MAX8688BHETG+ Maxim Integrated Products, MAX8688BHETG+ Datasheet

IC PWR SUPPLY CTRLR/MONTR 24TQFN

MAX8688BHETG+

Manufacturer Part Number
MAX8688BHETG+
Description
IC PWR SUPPLY CTRLR/MONTR 24TQFN
Manufacturer
Maxim Integrated Products
Datasheet

Specifications of MAX8688BHETG+

Applications
Power Supply Controller/Monitor
Voltage - Supply
3 V ~ 3.6 V
Current - Supply
6.7mA
Operating Temperature
-40°C ~ 85°C
Mounting Type
Surface Mount
Package / Case
24-TQFN Exposed Pad
Supply Voltage (max)
3.6 V
Supply Voltage (min)
3 V
Operating Temperature Range
- 40 C to + 85 C
Mounting Style
SMD/SMT
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Voltage - Input
-
Lead Free Status / Rohs Status
Lead free / RoHS Compliant
The MAX8688 fully integrated digital power-supply con-
troller and monitor IC works with any existing POL
(point-of-load) power supply to provide complete digital
programmability. By interfacing to the reference input,
feedback node, and output enable, the MAX8688 takes
control of the POL to provide functions such as perfect
tracking, sequencing, margining, and dynamic adjust-
ment of the output voltage.
The MAX8688 offers an accurate 12-bit analog-to-digi-
tal converter (ADC) accompanied with two differential
amplifiers for accurately monitoring both voltage and
current. An integrated 12-bit digital-to-analog converter
(DAC) is also available to margin power supplies as
well as dynamically adjust the output voltage with 0.2%
accuracy over temperature using this closed-loop sys-
tem. An internal temperature sensor provides an addi-
tional level of system monitoring.
The user-programmable registers provide flexible and
accurate control of time events such as a delay time
and transition period, monitoring for overvoltage and
undervoltage, overcurrent, reverse-current, overtemper-
ature fault and warning handling. The closed-loop oper-
ation is also programmable to make sure the MAX8688
works with any existing POL to provide superior regula-
tion accuracy and accurate margining.
The MAX8688 operates using a PMBus™-compliant
communication protocol. The device is programmed
using this protocol or simply with the use of 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 onto the part through
the PMBus at power-up. This allows remote configura-
tion of any POL using the MAX8688, replacing expen-
sive recalls or field service. Module current sharing is
also supported, since accurate current measurement
and fine resolution voltage control are available. The
MAX8688 can be programmed with up to 127 distinct
addresses to support large systems. The MAX8688 is
offered in a space-saving, 24-pin, lead-free 4mm x
4mm TQFN package.
19-3201; Rev 2; 2/11
PMBus is a trademark of SMIF, Inc.
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.
Telecom Networking
DC-DC Modules and POLs
Servers
High-Reliability Infrastructure Equipment
________________________________________________________________ Maxim Integrated Products
Digital Power-Supply Controller/Monitor
General Description
Applications
o PMBus Interface for Programming, Monitoring,
o Controls Output Voltage with 0.2% Accuracy for
o Output Voltage, Output Current, and Temperature
o Current Measurement with 2.6% Accuracy
o Programmable Soft-Start and Soft-Stop Ramp
o Controls Up to 26 Power Supplies with Hardwired
o Compatible with REFIN and FB Terminals of POL
o Protection for POL Against Overvoltage,
o Open-Drain FLT Signal for Fault Detection
o Master-Slave Clocking Option Eliminates External
o External EEPROM Interface for Auto-Programming
+ Denotes a lead(Pb)-free/RoHS-compliant package.
* EP = Exposed pad.
Pin Configuration appears at end of data sheet.
MAX8688AHETG+
MAX8688BHETG+
MAX8688ALETG+
MAX8688BLETG+
MAX8688AHETG+
MAX8688BHETG+
MAX8688ALETG+
MAX8688BLETG+
Sequencing Up and Down, and Accurate Output-
Voltage Control
Line, Load, and Temperature Variations
Monitoring with Adjustable Monitor Rate
Rates
Address Pins and Up to 127 POLs with Software
Addressing
Power Supplies
Undervoltage, Overcurrent, Negative Current and
Overtemperature Faults with No Action, Latch and
Retry (Hiccup) Options
Clock Requirement and Provides Accurate Timing
Reference
on Power-Up
with PMBus Interface
PART
PART
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
TEMP RANGE
ACCURACY
Ordering Information
(%)
0.2
0.2
0.4
0.4
Selector Guide
ENOUT POWER-UP
DEFAULT STATE
PIN-PACKAGE
24 TQFN-EP*
24 TQFN-EP*
24 TQFN-EP*
24 TQFN-EP*
Features
High
High
Low
Low
1

