SUMMIT
MICROELECTRONICS, Inc.
Distributed Power Hot-Swap Controller
SMT4004
FEATURES
l
Programmable Voltage and Current Monitoring
l
Programmable Watchdog and Longdog Timers
w
Monitors 4 independent supplies
w
Programmable Host-side Under- and Over-
Voltage Thresholds
w
Programmable Card-side Under-Voltage
Monitors
w
Programmable Card-side Circuit Breaker
Delay and QuickTrip™ Threshold Levels
l
Programmable Card-side Trakker Function
(0 to 6.4 seconds)
l
Operates From Any One of Four Supply Voltages
l
Nonvolatile Fault Register
w
Records Source of Any Interrupt
w
Readable in “Dead Board” Environment
l
All Communications to Configuration Registers
and Memory Array are via 2-wire Serial Inter-
face
w
Programmable Slew Rate Control
w
Guarantees and Enforces Supply Differential
Tracking
FUNCTIONAL BLOCK DIAGRAM
PWR_ON FORCE_SD SEATED1# SEATED2#
33
UV_OVERRIDE 12
27
10
11
MR# IRQ_CLR#
5
6
7
IRQ#
13 RST1#
VO1 20
CB1 37
VI1 41
SUPPLY
MANAGER
#1
14 RST2#
RESET &
STATUS
OUTPUT
CONTROL
LOGIC
SEQUENCE
ENABLE
LOGIC
15 RST3#
16 RST4#
3
CROWBAR
25 CBFAULT
26 HEALTHY#
32 VGATE1
31 VGATE2
CHARGE
PUMP &
VGATE
CONTROL
30 VGATE3
29 VGATE4
28 VGG_CAP
24 ENABLE
VO2 21
CB2 36
VI2 40
SUPPLY
MANAGER
#2
VO3 22
CB3 35
VI3 39
SUPPLY
MANAGER
#3
VO4 23
CB4 34
VI4 38
SUPPLY
MANAGER
#4
TRAKKER
LOGIC
9
TRKR_IRQ#
48 WLDI
TIMER
LOGIC
POWER
SUPPLY
ARBITRATION
1
2
4
LDO#
WDO#
1.25VREF
43 A0
MEMORY
& 2-WIRE
BUS
INTERFACE
44 A1
45 A2
46 SDA
47 SCL
42
8
18
DGND
19
AGND
17
PGND
2049 BD 2.1
VDD_CAP PGND
©SUMMIT MICROELECTRONICS, Inc., 2000 • 300 Orchard City Dr., Suite 131 • Campbell, CA 95008 • Phone 408-378-6461 • FAX 408-378-6586 • www.summitmicro.com
Characteristics subject to change without notice
2049 2.2 9/13/00
1
SMT4004
DESCRIPTION
The SMT4004 is a fully integrated programmable voltage
manager IC, providing supervisory functions and tracking
control for up to four independent power supplies. The
four internal managers perform the following functions:
Monitor source (bus-side) voltages for under- and over-
voltage conditions, monitor each supply for over-current
conditions, monitor back end (card-side) voltages for two
staged levels of under-voltage conditions, insure power to
the card-side logic tracks within the specified parametric
limits, and provide supply status information to a host
processor.
The SMT4004 incorporates nonvolatile programmable
circuits for setting all of the monitored thresholds for each
manager. Individual functions are also programmable
allowing interrupts or reset conditions to be generated by
any combination of events. Because of a proprietary
EEPROM technology that it employs it is also able to store
fault conditions as they occur. In the case of a catastrophic
failure the fault is recorded in the registers and then can be
read for analysis.
PIN CONFIGURATION
48-Pin TQFP
48
47
46
45
44
43
42
41
40
39
38
37
WLDI
SCL
SDA
A2
A1
A0
VDD_CAP
VI1
VI2
VI3
VI4
CB1
LDO#
WDO#
CROWBAR
1.25V
REF
MR#
IRQ_CLR#
IRQ#
PGND
TRKR_IRQ#
SEATED1#
SEATED2#
UV_OVERRIDE
1
2
3
4
5
6
7
8
9
10
11
12
36
35
34
33
32
31
30
29
28
27
26
25
CB2
CB3
CB4
PWR_ON
VGATE1
VGATE2
VGATE3
VGATE4
VGG_CAP
FORCE_SD
HEALTHY#
CBFAULT
RST1#
RST2#
RST3#
RST4#
PGND
DGND
AGND
VO1
VO2
VO3
VO4
ENABLE
13
14
15
16
17
18
19
20
21
22
23
24
2049 PCon 2.1
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 GND:
V
0
, V
1
, V
2
, and V
3
........... -0.3V to 6.0V
All Others ........................ -0.3V to 6.0V
*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.
