SUMMIT
MICROELECTRONICS, Inc.
Programmable Distributed Power Hot-Swap Controller
for High-Availability Systems
FEATURES
Soft Starts Main Power Supply on Card Insertion
or System Power Up
Senses Card Insertion via Short Pins or Ejector
Switches
Master Enable to Allow System Control of
Power Up or Down
Can be used as a Temperature Sense Input
Programmable Independent Controls of a DC/DC
Converter
Not Enabled until Host Supply Fully Soft
Started
Programmable Time Delay
Available Input to hold off Dependant En-
ables until Conditions are Satisfied
Highly Programmable Circuit Breaker
Programmable Quick-Trip
TM
Values
Programmable Current Limiting
Programmable Duty Cycle Times
Programmable Over-current Filter
SMH4811A
Preliminary
Programmable Host Voltage Fault Monitoring
Programmable Under-Voltage Hysteresis
Programmable UV/OV Voltage Filter
Programmable Fault Mode: Latched or Duty
Cycle
Programmable Forced Shutdown Timer
2.5V and 5.0V Reference Outputs
Eliminates the Need for Other Primary
Voltages
Easy Expansion of External Monitor Func-
tions
Internal Shunt Regulator Allows a Wide Supply
Range
SIMPLIFIED APPLICATION DRAWING
0V
Disable/Enable
VDD
Pin Detect
PD1#
ENPG
FAULT#
UV
SMH4811A
OV
PG#
DC/DC
Pin Detect
PD2#
VSS
CBSENSE VGATE 2.5VREF 5.0VREF
–48V
2044 SAD 5.1
©SUMMIT MICROELECTRONICS, Inc., 2006 • 757 North Mary Ave • Sunnyvale, CA 94085 • Phone 408-523-1000 • FAX 408-523-1266 • www.summitmicro.com
Characteristics subject to change without notice
2044 6.6
03/27/09
1
SMH4811A
Preliminary
DESCRIPTION
The SMH4811A is designed to control hot swapping of
plug-in cards operating from a single supply ranging from
20V to 500V. It provides under-voltage and over-voltage
monitoring of the host power supply, drives an external
power MOSFET switch that connects the supply to the
load, and also protects against over-current conditions
that might disrupt the host supply. When the input and
output voltages to its controls are within specification it
provides a Power Good logic output that may be used to
turn loads on (e.g., an isolated-output DC-DC converter,
or drive a LED status light). Additional features of the
SMH4811A include: temperature sense or master enable
input, 2.5V and 5V reference outputs for expanding moni-
tor functions, two Pin-Detect enable inputs for fault protec-
tion, and duty-cycle over-current protection.
PIN CONFIGURATION
DRAIN SENSE
VGATE
EN/TS
PD1#
PD2#
FAULT#
CBSENSE
V
SS
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
V
DD
PG#
ENPG
NC
2.5V
REF
5V
REF
OV
UV
2044 PCon 5.1
FUNCTIONAL BLOCK DIAGRAM
ENPG
14
VDD
16
12VREF
12
2.5VREF
+
DRAIN
1
SENSE
50kΩ
200kΩ
50kΩ
To EN/TS
To PD1#
To PD2#
–
11
5.0VREF
50kΩ
PROGRAMM-
ABLE
DELAY
5V
12V
2.5VREF
VSS
8
15
PG#
UV
9
–
2.5VREF
w/prog
hysteresis
2.5VREF
Reg6[3]
OV
10
EN/TS
3
2.5VREF
PD1#
4
PD2#
5
PROGRAMM-
ABLE
DELAY
50mV
CBSENSE
7
2
+
+
–
Reg6[2]
OV/UV Filter
t
UV/OVF
Reg4[2:1]
VGATE
SENSE
PD Timer
t
PD
2
VGATE
+
–
Reg9[1:0]
+
–
6
FAULT#
+
Programmable
Quick Response
Ref. Voltage
DUTY
CYCLE
TIMER
–
2044 6.6
03/27/09
SUMMIT MICROELECTRONICS, Inc.
SMH4811A
Preliminary
PIN DESCRIPTIONS
DRAIN SENSE (1)
The DRAIN SENSE input monitors the voltage at the drain
of the external power MOSFET switch with respect to V
SS
.
