled: the auxiliary supply has a
path, leaving the 3.3V auxiliary power available for system
fi xed 240m A active current limit and the 12V ramp rate
management functions. A fault on the 3.3V AUX supply
is controlled by an external capacitor. A timed circuit
shuts down both supplies.
breaker and fast current limit protect both supplies against
severe overcurrent faults. It also features an adjustable Advanced Mezzanine Card Application
analog current limit with a circuit breaker timeout for Figure 1 shows a typical Micro TCA application. The cur- the 12V supply. rent limit on the 12V rail is 7.6A, determined by the 6mΩ
L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. Hot Swap is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners.
6mΩ Si7336ADP
12VSENSE 12VGATE 12VOUT12VIN
3.3V AUXIN AUXOUT
VCC 330n F
LTC4223-1/LTC4223-2
AUXON 12ON AUXPGOOD 12PGOOD FAULT
12IMONADC EN
GND TIMER
DN437 F01
CARRIER MODULE CONNECTOR CONNECTOR
Figure 1. Advanced Mezzanine Card Application
Page Summary Contents For LINEAR Hot Swap Solution AMC & MicroTCA Compliance Design Note 437 by Vladimir Ostrerov Hot Swap Instructions User Guide
Manual Details
| Brand | Linear |
|---|---|
| Pages | 2 |
| File Size | 100.77 KB |
| Published | June 02, 2026 |
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Frequently Asked Questions
What standards does the LTC4223 meet?
It meets both AMC and MicroTCA standards, referencing the PCI PICMG specification.
How does the controller handle overcurrent faults on the 12V supply?
It has an adjustable analog current limit (ACL) with a circuit breaker timeout. Continued faults shut down power after a timer expires.
Can the LTC4223 provide individual card monitoring?
Yes, it supports individual card monitoring and control functions simplified by its status and control lines.
Does it offer separate protection for 12V and auxiliary supplies?
It provides separate power-good outputs for both supplies and independent control of the two rails.