Super Sequencer with Margining Control and Nonvolatile Fault Recording ADM1166 FEATURES FUNCTIONAL BLOCK DIAGRAM AUX1 AUX2 REFIN REFOUT REFGND ADM1166 MUX VREF EEPROM PDO1 CONFIGURABLE OUTPUT DRIVERS (LOGIC INPUTS OR SFDs) (HV CAPABLE OF DRIVING GATES OF N-FET) PDO4 CONFIGURABLE OUTPUT DRIVERS PDO7 VX3 VX5 FAULT RECORDING DUALFUNCTION INPUTS VX2 VX4 A0 SMBus INTERFACE 12-BIT SAR ADC CLOSED-LOOP MARGINING SYSTEM VX1 SDA SCL A1 PDO2 PDO3 PDO5 PDO6 SEQUENCING ENGINE VP1 VP3 PROGRAMMABLE RESET GENERATORS VP4 (SFDs) VP2 (LV CAPABLE OF DRIVING LOGIC SIGNALS) VH PDO8 PDO9 PDO10 AGND PDOGND VOUT DAC VOUT DAC VOUT DAC VOUT DAC VOUT DAC VOUT DAC DAC1 DAC2 DAC3 DAC4 DAC5 DAC6 VDD ARBITRATOR VCCP GND VDDCAP 09332-001 Complete supervisory and sequencing solution for up to 10 supplies 16 event deep black box nonvolatile fault recording 10 supply fault detectors enable supervision of supplies to <0.5% accuracy at all voltages at 25°C <1.0% accuracy across all voltages and temperatures 5 selectable input attenuators allow supervision of supplies to 14.4 V on VH 6 V on VP1 to VP4 (VPx) 5 dual-function inputs, VX1 to VX5 (VXx) High impedance input to supply fault detector with thresholds between 0.573 V and 1.375 V General-purpose logic input 10 programmable driver outputs, PDO1 to PDO10 (PDOx) Open-collector with external pull-up Push/pull output, driven to VDDCAP or VPx Open collector with weak pull-up to VDDCAP or VPx Internally charge-pumped high drive for use with external N-FET (PDO1 to PDO6 only) Sequencing engine (SE) implements state machine control of PDO outputs State changes conditional on input events Enables complex control of boards Power-up and power-down sequence control Fault event handling Interrupt generation on warnings Watchdog function can be integrated in SE Program software control of sequencing through SMBus Complete voltage-margining solution for 6 voltage rails 6 voltage output 8-bit DACs (0.300 V to 1.551 V) allow voltage adjustment via dc-to-dc converter trim/feedback node 12-bit ADC for readback of all supervised voltages 2 auxiliary (single-ended) ADC inputs Reference input (REFIN) has 2 input options Driven directly from 2.048 V (±0.25%) REFOUT pin More accurate external reference for improved ADC performance Device powered by the highest of VPx, VH for improved redundancy User EEPROM: 256 bytes Industry-standard 2-wire bus interface (SMBus) Guaranteed PDO low with VH, VPx = 1.2 V Available in 40-lead, 6 mm × 6 mm LFCSP and 48-lead, 7 mm × 7 mm TQFP packages For more information about the ADM1166 register map, refer to the AN-698 Application Note Figure 1. APPLICATIONS Central office systems Servers/routers Multivoltage system line cards DSP/FPGA supply sequencing In-circuit testing of margined supplies GENERAL DESCRIPTION The ADM1166 Super Sequencer® is a configurable supervisory/ sequencing device that offers a single-chip solution for supply monitoring and sequencing in multiple-supply systems. In addition to these functions, the ADM1166 integrates a 12-bit ADC and six 8-bit voltage output DACs. These circuits can be used to implement a closed-loop margining system that enables supply adjustment by altering either the feedback node or reference of a dc-to-dc converter using the DAC outputs. Supply margining can be performed with a minimum of external components. The margining loop can be used for in-circuit testing of a board during production (for example, to verify board functionality at −5% of nominal supplies), or it can be used dynamically to accurately control the output voltage of a dc-to-dc converter. Rev. 0 Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Specifications subject to change without notice. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Trademarks and registered trademarks are the property of their respective owners. One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: 781.329.4700 www.analog.com Fax: 781.461.3113 ©2010 Analog Devices, Inc. All rights reserved. ADM1166 TABLE OF CONTENTS Features .............................................................................................. 1 Sequencing Engine Application Example ............................... 18 Functional Block Diagram .............................................................. 1 Fault and Status Reporting ........................................................ 19 Applications ....................................................................................... 1 Nonvolatile Black Box Fault Recording................................... 20 General Description ......................................................................... 1 Black Box Writes with No External Supply ............................ 20 Revision History ............................................................................... 2 Voltage Readback............................................................................ 21 Detailed Block Diagram .................................................................. 3 Supply Supervision with the ADC ........................................... 21 Specifications..................................................................................... 4 Supply Margining ........................................................................... 22 Absolute Maximum Ratings............................................................ 7 Overview ..................................................................................... 22 Thermal Resistance ...................................................................... 7 Open-Loop Supply Margining ................................................. 22 ESD Caution .................................................................................. 7 Closed-Loop Supply Margining ............................................... 22 Pin Configurations and Function Descriptions ........................... 8 Writing to the DACs .................................................................. 23 Typical Performance Characteristics ........................................... 10 Choosing the Size of the Attenuation Resistor ....................... 23 Powering the ADM1166 ................................................................ 13 DAC Limiting and Other Safety Features ............................... 23 Inputs................................................................................................ 14 Applications Diagram .................................................................... 24 Supply Supervision ..................................................................... 14 Communicating with the ADM1166 ........................................... 25 Programming the Supply Fault Detectors ............................... 14 Configuration Download at Power-Up ................................... 25 Input Comparator Hysteresis .................................................... 14 Updating the Configuration ..................................................... 25 Input Glitch Filtering ................................................................. 15 Updating the Sequencing Engine ............................................. 26 Supply Supervision with VXx Inputs ....................................... 15 Internal Registers........................................................................ 26 VXx Pins as Digital Inputs ........................................................ 15 EEPROM ..................................................................................... 26 Outputs ............................................................................................ 16 Serial Bus Interface..................................................................... 26 Supply Sequencing Through Configurable Output Drivers . 16 SMBus Protocols for RAM and EEPROM .............................. 28 Default Output Configuration .................................................. 16 Write Operations ........................................................................ 29 Sequencing Engine ......................................................................... 17 Read Operations ......................................................................... 30 Overview...................................................................................... 17 Outline Dimensions ....................................................................... 32 Warnings ...................................................................................... 17 Ordering Guide .......................................................................... 32 SMBus Jump (Unconditional Jump) ........................................ 17 REVISION HISTORY 12/10—Revision 0: Initial Version Rev. 0 | Page 2 of 32 ADM1166 A block of nonvolatile EEPROM is available that can be used to store user-defined information and may also be used to hold a number of fault records that are written by the sequencing engine defined by the user when a particular fault or sequence occurs. The device also provides up to 10 programmable inputs for monitoring undervoltage faults, overvoltage faults, or out-ofwindow faults on up to 10 supplies. In addition, 10 programmable outputs can be used as logic enables. Six of these programmable outputs can also provide up to a 12 V output for driving the gate of an N-FET that can be placed in the path of a supply. The device is controlled via configuration data that can be programmed into an EEPROM. The entire configuration can be programmed using an intuitive GUI-based software package provided by Analog Devices, Inc. The logical core of the device is a sequencing engine. This statemachine-based construction provides up to 63 different states. This design enables very flexible sequencing of the outputs, based on the condition of the inputs. DETAILED BLOCK DIAGRAM REFIN REFOUT AUX2 AUX1 REFGND SDA SCL A1 ADM1166 A0 SMBus INTERFACE VREF DEVICE CONTROLLER 12-BIT SAR ADC OSC EEPROM FAULT RECORDING GPI SIGNAL CONDITIONING VX1 CONFIGURABLE OUTPUT DRIVER (HV) SFD PDO1 PDO2 VX2 PDO3 VX3 PDO4 PDO5 VX4 GPI SIGNAL CONDITIONING SEQUENCING ENGINE VX5 VP1 CONFIGURABLE OUTPUT DRIVER (HV) PDO6 CONFIGURABLE OUTPUT DRIVER (LV) PDO7 SFD SELECTABLE ATTENUATOR SFD VP2 VP3 PDO8 VP4 PDO9 SELECTABLE ATTENUATOR CONFIGURABLE OUTPUT DRIVER (LV) SFD AGND VDDCAP PDO10 PDOGND REG 5.25V CHARGE PUMP VDD ARBITRATOR GND VCCP VOUT DAC DAC1 VOUT DAC DAC2 DAC3 Figure 2. Detailed Block Diagram Rev. 0 | Page 3 of 32 DAC4 DAC5 DAC6 09332-002 VH ADM1166 SPECIFICATIONS VH = 3.0 V to 14.4 V 1 , VPx = 3.0 V to 6.0 V1, TA = −40°C to +85°C, unless otherwise noted. Table 1. Parameter POWER SUPPLY ARBITRATION