
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) 
 SUMMIT 
Microelectronics, Inc. 2003  
300 Orchard City Drive, #131  Campbell CA 95006 
 Phone 408 378-6461  FAX 408 378-6596          www.summitmicro.com 
2070  1.0 7/16/03 
1
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
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 
PUP
F
VM
F
PUP
A
VM
A
SMS66
μ
P/
DSP/
NPU/
FPGA
V
R
H
M
VDD (+2.7V to +5.5V Range)
RESET
DONE
HEALTHY
1
12VIN (+8V to +15V Range)
External
or
Internal
TEMP
SENSOR
AIN1
VREF_ADC
2.5VIN
1.2VIN
12V
SDA
SCL
I
2
C
BUS
3.3V
A2
VREF_OUT
VIN
Vout
DC/DC
Converter A
ON/OFF
VIN
Vout
DC/DC
Converter F
ON/OFF
External or
Internal
REFERENCE
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.