MIC2582/MIC2583
Micrel
MIC2582/MIC2583
Single Channel Hot Swap Controller
Preliminary Information
General Description
The MIC2582 and MIC2583 are single channel positive
voltage hot-swap controllers designed to allow the safe
insertion of boards into live system backplanes. Using few
external components, the parts act in conjunction with an
external N-Channel MOSFET device, for which the gate drive
is controlled to provide inrush current-limiting and output
voltage slew rate control. The MIC2582/3 are rated for
operation from supply voltages from 2.3V to 13.2V, but can
withstand transient voltages as high as 20V without damage.
Overcurrent fault protection is provided along with a program-
mable over-current threshold. Active current regulation dur-
ing start-up ensures that inrush current never exceeds the
programmed threshold. The MIC2582/3 provide a circuit
breaker function that latches the output MOSFET off if the
current limit threshold is exceeded for a programmed period
of time. Dual-level fault detection allows very fast response
to short-circuit faults while preventing lower level overcurrent
transients from causing “nuisance tripping” of the circuit
breaker. A /FAULT signal is provided indicating overcurrent
or undervoltage fault conditions.
Features
• Provides safe insertion and removal from live
backplanes
• 2.3V to 13V supply voltage operation
• Surge voltage protection up to 20V
• Undervoltage Lockout protection
• Programmable inrush current-limiting
• Current regulation limits inrush current regardless of
load capacitance
• Dual-level overcurrent fault sensing eliminates false
tripping
• Fast response to short circuit conditions (< 1
µs)
• Power-On Reset and Power-Good status outputs
(MIC2583)
• Programmable output undervoltage detection
• Electronic circuit breaker
• /FAULT status output
• Auto-restart function (MIC2583R)
Applications
•
•
•
•
•
RAID systems
Base stations
PC Board Hot-Swap insertion and removal
Hot-Swap CompactPCI Cards
Network Switches
Typical Application
V
IN
3.3V
R
SENSE
0.1µF
0.1µF
Logic Level
Input
VCC
ON
SENSE
GATE
FB
R2
12.4k
Open-Drain
Output
/POR
GND
Logic V
CC
CPOR
Logic
V
CC
/FAULT
GND
CPOR CFILTER
R1
CL
100µF
Logic Level
Input
VCC
ON
SENSE
GATE
FB
R3
12.4k
MIC2583
/PWRGD
/POR
DIS
R2
Logic V
CC
R1
10k
R1
10k
Power
Good
Power
Reset
V
OUT
V
IN
12V
R
SENSE
0.1µF
0.1µF
V
OUT
CL
100µF
MIC2582
Open-Drain
Output
0.1µF
0.1µF
C
FILTER
MIC2582 Typical Application Circuit
MIC2583 Typical Application Circuit
Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 944-0970 • http://www.micrel.com
April 2001
1
MIC2582/MIC2583
MIC2582/MIC2583
Micrel
Ordering Information
Part Number
MIC2582-xBM
Circuit Breaker Threshold
x = J, 50mV
x = K, 100mV
x = L, 150mV
x = M, 200mV
x = N, Off
MIC2582/83-xBQS
x = J, 50mV
x = K, 100mV
x = L, 150mV
x = M, 200mV
x = N, Off
MIC2583R-xBQS
x = J, 50mV
x = K, 100mV
x = L, 150mV
x = M, 200mV
x = N, Off
Auto-retry
16 pin QSOP
Latched off
16 pin QSOP
Circuit Breaker
Latched off
Package
8 pin SOIC
Pin Configuration
/POR 1
/PWRGD 2
/POR 1
ON 2
CPOR 3
GND 4
8 VCC
7 SENSE
6 GATE
5 FB
16 VCC
15 SENSE
14 GATE
13 DIS
12 FB
11 /FAULT
10 NC
9 NC
ON 3
CPOR 4
CFILTER 5
NC 6
GND 7
GND 8
8-Pin SOIC
16-Pin QSOP
MIC2582/MIC2583
2
April 2001
MIC2582/MIC2583
Micrel
Pin Description
Pin Name
/FAULT
ON
SOIC
NA
2
QSOP
11
3
Pin Function
Circuit Breaker Fault Output. Open-Drain, Active-Low. Asserted when the
circuit breaker is tripped.