VH, VPx VPx VH VDDCAP CVDDCAP POWER SUPPLY Supply Current, IVH, IVPx Additional Currents All PDOx FET Drivers On Current Available from VDDCAP DAC Supply Currents ADC Supply Current EEPROM Erase Current SUPPLY FAULT DETECTORS VH Pin Input Impedance Input Attenuator Error Detection Ranges High Range Midrange VPx Pins Input Impedance Input Attenuator Error Detection Ranges Midrange Low Range Ultralow Range VXx Pins Input Impedance Detection Range Ultralow Range Absolute Accuracy Threshold Resolution Digital Glitch Filter Min Typ Max Unit Test Conditions/Comments 4.75 6.0 14.4 5.4 V V V V μF Minimum supply required on one of VPx, VH Maximum VDDCAP = 5.1 V, typical VDDCAP = 4.75 V Regulated LDO output Minimum recommended decoupling capacitance 4.2 6 mA VDDCAP = 4.75 V, PDO1 to PDO10 off, DACs off, ADC off mA 3.0 2.7 10 1 2.2 1 10 mA mA mA VDDCAP = 4.75 V, PDO1 to PDO6 loaded with 1 μA each, PDO7 to PDO10 off Maximum additional load that can be drawn from all PDO pull-ups to VDDCAP Six DACs on with 100 μA maximum load on each Running round-robin loop 1 ms duration only, VDDCAP = 3 V 52 ±0.05 kΩ % Midrange and high range 2 6 2.5 14.4 6 52 ±0.05 2.5 1.25 0.573 6 3 1.375 1 mA V V kΩ % Low range and midrange V V V No input attenuation error MΩ 0.573 1.375 ±1 8 0 100 V % Bits μs μs Rev. 0 | Page 4 of 32 No input attenuation error VREF error + DAC nonlinearity + comparator offset error + input attenuation error Minimum programmable filter length Maximum programmable filter length ADM1166 Parameter ANALOG-TO-DIGITAL CONVERTER Signal Range Min 0 Range 1 Range 2 Range 3 Range 4 Output Voltage Range LSB Step Size INL DNL Gain Error Maximum Load Current (Source) Maximum Load Current (Sink) Maximum Load Capacitance Settling Time to 50 pF Load Load Regulation PSRR REFERENCE OUTPUT Reference Output Voltage Load Regulation Minimum Load Capacitance PSRR PROGRAMMABLE DRIVER OUTPUTS High Voltage (Charge-Pump) Mode (PDO1 to PDO6) Output Impedance VOH VOH VOH 2 IOUTAVG Max Unit Test Conditions/Comments VREFIN V The ADC can convert signals presented to the VH, VPx, and VXx pins; VPx and VH input signals are attenuated depending on the selected range; a signal at the pin corresponding to the selected range is from 0.573 V to 1.375 V at the ADC input 2.048 Input Reference Voltage on REFIN Pin, VREFIN Resolution INL Gain Error Conversion Time Offset Error Input Noise AUX1, AUX2 Input Impedance BUFFERED VOLTAGE OUTPUT DACs Resolution Code 0x7F Output Voltage Typ V 12 ±2.5 ±0.05 0.44 84 ±2 0.25 1 8 Bits LSB % ms ms LSB LSB rms MΩ Endpoint corrected, VREFIN = 2.048 V VREFIN = 2.048 V One conversion on one channel All 12 channels selected, 16× averaging enabled VREFIN = 2.048 V Direct input (no attenuator) Bits Six DACs are individually selectable for centering on one of four output voltage ranges 0.592 0.796 0.996 1.246 0.6 0.8 1 1.25 601.25 2.36 0.603 0.803 1.003 1.253 ±0.75 ±0.4 1 100 100 50 2 2.5 60 40 2.043 2.048 −0.25 0.25 2.053 1 60 11 10.5 8 500 12.5 12 10 20 14 13.5 13.5 V V V V mV mV LSB LSB % μA μA pF μs mV dB dB Same range, independent of center point Endpoint corrected Per mA DC 100 mV step in 20 ns with 50 pF load V mV mV μF dB No load Sourcing current, IDACxMAX = −100 μA Sinking current, IDACxMAX = 100 μA Capacitor required for decoupling, stability DC kΩ V V V μA IOH = 0 μA IOH = 1 μA IOH = 7 μA 2 V < VOH < 7 V Rev. 0 | Page 5 of 32 ADM1166 Parameter Standard (Digital Output) Mode (PDO1 to PDO10) VOH Min Typ Max Unit Test Conditions/Comments 0.50 20 60 29 2 V V V V mA mA kΩ mA 10 μA VPU (pull-up to VDDCAP or VPx) = 2.7 V, IOH = 0.5 mA VPU to VPx = 6.0 V, IOH = 0 mA VPU ≤ 2.7 V, IOH = 0.5 mA IOL = 20 mA Maximum sink current per PDOx pin Maximum total sink for all PDOx pins Internal pull-up Current load on any VPx pull-ups, that is, total source current available through any number of PDO pull-up switches configured onto any one VPx pin VPDO = 14.4 V 110 kHz All on-chip time delays derived from this clock V V μA μA pF μA Maximum VIN = 5.5 V Maximum VIN = 5.5 V VIN = 5.5 V VIN = 0 V 2.4 4.5 VOL IOL2 ISINK2 RPULL-UP ISOURCE (VPx)2 Three-State Output Leakage Current Oscillator Frequency DIGITAL INPUTS (VXx, A0, A1) Input High Voltage, VIH Input Low Voltage, VIL Input High Current, IIH Input Low Current, IIL Input Capacitance Programmable Pull-Down Current, IPULL-DOWN SERIAL BUS DIGITAL INPUTS (SDA, SCL) Input High Voltage, VIH Input Low Voltage, VIL Output Low Voltage, VOL2 SERIAL BUS TIMING 3 Clock Frequency, fSCLK Bus Free Time, tBUF Start Setup Time, tSU;STA Stop Setup Time, tSU;STO Start Hold Time, tHD;STA SCL Low Time, tLOW SCL High Time, tHIGH SCL, SDA Rise Time, tR SCL, SDA Fall Time, tF Data Setup Time, tSU;DAT Data Hold Time, tHD;DAT Input Low Current, IIL SEQUENCING ENGINE TIMING State Change Time VPU − 0.3 0 16 90 20 100 2.0 0.8 −1 1 5 20 2.0 0.8 0.4 400 1.3 0.6 0.6 0.6 1.3 0.6 300 300 100 250 1 10 VDDCAP = 4.75 V, TA = 25°C, if known logic state is required V V V IOUT = −3.0 mA kHz μs μs μs μs μs μs ns ns ns ns μA VIN = 0 V μs 1 At least one of the VH and VPx pins must be ≥ 3.0 V to maintain the device supply on VDDCAP. Specification is not production tested but is supported by characterization data at initial product release. 3 Guaranteed by design. 2 Rev. 0 | Page 6 of 32 ADM1166 ABSOLUTE MAXIMUM RATINGS THERMAL RESISTANCE Table 2. Parameter Voltage on VH Pin Voltage on VPx Pins Voltage on VXx Pins Voltage on AUX1, AUX2 Pins Voltage on A0, A1 Pins Voltage on REFIN, REFOUT Pins Voltage on VDDCAP, VCCP Pins Voltage on DACx Pins Voltage on PDOx Pins Voltage on SDA, SCL Pins Voltage on GND, AGND, PDOGND, REFGND Pins Input Current at Any Pin Package Input Current Maximum Junction Temperature (TJ max) Storage Temperature Range Lead Temperature Soldering Vapor Phase, 60 sec ESD Rating, All Pins Rating 16 V 7V −0.3 V to +6.5 V −0.3 V to +5 V −0.3 V to +7 V 5V 6.5 V 6.5 V 16 V 7V −0.3 V to +0.3 V ±5 mA ±20 mA 150°C −65°C to +150°C θJA is specified for the worst-case conditions, that is, a device soldered in a circuit board for surface-mount packages. Table 3. Thermal Resistance Package Type 40-Lead LFCSP 48-Lead TQFP ESD CAUTION 215°C 2000 V Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only; functional operation of the device at these or any other conditions above those indicated in the operational section of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Rev. 0 | Page 7 of 32 θJA 26.5 50 Unit °C/W °C/W ADM1166 NC GND VDDCAP AUX1 AUX2 SDA SCL A1 A0 VCCP PDOGND NC 48 47 46 45 44 43 42 41 40 39 38 37 NC 1 35 PDO1 VX2 3 34 PDO2 VX3 4 33 PDO3 VX4 5 32 PDO4 VX5 6 ADM1166 31 PDO5 VP1 7 TOP VIEW (Not to Scale) 30 PDO6 VP2 8 29 PDO7 VP3 9 28 PDO8 VP4 10 27 PDO9 14 15 16 17 18 19 20 21 22 23 24 DAC3 DAC4 DAC5 DAC6 NC NC 09332-003 13 DAC2 25 NC DAC1 26 PDO10 NC 12 REFOUT VH 11 REFIN AGND REFGND REFIN REFOUT DAC1 DAC2 DAC3 DAC4 DAC5 DAC6 NOTE 1. EXPOSED PAD SHOULD BE SOLDERED TO THE BOARD FOR IMPROVED MECHANICAL STABILITY. 36 NC PIN 1 INDICATOR VX1 2 REFGND TOP VIEW (Not to Scale) PDO1 PDO2 PDO3 PDO4 PDO5 PDO6 PDO7 PDO8 PDO9 PDO10 AGND ADM1166 30 29 28 27 26 25 24 23 22 21 11 12 13 14 15 16 17 18 19 20 VX1 1 VX2 2 VX3 3 VX4 4 VX5 5 VP1 6 VP2 7 VP3 8 VP4 9 VH 10 NC = NO CONNECT 09332-004 40 39 38 37 36 35 34 33 32 31 GND VDDCAP AUX1 AUX2 SDA SCL A1 A0 VCCP PDOGND PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS Figure 4. 48-Lead TQFP Pin Configuration Figure 3. 40-Lead LFCSP Pin Configuration Table 4. Pin Function Descriptions 40-Lead LFCSP 1 to 5 Pin No. 48-Lead TQFP 1, 12, 13, 24, 25, 36, 37, 48 2 to 6 Mnemonic NC Description No Connect. VX1 to VX5 (VXx) High Impedance Inputs to Supply Fault Detectors. Fault thresholds can be set from 0.573 V to 1.375 V. Alternatively, these pins can be used as general-purpose digital inputs. Low Voltage Inputs to Supply Fault Detectors. Three input ranges can be set by altering the input attenuation on a potential divider connected to these pins, the output of which connects to a supply fault detector. These pins allow thresholds from 2.5 V to 6.0 V, from 1.25 V to 3.00 V, and from 0.573 V to 1.375 V. High Voltage Input to Supply Fault Detectors. Two input ranges can be set by altering the input attenuation on a potential divider connected to this pin, the output of which connects to a supply fault detector. This pin allows thresholds from 6.0 V to 14.4 V and from 2.5 V to 6.0 V. Ground Return for Input Attenuators. Ground Return for On-Chip Reference Circuits. Reference Input for ADC. Nominally, 2.048 V. This pin must be driven by a reference voltage. The on-board reference can be used by connecting the REFOUT pin to the REFIN pin. Reference Output, 2.048 V. Typically connected to REFIN. Note that the capacitor must be connected between this pin and REFGND. A 10 μF capacitor is recommended for this purpose. Voltage Output DACs. These pins default to high impedance at power-up. Programmable Driver Outputs. Ground Return for Driver Outputs. Central Charge-Pump Voltage of 5.25 V. A reservoir capacitor must be connected between this pin and GND. A 10 μF capacitor is recommended for this purpose. Logic Input. This pin sets the seventh bit of the SMBus interface address. Logic Input. This pin sets the sixth bit of the SMBus interface address. SMBus Clock Pin. Bidirectional, open-drain pin that requires external resistive pull-up. SMBus Data Pin. Bidirectional, open-drain pin that requires external resistive pull-up. Auxiliary, Single-Ended ADC Inputs. 