2
2049 2.2 9/13/00
SUMMIT MICROELECTRONICS, Inc.
SMT4004
DC OPERATING CHARACTERISTICS
(Over
Recommended Operating Conditions; Voltages are relative to GND)
Symbol
VI
I
DD
On
I
DD
Off
P
VIT
VI
HYS
V
CB
Parameter
Supply voltages VI1 through VI4
Power supply current
Notes
Highest VI (
≥
2.7V) powers the
SMT4004
PWR_ON and ENABLE active
ENABLE inactive
0.9
10
20
Programmable.
Set by Register R1B,
data bits D1 & D0,
respectively
Programmable.
Set by Register R1A,
data bits D7 & D6
(
e.g.
), respectively
R
LOAD
= 2k
Ω
MOSFET switches On
VG
SINK
= 1mA
MOSFET switches On
Programmable.
Set by Register R10,
data bits D3 & D2 or
D1 & D0, respectively
VO pins, delta differential
allowed
8-bit resolution, 20mV/bit
0.9
10
VI = 2.7V
VI = 5V
VI = 2.7V
VI = 5V
I
SINK
= 2mA
2.5V min. into 1k
Ω
0.9
×
VI
0.7
×
VI
–0.1
–0.1
0
4
5
VI
VI
0.1
×
VI
0.3
×
VI
0.4
7
0
0
1
1
0
1
0
1
100
250
500
1000
100
6.0
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
1.23
14
0
25
25
50
100
200
Off
75
100
150
1.25
1.27
16
0.4
80
mV
mV
mV
V
V
V
µA
V/s
V/s
V/s
V/s
mV
V
mV
V
V
V
V
V
µs
2049 Elect Table 1.0
Min.
2.7
Typ.
Max.
5.5
Units
V
mA
mA
V
mV
1
3
0.1
6.0
Programmable VI input threshold
8-bit resolution, 20mV/bit
range
OV/UV trip hysteresis
Circuit breaker trip voltage
30
mV
µs
µs
µs
µs
CB
DELAY
Over-current filter
V
QCB
Quick-trip voltage
V
REF
V
VG
On
V
VG
Off
I
VG
1.25V
REF
output voltage
VGATE drive output voltage
VGATE drive output current
SR
VG
VGATE output voltage slew rate
SR
DELTA
TRAKKER slew differential
P
OVT
OV
HYS
V
IH
V
IL
V
OL
t
CROW
Programmable card-side voltage
threshold range
OV input hysteresis
Input high voltage
Input low voltage
Open drain outputs
Crowbar output pulse width
SUMMIT MICROELECTRONICS, Inc.
2049 2.2 9/13/00
3
SMT4004
PIN DESCRIPTIONS AND DEVICE OPERATION
THE
TRAKKER
SUPPLY VOLTAGES
The
VI
inputs of all four supply managers are diode ORed
and tied to the device's internal V
DD
node. The
TRAKKER
will use the highest VI input for its supply voltage. At least
one VI input must be at or above 2.7V for proper device
operation.
V
DD
_CAP —
Charge storage connection for the chip's
internal power suply. For most applications a 10µF
capacitor should be connected to his pin.
V
GG
_CAP
— This pin should be tied to a capacitor to be
charged by the charge pump. The capacitor should be of
sufficient size so as to provide current to the VGATE
outputs under varying load conditions.
PGND
— Power ground
DGND
— Digital Ground
AGND
— Analog Ground
SUPPLY MANAGERS
The electrical placement of the SMT4004 on a printed
circuit card is such that it separates the host power supply
and any on-board DC-to-DC converters (or LDOs) from
the backend circuitry such as multiple DSPs, micropro-
cessors and associated glue logic. The host supplies, and
any other regulated voltages that will be “switched” by the
device, are referred to as bus-side voltages. The voltages
that are on the backend circuitry side of the switches are
referred to as card-side voltages.
