Rainbow Electronics MAX16064 User Manual

General Description

The MAX16064 is a fully integrated 4-channel digital
power-supply controller and monitor IC that can be con­nected up to four power supplies to provide complete
digital configurability. By interfacing to the power-supply
reference input or feedback node, and the output enable,
the MAX16064 takes control of the power supply to pro­vide tracking, soft-start, sequencing, margining, and
dynamic adjustment of the output voltage.

Power-supply sequencing can be performed
autonomously or controlled over the PMBus™ interface.
Sequencing is controlled during power-down as well as
power-up. Multiple MAX16064s can be combined to
autonomously sequence more supplies. The sequencing
order is stored in an external configuration EEPROM so
sequence order changes can be reprogrammed without
changing the PCB layout.

The MAX16064 features an internal temperature sensor
providing an additional level of system monitoring.
Other features include a reset output and an SMBus™
alert output.

Each channel of the MAX16064 includes an accurate
12-bit analog-to-digital converter (ADC) input and a differen­tial amplifier for accurately monitoring and reporting the volt­age at the load without being influenced by any difference in
ground potentials. An integrated 12-bit digital-to-analog con­verter (DAC) can margin power supplies and dynamically
adjust the output voltage using a closed-loop control system
to provide an output-voltage accuracy of ±0.3%.

The user-programmable registers provide flexible and
accurate control of time events such as delay time and
transition period, monitoring for overvoltage and under­voltage, overtemperature fault and warning handling.
The closed-loop operation is also programmable to make
sure the MAX16064 works with any existing power sup­ply to provide superior regulation accuracy and accurate
margining.

The MAX16064 operates using a PMBus-compliant com­munication protocol. The device can be programmed
using this protocol or with a free graphic-user interface
(GUI) available from the Maxim website that significantly
reduces development time. Once the configuration is
complete, the results can be saved into an EEPROM or
loaded into the device through PMBus at power-up. This
allows remote configuration of any power supply using
the MAX16064, replacing expensive recalls or field ser­vice. The MAX16064 can be programmed with up to 114
distinct addresses to support large systems. The
MAX16064 is offered in a space-saving, 36-pin, lead-free,
6mm x 6mm TQFN package and is fully specified from

-40°C to +85°C.

Features

♦ Accurate Voltage Output Control (AVOC) Controls

Output Voltage with ±0.3% Accuracy

♦ PMBus Interface for Programming, Monitoring,

Sequencing Up and Down, and Margining

♦ Output Voltage and Temperature Monitoring with

Adjustable Monitor Rate

♦ Programmable Soft-Start and Soft-Stop Ramp

Rates

♦ Power-Supply Control using REFIN or FB

Terminals

♦ Master-Slave Clocking Option Provides Accurate

Timing Reference Across Multiple Devices

♦ External EEPROM Interface for Autoboot on

Power-Up

♦ 3.0V to 3.6V Operating Voltage Range

♦ 6mm x 6mm, 36-Pin TQFN Package

Applications

Routers

Servers

Storage Systems

Telecom/Networking

DC-DC Modules and Power Supplies

MAX16064

±0.3% Accurate, Quad, Power-Supply Controller with

Active-Voltage Output Control and PMBus Interface

________________________________________________________________

Maxim Integrated Products

1

Ordering Information

19-4807; Rev 0; 7/09

For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.

+

Denotes a lead(Pb)-free/RoHS-compliant package.

*

EP = Exposed pad.

PART TEMP RANGE

PIN-PACKAGE

MAX16064ETX+ -40°C to +85°C 36 TQFN-EP*

PMBus is a trademark of SMIF, Inc.

SMBus is a trademark of Intel Corp.

Pin Configuration and Typical Operating Circuit appears at
end of data sheet.

MAX16064

±0.3% Accurate, Quad, Power-Supply Controller with
Active-Voltage Output Control and PMBus Interface

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(V

AVDD

= V

DVDD

= 3.0V to 3.6V, VEN= 2V, V

RS_+

- V

RS_-

= 2V, V

RS_-

= 0V, TA= TJ= -40°C to +85°C, unless otherwise specified.

Typical values are at V

AVDD

= V

DVDD

= 3.3V, TA= +25°C.) (Note 2)

Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.

Note 1: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-

layer board. For detailed information on package thermal considerations, refer to www.maxim-ic.com/thermal-tutorial

.

AVDD, DVDD to AGND ............................................-0.3V to +4V

AVDD to DVDD......................................................-0.3V to +0.3V

AGND to DGND.....................................................-0.3V to +0.3V

AGND1 to DGND...................................................-0.3V to +0.3V

RS_+, RS_- to AGND................................................-0.3V to +6V

RS_C, A1/SCLE, A2/SDAE,

A3/CONTROL to AGND ......................-0.3V to (AVDD + 0.3V)

RESET, SMBALERT, ENOUT_ to AGND...................-0.3V to +6V

SCL, SDA to DGND ..................................................-0.3V to +4V

DACOUT_, EN, CLKIO, REFO to AGND.....-0.3V to (AVDD + 0.3V)

DACOUT_ Current ..............................................................10mA

