MIC2590B
Dual-Slot PCI Hot Plug Controller
General Description
The MIC2590B is a power controller supporting power
distribution requirements for Peripheral Component Inter-
connect (PCI) hot plug compliant systems incorporating
the Intelligent Platform Management Interface (IPMI). The
MIC2590B provides complete power control support for
two PCI slots including the 3.3V
AUX
defined by the PCI 2.2
specification.
Support for +5V, +3.3V, +12V and –12V supplies is
provided including programmable constant-current inrush
limiting, voltage supervision, programmable current limit,
fault reporting and circuit breaker functions which provide
fault isolation.
The MIC2590B also incorporates a SMBus interface in
which complete status and control of power within each
slot is provided. Data such as voltage and current from
each supply of each slot can be obtained for IPMI sensor
records in addition to power status of each slot.
Data sheets and support documentation can be found on
Micrel’s web site at: www.micrel.com.
Features
•
Supports two independent PCI 2.2 slots
•
SMBus interface for slot power control and status
•
+5V, +3.3V, +12V, –12V, +3.3VAUX supplies supported
per PCI specification 2.2
•
Programmable inrush current-limiting
•
Active current regulation controls inrush current
•
Electronic circuit breaker
•
Dual level fault detection for quick fault response
without nuisance tripping
•
Thermal isolation between circuitry for slot A and slot B
Applications
•
PCI hot-plug power distribution
___________________________________________________________________________________________________________
Ordering Information
Part Number
Standard
MIC2590B-2BTQ
MIC2590B-5BTQ*
Pb-Free
MIC2590B-2YTQ
MIC2590B-5YTQ*
5V & 3V Fast-trip
Threshold
100mV
Disabled
+12V & –12V Fast-trip
Threshold
1.5A/0.4A
1.5A/0.4A
Operating
Temp. Range
0° to +70°C
0° to +70°C
Package
48-Pin TQFP
48-Pin TQFP
Note:
* Contact factory for availability.
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 2008
M9999-091808
Micrel, Inc.
MIC2590B
Typical Application
Power
Supply
+12V
12V
+5.0V
+3.3V
1A Schotty Diode
(Clamp)
VSTBY
12VIN1 12VIN2
VSTBY1
VSTBY2
12SLEWA
12SLEWB
12MVIN1 12MVIN2
VAUXA
5VINA
5VSENA
5VGATEA
5VOUTA
C
GATE
CFILTERA
IREF
20k
1%
CFILTERB
3VGATEA
3VOUTA
12VOUTA
12MVOUTA
5VINB
GND
3VINA
3VSENSEA
C
GATE
R
3VGATEA
3.3V, 7.6A
12V, 0.5A
12V, 0.1A
4.7µF
R
SENSE
R
5VGATEA
5V, 5A
R
SENSE
PCI
Connector
PCI Bus
3.3VAUXA
MIC2590B
4.7µF
R
SENSE
PCI Bus
5VSENSEB
ONA/ONB
AUXENA/AUXENB
/FAULTA, /FAULTB
Hot-Plug
Controller
2
2
2
ONA/ONB
AUXENA/AUXENB
/FAULTA, /FAULTB
A0
A1
A2
/INT
SCL
SDA
5VGATEB
5VOUTB
C
GATE
3VINB
3VSENSEB
3VGATEB
3VOUTB
12VOUTB
12MVOUTB
VAUXB
4.7µF
R
5VGATEB
5V, 5A
R
SENSE
C
GATE
R
3VGATEB
3.3V, 7.6A
12V, 0.5A
12V, 0.1A
3.3VAUXB
4.7µF
SMBus I/O
SDA
SCL
/INT
SDA
SCL
Management
Controller
/INT
Bus Switch
A
B
/OE
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MIC2590B
Pin Configuration
48-Pin TQFP (TQ)
Pin Description
Pin Number
6, 31
Pin Name
5VINA, 5VINB
Pin Function
5V Supply Power and Sense Inputs [A/B]: Two pins are provided for Kelvin
connection (one for each slot). Pin 6 is the Kelvin sense connection to the
supply side of the sense resistor for 5V Slot A. Pin 31 is the Kelvin sense
connection to the supply side of the sense resistor for 5V Slot B. These two pins
must ultimately connect to each other within 10cm. An undervoltage lockout
circuit (UVLO) prevents the switches from turning on while this input is less than
its lockout threshold.
3.3V Supply Power and Sense Inputs [A/B]: Two pins are provided for Kelvin
connection (one for each slot). Pin 12 is the Kelvin sense connection to the
supply side of the sense resistor for 3V Slot A. Pin 25 is the Kelvin sense
connection to the supply side of the sense resistor for 3V Slot B. These two pins
must ultimately connect to each other within 10cm. An undervoltage lockout
circuit (UVLO) prevents the switches from turning on while this input is less than
its lockout threshold.
+12V Supply Input: An undervoltage lockout circuit prevents the switches from
turning on while this input is less than its lockout threshold. Both pins must be
tied together at the chip.
–12V Supply Input: An undervoltage lockout circuit prevents the switches from
turning on while this input is less than its lockout threshold. Both pins must be
tied together at the chip.
12V output [A/B]
–12V output [A/B]
12V Slew Rate Control [A/B]: Connect capacitors between these pins and
ground to set output slew rates of the +12V and -12V supplies.
12, 25
3VINA, 3VINB
5, 32
12VIN – 2 pins
17, 18
12VMIN – 2 pins
10, 27
19, 20
3, 34
12VOUTA, 12VOUTB
12MVOUTA, 12MVOUTB
12VSLEWA, 12VSLEWB
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Micrel, Inc.