An internal 10µA source pulls the DRAIN SENSE signal
towards the 5V reference level. DRAIN SENSE must be
held below 2.5V to enable the PG outputs.
VGATE (2)
The VGATE output activates an external power MOSFET
switch. This signal supplies a constant current output
(100µA typical), which allows easy adjustment of the
MOSFET turn on slew rate.
EN/TS (3)
The Enable/Temperature Sense input is the master en-
able input. If EN/TS is less than 2.5V, VGATE will be
disabled. This pin has an internal 200kΩ pull-up to 5V.
PD1# and PD2# (4 & 5)
These are logic level active low inputs that can optionally
be employed to enable VGATE and the PG outputs when
they are at V
SS
. These pins each have an internal 50kΩ
pull-up to 5V.
FAULT# (6)
This is an open-drain, active-low output that indicates the
fault status of the device.
CBSENSE (7)
The circuit breaker sense input is used to detect over-
current conditions across an external, low value sense
resistor (R
S
) tied in series with the Power MOSFET. A
voltage drop of greater than 50mV across the resistor for
longer than t
CBD
will trip the circuit breaker. A program-
mable Quick-Trip™ sense point is also available.
UV (9)
The UV pin is used as an under-voltage supply monitor,
typically in conjunction with an external resistor ladder.
VGATE will be disabled if UV is less than 2.5V. Program-
mable internal hysteresis is available on the UV input,
adjustable in increments of 62.5mV. Also available is a
filter delay on the UV input.
OV (10)
The OV pin is used as an over-voltage supply monitor,
typically in conjunction with an external resistor ladder.
VGATE will be disabled if OV is greater than 2.5V. A filter
delay is available on the OV input.
5.0VREF & 2.5VREF (11 & 12)
These are precision 5V and 2.5V output reference volt-
ages that may be use to expand the logic input functions
on the SMH4803A. The reference outputs are with re-
spect to V
SS
.
ENPG (14)
This is an active high input that controls the PG# output.
When ENPG is pulled low the PG# output is immediately
placed in a high impedance state. This pin has an internal
50kΩ pull-up to 5V.
PG# (15)
The PG# pin is an open-drain, active-low output with no
internal pull-up resistor. It can be used to switch a load or
enable a DC/DC converter. PG# is enabled immediately
after VGATE reaches V
DD
– V
GT
and the DRAIN SENSE
voltage is less than 2.5V. Voltage on these pins cannot
exceed 12V, as referenced to V
SS.
V
DD
(16)
V
DD
is the positive supply connection. An internal shunt
regulator limits the voltage on this pin to approximately
12V with respect to VSS. A resistor must be placed in
series with the V
DD
pin to limit the regulator current (R
D
in
the application illustrations).
V
SS
(8)
V
SS
is connected to the negative side of the supply.
RECOMMENDED OPERATING CONDITIONS
Temperature
–40°C to 85°C.
SUMMIT MICROELECTRONICS, Inc.
2044 6.6
03/27/09
3
SMH4811A
Preliminary
ABSOLUTE MAXIMUM RATINGS*
Temperature Under Bias ...................... –55°C to 125°C
Storage Temperature .............................. –65°C to 150°C
Lead Solder Temperature (10 secs) ..................... 300 °C
Terminal Voltage with Respect to V
SS
:
V
DD
................................. –0.5V to V
DD
OV, UV, DRAIN SENSE,
CBSENSE ........... –0.5V to V
DD
+0.5V
PD1#, PD2#, ENPG, EN/TS ......... 10V
FAULT#, PG# ........ –0.5V to V
DD
+0.5V
VGATE ................................. V
DD
+0.5V
Stresses listed under Absolute Maximum Ratings may cause permanent damage to the device. These
are stress ratings only, and functional operation of the device at these or any other conditions outside
those listed in the operational sections of this specification is not implied. Exposure to any absolute
maximum rating for extended periods may affect device performance and reliability.