SDA Current ........................................................-1mA to +50mA

Input/Output Current (all other pins) ...................................20mA

Continuous Power Dissipation (T

A

= +70°C)
36-Pin 6mm x 6mm TQFN

(derate 35.7mW/°C above +70°C).............................2857mW

Thermal Resistance (Note 1)

θ

JA

................................................................................28°C/W

θ

JC

..................................................................................1°C/W

Operating Temperature Range ...........................-40°C to +85°C

Junction Temperature......................................................+150°C

Storage Temperature Range .............................-65°C to +150°C

Lead Temperature (soldering, 10s) .................................+300°C

AVDD/DVDD Operating Voltage
Range

AVDD Undervoltage Lockout
(AVDD Rising)

AVDD Undervoltage Lockout
Hysteresis

AVDD and DVDD Total Supply
Current

OUTPUT-VOLTAGE SENSING

Voltage Regulation Accuracy
(2V Range)

Voltage Regulation Accuracy
(5.5V Range)

RS_+, RS_- Differential Mode
Range

RS_- to GND Differential Voltage -250 +250 mV

RS_+ Input Bias Current

RS_- Input Bias Current 2V or 5.5V range, V

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

V

UVLO

V

UVLO-HYS

= V

V

RS_+

TA = +25°C, V

T

= -40°C to +85°C, V

A

= 0V

V

RS_-

TA = +25°C, V

T

= -40°C to +85°C, V

A

V

= 0V

RS_-

2V range, V

5.5V range, V

RS_-

= 0V 12 18.5 mA

= 1.0V, V

RS_+

RS_+

= 2.5V, V

RS_+

RS_+

= -0.25V to +2V -20 +20

RS_+

= -0.25V to +5.5V -20 +100

RS_+

= -0.25V to +0.25V -20 0 µA

RS_-

= 0V -4 +4 mV

RS_-

= 1.0V,

= 0V -11 +11 mV

RS_-

= 2.5V,

3.0 3.6 V

2.75 2.8 2.95 V

100 mV

-6 +6 mV

-16.5 +16.5 mV

0 5.5 V

µA

MAX16064

±0.3% Accurate, Quad, Power-Supply Controller with

Active-Voltage Output Control and PMBus Interface

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS (continued)

(V

AVDD

= V

DVDD

= 3.0V to 3.6V, VEN= 2V, V

RS_+

- V

RS_-

= 2V, V

RS_-

= 0V, TA= TJ= -40°C to +85°C, unless otherwise specified.

Typical values are at V

AVDD

= V

DVDD

= 3.3V, TA= +25°C.) (Note 2)

INTERNAL TEMPERATURE SENSOR

Temperature Sensing Accuracy TA = 0°C to +85°C ±3 °C

INTERNAL OSCILLATOR

Frequency 7.6 8 8.4 MHz

ADC

Resolution 12 Bits

INTERNAL REFERENCE

Reference Voltage V

DAC

Resolution 12 Bits

Differential Nonlinearity DNL -2.5 +2.5 LSB

Maximum Output-Voltage Range No load

Capacitive Load 200 pF

Output-Voltage Slew Rate 0.35 V/µs

DAC Output Resistance 10 Ω

DAC Driving Capability DAC output > 100mV; output error < 25mV -1 +1 mA

DAC Output Leakage Current

CLKIO

Input Logic-Low Voltage 0.8 V

Input Logic-High Voltage 2.1 V

Input Bias Current V

Input Clock Duty Cycle 50 %

Output Low Voltage CLKIO in output mode, I

Output High Leakage V

CLKIO Pullup Voltage 3.6 V

CLKIO Input Frequency Range f

CLKIO Output Frequency 1 MHz

ENABLE INPUT (EN)

EN Falling Threshold Voltage V

EN Rising Threshold Voltage 1.175 1.23 1.281 V

EN Input Leakage Current -0.25 +0.25 µA

OUTPUTS (ENOUT_, RESET, SMBALERT)

Output Low Voltage V

Output Leakage V

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

REF

EXT_CLK

EN_TH

OL

TA = +25°C 2.048 V

DAC output switch open,
V

I

V

_ = V

DACOUT

= 3.6V or 0V -1 +1 µA

CLKIO

= 3.6V -1 +1 µA

CLKIO

= 10mA 0.4 V

SINK

= V

AVDD

ENOUT_

DVDD

= 5V, 0V -1 +1 µA

V

REF -

1 LSB

or 0V

REF

= 1.1V, I

= 4mA 0.4 V

SINK

= 100µA 0.4 V

SINK

-250 +250 nA

100 1000 kHz

1.17 1.21 1.23 V

V

MAX16064

±0.3% Accurate, Quad, Power-Supply Controller with
Active-Voltage Output Control and PMBus Interface

4 _______________________________________________________________________________________

ELECTRICAL CHARACTERISTICS (continued)

(V

AVDD

= V

DVDD

= 3.0V to 3.6V, VEN= 2V, V

RS_+

- V

RS_-

= 2V, V

RS_-

= 0V, TA= TJ= -40°C to +85°C, unless otherwise specified.