6 to 9 7 to 10 VP1 to VP4 (VPx) 10 11 VH 11 12 13 14 15 16 AGND 1 REFGND1 REFIN 14 17 REFOUT 15 to 20 21 to 30 31 32 18 to 23 26 to 35 38 39 DAC1 to DAC6 PDO10 to PDO1 PDOGND1 VCCP 33 34 35 36 37, 38 40 41 42 43 44, 45 A0 A1 SCL SDA AUX2, AUX1 Rev. 0 | Page 8 of 32 ADM1166 40-Lead LFCSP 39 40 1 Pin No. 48-Lead TQFP 46 47 Not applicable Mnemonic VDDCAP GND1 EPAD Description Device Supply Voltage. Linearly regulated from the highest of the VPx and VH pins to a typical of 4.75 V. Note that the capacitor must be connected between this pin and GND. A 10 μF capacitor is recommended for this purpose. Supply Ground. Exposed Pad. This pad is a no connect (NC). If possible, this pad should be soldered to the board for improved mechanical stability. In a typical application, all ground pins are connected together. Rev. 0 | Page 9 of 32 ADM1166 TYPICAL PERFORMANCE CHARACTERISTICS 6 180 160 5 140 120 IVP1 (µA) VVDDCAP (V) 4 3 2 100 80 60 40 1 0 1 2 3 4 5 6 VVP1 (V) 0 09332-050 0 0 1 2 3 4 5 6 VVP1 (V) 09332-053 20 Figure 8. IVP1 vs. VVP1 (VP1 Not as Supply) Figure 5. VVDDCAP vs. VVP1 5.0 6 4.5 5 4.0 3.5 3.0 IVH (mA) VVDDCAP (V) 4 3 2 2.5 2.0 1.5 1.0 1 0.5 4 6 8 10 12 14 16 VVH (V) 0 2 4 6 8 10 12 14 16 09332-054 2 6 09332-055 0 09332-051 0 0 VVH (V) Figure 9. IVH vs. VVH (VH as Supply) Figure 6. VVDDCAP vs. VVH 350 5.0 4.5 300 4.0 250 IVH (µA) 3.0 2.5 2.0 1.5 200 150 100 1.0 50 0.5 0 0 0 1 2 3 4 VVP1 (V) 5 6 09332-052 IVP1 (mA) 3.5 0 1 2 3 4 VVH (V) Figure 10. IVH vs. VVH (VH Not as Supply) Figure 7. IVP1 vs. VVP1 (VP1 as Supply) Rev. 0 | Page 10 of 32 5 ADM1166 14 1.0 0.8 0.6 10 0.4 0.2 DNL (LSB) CHARGE-PUMPED V PDO1 (V) 12 8 6 0 –0.2 –0.4 4 –0.6 2 5.0 7.5 10.0 12.5 15.0 ILOAD (µA) –1.0 0 1000 4.5 0.8 4.0 0.6 3.5 0.4 INL (LSB) 3.0 VP1 = 5V 2.5 VP1 = 3V 2.0 0.2 0 –0.2 1.5 –0.4 1.0 –0.6 0.5 –0.8 0 3 4 5 6 ILOAD (mA) –1.0 09332-057 VPDO1 (V) 1.0 2 4000 Figure 14. DNL for ADC 5.0 1 3000 CODE Figure 11. Charge-Pumped VPDO1 (FET Drive Mode) vs. ILOAD 0 2000 0 1000 2000 3000 4000 CODE 09332-063 2.5 09332-056 0 09332-066 –0.8 0 Figure 15. INL for ADC Figure 12. VPDO1 (Strong Pull-Up to VPx) vs. ILOAD 12000 4.5 9894 4.0 10000 3.5 VP1 = 5V HITS PER CODE 2.5 VP1 = 3V 2.0 1.5 8000 6000 4000 1.0 2000 0.5 0 10 20 30 40 50 ILOAD (µA) 60 2047 81 2048 2049 CODE Figure 16. ADC Noise, Midcode Input, 10,000 Reads Figure 13. VPDO1 (Weak Pull-Up to VPx) vs. ILOAD Rev. 0 | Page 11 of 32 09332-064 25 0 0 09332-058 VPDO1 (V) 3.0 ADM1166 1.005 1.004 1.003 DAC 20kΩ BUFFER OUTPUT 47pF DAC OUTPUT 1.002 PROBE POINT 1.001 VP1 = 3.0V 1.000 VP1 = 4.75V 0.999 0.998 0.997 1 756mV 0.996 0.995 –40 –20 0 20 40 60 80 100 09332-065 CH1 80 100 09332-061 M1.00µs 09332-059 CH1 200mV TEMPERATURE (°C) Figure 17. Transient Response of DAC Code Change into Typical Load Figure 19. DAC Output vs. Temperature 2.058 DAC 100kΩ BUFFER OUTPUT REFOUT (V) 2.053 1V VP1 = 3.0V 2.048 VP1 = 4.75V PROBE POINT 2.043 CH1 200mV M1.00µs CH1 944mV 09332-060 1 2.038 –40 –20 0 20 40 60 TEMPERATURE (°C) Figure 18. Transient Response of DAC to Turn-On from High-Z State Figure 20. REFOUT vs. Temperature Rev. 0 | Page 12 of 32 ADM1166 POWERING THE ADM1166 An external capacitor to GND is required to decouple the on-chip supply from noise. This capacitor should be connected to the VDDCAP pin, as shown in Figure 21. The capacitor has another use during brownouts (momentary loss of power). Under these conditions, when the input supply (VPx or VH) dips transiently below VDD, the synchronous rectifier switch immediately turns off so that it does not pull VDD down. The VDD capacitor can then act as a reservoir to keep the device active until the next highest supply takes over the powering of the device. A 10 μF capacitor is recommended for this reservoir/decoupling function. In cases where this 12 V supply is hot swapped, it is recommended that the ADM1166 not be connected directly to the supply. Suitable precautions, such as the use of a hot swap controller or RC filter network, should be taken to protect the device from transients that could cause damage during hot swap events. When two or more supplies are within 100 mV of each other, the supply that first takes control of VDD keeps control. For example, if VP1 is connected to a 3.3 V supply, VDD powers up to approximately 3.1 V through VP1. If VP2 is then connected to another 3.3 V supply, VP1 still powers the device, unless VP2 goes 100 mV higher than VP1. VDDCAP VP1 IN OUT 4.75V LDO EN VP2 IN OUT 4.75V LDO EN VP3 IN OUT 4.75V LDO EN VP4 IN OUT 4.75V LDO EN VH The value of the VDDCAP capacitor may be increased if it is necessary to guarantee a complete fault record is written into EEPROM should all supplies fail. The value of capacitor to use is discussed in the Black Box Writes with No External Supply section. The VH input pin can accommodate supplies up to 14.4 V, which allows the ADM1166 to be powered using a 12 V backplane supply. Rev. 0 | Page 13 of 32 IN OUT 4.75V LDO INTERNAL DEVICE SUPPLY EN SUPPLY COMPARATOR 09332-022 The ADM1166 is powered from the highest voltage input on either the positive-only supply inputs (VPx) or the high voltage supply input (VH). This technique offers improved redundancy because the device is not dependent on any particular voltage rail to keep it operational. The same pins are used for supply fault detection (see the Supply Supervision section). A VDD arbitrator on the device chooses which supply to use. The arbitrator can be considered an OR’ing of five low dropout regulators (LDOs) together. A supply comparator chooses the highest input to provide the on-chip supply. There is minimal switching loss with this architecture (~0.2 V), resulting in the ability to power the ADM1166 from a supply as low as 3.0 V. Note that the supply on the VXx pins cannot be used to power the device. Figure 21. VDD Arbitrator Operation ADM1166 INPUTS SUPPLY SUPERVISION The threshold value required is given by The ADM1166 has 10 programmable inputs. Five of these are dedicated supply fault detectors (SFDs). These dedicated inputs are called VH and VPx (VP1 to VP4) by default. The other five inputs are labeled VXx (VX1 to VX5) and have dual functionality. They can be used either as SFDs, with functionality similar to that of VH and VPx, or as CMOS-/TTL-compatible logic inputs to the device. Therefore, the ADM1166 can have up to 10 analog inputs, a minimum of five analog inputs and five digital inputs, or a combination thereof. If an input is used as an analog input, it cannot be used as a digital input. Therefore, a configuration requiring 10 analog inputs has no available digital inputs. Table 6 shows the details of each input. VT = (VR × N)/255 + VB where: VT is the desired threshold voltage (undervoltage or overvoltage). VR is the voltage range. N is the decimal value of the 8-bit code. VB is the bottom of the range. Reversing the equation, the code for a desired threshold is given by N = 255 × (VT − VB)/VR For example, if the user wants to set a 5 V overvoltage threshold on VP1, the code to be programmed in the PS1OVTH register (as discussed in the AN-698 Application Note) is given by PROGRAMMING THE SUPPLY FAULT DETECTORS The ADM1166 can have up to 10 SFDs on its 10 input channels. These highly programmable reset generators enable the supervision of up to 10 supply voltages. The supplies can be as low as 0.573 V and as high as 14.4 V. The inputs can be configured to detect an undervoltage fault (the input voltage drops below a preprogrammed value), an overvoltage fault (the input voltage rises above a preprogrammed value), or an out-of-window fault (the input voltage is outside a preprogrammed range). The thresholds can be programmed to an 8-bit resolution in registers provided in the ADM1166. This translates to a voltage resolution that is dependent on the range selected. N = 255 × (5 − 2.5)/3.5 Therefore, N = 182 (1011 0110 or 0xB6). INPUT COMPARATOR HYSTERESIS The UV and OV comparators shown in Figure 22 are always looking at VPx. To avoid chatter (multiple transitions when the input is very close to the set threshold level), these comparators have digitally programmable hysteresis. The hysteresis can be programmed up to the values shown in Table 6. RANGE SELECT ULTRA LOW + VPx The resolution is given by VREF Step Size = Threshold Range/255 OV COMPARATOR – GLITCH FILTER FAULT OUTPUT + LOW – MID UV FAULT TYPE COMPARATOR SELECT 09332-023 Therefore, if the high range is selected on VH, the step size can be calculated as (14.4 V − 6.0 V)/255 = 32.9 mV Table 5 lists the upper and lower limits of each available range, the bottom of each range (VB), and the range itself (VR). Table 5. Voltage Range Limits Voltage Range (V) 0.573 to 1.375 1.25 to 3.00 2.5 to 6.0 6.0 to 14.4 VB (V) 0.573 1.25 2.5 6.0 VR (V) 0.802 1.75 3.5 8.4 Figure 22. Supply Fault Detector Block The hysteresis is added after a supply voltage goes out of tolerance. Therefore, the user can program the amount above the undervoltage threshold to which the input must rise before an undervoltage fault is deasserted. Similarly, the user can program the amount below the overvoltage threshold to which an input must fall before an overvoltage fault is deasserted. Table 6. Input Functions, Thresholds, and Ranges Input VH Function High voltage analog input VPx Positive analog input VXx High-Z analog input Digital input Voltage Range (V) 2.5 to 6.0 6.0 to 14.4 0.573 to 1.375 1.25 to 3.00 2.5 to 6.0 0.573 to 1.375 0 to 5.0 Maximum Hysteresis 425 mV 1.02 V 97.5 mV 212 mV 425 mV 97.5 mV Not applicable Rev. 0 | Page 14 of 32 Voltage Resolution (mV) 13.7 32.9 3.14 6.8 13.7 3.14 Not applicable Glitch Filter (μs) 0 to 100 0 to 100 0 to 100 0 to 100 0 to 100 0 to 100 0 to 100 ADM1166 An additional supply supervision function is available when the VXx pins are selected as digital inputs. In this case, the analog function is available as a second detector on each of the dedicated analog inputs, VPx and VH. The analog function of VX1 is mapped to VP1, VX2 is mapped to VP2, and so on. VX5 is mapped to VH. In this case, these SFDs can be viewed as secondary or warning SFDs. VHYST = VR × NTHRESH/255 where: VHYST is the desired hysteresis voltage. NTHRESH is the decimal value of the 5-bit hysteresis code. Note that NTHRESH has a maximum value of 31. The maximum hysteresis for the ranges is listed in Table 6. INPUT GLITCH FILTERING The final stage of the SFDs is a glitch filter. This block provides time-domain filtering on the output of the SFD comparators, which allows the user to remove any spurious transitions such as supply bounce at turn-on. The glitch filter function is in addition to the digitally programmable hysteresis of the SFD comparators. The glitch filter timeout is programmable up to 100 μs. For example, when the glitch filter timeout is 100 μs, any pulse appearing on the input of the glitch filter block that is less than 100 μs in duration is prevented from appearing on the output of the glitch filter block. Any input pulse that is longer than 100 μs appears on the output of the glitch filter block. The output is delayed with respect to the input by 100 μs. The filtering process is shown in Figure 23. INPUT PULSE SHORTER THAN GLITCH FILTER TIMEOUT INPUT PULSE LONGER THAN GLITCH FILTER TIMEOUT PROGRAMMED TIMEOUT PROGRAMMED TIMEOUT INPUT tGF t0 tGF OUTPUT t0 tGF OUTPUT t0 tGF 09332-024 t0 INPUT Figure 23. Input Glitch Filter Function SUPPLY SUPERVISION WITH VXx INPUTS The VXx inputs have two functions. They can be used as either supply fault detectors or digital logic inputs. When selected as analog (SFD) inputs, the VXx pins have functionality that is very similar to the VH and VPx pins. The primary difference is that the VXx pins have only one input range: 0.573 V to 1.375 V. Therefore, these inputs can directly supervise only the very low supplies. However, the