Related parts for MAX8688BHETG+

MAX8688BHETG+ Summary of contents

Page 1

... Denotes a lead(Pb)-free/RoHS-compliant package Exposed pad. Selector Guide ACCURACY PART (%) MAX8688ALETG+ 0.2 MAX8688AHETG+ 0.2 MAX8688BLETG+ 0.4 MAX8688BHETG+ 0.4 Pin Configuration appears at end of data sheet. Features PIN-PACKAGE 24 TQFN-EP* 24 TQFN-EP* 24 TQFN-EP* 24 TQFN-EP* ENOUT POWER-UP DEFAULT STATE Low High Low ...

Page 2

Digital Power-Supply Controller/Monitor with PMBus Interface ABSOLUTE MAXIMUM RATINGS AVDD, DVDD to AGND .........................................-0.3V to +4.5V DGND to AGND ..................................................................±0.3V RS+, RS-, ISN+, ISN- to AGND ................................-0.3V to +6V RS_C, ISN_C, A1/SCLE, A2/SDAE, A3/ONOFF to AGND............................-0. DACOUT to ...

Page 3

Digital Power-Supply Controller/Monitor ELECTRICAL CHARACTERISTICS (continued 3.3V -40°C to +85°C, V AVDD DVDD A J PARAMETER RS- to AGND Differential Voltage RS+ Input Bias Current RS- Input Bias Current OUTPUT CURRENT SENSE ...

Page 4

Digital Power-Supply Controller/Monitor with PMBus Interface ELECTRICAL CHARACTERISTICS (continued 3.3V -40°C to +85°C, V AVDD DVDD A J PARAMETER SYMBOL DAC DAC Resolution DAC Output-Voltage Range DAC Output-Voltage Slew Rate DAC Output ...

Page 5

Digital Power-Supply Controller/Monitor ELECTRICAL CHARACTERISTICS (continued 3.3V -40°C to +85°C, V AVDD DVDD A J PARAMETER RST INPUT RST Input Low Voltage RST Input High Voltage RST Input Bias Current Minimum SMBus ...

Page 6

Digital Power-Supply Controller/Monitor with PMBus Interface ( 3.3V +25°C, unless otherwise noted.) AVDD DVDD A REFIN MODE SOFT-START WITH SEQUENCING 2ms/div REFIN MODE IMMEDIATE OFF WITH SEQUENCING V = 1.8V OUT_4 V = 1.5V OUT_3 ...

Page 7

Digital Power-Supply Controller/Monitor ( 3.3V +25°C, unless otherwise noted.) AVDD DVDD A REFIN MODE MARGINING 200mV HIGH AT 1mV/µs V OUT 200mV/div V RS_C 500mV/div V DACOUT 200mV/div 200µs/div FB MODE MARGINING HIGH FROM 1.0V ...

Page 8

Digital Power-Supply Controller/Monitor with PMBus Interface PIN NAME Digital Power-Supply Input (3.3V, typ). Connect AVDD to DVDD externally. Connect a 0.1µF capacitor from 1, 3 DVDD DVDD to DGND. 2 DGND Digital Ground. Connect AGND to DGND externally close to ...

Page 9

... Moreover desirable to sequence startup and shutdown of multi- ple power supplies in an application with programma- ble start, stop delays, and soft-start ramp rates to avoid MAXQ is a registered trademark of Maxim Integrated Products, Inc. _______________________________________________________________________________________ with PMBus Interface MAX8688 ...

Page 10

Digital Power-Supply Controller/Monitor with PMBus Interface SCL SDA SYSTEM IRQ CONTROLLER RST Figure 2. System Application Showing Multiple MAX8688s Controlling POL Power Supplies MAX8688 Operating Modes Reference Input (REFIN) Mode Figure 3 shows the typical manner in which the MAX8688 ...