Typical values are at V

AVDD

= V

DVDD

= 3.3V, TA= +25°C.) (Note 2)

Note 2: 100% production tested at TA= +25°C. Limits over temperature are guaranteed by design.
Note 3: The MAX16064 supports SCL clock stretching.

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

ADDRESS PINS (A1/SCLE, A2/SDAE, A3/CONTROL)

Input Logic-Low Voltage 0.3 V

Input Logic-Low Hysteresis 50 mV

V

Input Logic-High Voltage

AVDD

- 0.4

Input Logic-High Hysteresis 50 mV

Input Leakage Current -12 +12 µA

SMBus INTERFACE (SCL, SDA) (Note 3)

SCL, SDA Input Low Voltage V

SCL, SDA Input High Voltage V

SCL, SDA Input Leakage Current
(Per Pin)

Input Capacitance C

SCL, SDA Output Low Voltage V

Input voltage falling 0.8 V

IL

Input voltage rising 2.1 V

IH

Device powered or unpowered, V

IN

OL

to 3.6V, V

I

= 3mA 0.4 V

SINK

SCL

= V

SDA

= 0 or V

AVDD

AVDD

= 0V

-1 +1 µA

10 pF

SMBUS TIMING

Serial-Clock Frequency f

Bus Free Time Between STOP
and START Condition

START Condition Setup Time t

START Condition Hold Time t

STOP Condition Setup Time t

SU:STA

HD:STA

SU:STO

Clock Low Period t

Clock High Period t

Data Setup Time t

SU:DAT

Output Fall Time t

Data Hold Time t

HD:DAT

Pulse Width of Spike Suppressed t

SMBus Timeout t

TIMEOUT

SCL

t

BUF

LOW

HIGH

OF

SP

C

= 10pF to 400pF 300 ns

BUS

From 50% SCL falling to SDA change 300 ns

SMBCLK time low for reset 25 55 ms

10 100 kHz

4.7 µs

4.7 µs

4.0 µs

4.0 µs

4.7 µs

4.0 µs

250 ns

30 ns

OTHER TIMING PARAMETERS

PMBus Command Response
Time

Fault Response Time t

Recovery Time After Device
Reset

t

PMB_RSP

FAULT_RSP

t

RST_WAIT

300 µs

5ms

15 µs

V

MAX16064

±0.3% Accurate, Quad, Power-Supply Controller with

Active-Voltage Output Control and PMBus Interface

_______________________________________________________________________________________ 5

Typical Operating Characteristics

(V

AVDD

= V

DVDD

= 3.3V, TA= +25°C, unless otherwise noted.)

TOTAL SUPPLY CURRENT

vs. SUPPLY VOLTAGE

20

16

12

8

TOTAL SUPPLY CURRENT (mA)

4

0

2.6 3.6

TA = +85

V

AVDD

NC

= V

TA = +25NC

DVDD

UV_FAULT TO RESET RESPONSE

5V

3.3V

1ms/div

(V)

TA = -40NC

3.43.23.02.8

MAX16064 toc04

1.010

1.008

1.006

MAX16064 toc01

1.004

1.002

1.000

0.998

0.996

NORMALIZED EN THRESHOLD

0.994

0.992

0.990

-40 85

0.8

0.7

0.6

V

OUT0

2V/div

RESET
2V/div

0.5

0.4

0.3

0.2

ENOUT_ OUTPUT LOW VOLTAGE (V)

0.1

0

040

NORMALIZED EN THRESHOLD

vs. TEMPERATURE

NORMALIZED AT TA = +25NC

603510-15

TEMPERATURE (NC)

ENOUT_ OUTPUT LOW VOLTAGE

vs. SINK CURRENT

I

(mA)

SINK

NORMALIZED RESET TIMEOUT

1.10

1.08

MAX16064 toc02

1.06

1.04

1.02

1.00

0.98

0.96

NORMALIZED RESET TIMEOUT

0.94

0.92

0.90

0.5

0.4

0.3

MAX16064 toc05

0.2

0.1

-0.1

-0.2

-0.3

-0.4

POWER SUPPLIES OUTPUT ACCURACY (%)

35305 10 15 20 25

-0.5

PERIOD vs. TEMPERATURE

NORMALIZED AT TA = +25NC

-40 85
TEMPERATURE (NC)

603510-15

POWER SUPPLIES OUTPUT ACCURACY

vs. TEMPERATURE

VOUT2 = 1.8V

0

VOUT0 = 5V

VOUT1 = 3.3V

-40 85
TEMPERATURE (NC)

VOUT3 = 1.1V

603510-15

MAX16064 toc03

MAX16064 toc06

ENOUT_WITH AVDD = DVDD RISING

AVDD = DVDD RISING 3.3V/ms

200ms/div

MAX16064 toc07

AVDD = DVDD
1V/div

ENOUT1,2,3,4
2V/div

ENOUT_ WITH AVDD = DVDD FALLING

400Fs/div

MAX16064 toc08

AVDD = DVDD
1V/div

ENOUT1,2,3,4
2V/div

MAX16064

±0.3% Accurate, Quad, Power-Supply Controller with
Active-Voltage Output Control and PMBus Interface

6 _______________________________________________________________________________________

Typical Operating Characteristics (continued)

(V

AVDD

= V

DVDD

= 3.3V, TA= +25°C, unless otherwise noted.)

