SMM605
Six-Channel Supply Voltage Marginer and Active DC Output Controller (ADOC
TM
)
FEATURES & APPLICATIONS
•
Extremely accurate (±0.1% Typ.) Active
DC Output Control (ADOC
TM
)
Preliminary Information
1
(See Last Page)
INTRODUCTION
The SMM605 actively controls the output voltage level
of up to six DC/DC converters that use a ‘Trim’ or
‘VADJ/FB’ pin to adjust the output. An Active DC
Output Control (ADOC
TM
) feature is used during
normal operation to maintain extremely accurate
settings of supply voltages and, during system test, to
control margining of the supplies using the industry
standard I
2
C 2-wire data bus commands.
Total
accuracy with a ±0.1% external reference is ±0.2%,
and ±0.5% using the internal reference. The device
can margin supplies with either positive or negative
trim pin control within a range of 0.35V to VDD. The
SMM605 supply can range from 2.7V to 5.5V or 6V to
14V to accommodate any intermediate bus supply.
The voltage settings (margin high/low and
nominal) are programmed into nonvolatile memory.
The I
2
C bus is used to enable margin high, margin low,
ADOC or normal operation. When margining, the
SMM605 will check the voltage output of the converter
and make adjustments to the trim pin via a feedback
loop to bring the voltage to the margin setting. A
margining status register is set to indicate that the
system is ready for test.
•
Six channel control of DC/DC converters
•
ADOC Automatically adjusts supply output
voltage level under all DC load conditions
•
Capable of margining supplies with trim inputs
using either positive or negative trim pin control
•
Wide Margin/ADOC range from 0.35V to VDD
•
Uses either an internal or external VREF
•
Operates from any intermediate bus supply
from 8V to 15V and from 2.7V to 5.5V
•
Programmable START and READY pins
•
General Purpose 4k EEPROM with Write Protect
•
I
2
C 2-wire serial bus for programming
configuration and monitoring status.
•
48 lead TQFP package
Applications
•
Monitor/Control Distributed and POL Supplies
•
Multi-voltage Processors, DSPs, ASICs used in
Telecom, CompactPCI or server systems
SIMPLIFIED APPLICATIONS DRAWING
12VIN (+6V to +14V Range)
3.3VIN (+2.7V to +5.5V Range)
12VIN
VDD
CAP
A
TRIM_CAP
A
DC/DC
Converter C, E
VIN
DC/DC
Converter A
Vout
TRIM
12V
3.3V
SDA
I
2
C
BUS
SCL
A2
VDD_CAP
2.5VIN
TRIM
A
2 of 6 DC-DC
Converters shown
VM
A
CAP
B
SMM605
DC/DC
Converter D, F
VIN
DC/DC
Converter B
Vout
TRIM
TRIM_CAP
B
µP/
ASIC
1.2VIN
External or
Internal
REFERENCE
VREF_CNTL
TRIM
B
START
READY
RST
MR
VM
B
HEALTHY
RESET
READY
POWER GOOD
Figure 1 – Applications Schematic using the SMM605 Controller to actively control and margin the output
levels of up to six DC/DC Converters.
Note: This is an applications example only. Some pins, components and values are not shown.
© SUMMIT
Microelectronics, Inc. 2003
• 1717 Fox Drive • San Jose CA 95131 • Phone 408 436-9890 • FAX 408 436-9897
2064 1.1 9/16/03
www.summitmicro.com
1
SMM605
Preliminary Information
Figure 2 – Example Power Supply Margining using the SMM605. The waveform on the left is margin low to
high from 1.6V to 2.0V and the waveform on the right is margin high to nominal from 2.0V to 1.8V. The ADOC
function guarantees the output level to be within ±0.2% maximum with a ±0.1% external reference. The
bottom waveform is the READY signal indicating margin is complete.
GENERAL DESCRIPTION
The SMM605 is capable of controlling the DC output
of up to six DC/DC Modules, switching regulators or
LDOs that use a trim/adjust pin and automatically
change the level using a unique Active DC Output
Control (ADOC
TM
). The ADOC function is
programmable over a standard 2-wire I
2
C serial data
interface and can be used to set the nominal DC
output voltage as well as the margin high and low
settings. The part actively controls the programmed
set levels to maintain tight control over load variations
and voltage drops at the point of load. The margin
range will vary depending on the supply manufacturer
and model but the normal range is 10% adjustment
around the nominal output setting. However, the
SMM605 has the capability to margin from 0.35V to
VDD. The user can set the desired voltage settings
(nominal, margin high and margin low) into the EE
memory array for the device. Then, volatile registers
are used to select one of these settings. These
registers are accessed over the I
2
C bus.
In normal operation, Active DC Output Control is set to
adjust the nominal output voltage of the converter.
Typical converter accuracy ratings range from
±2%
to
±5%
of their output voltage. Using the Active DC
Output Control feature of the SMM605 can increase
the accuracy to
±0.1%
(±0.2% Max.). This high
accuracy control of the converter output voltage is
extremely important in low voltage applications where
deviations in power supply voltage can result in lower
system performance. Active DC Output Control can
also be used for margining a supply during system test
or may be turned off by de-selecting the function in the
Control Register.
The margin high and margin low voltage settings can
range from 0.35V to VDD around the converters’
nominal output voltage setting depending on the
specified margin range of the DC-DC converter.
