SMS66
Six-Channel Power Supply Supervisor and Cacsade Sequence Controller
FEATURES & APPLICATIONS
•
•
•
•
•
•
•
•
Very accurate monitor function – 5mV steps
Monitors and sequences up to six supplies
Programmable Power-on/-off sequencing
Monitors internal temperature sensor
Operates from 12V or 3.3V supply
Monitors 12V input and VDD
Monitors two general-purpose 10-bit ADC inputs
Programmable threshold limits (2 OV/2 UV) for
each monitored input
•
Programmable RESET, HEALTHY and FAULT
functions
•
4k-bit general purpose nonvolatile memory
•
I
2
C 2-wire serial bus for programming
configuration and monitoring status, including
10-bit ADC conversion results
Applications
•
Monitor and Sequence Distributed Power and
Point of Load Power Supplies
•
Multi-voltage Processors, DSPs, ASICs used in
Telecom, CompactPCI or server systems
Preliminary Information
1
(See Last Page)
INTRODUCTION
The SMS66 is a very accurate programmable power
supply supervisor that monitors and sequences. It
controls sequencing time and position of up to six
isolated or non-isolated distributed or POL DC/DC
converters. The monitor supervisory function has two
independent UV and OV settings for each supply and
can be set in 5mV steps. The SMS66 also sequences
the power supplies in any order using enable outputs
with programmable polarity.
The SMS66 monitors six power supply channels as
well as VDD, 12V input, two general-purpose analog
inputs and an internal temperature sensor using a 10-
bit ADC. The 10-bit ADC can measure the value on
any one of the input channels and output the
conversion data via the I
2
C bus.
Using the I
2
C interface, a host system can
communicate with the SMS66 status register,
optionally control Power-on/off, and utilize 4 K-bits of
nonvolatile memory.
SIMPLIFIED APPLICATIONS DRAWING
12VIN (+8V to +15V Range)
VDD (+2.7V to +5.5V Range)
12VIN
VDD
DC/DC
Converter A
VIN
Vout
2.5VIN
12V
3.3V
SDA
I
2
C
BUS
SCL
A2
PUP
A
External
or
Internal
TEMP
SENSOR
ON/OFF
AIN1
SMS66
VM
A
DC/DC
Converter F
VIN
Vout
µP/
DSP/
NPU/
FPGA
1.2VIN
External or
Internal
REFERENCE
VREF_OUT
VREF_ADC
HEALTHY
PUP
F
ON/OFF
RST
MR
VM
F
HEALTHY
RESET
DONE
Figure 1 – Applications Schematic using the SMS66 Controller to cascade sequence up to six DC/DC
Converters while also providing supervisory functions.
Note: This is an applications example only. Some pins, components and values are not shown.
© SUMMIT
Microelectronics, Inc. 2003 •
300 Orchard City Drive, #131 • Campbell CA 95006
• Phone 408 378-6461 • FAX 408 378-6596
2070 1.0 7/16/03
www.summitmicro.com
1
SMS66
Preliminary Information
VDD (+2.7V to +5.5V)
or 12VIN ( +8V to +15V)
2.7V
2.5V
2.0V
1.8V
1.5V
t
DPONA
t
DPONB
RST#
t
DPONC
t
DPOND
t
DPONE
t
DPONF
t
PRTO
Figure 2 – Example Power Supply Sequencing and System Start-up Initialization using the SMS66.
Any order of supply sequencing can be applied using the SMS66 with very accurate monitoring and
supervisory functions.
GENERAL DESCRIPTION
The SMS66 is a highly integrated power supply
controller, monitor and sequencer. It has the ability to
control, monitor and sequence up to six power
supplies. Also, the SMS66 can monitor the VDD input,
the 12V input, two general-purpose analog inputs and
the internal temperature sensor. The SMS66 has
three operating modes: Power-on sequencing mode,
monitor mode, and Power-off sequencing mode.
Power-on sequencing can be initiated via the
PWR_ON/OFF pin or I
2
C control. In this mode, the
SMS66 will sequence the power supply channels on in
any order by activating the PUP outputs and
monitoring the respective converter voltages to ensure
cascading of the supplies. A programmable sequence
termination timer can be set to disable all channels if
the Power-on sequence stalls. During this mode the
HEALTHY output will remain inactive and the RST
output will remain active.
Once the Power-on sequencing mode is complete, the
SMS66 enters monitor mode. In the monitor mode the
SMS66 supervises the supplies to within 5mV, and
enables the triggering of outputs by monitored fault
conditions.
The 10-bit ADC cycles through all 11 channels every
2ms and checks the conversions against the
programmed threshold limits. The results can be used
to trigger RST, HEALTHY and FAULT outputs as well
as to trigger a Power-off or a Force Shutdown
operation.
The Power-off sequencing mode can only be entered
while the SMS66 is in the monitoring mode. It can be
initiated by either bringing the PWR_ON/OFF pin
inactive, through I
2
C control or triggered by a channel
exceeding its programmed thresholds. Once Power-
off is initiated it will disable the Active DC Control and
sequence the PUP outputs off in either the same or
reverse order as Power-on sequencing and monitor
the supply voltages to ensure cascading of the
supplies as they turn off. The sequence termination
timer can be programmed to immediately disable all
channels if the Power-off sequencing stalls. The RST
output will remain active throughout this mode while
the HEALTHY output remains inactive.