REFIN MODE SOFT-START

WITH SEQUENCING

2ms/div

REFIN MODE SOFT-STOP

WITH TRACKING

MAX16064 toc09

MAX16064 toc11

VOUT0 = 5V

VOUT1 = 3.3V

VOUT2 = 1.8V

VOUT3 = 1.1V

VOUT0 = 5V

VOUT1 = 3.3V

VOUT2 = 1.8V

VOUT3 = 1.1V

REFIN MODE SOFT-STOP

WITH SEQUENCING

2ms/div

MAX16064 toc10

REFIN MODE OPERATION OFF

WITH SEQUENCING

MAX16064 toc12

VOUT0 = 5V

VOUT1 = 3.3V

VOUT2 = 1.8V

VOUT3 = 1.1V

VOUT0 = 5V

VOUT1 = 3.3V

VOUT2 = 1.8V

VOUT3 = 1.1V

2ms/div

REFIN MODE SOFT-START FROM

A3 WITH SEQUENCING

2ms/div

MAX16064 toc13

REFIN MODE SOFT-STOP FROM

A3/CONTROL
5V/div

VOUT0 = 5V

VOUT1 = 3.3V

VOUT2 = 1.8V
VOUT3 = 1.1V

40ms/div

A3 WITH SEQUENCING

2ms/div

MAX16064 toc14

A3/CONTROL
5V/div

VOUT0 = 5V

VOUT1 = 3.3V

VOUT2 = 1.8V
VOUT3 = 1.1V

MAX16064

±0.3% Accurate, Quad, Power-Supply Controller with

Active-Voltage Output Control and PMBus Interface

_______________________________________________________________________________________

7

Typical Operating Characteristics (continued)

(V

AVDD

= V

DVDD

= 3.3V, TA= +25°C, unless otherwise noted.)

REFIN MODE MARGINING

500mV HIGH AT 1mV/µs

400Fs/div

FB MODE MARGINING HIGH

FROM 5V TO 5.5V

5V

0.6V

MAX16064 toc15

MAX16064 toc17

5V
VOUT0
1V/div

0.6V
VDACOUT0
200mV/div

VOUT0
1V/div

4.5V

0.54V

0.6V

REFIN MODE MARGINING

500mV LOW AT 1mV/µs

400Fs/div

FB MODE MARGINING LOW

FROM 5V TO 4.5V

5V

MAX16064 toc16

VOUT0
1V/div

VDACOUT0
200mV/div

MAX16064 toc18

VOUT0
1V/div

VDACOUT0
200mV/div

VDACOUT0
200mV/div

400ms/div

400ms/div

MAX16064

±0.3% Accurate, Quad, Power-Supply Controller with
Active-Voltage Output Control and PMBus Interface

8 _______________________________________________________________________________________

Pin Description

PIN NAME FUNCTION

1 RS2-

2 RS2+

3 RS3+

4 RS3-

5 RS3C Filter Capacitor for V

6EN

7 DACOUT1

8 AGND Analog Ground. Connect AGND to AGND1 and to DGND externally close to the device.

9 ENOUT0

10 ENOUT1

11 ENOUT2

12 ENOUT3

13 CLKIO

14 A1/SCLE

15 A2/SDAE

Differential Remote-Sense Input 2 Return of the DC-DC Output Voltage. Connect to the return terminal
at the load.

Differential Remote-Sense Input 2 of DC-DC Output Voltage. Connect to the load terminal where the
output must be regulated.

Differential Remote-Sense Input 3 of DC-DC Output Voltage. Connect to the load terminal where the
output must be regulated.

Differential Remote-Sense Input 3 Return of the DC-DC Output Voltage. Connect to the return terminal
at the load.

Amplifier 3. Connect a 1µF capacitor from RS3C to AGND.

SENSE

Enable Input. All ENOUT_ are deasserted when the voltage on EN is below 1.2V (typ). Used to turn
on/off the controlled power supplies in conjunction with the PMBus OPERATION command.

Analog Voltage Output of Internal 12-Bit DAC 1. Connect to TRIM, REFIN, or FB of a DC-DC module
or an LDO to adjust the power-supply output voltage. High impedance in shutdown.

On/Off Signal Output 0. Typically used to turn on/off a power supply. Controlled by the PMBus
OPERATION command or the sequencer. Can be configured as either an active-high or an active-low
open-drain output. See the ENOUT_ Operation section.

On/Off Signal Output 1. Typically used to turn on/off a power supply. Controlled by the PMBus
OPERATION command or the sequencer. Can be configured as either an active-high or an active-low
open-drain output. See the ENOUT_ Operation section.

On/Off Signal Output 2. Typically used to turn on/off a power supply. Controlled by the PMBus
OPERATION command or the sequencer. Can be configured as either an active-high or an active-low
open-drain output. See the ENOUT_ Operation section.

On/Off Signal Output 3. Typically used to turn on/off a power supply. Controlled by the PMBus
OPERATION command or the sequencer. Can be configured as either an active-high or an active-low
open-drain output. See the ENOUT_ Operation section.