RECOMMENDED OPERATING CONDITIONS
Temperature Range (Ambient)
Supply Voltage . (V
DD
) (I
DD
= 5 mA)
Package Thermal Resistance (θ
JA
) 16-pin SOIC
-40
o
C to +85
o
C
11V to 13V
46
o
C/W
Moisture Classification Level 1 (MSL 1) per J-STD-020
Reliability Characteristics
Data Retention .............................
...........................100
Years
.
Endurance
1
....................................................100,000
Cycles
AC OPERATING CHARACTERISTICS
Symbol
Description
Min.
Typ.
400
t
CBD
50mV Circuit Breaker Delay (filter)
150
50 *
5
50
250
500
t
PGD
Programmable Power Good Delay
1.5
5*
20
80
160
t
FSTSHTDN
t
CYC
Fast Shut Down delay from fault to VGATE off
Circuit breaker cycle mode time
200
2.5 *
Off *
t
PUVF
Programmable Under-Voltage filter
5
80
160
0.5
t
PDD
Programmable Pin Detect Delay
5
80 *
160
Note:
*
Indicates default value
Note (1)
Guaranteed by Design
Max.
Units
µs
µs
µs
µs
µs
µs
µs
ms
ms
ms
ms
ms
ns
s
—
ms
ms
ms
ms
ms
ms
ms
2044 Prog Table
4
2044 6.6
03/27/09
SUMMIT MICROELECTRONICS, Inc.
SMH4811A
Preliminary
DC OPERATING CHARACTERISTICS
(Over
Recommended Operating Conditions; Voltages are relative to
V
SS
)
Symbol
V
DD
5.0VREF
I
LOAD5
2.5VREF
I
LOAD2.5
I
DD
(2)
V
UV
V
UVHYST
V
OV
V
OVHYST
V
VGATE
I
VGATE
V
SENSE
I
SENSE
V
CB
Parameter
Supply voltage
5V reference output
5V reference output current
2.5V reference output
2.5V reference output current
Power supply current
Under-Voltage threshold
Under-Voltage hysteresis
Over-Voltage threshold
Over-Voltage hysteresis
VGATE output voltage
VGATE current output
DRAIN SENSE threshold
DRAIN SENSE current output
Circuit breaker threshold
Programmable Quick Trip circuit
breaker threshold
Off
V
ENTS
V
ENTSHYST
V
IH
V
IL
V
OL
V
GT
EN/TS threshold
EN/TS hysteresis
Input high voltage: ENPG, PD1#,
PD2#
Input low voltage: ENPG, PD1#,
PD2#
Output low voltage: FAULT#
Output low voltage: PG#
Gate threshold
(2) This value is set by the R
D
resistor.
Conditions
I
DD
= 3mA
I
DD
= 3mA
I
DD
= 3mA
I
DD
= 3mA (1)
I
DD
= 3mA
I
DD
= 3mA
Output enabled
I
DD
= 3mA (1)
I
DD
= 3mA
I
DD
= 3mA
I
DD
= 3mA (1)
I
DD
= 3mA
I
DD
= 3mA
Min.
11
4.75
–1
2.475
2.425
–0.2
2
2.475
2.425
2.475
2.425
Typ.
12
5.00
2.500
2.500
Max.
13
5.25
1
2.525
2.575
1
10
Units
V
V
mA
V
V
mA
mA
V
V
mV
V
V
mV
V
µA
V
V
µA
mV
mV
mV
mV
—
2.500
2.500
10
2.500
2.500
10
2.525
2.575
2.525
2.575
V
DD
100
I
DD
= 3mA (1)
I
DD
= 3mA
V
SENSE
= V
SS
(1)
I
DD
= 3mA
2.475
2.425
9
40
2.500
2.500
10
50
200
100
60
I
DD
= 3mA (1)
I
DD
= 3mA
I
DD
= 3mA
2
–0.1
I
OL
= 2mA
I
SINK
= 2mA
0
0
0.7
1.8
2.475
2.425
2.500
2.500
10
5.0VREF
0.8
0.4
0.4
3.0
2.525
2.575
2.525
2.575
11
60
V
QCB
V
V
mV
V
V
V
V
V
2044 Elect Table
Note: (1) T
A
= 25ºC.
SUMMIT MICROELECTRONICS, Inc.
2044 6.6
03/27/09
5
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