input impedance of the VXx pins is high, allowing an external resistor divide network to be connected to the pin. Thus, potentially any supply can be divided down into the input range of the VXx pin and supervised. This enables the ADM1166 to monitor other supplies, such as +24 V, +48 V, and −5 V. The secondary SFDs are fixed to the same input range as the primary SFDs. They are used to indicate warning levels rather than failure levels. This allows faults and warnings to be generated on a single supply using only one pin. For example, if VP1 is set to output a fault when a 3.3 V supply drops to 3.0 V, VX1 can be set to output a warning at 3.1 V. Warning outputs are available for readback from the status registers. They are also OR’ed together and fed into the SE, allowing warnings to generate interrupts on the PDOs. Therefore, in this example, if the supply drops to 3.1 V, a warning is generated, and remedial action can be taken before the supply drops out of tolerance. VXx PINS AS DIGITAL INPUTS As discussed in the Supply Supervision with VXX Inputs section, the VXx input pins on the ADM1166 have dual functionality. The second function is as a digital logic input to the device. Therefore, the ADM1166 can be configured for up to five digital inputs. These inputs are TTL-/CMOS-compatible inputs. Standard logic signals can be applied to the pins: RESET from reset generators, PWRGD signals, fault flags, and manual resets. These signals are available as inputs to the SE and, therefore, can be used to control the status of the PDOs. The inputs can be configured to detect either a change in level or an edge. When configured for level detection, the output of the digital block is a buffered version of the input. When configured for edge detection, a pulse of programmable width is output from the digital block once the logic transition is detected. The width is programmable from 0 μs to 100 μs. The digital blocks feature the same glitch filter function that is available on the SFDs. This enables the user to ignore spurious transitions on the inputs. For example, the filter can be used to debounce a manual reset switch. When configured as digital inputs, each VXx pin has a weak (10 μA) pull-down current source available for placing the input into a known condition, even if left floating. The current source, if selected, weakly pulls the input to GND. VXx (DIGITAL INPUT) Rev. 0 | Page 15 of 32 + DETECTOR GLITCH FILTER TO SEQUENCING ENGINE – VREF = 1.4V Figure 24. VXx Digital Input Function 09332-027 The hysteresis value is given by ADM1166 OUTPUTS The data driving each of the PDOs can come from one of three sources. The source can be enabled in the PDOxCFG configuration register (see the AN-698 Application Note for details). SUPPLY SEQUENCING THROUGH CONFIGURABLE OUTPUT DRIVERS Supply sequencing is achieved with the ADM1166 using the programmable driver outputs (PDOs) on the device as control signals for supplies. The output drivers can be used as logic enables or as FET drivers. The data sources are as follows: The sequence in which the PDOs are asserted (and, therefore, the supplies are turned on) is controlled by the sequencing engine (SE). The SE determines what action is taken with the PDOs, based on the condition of the ADM1166 inputs. Therefore, the PDOs can be set up to assert when the SFDs are in tolerance, the correct input signals are received on the VXx digital pins, and no warnings are received from any of the inputs of the device. The PDOs can be used for a variety of functions. The primary function is to provide enable signals for LDOs or dc-to-dc converters that generate supplies locally on a board. The PDOs can also be used to provide a PWRGD signal, when all the SFDs are in tolerance, or a RESET output if one of the SFDs goes out of specification (this can be used as a status signal for a DSP, FPGA, or other microcontroller). • Directly from the SMBus. A PDO can be configured so that the SMBus has direct control over it. This enables software control of the PDOs. Therefore, a microcontroller can be used to initiate a software power-up/power-down sequence. • On-chip clock. A 100 kHz clock is generated on the device. This clock can be made available on any of the PDOs. It can be used, for example, to clock an external device such as an LED. All of the internal registers in an unprogrammed ADM1166 device from the factory are set to 0. Because of this, the PDOx pins are pulled to GND by a weak (20 kΩ), on-chip pull-down resistor. As the input supply to the ADM1166 ramps up on VPx or VH, all PDOx pins behave as follows: • • Open drain (allowing the user to connect an external pull-up resistor). Open drain with weak pull-up to VDD. Open drain with strong pull-up to VDD. Open drain with weak pull-up to VPx. Open drain with strong pull-up to VPx. Strong pull-down to GND. Internally charge pumped high drive (12 V, PDO1 to PDO6 only). Input supply = 0 V to 1.2 V. The PDOs are high impedance. Input supply = 1.2 V to 2.7 V. The PDOs are pulled to GND by a weak (20 kΩ), on-chip pull-down resistor. Supply > 2.7 V. Factory-programmed devices continue to pull all PDOs to GND by a weak (20 kΩ), on-chip pull-down resistor. Programmed devices download current EEPROM configuration data, and the programmed setup is latched. The PDO then goes to the state demanded by the configuration. This provides a known condition for the PDOs during power-up. • The internal pull-down can be overdriven with an external pull-up of suitable value tied from the PDOx pin to the required pull-up voltage. The 20 kΩ resistor must be accounted for in calculating a suitable value. For example, if PDOx must be pulled up to 3.3 V, and 5 V is available as an external supply, the pull-up resistor value is given by The last option (available only on PDO1 to PDO6) allows the user to directly drive a voltage high enough to fully enhance an external N-FET, which is used to isolate, for example, a cardside voltage from a backplane supply (a PDO can sustain greater than 10.5 V into a 1 μA load). The pull-down switches can also be used to drive status LEDs directly. 3.3 V = 5 V × 20 kΩ/(RUP + 20 kΩ) Therefore, RUP = (100 kΩ − 66 kΩ)/3.3 V = 10 kΩ VFET (PDO1 TO PDO6 ONLY) VDD VP4 10Ω 20kΩ 10Ω 10Ω VP1 SEL 20kΩ CFG4 CFG5 CFG6 20kΩ SE DATA PDO SMBus DATA 20kΩ CLK DATA Figure 25. Programmable Driver Output Rev. 0 | Page 16 of 32 09332-028 • • • • • • Output from the SE. DEFAULT OUTPUT CONFIGURATION The PDOs can be programmed to pull up to a number of different options. The outputs can be programmed as follows: • • ADM1166 SEQUENCING ENGINE OVERVIEW The SE state machine comprises 63 state cells. Each state has the following attributes: • • • • • • • Monitors signals indicating the status of the 10 input pins, VP1 to VP4, VH, and VX1 to VX5. Can be entered from any other state. Three exit routes move the state machine onto a next state: sequence detection, fault monitoring, and timeout. Delay timers for the sequence and timeout blocks can be programmed independently and changed with each state change. The range of timeouts is from 0 ms to 400 ms. Output condition of the 10 PDO pins is defined and fixed within a state. Transition from one state to the next is made in less than 20 μs, which is the time needed to download a state definition from EEPROM to the SE. Can trigger a write of the black box fault and status registers into the black box section of EEPROM. MONITOR FAULT STATE TIMEOUT SEQUENCE 09332-029 The ADM1166 sequencing engine (SE) provides the user with powerful and flexible control of sequencing. The SE implements state machine control of the PDO outputs, with state changes conditional on input events. SE programs can enable complex control of boards such as power-up and power-down sequence control, fault event handling, and interrupt generation on warnings. A watchdog function that verifies the continued operation of a processor clock can be integrated into the SE program. The SE can also be controlled via the SMBus, giving software or firmware control of the board sequencing. Figure 26. State Cell The ADM1166 offers up to 63 state definitions. The signals monitored to indicate the status of the input pins are the outputs of the SFDs. WARNINGS The SE also monitors warnings. These warnings can be generated when the ADC readings violate their limit register value or when the secondary voltage monitors on VPx or VH are triggered. The warnings are OR’ed together and are available as a single warning input to each of the three blocks that enable exiting a state. SMBus JUMP (UNCONDITIONAL JUMP) The SE can be forced to advance to the next state unconditionally. This enables the user to force the SE to advance. Examples of the use of this feature include moving to a margining state or debugging a sequence. The SMBus jump or go-to command can be seen as another input to sequence and timeout blocks to provide an exit from each state. Table 7. Sample Sequence State Entries State IDLE1 IDLE2 EN3V3 Sequence If VX1 is low, go to State IDLE2. If VP1 is okay, go to State EN3V3. If VP2 is okay, go to State EN2V5. DIS3V3 EN2V5 If VX1 is high, go to State IDLE1. If VP3 is okay, go to State PWRGD. DIS2V5 FSEL1 FSEL2 PWRGD If VX1 is high, go to State IDLE1. If VP3 is not okay, go to State DIS2V5. If VP2 is not okay, go to State DIS3V3. If VX1 is high, go to State DIS2V5. Timeout Monitor If VP2 is not okay after 10 ms, go to State DIS3V3. If VP1 is not okay, go to State IDLE1. If VP3 is not okay after 20 ms, go to State DIS2V5. If VP1 or VP2 is not okay, go to State FSEL2. If VP1 or VP2 is not okay, go to State FSEL2. If VP1 is not okay, go to State IDLE1. If VP1, VP2, or VP3 is not okay, go to State FSEL1. Rev. 0 | Page 17 of 32 ADM1166 If a timer delay is specified, the input to the sequence detector must remain in the defined state for the duration of the timer delay. If the input changes state during the delay, the timer is reset. SEQUENCING ENGINE APPLICATION EXAMPLE The application in this section demonstrates the operation of the SE. Figure 28 shows how the simple building block of a single SE state can be used to build a power-up sequence for a three-supply system. Table 8 lists the PDO outputs for each state in the same SE implementation. In this system, a good 5 V supply on the VP1 pin and the VX1 pin held low are the triggers required to start a power-up sequence. Next, the sequence turns on the 3.3 V supply, then the 2.5 V supply (assuming successful turn-on of the 3.3 V supply). When all three supplies have turned on correctly, the PWRGD state is entered, where the SE remains until