Clock Input/Output. User-configurable clock input/output signal. The system controller can provide a
clock input to synchronize the time bases of multiple MAX16064 devices. Alternatively, a MAX16064
can provide a 1MHz output clock to other MAX16064s for synchronization. See the MFR_MODE (D1h)
section. When configured as an output, CLKIO is an open-drain output and a pullup resistor is
required.

Dual-Functioned MAX16064 Slave Address Identifier (LSB) and EEPROM I
MAX16064 Address Assignment and External EEPROM Interface sections.

Dual-Functioned MAX16064 Slave Address Identifier and EEPROM I
MAX16064 Address Assignment and External EEPROM Interface sections.

2

C Clock Output. See the

2

C Data Input/Output. See the

Dual-Functioned MAX16064 Slave Address Identifier (MSB) and Power-Supply On/Off Control Using

16 A3/CONTROL

17 RESET Active-Low, Open-Drain Reset Output

the MFR_MODE Command. See the MAX16064 Address Assignment and A3/CONTROL Operation
sections.

MAX16064

±0.3% Accurate, Quad, Power-Supply Controller with

Active-Voltage Output Control and PMBus Interface

_______________________________________________________________________________________ 9

Pin Description (continued)

PIN NAME FUNCTION

18 SMBALERT Active-Low, Open-Drain Fault-Detection Interrupt Output

19 SCL SMBus Serial-Clock Input/Output

20 SDA SMBus Serial-Data Input/Output

21 DGND Digital Ground. Connect DGND to AGND and AGND1 externally close to the device.

22 DVDD Digital Power-Supply Input. Connect a 1µF capacitor from DVDD to DGND.

23 RSVD Reserved. Connect to DVDD externally.

24 DACOUT3

25 AGND1 Analog Ground. Connect to AGND and DGND externally close to the device.

26 AVDD Analog Power-Supply Input. Connect a 1µF capacitor from AVDD to AGND.

27 DACOUT2

28 RS1-

29 RS1+

30 RS1C Filter Capacitor for V

31 REFO Reference Output. Connect a 1µF capacitor from REFO to AGND.

32 RS0+

33 RS0C Filter Capacitor for V

34 RS0-

35 DACOUT0

36 RS2C Filter Capacitor for V

—EP

Analog Voltage Output of Internal 12-Bit DAC 3. Connect to TRIM, REFIN, or FB of a DC-DC module
or an LDO to adjust the power-supply output voltage. High impedance in shutdown.

Analog Voltage Output of Internal 12-Bit DAC 2. Connect to TRIM, REFIN, or FB of a DC-DC module
or an LDO to adjust the power-supply output voltage. High impedance in shutdown.

Differential Remote-Sense Input 1 Return of the DC-DC Output Voltage. Connect to the return terminal
at the load.

Differential Remote-Sense Input 1 of DC-DC Output Voltage. Connect to the load terminal where the
output must be regulated.

Amplifier 1. Connect a 1µF capacitor from RS1C to AGND.

SENSE

Differential Remote-Sense Input 0 of DC-DC Output Voltage. Connect to the load terminal where the
output must be regulated.

Amplifier 0. Connect a 1µF capacitor from RS0C to AGND.

SENSE

Differential Remote-Sense Input 0 Return of the DC-DC Output Voltage. Connect to the return terminal
at the load.

Analog Voltage Output of Internal 12-Bit DAC 0. Connect to TRIM, REFIN, or FB of a DC-DC module
or an LDO to adjust the power-supply output voltage. High impedance in shutdown.

Amplifier 2. Connect a 1µF capacitor from RS2C to AGND.

SENSE

Exposed Pad. Internally connected to AGND. Connect EP to the ground plane of the power supplies
for best temperature measurement performance.

MAX16064

±0.3% Accurate, Quad, Power-Supply Controller with
Active-Voltage Output Control and PMBus Interface

10 ______________________________________________________________________________________

Figure 1. MAX16064 Functional Diagram

RS0+

RS0-

RS0C

RS1+

RS1-

RS1C

RS2+

RS2-

RS2C

RS3+

RS3-

RS3C

EN

VOLTAGE
SCALING

AND
MUX

RSVDDVDDAVDD

INTERNAL

TEMP

SENSOR

REFO

REF

12-BIT ADC

(SAR)

DIGITAL

COMPARATORS

AND

SEQUENCER

12-BIT VOUT

DAC 0

12-BIT VOUT

DAC 1

12-BIT VOUT

DAC 2

12-BIT VOUT

DAC 3

CLK0

ENOUT0

S0

DACOUT0

ENOUT1

S1

DACOUT1

ENOUT2

S2

DACOUT2

ENOUT3

S3

DACOUT3

RESET

1.2V

PMBus DEFAULT MEMORY

(EXTERNAL EEPROM)

PAGE

PAGE1PAGE2PAGE

0

EXTERNAL

EEPROM

INTERFACE

A1/SCLE A2/SDAE A3/CONTROL SCL SDA DGND AGND AGND1SMBALERT

3

I2C SMBus INTERFACE

PAGE

PMBus CONTROL

PMBus

OPERATING MEMORY

PAGE1PAGE2PAGE

0

3

MAX16064

MAX16064

±0.3% Accurate, Quad, Power-Supply Controller with

Active-Voltage Output Control and PMBus Interface

______________________________________________________________________________________ 11

Detailed Description

The MAX16064 adds digital control functionality to four
power supplies. Using a closed-loop control system,
the MAX16064 can continuously adjust the power-sup­ply output voltages to maintain ±0.3% output-voltage
accuracy. The MAX16064 can also be programmed to
sequence, track, and margin each power supply.