ON input. With this pin high, the device is enabled, a start-up sequence is
initiated, and the GATE pin starts ramping up towards its final operating
voltage. The ON input is compared to a V
TH
reference which has 25mV of
hysteresis.
Toggling ON is also used to reset the circuit breaker. ON must be low for
20µs in order to initiate a start-up sequence. This pin should not be taken
higher than V
CC
+ 0.3V, or 7.5V, whichever is less.
Power-On Reset Output. Open-Drain. Asserted during start-up until a time
period t
POR
after the Power-Good threshold is reached. Also asserted
during undervoltage lockout fault conditions. (C
POR
determines time period
t
POR
)
Power-On-Reset Timer. A capacitor connected between this pin and ground
sets the Power-On-Reset interval, t
POR
, and start-up delay t
DELAY
. When
V
CC
rises above the UVLO, the capacitor connected to CPOR begins to
charge. When the voltage at CPOR crosses 0.3V, a start cycle is initiated if
ON is asserted. CPOR is reset to zero volts.
When the voltage at FB rises above V
FBTH
, C
POR
begins to charge again.
When the voltage at CPOR rises above V
PORDLY
, the timer resets, pulls
CPOR to ground, and /POR is de-asserted. If CPOR = 0, then t
DELAY
is set
to 20µs.
Circuit Breaker Sense Input. A resistor between this pin and VCC sets the
current-limit threshold. When the current-limit threshold of 50mV is ex-
ceeded for t
OCSLOW
(internally set at 5µs for the MIC2582), the circuit
breaker is tripped and the GATE pin is immediately pulled low. If the voltage
across the sense resistor exceeds V
THSLOW
due to fast high amplitude faults
such as short-circuits, then the GATE pin is immediately brought low (no
delay).
V
THSLOW
is available for values of 50mV, 100mV, 200mV, or Off. Whenever
the voltage across the sense resistor exceeds the current-limit threshold, the
GATE voltage is adjusted to ensure a constant load current. To disable the
circuit breaker, the SENSE and VCC pins can be tied together.
Gate Drive Output. Connects to the gate of an N-Channel MOSFET. An
internal clamp ensures that no more than 8V is applied between the GATE
and Source. When the circuit breaker trips or when undervoltage lockout
occurs the GATE pin is immediately brought low.
Power-Good Threshold Input. This input is internally compared to a 1.24V
reference which has 30mV of hysteresis. Whenever this input goes below
1.24V, /POR is asserted. A 5µs filter on this pin prevents negative-going
glitches from causing nuisance activation of this pin. If this input momentarily
goes below 1.24V, then /POR is activated for one timing cycle, t
POR
.
Positive Supply Input. 2.3V - 13.2V. The GATE pin is held low by an internal
undervoltage lockout circuit until VCC exceeds a threshold of 2.1V. If VCC
exceeds 13.2V, an internal shunt regulator protects the chip from transient
voltages up to 20V at the VCC and SENSE pins.
Current-limit Response Timer. A capacitor connected to this pin defines the
period of time t
OCSLOW
in which an overcurrent event must last to signal a
fault condition and trip the circuit breaker. If no capacitor is connected to this
pin, then t
OCSLOW
is set to 5µs.
During auto-retry, the MIC2583R exhibits a preset duty cycle of 10%. The
value of C
FILTER
will set the interval between auto-retry attempts.
See Applications section.
/POR
1
1
CPOR
3
4
SENSE
7
15
GATE
6
14
FB
5
12
VCC
8
16
CFILTER
NA
5
April 2001
3
MIC2582/MIC2583
MIC2582/MIC2583
Pin Name
/PWRGD
SOIC
NA
QSOP
2
Pin Function
Micrel
Power-Good Output. Open Drain. When the voltage at the FB pin is lower
than 1.24V, /PWRGD output is held low. When the voltage at the FB pin is
higher than 1.24V, then /PWRGD is de-asserted. A pull-up resistor con-
nected to this pin and to VCC will pull the output up to VCC.