a fault occurs on one of the three supplies or until it is instructed to go through a power-down sequence by VX1 going high. The sequence detector can also help to identify monitoring faults. In the sample application shown in Figure 28, the FSEL1 and FSEL2 states first identify which of the VP1, VP2, or VP3 pins has faulted, and then they take appropriate action. SEQUENCE STATES IDLE1 VX1 = 0 IDLE2 Faults are dealt with throughout the power-up sequence on a case-by-case basis. The following three sections (the Sequence Detector section, the Monitoring Fault Detector section, and the Timeout Detector section) describe the individual blocks and use the sample application shown in Figure 28 to demonstrate the actions of the state machine. VP1 = 1 MONITOR FAULT STATES EN3V3 10ms VP1 = 0 Sequence Detector VP2 = 1 The sequence detector block is used to detect when a step in a sequence has been completed. It looks for one of the SE inputs to change state, and is most often used as the gate for successful progress through a power-up or power-down sequence. A timer block that is included in this detector can insert delays into a power-up or power-down sequence, if required. Timer delays can be set from 10 μs to 400 ms. Figure 27 is a block diagram of the sequence detector. VP1 TIMEOUT STATES SUPPLY FAULT DETECTION EN2V5 DIS3V3 20ms (VP1 + VP2) = 0 VX1 = 1 VP3 = 1 PWRGD DIS2V5 VP2 = 0 (VP1 + VP2 + VP3) = 0 VX1 = 1 FSEL1 VX1 = 1 (VP1 + VP2) = 0 VP3 = 0 SEQUENCE DETECTOR FSEL2 VP1 = 0 LOGIC INPUT CHANGE OR FAULT DETECTION VP2 = 0 09332-030 VX5 TIMER WARNINGS Figure 28. Sample Application Flow Diagram INVERT 09332-032 FORCE FLOW (UNCONDITIONAL JUMP) SELECT Figure 27. Sequence Detector Block Diagram Table 8. PDO Outputs for Each State PDO Outputs PDO1 = 3V3ON PDO2 = 2V5ON PDO3 = FAULT IDLE1 0 0 0 IDLE2 0 0 0 EN3V3 1 0 0 EN2V5 1 1 0 DIS3V3 0 1 1 Rev. 0 | Page 18 of 32 DIS2V5 1 0 1 PWRGD 1 1 0 FSEL1 1 1 1 FSEL2 1 1 1 ADM1166 Monitoring Fault Detector Timeout Detector The monitoring fault detector block is used to detect a failure on an input. The logical function implementing this is a wide OR gate that can detect when an input deviates from its expected condition. The clearest demonstration of the use of this block is in the PWRGD state, where the monitor block indicates that a failure on one or more of the VPx, VXx, or VH inputs has occurred. The timeout detector allows the user to trap a failure to ensure proper progress through a power-up or power-down sequence. No programmable delay is available in this block because the triggering of a fault condition is likely to be caused by a supply falling out of tolerance. In this situation, the device must react as quickly as possible. Some latency occurs when moving out of this state because it takes a finite amount of time (~20 μs) for the state configuration to download from the EEPROM into the SE. Figure 29 is a block diagram of the monitoring fault detector. 1-BIT FAULT DETECTOR FAULT SUPPLY FAULT DETECTION FAULT AND STATUS REPORTING MASK SENSE The ADM1166 has a fault latch for recording faults. Two registers, FSTAT1 and FSTAT2, are set aside for this purpose. A single bit is assigned to each input of the device, and a fault on that input sets the relevant bit. The contents of the fault register can be read out over the SMBus to determine which input(s) faulted. The fault register can be enabled or disabled in each state. To latch data from one state, ensure that the fault latch is disabled in the following state. This ensures that only real faults are captured and not, for example, undervoltage conditions that may be present during a power-up or power-down sequence. 1-BIT FAULT DETECTOR FAULT LOGIC INPUT CHANGE OR FAULT DETECTION MASK SENSE 1-BIT FAULT DETECTOR FAULT WARNINGS MASK Figure 29. Monitoring Fault Detector Block Diagram 09332-033 VX5 This supply rail is connected to the VP2 pin, and the sequence detector looks for the VP2 pin to go above its undervoltage threshold, which is set in the supply fault detector (SFD) attached to that pin. The power-up sequence progresses when this change is detected. If, however, the supply fails (perhaps due to a short circuit overloading this supply), the timeout block traps the problem. In this example, if the 3.3 V supply fails within 10 ms, the SE moves to the DIS3V3 state and turns off this supply by bringing PDO1 low. It also indicates that a fault has occurred by taking PDO3 high. Timeout delays of 100 μs to 400 ms can be programmed. MONITORING FAULT DETECTOR VP1 In the sample application shown in Figure 28, the timeout nextstate transition is from the EN3V3 and EN2V5 states. For the EN3V3 state, the signal 3V3ON is asserted on the PDO1 output pin upon entry to this state to turn on a 3.3 V supply. The ADM1166 also has a number of input status registers. These include more detailed information, such as whether an undervoltage or overvoltage fault is present on a particular input. The status registers also include information on ADC limit faults. There are two sets of these registers with different behaviors. The first set of status registers is not latched in any way and, therefore, can change at any time in response to changes on the inputs. These registers provide information as the UV and OV state of the inputs, the digital state of the GPI VXx inputs, and also the ADC warning limit status. The second set of registers update each time the sequence engine changes state and are latched until the next state change. The second set of registers provides the same information as the first set, but in a more compact form. The reason for this is that these registers are used by the black box feature when writing status information for the previous state into EEPROM. See the AN-698 Application Note for full details about the ADM1166 registers. Rev. 0 | Page 19 of 32 ADM1166 NONVOLATILE BLACK BOX FAULT RECORDING A section of EEPROM, from Address 0xF900 to Address 0xF9FF, is provided which, by default, can be used to store user-defined settings and information. Part of this section of EEPROM, Address 0xF980 to Address 0xF9FF, can, instead, be used to store up to 16 fault records. Any sequencing engine state can be designated as a black box write state. Each time the sequence engine enters that state a fault record is written into EEPROM. The fault record provides a snapshot of the entire ADM1166 state at the point in time when the last state was exited, just prior to entering the designated black box write state. A fault record contains the following information: • • • • • • • A flag bit set to 0 after the fault record has been written The state number of the previous state prior to the fault record write state Did a sequence/timeout/monitor condition cause the previous state to exit? UVSTATx and OVSTATx input comparator status VXx GPISTAT status LIMSTATx status A checksum byte are fault records to be read. Alternatively, one of the PDOx outputs can be used to generate an interrupt for a processor in the fault record write state to signal the need to come and read one or more fault records. After reading fault records during normal operation, the following two things must be done before the fault recorder will be able to reuse the EEPROM locations: • • The EEPROM section must be erased. The fault recorder must be reset so that it performs its search again for the first unused location of EEPROM that is available to store a fault record. BLACK BOX WRITES WITH NO EXTERNAL SUPPLY Each fault record contains eight bytes, with each byte taking typically about 250 μs to write to EEPROM, for a total write time of about 2 ms. Once the black box begins to write a fault record into EEPROM, the ADM1166 ensures the write is complete before attempting to write any additional fault records. This means that if consecutive sequencing engine states are designated as black box write states, then a time delay must be used in the first state to ensure that the fault record is written before moving to the next state. When the ADM1166 powers on initially, it performs a search to find the first fault record that has not been written to. It does this by checking the flag bit in each fault record until it finds one where the flag bit is 1. The first fault record is stored at Address 0xF980 and at multiples of eight bytes after that, with the last record stored at Address 0xF9F8. The fault recorder is only able to write in the EEPROM. It is not able to erase the EEPROM prior to writing the fault record. Therefore, to ensure correct operation, it is important that the fault record EEPROM be erased prior to use. Once all the EEPROM locations for the fault records are used, no more fault records can be written. This ensures that the first fault in any cascading fault is stored and not overwritten and lost. In cases where all the input supplies fail, for example, if the card has been removed from a powered backplane, the state machine can be programmed to trigger a write into the black box EEPROM. The decoupling capacitors on the rail that power the ADM1166 and other loads on the board form an energy reservoir. Depending on the other loads on the board and their behavior as the supply rails drop, there may be sufficient energy in the decoupling capacitors to allow the ADM1166 to write a complete fault record (8 bytes of data). Typically, it takes 2 ms to write to the eight bytes of a fault record. If the ADM1166 is powered using a 12 V supply on the VH pin, then a UV threshold at 6 V could be set and used as the state machine trigger to start writing a fault record to EEPROM. The higher the threshold, the earlier the black box write will begin, and the more energy available in the decoupling capacitors to ensure it completes successfully. Provided the VH supply, or another supply connected to a VPx pin, remains above 3.0 V during the time to write, the entire fault record would always be written to EEPROM. In many cases, there will be sufficient decoupling capacitors on a board to power the ADM1166 as it writes into EEPROM. In cases where the decoupling capacitors are not able to supply sufficient energy for a complete fault record to be written after the board is removed, the value of the capacitor on VDDCAP may be increased. In the worst case, assuming that no energy is supplied to the ADM1166 by external decoupling capacitors, but that the VDDCAP capacitor has 4.75 V across it at the start of the black box write to EEPROM, then a VDDCAP of 68 μF is sufficient to guarantee a single complete black box record can be written to EEPROM. To avoid the fault recorder filling up and fault records