When the SMM605 receives the command to margin,
the Active DC Output Control will adjust the supply to
the selected margin voltage. Once the supply has
reached its margined set point, the Ready bit in the
status register will set and the READY pin will go
active. If Active DC Control is disabled, a margined
supply can return to its nominal voltage by writing to
the margin command register.
In order to obtain maximum accuracy, the SMM605
requires an external voltage reference. An external
reference with ±0.1% accuracy will enable an overall
±0.2% accuracy for the device. A configuration option
also exists so that an internal voltage reference can be
used, but with less accuracy. Total accuracy using the
internal reference is ±0.5%.
The SMM605 has additional filter pins to filter
unwanted switching regulator noise.
They are
VDD_CAP and FILT_CAP.
The SMM605 can be powered from either the 12VIN
supply pin (6V to 14V range) via an internal regulator
or the VDD supply pin (+2.7 to 5.5V range), see Figure
3.
Programming of the SMM605 is performed over the
industry standard I
2
C 2-wire serial data interface. A
status register is available to read the state of the part
and a Write Protect bit is available to prevent writing to
the configuration registers and EE memory.
Summit Microelectronics, Inc
2064 1.1 09/16/03
2
SMM605
Preliminary Information
INTERNAL FUNCTIONAL BLOCK DIAGRAM
12VIN
VDD
VDD_CAP
VREF_CNTL
Level
Shift
Vout
3.6V or
5.5V
Regulator
V+
V-
Power
Supply
Arbitrator
Trim Drive
Trim Drive
Trim Drive
TRIMA
TRIM_CAPA
Output
Control
1:6 MUX
Trim Drive
Trim Drive
Trim Drive
TRIMF
TRIM_CAPF
START
READY
A2
SDA
SCL
CONTROL
LOGIC
Input Voltage
Sensing and
Signal
Conditioning
6:1 MUX
VMA
EE
Memory
FILT_CAP
VMF
Figure 3 –SMM605 Internal Functional Block Diagram.
Summit Microelectronics, Inc
2064 1.1 09/16/03
3
SMM605
Preliminary Information
PIN DESCRIPTIONS
Pin
Number
1
Pin
Type
Pin Name
VM
A
VM
B
VM
C
IN
VM
D
VM
E
VM
F
TRIM
A
TRIM
B
TRIM
C
OUT
TRIM
D
TRIM
E
TRIM
F
TRIM_CAP
A
TRIM_CAP
B
TRIM_CAP
C
I/O
TRIM_CAP
D
TRIM_CAP
E
TRIM_CAP
F
IN
PWR
47
46
5,6,12,13
PWR
GND
VDD
GND
VDD_CAP
12VIN
External capacitor input used to filter the internal supply rail.
12V power supply input internally regulated to 3.6 or 5.5V. Input range is 6V to
14V using the 3.6V internal regulator setting and 10V to 14V using the 5.5V
internal regulator setting.
2.7V to 5.5V Power supply of the part.
Ground of the part.
External sample and hold capacitor input used to set the voltage on the TRIM
pins.
Output voltage used to margin and/or trim converter voltages. Connect to the
converter Trim input or to the VADJ or FB pin of an adjustable output switching
regulator or LDO through a resistor.
Pin Description
41
36
31
26
21
16
44
39
34
29
24
19
45
40
35
30
25
20
48
Voltage monitor pin. Connect to the DC-DC converter + sense line or +Vout
pin.
Summit Microelectronics, Inc
2064 1.1 09/16/03
4
SMM605
Preliminary Information
PIN DESCRIPTIONS (Cont.)
Pin
Number
15
14
1
2
3
Pin
Type
IN
IN
I/O
IN
IN
Pin Name
FILT_CAP
VREF_CNTL
SDA
SCL
A2
Pin Description
External capacitor input used to filter VM
X
inputs. . This provides an RC filter
where R = 1kΩ.
Voltage reference input used for DC output control and margining.
Bi-directional I
2
C data line.
I
2
C clock line.
The address pin is biased either to VDD_CAP or GND.
When
communicating with the SMM605 over the 2-wire bus A2 provides a
mechanism for assigning a unique bus address.
Programmable active high/low input. The START input is used solely for
enabling Active Control and/or margining.
Programmable active high/low open drain output signals indicating when all
programmed power supplies have reached their preprogrammed setpoints.
Leave the NC pins floating.
4
7
IN
OUT
NC
START
READY
No Connect
PACKAGE AND PIN CONFIGURATION
48 LEAD TQFP
TRIM_CAPA
TRIM_CAPB
VDD_CAP
TRIMB
TRIMA
12VIN
VDD
VMA
NC
38
48
47
46
45
44
43
NC
42
NC
41
40
39
SDA
SCL
A2
START
GND
GND
READY
NC
NC
NC
NC
GND
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
37
36
35
34
33
32
31
30
29
28
27
26
25
NC
VMB
TRIM_CAPC
TRIMC
NC
NC
VMC
TRIM_CAPD
TRIMD
NC
NC
VMD
TRIM_CAPE
VREF_CNTL
TRIM_CAPF
FILT_CAP
TRIMF
Summit Microelectronics, Inc
2064 1.1 09/16/03
TRIME
GND
VMF
VME
NC
NC
NC
NC
5
