MIC2588/MIC2594
Micrel
MIC2588/MIC2594
Single-Channel, Negative High-Voltage Hot
Swap Power Controllers
General Description
The MIC2588 and the MIC2594 are single-channel, nega-
tive-voltage hot swap controllers designed to address the
need for safe insertion and removal of circuit boards into
“live” high-voltage system backplanes, while using very few
external components. The MIC2588 and the MIC2594 are
each available in an 8-pin SOIC package and work in con-
junction with an external N-Channel MOSFET for which the
gate drive is controlled to provide inrush current limiting and
output voltage slew-rate control. Overcurrent fault protection
is also provided and includes a programmable overcurrent
threshold. During an output overload condition, a constant-
current regulation loop is engaged to ensure that the system
power supply maintains regulation. If a fault condition exceeds
a built-in 400µs nuisance-trip delay, the MIC2588 and the
MIC2594 will latch the circuit breaker’s output off and will
remain in the off state until reset by cycling either the UV/OFF
pin or the power to the IC. A master Power-Good signal is
provided to indicate that the output voltage of the soft-start
circuit is within its valid output range. This signal can be used
to enable one or more DC-DC converter modules.
All support documentation can be found on Micrel’s web site
at www.micrel.com.
Features
• MIC2588:
Pin-for-pin functional equivalent to the
LT1640/LT1640A/LT4250
• Provides safe insertion and removal from live –48V
(nominal) backplanes
• Operates from –19V to –80V
• Electronic circuit breaker function
• Built-in 400µs “nuisance-trip” delay (t
FLT
)
• Regulated maximum output current into faults
• Programmable inrush current limiting
• Fast response to short circuit conditions (< 1µs)
• Programmable undervoltage and overvoltage lockouts
(MIC2588-xBM)
• Programmable UVLO hysteresis (MIC2594-xBM)
• Fault reporting:
Active-HIGH (-1BM) and Active-LOW (-2BM)
Power-Good output signal
Applications
•
•
•
•
Central office switching
–48V power distribution
Distributed power systems
Server Networks
Typical Application
-48V RTN
(Long Pin)
-48V RTN
DC-DC
CONVERTER
1
/PWRGD
VDD
8
IN+
C5
100uF
C4
0.1uF
OUT+
+2.5V
OUT
*D1
SMAT70A
100V
ON/OFF
#
IN-
2
-48V RTN
(Short Pin)
R1
698kΩ
1%
R2
11.8kΩ
1%
OV
DRAIN
7
OUT-
MIC2588-2BM
3
UV
GATE
+2.5V RTN
6
R3
12.4kΩ
1%
4
VEE
SENSE
5
*C2
22nF
R
FDBK
15kΩ
C
FDBK
6.8nF
100V
C1
1uF
VDD
*C6
0.33uF
R4
10Ω
C3
0.22uF
-48V
IN
(Long Pin)
R
SENSE
0.01Ω
5%
-48V
OUT
M1
SUM110N10-09
Nominal Undervoltage and Overvoltage Thresholds:
V
UV
= 36.5V
V
OV
= 71.2V
* Optional components (See Applications Information for more details)
# An external pull-up resistor for the power-good signal is necessary for DC-DC supplies
(and all other load modules) not equipped with internal pull-up impedence
Micrel, Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
September 2005
1
M9999-083005
MICREL [ MICREL SEMICONDUCTOR ]