being lost, an application can periodically poll the ADM1166 to determine if there Rev. 0 | Page 20 of 32 ADM1166 VOLTAGE READBACK The ADM1166 has an on-board, 12-bit accurate ADC for voltage readback over the SMBus. The ADC has a 12-channel analog mux on the front end. The 12 channels consist of the 10 SFD inputs (VH, VPx, and VXx) and two auxiliary (singleended) ADC inputs (AUX1 and AUX2). Any or all of these inputs can be selected to be read, in turn, by the ADC. The circuit controlling this operation is called the round-robin circuit. This circuit can be selected to run through its loop of conversions once or continuously. Averaging is also provided for each channel. In this case, the round-robin circuit runs through its loop of conversions 16 times before returning a result for each channel. At the end of this cycle, the results are written to the output registers. The ADC samples single-sided inputs with respect to the AGND pin. A 0 V input gives out Code 0, and an input equal to the voltage on REFIN gives out full code (4095 decimal). The inputs to the ADC come directly from the VXx pins and from the back of the input attenuators on the VPx and VH pins, as shown in Figure 30 and Figure 31. DIGITIZED VOLTAGE READING NO ATTENUATION 09332-025 12-BIT ADC VXx 2.048V VREF ATTENUATION NETWORK (DEPENDS ON RANGE SELECTED) DIGITIZED VOLTAGE READING 09332-026 12-BIT ADC 2.048V VREF Figure 31. ADC Reading on VPx/VH Pins The voltage at the input pin can be derived from the following equation: V= ADC Code 4095 SFD Input Range (V) 0.573 to 1.375 1.25 to 3.00 2.5 to 6.0 6.0 to 14.4 1 Attenuation Factor 1 2.181 4.363 10.472 ADC Input Voltage Range (V) 0 to 2.048 0 to 4.46 0 to 6.01 0 to 14.41 The upper limit is the absolute maximum allowed voltage on the VPx and VH pins. The typical way to supply the reference to the ADC on the REFIN pin is to connect the REFOUT pin to the REFIN pin. REFOUT provides a 2.048 V reference. As such, the supervising range covers less than half the normal ADC range. It is possible, however, to provide the ADC with a more accurate external reference for improved readback accuracy. Supplies can also be connected to the input pins purely for ADC readback, even though these pins may go above the expected supervisory range limits (but not above the absolute maximum ratings on these pins). For example, a 1.5 V supply connected to the VX1 pin can be correctly read out as an ADC code of approximately 3/4 full scale, but it always sits above any supervisory limits that can be set on that pin. The maximum setting for the REFIN pin is 2.048 V. SUPPLY SUPERVISION WITH THE ADC Figure 30. ADC Reading on VXx Pins VPx/VH Table 9. ADC Input Voltage Ranges × Attenuation Factor × VREFIN where VREFIN = 2.048 V when the internal reference is used (that is, the REFIN pin is connected to the REFOUT pin). The ADC input voltage ranges for the SFD input ranges are listed in Table 9. In addition to the readback capability, another level of supervision is provided by the on-chip 12-bit ADC. The ADM1166 has limit registers with which the user can program a maximum or minimum allowable threshold. Exceeding the threshold generates a warning that can either be read back from the status registers or input into the SE to determine what sequencing action the ADM1166 should take. Only one register is provided for each input channel. Therefore, either an undervoltage threshold or overvoltage threshold (but not both) can be set for a given channel. The round-robin circuit can be enabled via a SMBus write, or it can be programmed to turn on in any state in the SE program. For example, it can be set to start after a power-up sequence is complete and all supplies are known to be within expected tolerance limits. Note that latency is built into this supervision, dictated by the conversion time of the ADC. With all 12 channels selected, the total time for the round-robin operation (averaging off) is approximately 6 ms (500 μs per channel selected). Supervision using the ADC, therefore, does not provide the same real-time response as the SFDs. Rev. 0 | Page 21 of 32 ADM1166 SUPPLY MARGINING fall to compensate for this. The dc-to-dc converter output can be forced high by setting the DACx output voltage lower than the feedback node voltage. The series resistor can be split in two, and the node between them can be decoupled with a capacitor to ground. This can help to decouple any noise picked up from the board. Decoupling to a ground local to the dc-to-dc converter is recommended. OVERVIEW It is often necessary for the system designer to adjust supplies, either to optimize their level or force them away from nominal values to characterize the system performance under these conditions. This is a function typically performed during an in-circuit test (ICT), such as when a manufacturer wants to guarantee that a product under test functions correctly at nominal supplies minus 10%. The ADM1166 can be commanded to margin a supply up or down over the SMBus by updating the values on the relevant DAC output. OPEN-LOOP SUPPLY MARGINING The simplest method of margining a supply is to implement an open-loop technique (see Figure 32). A popular way to do this is to switch extra resistors into the feedback node of a power module, such as a dc-to-dc converter or LDO. The extra resistor alters the voltage at the feedback or trim node and forces the output voltage to margin up or down by a certain amount. CLOSED-LOOP SUPPLY MARGINING A more accurate and comprehensive method of margining is to implement a closed-loop system (see Figure 33). The voltage on the rail to be margined can be read back to accurately margin the rail to the target voltage. The ADM1166 incorporates all the circuits required to do this, with the 12-bit successive approximation ADC used to read back the level of the supervised voltages, and the six voltage output DACs, implemented as described in the OpenLoop Supply Margining section, used to adjust supply levels. These circuits can be used along with other intelligence, such as a microcontroller, to implement a closed-loop margining system that allows any dc-to-dc converter or LDO supply to be set to any voltage, accurate to within ±0.5% of the target. The ADM1166 can perform open-loop margining for up to six supplies. The six on-board voltage DACs (DAC1 to DAC6) can drive into the feedback pins of the power modules to be margined. The simplest circuit to implement this function is an attenuation resistor that connects the DACx pin to the feedback node of a dc-to-dc converter. When the DACx output voltage is set equal to the feedback voltage, no current flows into the attenuation resistor, and the dc-to-dc converter output voltage does not change. Taking DACx above the feedback voltage forces current into the feedback node, and the output of the dc-to-dc converter is forced to VIN MICROCONTROLLER VOUT ADM1166 DEVICE CONTROLLER (SMBus) OUTPUT ATTENUATION RESISTOR, R3 R1 DACx FEEDBACK R2 DAC PCB TRACE NOISE DECOUPLING CAPACITOR GND 09332-067 DC-TO-DC CONVERTER Figure 32. Open-Loop Margining System Using the ADM1166 MICROCONTROLLER VIN ADM1166 VH/VPx/VXx MUX ATTENUATION RESISTOR, R3 OUTPUT ADC R1 DACx FEEDBACK R2 GND DAC DEVICE CONTROLLER (SMBus) PCB TRACE NOISE DECOUPLING CAPACITOR Figure 33. Closed-Loop Margining System Using the ADM1166 Rev. 0 | Page 22 of 32 09332-034 DC-TO-DC CONVERTER ADM1166 To implement closed-loop margining, 1. Disable the six DACx outputs. 2. Set the DAC output voltage equal to the voltage on the feedback node. 3. Enable the DAC. 4. Read the voltage at the dc-to-dc converter output that is connected to one of the VPx, VH, or VXx pins. 5. If necessary, modify the DACx output code up or down to adjust the dc-to-dc converter output voltage. Otherwise, stop because the target voltage has been reached. 6. Set the DAC output voltage to a value that alters the supply output by the required amount (for example, ±5%). 7. Repeat Step 4 through Step 6 until the measured supply reaches the target voltage. Step 1 to Step 3 ensures that when the DACx output buffer is turned on, it has little effect on the dc-to-dc converter output. The DAC output buffer is designed to power up without glitching by first powering up the buffer to follow the pin voltage. It does not drive out onto the pin at this time. Once the output buffer is properly enabled, the buffer input is switched over to the DAC, and the output stage of the buffer is turned on. Output glitching is negligible. WRITING TO THE DACS Four DAC ranges are offered. They can be placed with midcode (Code 0x7F) at 0.6 V, 0.8 V, 1.0 V, and 1.25 V. These voltages are placed to correspond to the most common feedback voltages. Centering the DAC outputs in this way provides the best use of the DAC resolution. For most supplies, it is possible to place the DAC midcode at the point where the dc-to-dc converter output is not modified, thereby giving half of the DAC range to margin up and the other half to margin down. The DAC output voltage is set by the code written to the DACx register. The voltage is linear with the unsigned binary number in this register. Code 0x7F is placed at the midcode voltage, as described previously. The output voltage is given by DAC Output = (DACx − 0x7F)/255 × 0.6015 + VOFF where VOFF is one of the four offset voltages. There are 256 DAC settings available. The midcode value is located at DAC Code 0x7F as close as possible to the middle of the 256 code range. The full output swing of the DACs is +302 mV (+128 codes) and −300 mV (−127 codes) around the selected midcode voltage. The voltage range for each midcode voltage is shown in Table 10. Table 10. Ranges for Midcode Voltages Midcode Voltage (V) 0.6 0.8 1.0 1.25 Minimum Voltage Output (V) 0.300 0.500 0.700 0.950 Maximum Voltage Output (V) 0.902 1.102 1.302 1.552 CHOOSING THE SIZE OF THE ATTENUATION RESISTOR The size of the attenuation resistor, R3, determines how much the DAC voltage swing affects the output voltage of the dc-to-dc converter that is being margined (see Figure 33). Because the voltage at the feedback pin remains constant, the current flowing from the feedback node to GND through R2 is a constant. In addition, the feedback node itself is high impedance. This means that the current flowing through R1 is the same as the current flowing through R3. Therefore, a direct relationship exists between the extra voltage drop across R1 during margining and the voltage drop across R3. This relationship is given by the following equation: ΔVOUT = R1 (VFB − VDACOUT) R3 where: ΔVOUT is the change in VOUT. VFB is the voltage