Discharge output. When the MIC2582/MIC2583 is turned off, a 500Ω resistor
connected to this output allows the discharging of external load capacitance
to ground.
Ground connection
No Connection
DIS
NA
13
GND
NC
4
NA
7,8
6,9,10
MIC2582/MIC2583
4
April 2001
MIC2582/MIC2583
Micrel
Absolute Maximum Ratings
(Note 1)
All voltages are referred to GND
Supply Voltage (V
CC
) ..................................... –0.3V to 20V
/POR, /FAULT , /PWRGD pins ....................... –0.3V to 15V
SENSE pin ............................................ –0.3V to V
CC
+0.3V
ON pin ......... -0.3V to Vcc+0.3V OR 8V, whichever is lower
GATE pin ........................................................ –0.3V to 20V
FB input pins .................................................... –0.3V to 6V
Junction Temperature ............................................... 125°C
ESD Rating,
Note 3
Operating Ratings
(Note 2)
Supply Voltage (V
CC
) .................................... 2.3V to 13.2V
Thermal Resistance R
θ(J-A)
(8-pin SOIC) .............. 163°C/W
Thermal Resistance R
θ(J-A)
(16-pin SOIC) .......... 112°C/W
Operating Temperature Range .................. –40°C to +85°C
Electrical Characteristics
V
CC
= 5.0V, T
A
= 25°C unless otherwise noted.
Bold
values indicate –40°C
≤
T
A
≤
+85°C.
Symbol
V
CC
I
CC
V
TRIP
V
GS
I
GATEON
Parameter
Supply voltage
Condition
Temp = –20°C to +85°C
Temp = –40°C to +85°C
Supply current
Circuit breaker trip voltage
External Gate Drive
GATE pin pull-up current
V
ON
= 2V
V
TRIP
= V
CC
– V
SENSE
|V
CC
– V
GATE
|
Start cycle, V
GATE
= 0V
V
CC
=13.2V
V
CC
= 2.3V
I
GATEOFF
GATE pin sink current
/FAULT = 0, V
GATE
>1V V
CC
= 13.2V
V
CC
= 2.3V
Turn off
I
TIMER
I
POR
V
TH
V
UV
V
UVHYS
V
ONTH
I
ON
V
ONHYS
V
DELAYTH
V
AUTO
Current-limit timer current
V
CC
– V
SENSE
> V
TRIPSLOW
V
CC
– V
SENSE
< V
TRIPSLOW
Timer On
Timer Off
POR Delay and C
FILTER
timer
threshold
Undervoltage Lockout threshold
V
CPOR
rising
V
CFILTER
rising
V
CC
rising
V
CC
falling
Undervoltage Lockout hysteresis
ON pin threshold voltage
ON rising
ON falling
ON pin input current
ON pin hysteresis
Under-voltage start-up timer
threshold
Auto-restart threshold voltage
V
CPOR
rising
Upper Threshold
Lower Threshold
.28
V
ON
= V
CC
25
.33
1.24
0.33
.38
1.19
1.16
1.19
2.1
1.9
1.24
2.2
2.05
175
1.23
1.21
1.29
1.26
–0.5
1.29
2.3
2.2
V
V
V
mV
V
V
µA
mV
V
V
V
4.5
–8.5
12
0.5
V
TRIPSLOW
V
TRIPFAST
V
CC
> 3V
V
CC
= 2.3V
37
85
5.5
2.7
10
9
Min
2.3
2.7
1.6
43
91
6.3
3.8
16
14
100
50
110
6.5
–6.5
14
1.45
8.5
–4.5
16
Typ
Max
13.2
13.2
2.5
50
105
8
5
24
19
Units
V
V
mA
mV
mV
V
V
µA
µA
mA
mA
µA
µA
µA
µA
mA
Power-On-Reset timer current
April 2001
5
MIC2582/MIC2583
嵌入式系统
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