SUMMIT
MICROELECTRONICS, Inc.
Distributed Power Hot-Swap Controller
SMH4811A
Preliminary
FEATURES
l
Supply Range ±20VDC to >±500VDC
l
Versatile Card Insertion Detection Supports:
w
Multi-length Pin Systems
w
Card Injector Switch Sensing
w
Programmable Debounce Periods
l
Control Powering-on of DC/DC Converters
l
Highly Programmable Host Voltage Monitoring
w
Programmable Under- and Over-voltage
Detection
w
Programmable UV Filter
l
Programmable Power Good Delay for enabling
the DC/DC Converter
l
Programmable Circuit Breaker Function
w
Programmable Over-Current Filter
w
Programmable Quick-Trip™ Circuit Breaker
Values
l
2.5V and 5.0V reference outputs
w
Easy Expansion of External Monitor
Functions
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.
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
Characteristics subject to change without notice
2044 SAD 5.1
©SUMMIT MICROELECTRONICS, Inc., 2000 • 300 Orchard City Dr., Suite 131 • Campbell, CA 95008 • Phone 408-378-6461 • FAX 408-378-6586 • www.summitmicro.com
2044 6.1 2/8/01
1
SMH4811A
Preliminary
PIN CONFIGURATION
16-Pin SOIC
RECOMMENDED OPERATING CONDITIONS
Temperature
–40°C to 85°C.
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 5.0
FUNCTIONAL BLOCK DIAGRAM
ENPG
14
VDD
16
12VREF
12
2.5VREF
+
DRAIN
1
SENSE
50kΩ
200kΩ
50kΩ
–
11
5.0VREF
EN/TS
3
PD1#
4
PD2#
5
+
–
PROGRAMM-
ABLE
DELAY
15
PG#
UV
9
+
–
FILTER
+
OV
10
5V
12V
2.5V
2
VGATE
VSS
8
PROGRAMM-
ABLE
DELAY
50mV
CBSENSE
7
Programmable
Quick Response
Ref. Voltage
2
–
50kΩ
VGATE
SENSE
+
–
+
–
6
FAULT#
DUTY
CYCLE
TIMER
2044 BD 5.2
2044 6.1 2/8/01
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.
SUMMIT MICROELECTRONICS, Inc.
2044 6.1 2/8/01
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
*COMMENT
Stresses listed under Absolute Maximum Ratings may cause perma-
nent 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.
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
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 6.1 2/8/01
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
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
Input low voltage: ENPG
Output low voltage: FAULT#
Output low voltage: PG#
Gate threshold
I
OL
= 2mA
I
SINK
= 2mA
I
DD
= 3mA (1)
I
DD
= 3mA
I
DD
= 3mA
2
–0.1
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
I
DD
= 3mA (1)
I
DD
= 3mA
V
SENSE
= V
SS
(1)
I
DD
= 3mA
2.475
2.425
9
40
100
2.500
2.500
10
50
200
V
QCB
100
60
2.525
2.575
11
60
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
2.475
2.425
Min.
11
4.75
–1
2.475
2.425
–0.2
2
2.475
2.425
2.500
2.500
10
2.500
2.500
10
V
DD
2.525
2.575
2.500
2.500
Typ.
12
5.00
Max.
13
5.25
1
2.525
2.575
1
10
2.525
2.575
Units
V
V
mA
V
V
mA
mA
V
V
mV
V
V
mV
V
µA
V
V
µA
mV
mV
mV
mV
—
V
V
mV
V
V
V
V
V
2044 Elect Table
Note:
(1)
TA = 25ºC.
SUMMIT MICROELECTRONICS, Inc.
2044 6.1 2/8/01
5
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