at the feedback node of the dc-to-dc converter. VDACOUT is the voltage output of the margining DAC. This equation demonstrates that if the user wants the output voltage to change by ±300 mV, then R1 = R3. If the user wants the output voltage to change by ±600 mV, R1 = 2 × R3, and so on. It is best to use the full DAC output range to margin a supply. Choosing the attenuation resistor in this way provides the most resolution from the DAC, meaning that with one DAC code change, the smallest effect on the dc-to-dc converter output voltage is induced. If the resistor is sized up to use a code such as 27 decimal to 227 decimal to move the dc-to-dc converter output by ±5%, it takes 100 codes to move 5% (each code moves the output by 0.05%). This is beyond the readback accuracy of the ADC, but it should not prevent the user from building a circuit to use the most resolution. DAC LIMITING AND OTHER SAFETY FEATURES Limit registers (called DPLIMx and DNLIMx) on the device offer the user some protection from firmware bugs that can cause catastrophic board problems by forcing supplies beyond their allowable output ranges. Essentially, the DAC code written into the DACx register is clipped such that the code used to set the DAC voltage is given by DAC Code = DACx, = DNLIMx, = DPLIMx, DACx ≥ DNLIMx and DACx ≤ DPLIMx DACx < DNLIMx DACx > DPLIMx In addition, the DAC output buffer is three-stated if DNLIMx > DPLIMx. By programming the limit registers this way, the user can make it very difficult for the DAC output buffers to be turned on during normal system operation. The limit registers are among the registers downloaded from EEPROM at startup. Rev. 0 | Page 23 of 32 ADM1166 APPLICATIONS DIAGRAM 12V IN 12V OUT 5V IN 5V OUT 3V IN 3V OUT IN DC-TO-DC1 EN VH 5V OUT 3V OUT 3.3V OUT 2.5V OUT 1.8V OUT 1.2V OUT 0.9V OUT POWRON OUT 3.3V OUT ADM1166 VP1 VP2 VP3 VP4 VX1 VX2 VX3 PDO1 PDO2 VX4 PDO6 IN DC-TO-DC2 PDO3 PDO4 PDO5 PDO7 RESET EN SIGNAL VALID IN DC-TO-DC3 PDO8 EN PDO9 PDO10 REFOUT 2.5V OUT PWRGD SYSTEM RESET VX5 OUT OUT 1.8V OUT 3.3V OUT DAC1* IN REFIN VCCP VDDCAP GND LDO 10µF EN 10µF OUT 0.9V OUT 3.3V OUT *ONLY ONE MARGINING CIRCUIT SHOWN FOR CLARITY. DAC1 TO DAC6 ALLOW MARGINING FOR UP TO SIX VOLTAGE RAILS. IN OUT EN DC-TO-DC4 Figure 34. Applications Diagram Rev. 0 | Page 24 of 32 1.2V OUT TRIM 09332-068 10µF ADM1166 COMMUNICATING WITH THE ADM1166 CONFIGURATION DOWNLOAD AT POWER-UP Option 1 The configuration of the ADM1166 (undervoltage/overvoltage thresholds, glitch filter timeouts, and PDO configurations) is dictated by the contents of the RAM. The RAM comprises digital latches that are local to each function on the device. The latches are double buffered and have two identical latches, Latch A and Latch B. Therefore, when an update to a function occurs, the contents of Latch A are updated first, and then the contents of Latch B are updated with identical data. The advantages of this architecture are explained in detail in the Updating the Configuration section. The two latches are volatile memory and lose their contents at power-down. Therefore, the configuration in the RAM must be restored at power-up by downloading the contents of the EEPROM (nonvolatile memory) to the local latches. This download occurs in steps, as follows: 1. With no power applied to the device, the PDOs are all high impedance. 2. When 1.2 V appears on any of the inputs connected to the VDD arbitrator (VH or VPx), the PDOs are all weakly pulled to GND with a 20 kΩ resistor. 3. When the supply rises above the undervoltage lockout of the device (UVLO is 2.5 V), the EEPROM starts to download to the RAM. 4. The EEPROM downloads its contents to all Latch As. 5. When the contents of the EEPROM are completely downloaded to the Latch As, the device controller signals all Latch As to download to all Latch Bs simultaneously, completing the configuration download. 6. At 0.5 ms after the configuration download completes, the first state definition is downloaded from the EEPROM into the SE. Note that any attempt to communicate with the device prior to the completion of the download causes the ADM1166 to issue a no acknowledge (NACK). Update the configuration in real time. The user writes to the RAM across the SMBus, and the configuration is updated immediately. Option 2 Update the Latch As without updating the Latch Bs. With this method, the configuration of the ADM1166 remains unchanged and continues to operate in the original setup until the instruction is given to update the Latch Bs. Option 3 Change the EEPROM register contents without changing the RAM contents, and then download the revised EEPROM contents to the RAM registers. With this method, the configuration of the ADM1166 remains unchanged and continues to operate in the original setup until the instruction is given to update the RAM. The instruction to download from the EEPROM in Option 3 is also a useful way to restore the original EEPROM contents if revisions to the configuration are unsatisfactory. For example, if the user needs to alter an overvoltage threshold, the RAM register can be updated as described in the Option 1 section. However, if the user is not satisfied with the change and wants to revert to the original programmed value, the device controller can issue a command to download the EEPROM contents to the RAM again, as described in the Option 3 section, restoring the ADM1166 to its original configuration. The topology of the ADM1166 makes this type of operation possible. The local, volatile registers (RAM) are all doublebuffered latches. Setting Bit 0 of the UPDCFG register to 1 leaves the double-buffered latches open at all times. If Bit 0 is set to 0 when a RAM write occurs across the SMBus, only the first side of the double-buffered latch is written to. The user must then write a 1 to Bit 1 of the UPDCFG register. This generates a pulse to update all the second latches at once. EEPROM writes occur in a similar way. The final bit in this register can enable or disable EEPROM page erasure. If this bit is set high, the contents of an EEPROM page can all be set to 1. If this bit is set low, the contents of a page cannot be erased, even if the command code for page erasure is programmed across the SMBus. The bit map for the UPDCFG register is shown in the AN-698 Application Note. A flow diagram for download at power-up and subsequent configuration updates is shown in Figure 35. UPDATING THE CONFIGURATION After power-up, with all the configuration settings loaded from the EEPROM into the RAM registers, the user may need to alter the configuration of functions on the ADM1166, such as changing the undervoltage or overvoltage limit of an SFD, changing the fault output of an SFD, or adjusting the rise time delay of one of the PDOs. The ADM1166 provides several options that allow the user to update the configuration over the SMBus interface. The following three options are controlled in the UPDCFG register. SMBus E E P R O M L D DEVICE CONTROLLER R A M L D D A T A U P D LATCH A LATCH B EEPROM Figure 35. Configuration Update Flow Diagram Rev. 0 | Page 25 of 32 FUNCTION (OV THRESHOLD ON VP1) 09332-035 POWER-UP (VCC > 2.5V) ADM1166 UPDATING THE SEQUENCING ENGINE Sequencing engine (SE) functions are not updated in the same way as regular configuration latches. The SE has its own dedicated 512-byte nonvolatile, electrically erasable, programmable, readonly memory (EEPROM) for storing state definitions, providing 63 individual states each with a 64-bit word (one state is reserved). At power-up, the first state is loaded from the SE EEPROM into the engine itself. When the conditions of this state are met, the next state is loaded from the EEPROM into the engine, and so on. The loading of each new state takes approximately 10 μs. To alter a state, the required changes must be made directly to the EEPROM. RAM for each state does not exist. The relevant alterations must be made to the 64-bit word, which is then uploaded directly to the EEPROM. INTERNAL REGISTERS The ADM1166 contains a large number of data registers. The principal registers are the address pointer register and the configuration registers. Address Pointer Register The address pointer register contains the address that selects one of the other internal registers. When writing to the ADM1166, the first byte of data is always a register address that is written to the address pointer register. Configuration Registers The configuration registers provide control and configuration for various operating parameters of the ADM1166. EEPROM The ADM1166 has two 512-byte cells of nonvolatile EEPROM from Address 0xF800 to Address 0xFBFF. The EEPROM is used for permanent storage of data that is not lost when the ADM1166 is powered down. One EEPROM cell, 0xF800 to 0xF9FF, contains the configuration data, user information and, if enabled, any fault records of the device; the other section, 0xFA00 to 0xFBFF, contains the state definitions for the SE. Although referred to as read-only memory, the EEPROM can be written to, as well as read from, using the serial bus in exactly the same way as the other registers. The major differences between the EEPROM and other registers are as follows: • • • Page 8 to Page 11 are available for customer use to store any information that may be required by the customer in their application. Customers can store information on Page 12 to Page 15, or these pages can store the fault records written by the sequencing engine if users have decided to enable writing of the fault records for different states. Data can be downloaded from the EEPROM to the RAM in one of the following ways: • • At power-up, when Page 0 to Page 4 are downloaded. By setting Bit 0 of the UDOWNLD register (0xD8), which performs a user download of Page 0 to Page 4. When the sequence engine is enabled, it is not possible to access the section of EEPROM from Address 0xFA00 to Address 0xFBFF. The sequence engine must be halted before it is possible to read or write to this range. Attempting to read or write to this range if the sequence engine is not halted will generate a no acknowledge, or NACK. Read/write access to the configuration and user EEPROM ranges from Address 0xF800 to Address 0xF89F and Address 0xF900 to Address 0xF9FF depends on whether the black box fault recorder is enabled. If the fault recorder is enabled and one or more states have been set as fault record trigger states, then it is not possible to access any EEPROM location in this range without first halting the black box. Attempts to read or write this EEPROM range while the fault recorder is operating are acknowledged