Datasheet

LTC4223-1/LTC4223-2
10
422312f
The typical LTC4223 application is in a Carrier board
for Advanced Mezzanine Cards (AMC), delivering 3.3V
auxiliary and 12V power to the AMC module. A control-
ler on the Carrier board sequences the turn-on of power
supplies and manages the fault and power-good reports
from the LTC4223.
The LTC4223 detects board presence during insertion and
extraction, allowing power to be delivered in a controlled
manner without damaging the connector. The typical
LTC4223 application circuit is shown in Figure 1. External
component selection is discussed in detail in the Design
Example section.
APPLICATIONS INFORMATION
Turn-On Sequence
The power supplies delivered to an AMC module are
controlled by the external N-channel pass transistor, Q1 in
the 12V power path and an internal pass transistor in the
3.3V auxiliary power path. Sense resistor R
S
monitors the
12V load current for fault detection and current sensing
information. GATE capacitor C
G
provides gate slew rate
control to limit the inrush current. Resistor R
G
with C
G
compensates the current control loop while R3 prevents
parasitic oscillations in Q1.
422312 F01
12V
OUT
12V
SENSE
12V
GATE
12V
IN
V
CC
AUXIN
AUXOUT
EN
AUXON
12ON
AUXPGOOD
12PGOOD
FAULT
12V
5
21 16
15
12
10
89
6
7
4
11
13
3
58
2
3
4
7
6
1
14
3.3V
R
S
6mΩ
Q1
Si7336ADP
PWR
MP
PS1
PS0
CARRIER AMC
CONNECTOR
MODULE AMC
CONNECTOR
TIMER
LTC4223-1
GND
12V
7.4A
3.3V
150mA
R3
10Ω
R2
51Ω
MP ENABLE
PWR ENABLE
MP GOOD
PWR GOOD
FAULT
C2
330nF
BULK SUPPLY
BYPASS CAPACITOR
C
T
0.1μF
1μF
R
G
47Ω
C
G
15nF
3.3V
3.3V
INTELLIGENT
PLATFORM
MANAGEMENT
CONTROLLER
ENABLE
PRESENCE
RESET
12IMON
R4*
10k
2.2k
*OPTIONAL
3.3V
10k
R5*
10k
R6*
10k
3.3V 3.3V 3.3V
BULK SUPPLY
BYPASS CAPACITOR
LTC1197L
V
REF
CLK
D
OUT
CS
+IN
–IN
V
CC
GND
3
Figure 1. Advanced Mezzanine Card/MicroTCA Application