A PMBus-compliant interface bus provides access to
configuration parameters of the MAX16064, including
monitoring thresholds, sequence delays, soft-start and

soft-stop slew rates, output-voltage settings, an on-chip
temperature sensor, and more.

Up to 114 MAX16064s can reside on the same PMBus
bus, each controlling its own power supplies, under
commands from the PMBus system controller, as shown
in Figure 2. The MAX16064s can be placed close to the
power supplies they control so that all sensitive analog
traces are short and less susceptible to noise. The
power supplies can also be placed close to the load
where they provide the best transient response and low­est losses with short power plane runs.

MAX16064

RS0+ VO+

RS0- VO-

DACOUT0 FB

ENOUT0 EN

POWER

SUPPLY

0

RS1+ VO+

RS1- VO-

DACOUT1 FB

ENOUT1 EN

POWER

SUPPLY

1

RS2+ VO+

RS2- VO-

DACOUT2 FB

ENOUT2 EN

POWER

SUPPLY

2

RS3+ VO+

RS3- VO-

DACOUT3 FB

ENOUT3 EN

POWER

SUPPLY

3

SCL

SDA

IRQ

RST

SYSTEM
CONTROLLER

SCL

SDA

SMBALERT

RESET

MAX16064

RS0+ VO+

RS0- VO-

DACOUT0 FB

ENOUT0 EN

POWER

SUPPLY

(N-3)

RS1+ VO+

RS1- VO-

DACOUT1 FB

ENOUT1 EN

POWER

SUPPLY

(N-2)

RS2+ VO+

RS2- VO-

DACOUT2 FB

ENOUT2 EN

POWER

SUPPLY

(N-1)

RS3+ VO+

RS3- VO-

DACOUT3 FB

ENOUT3 EN

POWER

SUPPLY

(N)

SCL

SDA

SMBALERT

RESET

Figure 2. System Application Showing Multiple MAX16064s Controlling Power Supplies

MAX16064

±0.3% Accurate, Quad, Power-Supply Controller with
Active-Voltage Output Control and PMBus Interface

12 ______________________________________________________________________________________

MAX16064 Operating Modes

Reference Input (REFIN) Mode

Figure 3 shows how to connect a MAX16064 to the ref­erence voltage input of a typical power supply, allowing
the MAX16064 to fully control the power-supply output
voltage. Connect a DACOUT_ of the MAX16064 to the
REFIN input of the power supply and connect the out­put-voltage terminals of the power supply to the RS_+
and RS_- sense inputs of the MAX16064. The sensed
voltage on RS_+ and RS_- is filtered by an internal
200Ω resistor and an external capacitor connected to
RS_C, and is digitized by a 12-bit ADC that uses an
accurate internal reference voltage.

Normal operation begins as follows: upon receiving an
OPERATION ON command or a turn-on signal from
A3/CONTROL, the MAX16064 waits the programmed
t

ON_DELAY

time, then switches on the associated
ENOUT_ output and ramps up the power-supply output
voltage to its target VOUT_COMMAND value precisely
in the programmed t

ON_RISE

time. This facilitates easy
implementation of tracking of multiple output rails. On
reaching the target output voltage, the MAX16064 con­tinuously monitors the power-supply output voltage
obtained at the RS_+ and RS_- inputs, and regulates it
to within ±0.3% by incrementing or decrementing the
DACOUT_ output 1 LSB (0.5mV) at a time. The
MAX16064 output-voltage correction rate is controlled
by MFR_MODE.1, VLTO, and DAC_ACT_CNT, as dis­cussed in the

ADC Conversion, Monitoring, and AVOC

Adjustment Rates

section.

Once the requested target power-supply voltage is
reached, it can be margined up or down at a slew rate
programmed by the VOUT_TRANSITION_RATE para­meter. To achieve this, the MAX16064 increments or
decrements the DACOUT_ output in a suitable number
of steps that depend on the programmed transition
rate. The number of steps is calculated from the
VOUT_SCALE_LOOP parameter, which must be set to
the ratio of the power-supply output voltage to the
power-supply reference voltage. This ratio is the same
as the voltage-divider ratio implemented on the power
supply from its output voltage node to the inverting
input of its error amplifier. This allows the MAX16064 to
correctly calculate the number of DACOUT steps and
voltage increments/decrements per step and thus
achieve the programmed rise time and transition time.

Since the reference voltage input is provided by the
MAX16064, the REFIN mode provides complete control
of the power supply in terms of soft-start, soft-stop, and
margining transitions.