Page 11

Digital Power-Supply Controller/Monitor Since the reference voltage input is provided by the MAX8688, the REFIN mode provides complete control of the POL in terms of soft-start, soft-stop, and margin- ing transitions. It may be noted that the slew rates dur- ...

Page 12

Digital Power-Supply Controller/Monitor with PMBus Interface t ON_DELAY t PMB_RSP ENOUT CLOSE S1 DAC OUTPUT POL V OUT POL OPERATION Figure 4. REFIN Mode Timing Feedback (FB) Mode In applications where a REFIN input is not available, the MAX8688 interfaces ...

Page 13

Digital Power-Supply Controller/Monitor is the upper feedback divider resistor, ∆V where R 1 the required change in output voltage, and ∆V the DACOUT output voltage change that the user allows. The recommended operating range for the DACOUT voltage for POL ...

Page 14

Digital Power-Supply Controller/Monitor with PMBus Interface t ON_DELAY t PMB_RSP ENOUT DAC HIGH- OUTPUT IMPEDANCE POL V OUT POL OPERATION IN FB MODE, t AND t ARE NOT CONTROLLED BY THE MAX8688 AND ARE DEPENDENT ON POL IMPLEMENTATION. POL_RISE POL_FALL ...

Page 15

Digital Power-Supply Controller/Monitor ISN+ Figure 7. DCR Sensing Temperature Sensing It is intended that the MAX8688 be placed in close prox- imity to the POL. An on-chip temperature sensor ...

Page 16

Digital Power-Supply Controller/Monitor with PMBus Interface Table 1. EEPROM Contents OFFSET (BYTES) 0 MFR_TEMPERATURE_PEAK 2 MFR_VOUT_PEAK 4 MFR_IOUT_PEAK 6 MFR_STATUS_WORD (set to 0) 8–13 Reserved (set VOUT_COMMAND 16 VOUT_SCALE_LOOP 18 TON_RISE 10 TON_DELAY MFR_TICK_RELOAD 22 This value ...

Page 17

Digital Power-Supply Controller/Monitor Figure 8 shows how the MAX8688 interfaces to an exter- nal serial SOT23 EEPROM (such as Atmel AT24C01A) using the A1/SCLE and A2/SDAE in applications where a master controller does not exist or is not required. Using ...

Page 18

Digital Power-Supply Controller/Monitor with PMBus Interface RESET INITIALIZE INTERNAL REGISTERS SET ADDRESS ACCORDING TO A3:A1 N VALID EEPROM? Y RESTORE CONFIGURATION FROM EEPROM INTERNAL N REFERENCE STABLE? Y ENABLE PMBus COMMUNICATION PMBus N COMMAND? Y EXECUTE PMBus COMMAND Figure 9. ...

Page 19

Digital Power-Supply Controller/Monitor SET SLAVE ADDRESS RESET ACCORDING TO A3:A1 Y VALID EEPROM MFR_SET_ADDR? N SAVE TO Y EEPROM? N Figure 10. MAX8688 Address Assignment The MAX8688 reads A3:A2:A1 address pins upon device reset and determines its address ...

Page 20

Digital Power-Supply Controller/Monitor with PMBus Interface A3/ONOFF Operation In addition to providing address information to the MAX8688, A3/ONOFF can also be used as a control sig- nal for turning the POL on or off, similar to the OPERATION command. To ...

Page 21

Digital Power-Supply Controller/Monitor PMBus Digital Interface From a software perspective, the MAX8688 appears as a PMBus device capable of executing a subset of PMBus commands. A PMBus 1.0-compliant device uses the SMBus version 1.1 for transport protocol and responds to ...

Page 22

Digital Power-Supply Controller/Monitor with PMBus Interface S ADDR1 7 BITS SLAVE ADDRESS OF DEVICE 1 SR ADDR2 7 BITS SLAVE ADDRESS OF DEVICE 2 SR ADDR3 7 BITS SLAVE ADDRESS OF DEVICE 3 SR ADDRn 7 BITS SLAVE ADDRESS OF ...

Page 23

Digital Power-Supply Controller/Monitor The MAX8688 SMBus interface does not support pack- et error checking (PEC). It does not support the 35ms timeout either. Therefore, to reset the MAX8688 SMBus interface, the host controller has to hold RST low for . ...