Pin Number
45, 42
Pin Name
AUXENA, AUXENB
Pin Function
MIC2590B
AUX Enable Inputs [A/B]: Rising-edge sensitive enable inputs for VAUXA and
VAUXB outputs. Taking AUXENA/AUXENB low after a fault resets the
respective slot’s Aux Output Fault Latch. Tie these pins to ground if using
SMBus-mode power control.
3.3V Power-Good Sense Inputs: Connect to 3.3V[A/B] outputs. Used to monitor
the 3.3V output voltages for Power-Good status.
5V Power-Good Sense Inputs: Connect to 5V[A/B] outputs. Used to monitor the
5V output voltages for Power-Good status.
A resistor connected between this pin and ground sets the ADC current
measurement gain. This resistor must be 20kΩ ±1%.
5V Circuit Breaker Sense Input [A/B]: The current-limit thresholds are set by
connecting sense resistors between these pins and 5VIN[A/B]. When the
current-limit threshold of IR = 50mV is reached, the 5VGATE[A/B] pin is
modulated to maintain a constant voltage across the sense resistor and
therefore a constant current into the load. If the 50mV threshold is exceeded for
t
FLT
, the circuit breaker is tripped and the GATE pin for the affected slot is
immediately pulled low.
3V Circuit Breaker Sense Input [A/B]: The current limit thresholds are set by
connecting sense resistors between these pins and 3VIN[A/B]. When the
current limit threshold of IR = 50mV is reached, the 3VGATE[A/B] pin is
modulated to maintain a constant voltage across the sense resistor and
therefore a constant current into the load. If the 50mV threshold is exceeded for
t
FLT
, the circuit breaker is tripped and the GATE pin for the affected slot is
immediately pulled low.
5V Gate Drive Outputs [A/B]: Each connects to the gate of an external N-
Channel MOSFET. During power-up the C
GATE
and the gate of the MOSFETs
are charged by a 20µA current source. This controls the value ofdv/dt seen at
the source of the MOSFETs, and hence the current flowing into the load
capacitance.
During current limit events, the voltage at this pin is adjusted to maintain
constant current through the switch for a period of t
FLT
. Whenever an
overcurrent, thermal shutdown or input undervoltage fault condition occur sthe
GATE pin for the affected slot is immediately brought low.
During power-down these pins are discharged by an internal current source.
16, 21
9, 28
33
7, 30
3VOUTA, 3VOUTB
5VOUTA, 5VOUTB
IREF
5VSENSEA, 5VSENSEB
13, 24
3VSENSEA, 3VSENSEB
8, 29
5VGATEA, 5VGATEB
14, 23
3VGATEA, 3VGATEB
3V Gate Drive Outputs [A/B]: Each connects to the gate of an external N-
Channel MOSFET. During power-up the C
GATE
and the gate of the MOSFETs
are charged by a 20µA current source. This controls the value ofdv/dt seen at
the source of the MOSFETs, and hence the current flowing into the load
capacitance.
During current limit events, the voltage at this pin is adjusted to maintain
constant current through the switch for a period of t
FLT
. Whenever an
overcurrent, thermal shutdown or input undervoltage fault condition occurs the
GATE pin for the affected slot is immediately brought low.
During power-down these pins are discharged by an internal current source.
11, 26
VSTBY – 2 pins
3.3V Standby input voltage required to support PCI 2.2 VAUX input: SMBus,
internal registers and A/D converter run off of VSTBY to ensure chip access
during standby modes. A UVLO circuit prevents turn-on of this supply until
VSTBY rises above its UVLO threshold. Both pins must be tied together at the
chip.
V
AUX
[A/B] output voltages to PCI card slots: These outputs connect the VAUX
pin of the PCI 2. 2 Connectors VSTBY via internal 400mΩ MOSFETs which are
current-limited and protected against short circuit faults.
Enable input for MAIN outputs: Rising-edge sensitive. Used to enable or
disable MAIN (5V, 3.3V, +12V, –12V) outputs. Taking ONA/ONB low after a
fault resets the respective slot’s Main Output Fault Latch. Tie these pins to
ground if using SMBus-mode power control.
15, 22
VAUXA, VAUXB
44, 43
ONA, ONB
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Pin Number
1, 36
Pin Name
/FAULTA, /FAULTB
Pin Function
MIC2590B
Open Drain, Active-Low: Asserted whenever the circuit breaker trips due to a
fault condition.
/FAULT[A/B] is reset by bringing the faulted slot’s ON pin low if /FAULT was
asserted in response to a fault condition on one of the slot’s MAIN outputs(+12V,
+5V, +3.3V, or –12V).
/FAULT[A/B] is reset by bringing the faulted slot’s AUXEN pin low if /FAULT was
asserted in response to a fault condition on the slot’s VAUX output.
If a fault condition occurred on both the MAIN and AUX outputs of the same slot,
then both ON and AUXEN must be brought low to de-assert the /FAULT output.
2, 35
CFILTERA, CFILTERB
Filter Capacitor [A/B]: Capacitors connected between these pins and ground set
the duration of t
FLT
. t
FLT
is the amount of time for which a slot remains incurrent-
limit before its circuit breaker is tripped.
Interrupt Output: Open Drain, Active-low. Asserted whenever a power faulti s
detected. Cleared by writing a logic 1 to the respective active bit into the Status
Register.
SMBus Data: Bidirectional SMBus data line.
SMBus Clock: Input.
SMBus Address Select pins: Connect to ground or leave open in order to
program device SMBus base address. There is an internal pull-up to VSTBY on
each of these inputs.
General Purpose Inputs: The state of these inputs are available by reading the
Common Status Register.
Ground
37
/INT
48
47
39, 40, 41
SDA
SCL
A2, A1, A0
4, 38
46
GPIA, GPIB
GND
September 2008
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M9999-091808
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