Upon receiving an OPERATION OFF command or a
turn-off signal from A3/CONTROL, the MAX16064 waits
the programmed t

OFF_DELAY

time, ramps the output

voltage down to zero in the programmed t

OFF_FALL

time, then deasserts the ENOUT_ output. Each of the
four power-supply converters has its own set of delay
parameters, so sequencing is accomplished by loading
different delay times for each power supply.

Feedback (FB) Mode

Some power-supply converters do not provide a refer­ence input. In these applications, the feedback node
can be used instead. Connect a DACOUT_ output of
the MAX16064 to the feedback node (FB) through a
resistor RFBas shown in Figure 5. In steady-state oper­ation, the MAX16064 controls the power-supply voltage
as measured between RS_+ and RS_- to 0.3% accura­cy by adjusting DACOUT_ 1 LSB at a time (0.5mV), up
and down as required. This mode of operation is
termed FB mode. Since the MAX16064 does not have
control over the power-supply error-amplifier reference
voltage, this mode relies on the power-supply soft-start
setting to implement the required soft-start time.

Upon receiving an OPERATION ON command or a
turn-on signal from A3/CONTROL, the MAX16064 waits
the programmed t

ON_DELAY

time, turns on the ENOUT_
output, causing the power supply to ramp up its output
voltage to its target value. The soft-start time taken by
the power supply to ramp from zero to its commanded
output voltage should be entered into the MAX16064
with the t

ON_RISE

parameter.

During t

ON_RISE

, the MAX16064 maintains DACOUT_ in
a high-impedance state by keeping the S_ switches
open. This allows the voltage at DACOUT_ to equal that
of the FB node of the power supply. At the end of the
t

ON_RISE

delay time, the internal DAC output voltage is
set to match the external voltage measured on
DACOUT_, and then the DACOUT_ switch S_ is closed.
The voltages on either side of the resistor RFBshould
be equal, or very close to equal. Under these condi­tions, little or no current flows into the FB node from
DACOUT_ and no perturbations are introduced to the
output voltage. From this point on, the MAX16064
adjusts the voltage at DACOUT_ to provide accurate
output-voltage control. In FB mode, the user must sup­ply t

ON_DELAY

and t

ON_RISE

. If those parameters are
not set (the default values are zero), S_ closes prema­turely and causes the supply voltage to overshoot or
undershoot.

MAX16064

±0.3% Accurate, Quad, Power-Supply Controller with

Active-Voltage Output Control and PMBus Interface

______________________________________________________________________________________ 13

Figure 3. Typical System Application—REFIN Mode

3.3V

1µF

SYSTEM

CONTROLLER

IRQ

1µF

AVDD

DVDD

RSVD

AGND

AGND1

DGND

A1/SCLE

A2/SDAE

A3/CONTROL

REFO

SCL

SDA

EN

RESET

SMBALERT

MAX16064

200Ω

S0

200Ω

S1

200Ω

S2

200Ω

S3

RS0-

RS0+

RS0C

DACOUT0

ENOUT0

RS1-

RS1+

RS1C

DACOUT1

ENOUT1

RS2-

RS2+

RS2C

DACOUT2

ENOUT2

RS3-

RS3+

RS3C

DACOUT3

ENOUT3

LOAD

VO+ VO-

POWER
SUPPLY

REFIN

0

EN

LOAD

VO+ VO-

POWER
SUPPLY

REFIN

1

EN

LOAD

VO+ VO-

POWER
SUPPLY

REFIN

2

EN

LOAD

VO+ VO-

POWER
SUPPLY

REFIN

3

EN

VIN+

VIN-

VIN+

VIN-

VIN+

VIN-

VIN+

VIN-

MAX16064

±0.3% Accurate, Quad, Power-Supply Controller with
Active-Voltage Output Control and PMBus Interface

14 ______________________________________________________________________________________

After receiving an OPERATION OFF command or a
turn-off signal from A3/CONTROL, the MAX16064 waits
the programmed t

OFF_DELAY

time, deasserts the

ENOUT_ output, and turns off the power supply.

For the FB mode, use the following formula to calculate
the value of RFB:

Where R1is the upper feedback divider resistor, ∆VOis
the required change in output voltage, and ∆V

DAC

is
the DACOUT output-voltage change that the user
allows. The recommended operating range for the
DACOUT_ voltage for power-supply output voltage
adjustment is between 30mV and 2V. Note that ∆V

DAC

is the difference between the steady-state power-sup­ply FB node voltage, VFB, and the voltage limits on
DACOUT_. This is best illustrated with an example as
follows:

Consider an application involving a power supply with
VFB= 0.6V. Let the desired margining be ±10% for a
power-supply output voltage of 1V. For a power supply

with an upper voltage divider resistor R

1

= 10kΩ, RFBis

calculated as follows:

This value of RFBallows the MAX16064 to margin the
power-supply output voltage up by 10%. It is useful to
check the margin low condition by using the formula:

The effective margining range for the 57kΩ resistor
therefore turns out to be between +10% and -24.5%.