Summit Microelectronics, Inc
2070 1.0 7/16/03
2
SMS66
Preliminary Information
INTERNAL FUNCTIONAL BLOCK DIAGRAM
12VIN
VDD
VDD_CAP
PWR_ON/OFF FS
VREF_ADC
AIN
1
AIN
2
VM
A
CAP
A
3.6V or
5.5V
Regulator
Power
Supply
Arbitrator
Sequence
Control
PUP
A
PUP
B
PUP
C
PUP
D
PUP
E
PUP
F
10-Bit ADC
Temperature
Sensor
VM
F
MR
CAP
F
RST
HEALTHY
FAULT
Output
Control
VREF_OUT
Reference
Memory and
Limit Registers
I
2
C
Interface
SDA
SCL
A2
GND
Figure 3 –SMS66 Internal Functional Block Diagram.
Summit Microelectronics, Inc
2070 1.0 7/16/03
3
SMS66
Preliminary Information
PIN DESCRIPTIONS
Pin
Number
1
2
3
Pin
Type
DATA
CLK
IN
Pin Name
SDA
SCL
A2
I
2
C Bi-directional data line
I
2
C Clock line
The address pin is biased either to VDD_CAP or GND.
When
communicating with the SMS66 over the 2-wire bus A2 provides a
mechanism for assigning a unique bus address.
Programmable active high/low input. When asserted the RST output will be
go active. When de-asserted the RST output will go inactive immediately
after a reset timeout period (t
PRTO
) if there are no RST trigger sources active.
This timeout period makes it suitable to use a pushbutton for manual reset.
Programmable active high/low input signals the start of the power
sequencing. When asserted the part will sequence the supplies on and
when de-asserted the part will sequence the supplies off.
Programmable active high/low input. Force shutdown is used to immediately
turn off all converter enable signals (PUP outputs)
Programmable active high/low open drain Fault output. Active when a
programmed fault condition exists on AIN1, AIN2, or the internal temperature
sensor.
Programmable active high/low open drain Healthy output. Active when all
programmed power supply inputs and monitored inputs are within OV and
UV limits.
Programmable active high/low open drain Reset output. Active when a
programmed fault condition exists on any power supply inputs or monitored
inputs or when MR is active. RST has a programmable timeout period with
options for 0.64ms, 25ms, 100ms and 200ms.
General purpose monitored analog input
General purpose monitored analog input
Ground
Voltage reference input used for A/D conversion where:
(4XVREF_ADC) = Full Scale for VM
A-F
and VDD
(12XVREF_ADC) = FS for 12VIN
(2XVREF_ADC) = FS for AIN1 and AIN2.
VREF_ADC can be connected to VREF_CNTL in most applications.
Voltage reference output for the internal 1.25V reference.
Monitored voltage input, VM
A
through VM
F
Pin Description
4
IN
MR
5
6
7
IN
IN
OUT
PWR_ON/OFF
FS
FAULT
8
OUT
HEALTHY
9
OUT
RST
10
11
12, 44,
39, 34,
29, 24,
19
IN
IN
GND
AIN1
AIN2
GND
13
IN
VREF_ADC
14
41,36,
31,26,
21,16
O
IN
VREF_OUT
VM
X
Summit Microelectronics, Inc
2070 1.0 7/16/03
4
SMS66
Preliminary Information
PIN DESCRIPTIONS (Cont.)
Pin
Number
42,37,
32,27,
22,17
43,38,
33,28,
23,18
45, 40,
35, 30,
25, 20,
15
46
47
48
Pin
Type
CAP
OUT
Pin Name
CAP
X
PUP
X
Pin Description
External capacitor input used to filter the VM
X
inputs to the 10-bit ADC, CAP
A
through CAP
F
. This provides an RC filter where R = 25kΩ.
Programmable active high/low open drain converter enable output, PUP
A
through PUP
F
No Connection
Power supply of the part
12V power supply input internally regulated to either 3.6V or 5.5V
External capacitor input used to filter the internal supply
NC
PWR
PWR
CAP
NC
VDD
12VIN
VDD_CAP
PACKAGE AND PIN CONFIGURATION
48 LEAD TQFP
VDD_CAP
CAPA
PUPB
38
12VIN
CAPB
37
36
35
34
33
32
31
30
29
28
27
26
25
13
14
15
16
17
18
19
20
21
22
23
24
PUPA
GND
VDD
VMA
GND
39
48
47
46
45
NC
44
43
42
41
SDA
SCL
A2
MR
PWR_ON/OFF
FS
FAULT
HEALTHY
RST
AIN1
AIN2
GND
1
2
3
4
5
6
7
8
9
10
11
12
40
NC
VMB
NC
GND
PUPC
CAPC
VMC
NC
GND
PUPD
CAPD
VMD
NC
VREF_ADC
VREF_OUT
VME
PUPF
CAPE
Summit Microelectronics, Inc
2070 1.0 7/16/03
PUPE
CAPF
GND
VMF
GND
NC
NC
5
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