Page 24

Digital Power-Supply Controller/Monitor with PMBus Interface Table 4. MAX8688 PMBus Command Summary (continued) COMMAND COMMAND NAME CODE 18 51h OT_WARN_LIMIT 19 60h TON_DELAY 20 61h TON_RISE 21 64h TOFF_DELAY 22 65h TOFF_FALL 23 78h STATUS_BYTE 24 8Bh READ_VOUT 25 8Ch ...

Page 25

Digital Power-Supply Controller/Monitor Sending a DIRECT Format Value To send a value, the host must use the equation below to solve for ( where the 2-byte, two’s complement integer to be ...

Page 26

Digital Power-Supply Controller/Monitor with PMBus Interface PMBus Commands A summary of the PMBus commands supported by the MAX8688 is described in Table 4. OPERATION (01h) The OPERATION command is used to turn the POL on and off in conjunction with ...

Page 27

Digital Power-Supply Controller/Monitor VOUT_COMMAND (21h) The VOUT_COMMAND command loads the MAX8688 with the voltage to which the POL output changed when it is commanded to turn on using the OPERATION command or A3/ONOFF transition when enabled. Once ...

Page 28

Digital Power-Supply Controller/Monitor with PMBus Interface IOUT_SCALE (38h) The IOUT_SCALE command is used to set the ratio of the voltage at the current-sense pins to the sensed cur- rent. For devices using a fixed current-sense resistor the same ...

Page 29

Digital Power-Supply Controller/Monitor 3) Responds as specified by IOUT_OC_FAULT_ RESPONSE bits in the MFR_FAULT_RESPONSE register. 4) Notifies the host using FLT assertion. IOUT_OC_WARN_LIMIT (4Ah) The IOUT_OC_WARN_LIMIT command sets the value of the output current, in amperes, measured across ISN+ and ...

Page 30

Digital Power-Supply Controller/Monitor with PMBus Interface TOFF_FALL (65h) The TOFF_FALL command sets the time, in millisec- onds, from the end of the turn-off delay time until the output voltage is commanded to zero. Note that this command can only be ...

Page 31

Digital Power-Supply Controller/Monitor PMBUS_REVISION (98h) The PMBUS_REVISION command returns the revision of the PMBus specification to which the MAX8688 is compliant. The command has 1 data byte. Bits [7:5] indicate the revision of PMBus specification Part I to which the ...

Page 32

Digital Power-Supply Controller/Monitor with PMBus Interface Table 8. MFR_MODE Bit Definition (continued) BIT BIT NAME The EEPROM Lock Enable bit is used to protect external EEPROM data from being overwritten. When EEPROM Lock this bit is set to 1, the ...

Page 33

Digital Power-Supply Controller/Monitor MFR_VOUT_PEAK (D4h) The MFR_VOUT_PEAK command returns the maximum actual measured (not commanded) output voltage in volts across RS+ and RS-. If the filter mode is enabled, instead of returning the instantaneous value, the filtered output voltage is ...

Page 34

Digital Power-Supply Controller/Monitor with PMBus Interface IOUT_NC_FAULT is set to 1 when a negative current flow is detected. The MFR_FAULT_STATUS command value cannot be restored by the RESTORE_DEFAULT_ALL command. This command is read only. MFR_FAULT_RESPONSE (D9h) The MFR_FAULT_RESPONSE command specifies ...

Page 35

Digital Power-Supply Controller/Monitor Performance Consideration The MAX8688 can be viewed as a task scheduler where it periodically goes through its task list and per- forms the required tasks. While it may be tempting to monitor the POL at the highest ...

Page 36

Digital Power-Supply Controller/Monitor with PMBus Interface Figure 17. MAX8688 Graphic User Interface 36 ______________________________________________________________________________________ ...

Page 37

Digital Power-Supply Controller/Monitor Pin Configuration TOP VIEW RS_C 19 RS- 20 RS+ 21 MAX8688 22 ISN- ISN+ 23 *EP + ISN_C TQFN *CONNECT EP TO AGND ______________________________________________________________________________________ with PMBus ...

Page 38

... Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. 38 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 2011 Maxim Integrated Products ...

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