The four supply manager blocks are identical. Each
contains three primary functional blocks: the first monitors
the bus-side voltages, the second monitors the card-side
voltages, and the third monitors over-current conditions
for that particular supply.
BUS-SIDE MANAGEMENT
Figure 1 illustrates the functional blocks of the four supply
managers. Each manager block can be independently
enabled or electrically removed from the device.
The VI input monitors the bus-side voltage for both under-
voltage and over-voltage conditions. The thresholds for
the under-voltage detection for VI inputs are programmed
in Registers
R00
through
R03
. The VI input is effectively
the V
REF
of a nonvolatile DAC. The DAC has been
designed so that the threshold can be determined by
multiplying the binary value of the Register times 20mV
and adding that to 0.9V in the formula P
VIT
= 0.9V + (0.2mV
×
n),
where
n
is the register value (0 - 255 decimal). This
allows very precise monitoring of voltages in the range of
0.9V to 6V without the use of external resistor divider
networks.
The over-voltage section works in a similar manner, with
the formula being Offset = (P
VIT
×
1.2) + [(0.04
×
P
VIT
)
×
n],
where
n
is the register value in
R04
through
R07
. All
enabled manager blocks must ensure their respective VI
inputs are within the programmed limits before the VGATE
outputs can be turned on and the
TRAKKER
logic en-
abled. The VI comparator outputs can also be used to
generate a general interrupt.
It should be noted that either one or both of the bus-side
monitors could be disabled via Registers
R04
through
R07
.
TIMERS
LDO#
— The longdog timer output is an active-low open-
drain output that can be wire-ORed with other open-drain
signals. The longdog timer is generally programmed to
generate an output at a time interval longer than the
watchdog timer. The time interval is programmed in
Register
R1C
.
WDO#
— The watchdog timer output is an active-low
open-drain output that can be wire-ORed with other open-
drain signals. The watchdog timer is generally pro-
grammed to generate an output at a time interval shorter
than the longdog timer. The time interval is programmed
in Register
R1C
.
WLDI
— Watchdog and longdog timer reset input. A low-
to-high transition on this pin will reset both the watchdog
timer and the longdog timer.
The watchdog and longdog work in tandem: resetting one
resets the other. Generally, the longdog will be pro-
grammed to time out sometime after the watchdog. As an
example, the WDO# output could be used to generate a
warning interrupt and the LDO# output could be tied to a
system reset line.
Both timers can be turned off, facilitating system debug
and also allowing operating systems to ‘boot up’ and
configure themselves without interrupts or resets.
4
2049 2.2 9/13/00
SUMMIT MICROELECTRONICS, Inc.
SMT4004
VIX
–
+
OV
Comparator
VGATE Enable
VGATE and
TRAKKER
Logic
+
VREF
–
UV
Comparator
CBX
Programmable
Delay
25mV
+
–
Circuit
Breaker
Comparator
( = Programmable)
OC
+
–
Programmable
Quick Trip
Threshold
VOX
Quick Trip
Quick
Trip
Comparator
To IRQ
To Crowbar
–
+
UV1
Comparator
To RST
+
VREF
–
UV2
Comparator
2049 Fig01 1.0
Figure 1. Supply Manager Circuit
CARD-SIDE MANAGEMENT
On the card-side the
TRAKKER
monitors two program-
mable under-voltage thresholds on the VO inputs: UV1
and UV2. UV1 can be used to generate a warning interrupt
that the supply is decaying, and UV2 can be used to
generate a reset condition or a crowbar output. The card-
side under-voltage (UV1) threshold value is programmed
in Registers
R08
through
R0B.
Like the bus-side thresh-
olds the levels can be programmed in 20mV increments
(on top of 0.9V). The second level (UV2) is determined by
the formula UV2 = UV1 – [(UV1
×
0.01)
×
n],
where
n
is the
value in Registers
R0C
through
R0F.
It should be noted that either one or both of the card-side
monitors can be disabled via Registers
R0C
through
R0F
.
OVER-CURRENT PROTECTION
The CB inputs are the circuit breaker inputs for the supply
voltages. With a series resistor placed in the supply path
between VI and CB the circuit breaker will trip whenever
the voltage across the resistor exceeds 25mV.
SUMMIT MICROELECTRONICS, Inc.
2049 2.2 9/13/00
5
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