Note that the VOUT_TRANSITION_RATE parameter has
no effect on FB mode. The transition time for margining
in the FB mode of operation is a function of the update
rate (f

AVOC

), see the

MFR_DAC_ACT_CNT (E0h)

sec-

tion for the calculation of f

AVOC

. RFBand R1, and is

given by the following formula:

Figure 4. REFIN Mode Timing

t

PMB_RSPtON_DELAY

PMBus

ENOUT_

OPERATION

ON

IDLE IDLE

CLOSE S_

DAC OUTPUT

POWER-SUPPLY

V

OUT

POWER-SUPPLY

OPERATION

RR

=×

FB

V

∆

DAC

1

V

∆

O

t

ON_RISE

TURN-ON

t

PMB_RSPtOFF_DELAY

OPERATION

OFF

t

ON_FALL

TURN-OFF

−

VV

06 003

Rk

=× =

10

FB

(. . )

V

01

.

∆

V

∆

VR

=× = × =

O

DAC

1

R

FB

10

Ω

k

−

VV

20 06

(. . )

Ω

k

57

RxVx

t

FB

⎛

=

⎜
⎝

∆ 2000

FB O

fxR

AVOC

⎞
⎟

⎠

1

k

57ΩΩ

024

.55V

MAX16064

±0.3% Accurate, Quad, Power-Supply Controller with

Active-Voltage Output Control and PMBus Interface

______________________________________________________________________________________ 15

Figure 5. Typical System Application—Feedback Mode

3.3V

1µF

1µF

AVDD

DVDD

RSVD

AGND

AGND1

DGND

A1/SCLE

A2/SDAE

A3/CONTROL

REFO

MAX16064

200Ω

S0

200Ω

S1

RS0-

RS0+

RS0C

DACOUT0

ENOUT0

RS1-

RS1+

RS1C

DACOUT1

LOAD

R1

VO+ VO-

FB

R

FB

R1

R

FB

POWER
SUPPLY
0

EN

LOAD

VO+ VO-

FB

POWER
SUPPLY
1

VIN+

VIN-

VIN+

VIN-

SCL

SDA

SYSTEM

CONTROLLER

IRQ

EN

RESET

SMBALERT

200Ω

S2

200Ω

S3

ENOUT1

RS2-

RS2+

RS2C

DACOUT2

ENOUT2

RS3-

RS3+

RS3C

DACOUT3

ENOUT3

EN

LOAD

R1

VO+ VO-

FB

R

FB

R1

R

FB

POWER
SUPPLY
2

EN

LOAD

VO+ VO-

FB

POWER
SUPPLY
3

EN

VIN+

VIN-

VIN+

VIN-

MAX16064

±0.3% Accurate, Quad, Power-Supply Controller with
Active-Voltage Output Control and PMBus Interface

16 ______________________________________________________________________________________

Temperature Sensing

To obtain useful temperature readings, place the
MAX16064 in close proximity to the power supplies.
The on-chip temperature sensor on the MAX16064
senses the temperature of the die, which is related to
the exposed pad temperature of the MAX16064 by the
junction-to-case thermal resistance. The exposed pad
of the MAX16064 can connect to the heat dissipating
ground plane of the power supplies, and the power
supplies’ boards can be characterized to obtain the
relationship between the power supplies’ temperature
and temperature as measured by the MAX16064. This
information can be used to set overtemperature fault
settings in the MAX16064.

ADC Conversion, Monitoring,
and AVOC Adjustment Rates

Several timing parameters control the rate at which the
MAX16064 monitors voltages and temperatures and the
rate at which the MAX16064 adjusts the power-supply
output voltages. Each of the four voltage input channels

and the single temperature channel conversions are
performed round-robin fashion. If the input filter is
turned on by setting register MFR_MODE[1] to 0, then
four conversions are performed for each channel
instead of just one. A small programmable delay is
inserted in between each conversion, determined by
the MFR_VLTO register. This establishes the total con­version rate of the voltages and temperature. Smaller
values of MFR_VLTO results in a higher sampling rate,
and larger values of MFR_VLTO allow for more ADC
settling time.

The ADC conversion result registers are compared to
the fault threshold registers at a rate that is indepen­dent of the total conversion rate. The value of register
MFR_SAMPLE_RATE determines how frequently this
comparison occurs. Using higher fault comparison
rates increases glitch sensitivity, but slows the
response time of the MAX16064 to PMBus commands.
Using lower fault comparison rates makes the
MAX16064 less sensitive to power-supply output volt­age glitches.

PMBus

OPERATION

ON

IDLEIDLE

t

PMB_RSPtON_DELAY

t

ON_RISE

t

PS_RISE

t

PS_FALL

t

PMB_RSPtOFF_DELAY

t

OFF_FALL

HIGH-Z

ENOUT_

DAC OUTPUT

POWER-SUPPLY

V

OUT

POWER-SUPPLY

OPERATION

IN FB MODE, t

PS_RISE

AND t

PS_FALL

ARE NOT CONTROLLED BY THE MAX16064 AND ARE DEPENDENT ON POWER-SUPPLY IMPLEMENTATION.

CLOSE S_

TURN-ON

TURN-OFF

OPEN S_

HIGH-Z

OPERATION

OFF

Figure 6. Feedback Mode Timing