by the device but do not return any useful data or modify the EEPROM in any way. If none of the states are set as fault record trigger states, then the black box is considered disabled, and read/write access is allowed without having to halt the black box fault recorder. SERIAL BUS INTERFACE The ADM1166 is controlled via the serial system management bus (SMBus) and is connected to this bus as a slave device under the control of a master device. It takes approximately 1 ms after power-up for the ADM1166 to download from its EEPROM. Therefore, access to the ADM1166 is restricted until the download is complete. Identifying the ADM1166 on the SMBus An EEPROM location must be blank before it can be written to. If it contains data, the data must first be erased. Writing to the EEPROM is slower than writing to the RAM. Writing to the EEPROM should be restricted because it has a limited write/cycle life of typically 10,000 write operations due to the usual EEPROM wear-out mechanisms. The first EEPROM is split into 16 (0 to 15) pages of 32 bytes each. Page 0 to Page 3, from Address 0xF800 to Address 0xF89F, hold the configuration data for the applications on the ADM1166 (such as the SFDs and PDOs). These EEPROM addresses are the same as the RAM register addresses, prefixed by F8. Page 5 to Page 7, from Address 0xF8A0 to Address 0xF8FF, are reserved. The ADM1166 has a 7-bit serial bus slave address (see Table 11). The device is powered up with a default serial bus address. The five MSBs of the address are set to 01101; the two LSBs are determined by the logical states of Pin A1 and Pin A0. This allows the connection of four ADM1166s to one SMBus. Table 11. Serial Bus Slave Address A1 Pin Low Low High High 1 A0 Pin Low High Low High Hex Address 0x68 0x6A 0x6C 0x6E 7-Bit Address1 0110100x 0110101x 0110110x 0110111x x = Read/write bit. The address is shown only as the first 7 MSBs. Rev. 0 | Page 26 of 32 ADM1166 The device also has several identification registers (read-only) that can be read across the SMBus. Table 12 lists these registers with their values and functions. Table 12. Identification Register Values and Functions Name MANID Address 0xF4 Value 0x41 REVID MARK1 MARK2 0xF5 0xF6 0xF7 0x02 0x00 0x00 All other devices on the bus remain idle while the selected device waits for data to be read from or written to it. If the R/W bit is a 0, the master writes to the slave device. If the R/W bit is a 1, the master reads from the slave device. Data is sent over the serial bus in sequences of nine clock pulses: eight bits of data followed by an acknowledge bit from the slave device. Data transitions on the data line must occur during the low period of the clock signal and remain stable during the high period because a low-to-high transition when the clock is high could be interpreted as a stop signal. If the operation is a write operation, the first data byte after the slave address is a command byte. This command byte tells the slave device what to expect next. It may be an instruction telling the slave device to expect a block write, or it may be a register address that tells the slave where subsequent data is to be written. Because data can flow in only one direction, as defined by the R/W bit, sending a command to a slave device during a read operation is not possible. Before a read operation, it may be necessary to perform a write operation to tell the slave what sort of read operation to expect and/or the address from which data is to be read. When all data bytes have been read or written, stop conditions are established. In write mode, the master pulls the data line high during the 10th clock pulse to assert a stop condition. In read mode, the master device releases the SDA line during the low period before the ninth clock pulse, but the slave device does not pull it low. This is known as a no acknowledge. The master then takes the data line low during the low period before the 10th clock pulse and then high during the 10th clock pulse to assert a stop condition. 2. Function Manufacturer ID for Analog Devices Silicon revision Software brand Software brand General SMBus Timing Figure 36, Figure 37, and Figure 38 are timing diagrams for general read and write operations using the SMBus. The SMBus specification defines specific conditions for different types of read and write operations, which are discussed in the Write Operations and the Read Operations sections. The general SMBus protocol operates in the following three steps. The master initiates data transfer by establishing a start condition, defined as a high-to-low transition on the serial data line SDA, while the serial clock line SCL remains high. This indicates that a data stream follows. All slave peripherals connected to the serial bus respond to the start condition and shift in the next eight bits, consisting of a 7-bit slave address (MSB first) plus an R/W bit. This bit determines the direction of the data transfer, that is, whether data is written to or read from the slave device (0 = write, 1 = read). The peripheral whose address corresponds to the transmitted address responds by pulling the data line low during the low period before the ninth clock pulse, known as the acknowledge bit, and by holding it low during the high period of this clock pulse. 1 9 3. 1 9 SCL 0 SDA 1 1 0 1 A1 A0 D7 R/W D6 D5 D4 D3 D2 D1 ACK. BY SLAVE START BY MASTER D0 ACK. BY SLAVE FRAME 1 SLAVE ADDRESS FRAME 2 COMMAND CODE 1 9 1 9 SCL (CONTINUED) SDA (CONTINUED) D7 D6 D5 D4 D3 D2 FRAME 3 DATA BYTE D1 D0 D7 ACK. BY SLAVE D6 D5 D4 D2 FRAME N DATA BYTE Figure 36. General SMBus Write Timing Diagram Rev. 0 | Page 27 of 32 D3 D1 D0 ACK. BY SLAVE STOP BY MASTER 09332-036 1. ADM1166 1 9 1 9 SCL 0 SDA 1 1 0 1 A1 A0 R/W D7 D6 D5 D4 D3 D2 D1 ACK. BY SLAVE START BY MASTER 1 FRAME 1 SLAVE ADDRESS D0 ACK. BY MASTER 9 FRAME 2 DATA BYTE 1 9 SCL (CONTINUED) D7 D6 D5 D4 D3 D2 D1 D0 D7 D6 D5 ACK. BY MASTER FRAME 3 DATA BYTE D4 D3 D2 D1 D0 STOP BY MASTER NO ACK. FRAME N DATA BYTE 09332-037 SDA (CONTINUED) Figure 37. General SMBus Read Timing Diagram tR tF t HD; S TA t LO W t HI G H t HD; S TA t HD; D AT t SU; S TA t SU; S TO t SU; D AT SDA t BUF P S S P 09332-038 SCL Figure 38. Serial Bus Timing Diagram SMBus PROTOCOLS FOR RAM AND EEPROM The ADM1166 contains volatile registers (RAM) and nonvolatile registers (EEPROM). User RAM occupies Address 0x00 to Address 0xDF, and the EEPROM occupies Address 0xF800 to Address 0xFBFF. Data can be written to and read from both the RAM and the EEPROM as single data bytes. Data can be written only to unprogrammed EEPROM locations. To write new data to a programmed location, the location contents must first be erased. EEPROM erasure cannot be done at the byte level. The EEPROM is arranged as 32 pages of 32 bytes each, and an entire page must be erased. Page erasure is enabled by setting Bit 2 in the UPDCFG register (Address 0x90) to 1. If this bit is not set, page erasure cannot occur, even if the command byte (0xFE) is programmed across the SMBus. Rev. 0 | Page 28 of 32 ADM1166 The SMBus specification defines several protocols for different types of read and write operations. The following abbreviations are used in Figure 39 to Figure 47: S = Start P = Stop R = Read W = Write A = Acknowledge A = No acknowledge In a send byte operation, the master device sends a single command byte to a slave device, as follows: The master device asserts a start condition on SDA. The master sends the 7-bit slave address followed by the write bit (low). The addressed slave device asserts an acknowledge (ACK) on SDA. The master sends a command code. The slave asserts an ACK on SDA. The master asserts a stop condition on SDA, and the transaction ends. In the ADM1166, the send byte protocol is used for two purposes: To write a register address to the RAM for a subsequent single byte read from the same address, or for a block read or block write starting at that address, as shown in Figure 39. 1 2 S SLAVE ADDRESS W 3 4 5 6 A RAM ADDRESS (0x00 TO 0xDF) A P 09332-039 • 5 6 A A P Write Byte/Word In a write byte/word operation, the master device sends a command byte and one or two data bytes to the slave device, as follows: 1. 2. The master device asserts a start condition on SDA. The master sends the 7-bit slave address followed by the write bit (low). 3. The addressed slave device asserts an ACK on SDA. 4. The master sends a command code. 5. The slave asserts an ACK on SDA. 6. The master sends a data byte. 7. The slave asserts an ACK on SDA. 8. The master sends a data byte or asserts a stop condition. 9. The slave asserts an ACK on SDA. 10. The master asserts a stop condition on SDA to end the transaction. In the ADM1166, the write byte/word protocol is used for three purposes: Figure 39. Setting a RAM Address for Subsequent Read • W 4 COMMAND BYTE (0xFE) To erase a page of EEPROM memory. EEPROM memory can be written to only if it is unprogrammed. Before writing to one or more EEPROM memory locations that are already programmed, the page(s) containing those locations must first be erased. EEPROM memory is erased by writing a command byte. • To write a single byte of data to the RAM. In this case, the command byte is RAM Address 0x00 to RAM Address 0xDF, and the only data byte is the actual data, as shown in Figure 41. 1 2 3 SLAVE S W A ADDRESS 4 5 6 7 8 RAM ADDRESS A DATA A P (0x00 TO 0xDF) Figure 41. Single Byte Write to the RAM • To set up a 2-byte EEPROM address for a subsequent read, write, block read, block write, or page erase. In this case, the command byte is the high byte of EEPROM Address 0xF8 to EEPROM Address 0xFB. The only data byte is the low byte of the EEPROM address, as shown in Figure 42. 1 2 3 S SLAVE W A ADDRESS 4 5 6 Figure 42. Setting an EEPROM Address Rev. 0 | Page 29 of 32 7 8 EEPROM EEPROM ADDRESS ADDRESS A A P LOW BYTE HIGH BYTE (0x00 TO 0xFF) (0xF8 TO 0xFB) 09332-042 4. 5. 6. S 3 As soon as the ADM1166 receives the command byte, page erasure begins. The master device can send a stop command as soon as it sends the command byte. Page erasure takes approximately 20 ms. If the ADM1166 is accessed before erasure is complete, it responds with a no acknowledge (NACK). Send Byte 3. 2 SLAVE ADDRESS Figure 40. EEPROM Page Erasure The ADM1166 uses the following SMBus write protocols. 1. 2. 1 09332-041 • • • • • • 09332-040 The master sends a command code telling the slave device to erase the page. The ADM1166 command code for a page erasure is 0xFE (1111 1110). Note that for a page erasure to take place, the page address must be given in the previous write word transaction (see the Write Byte/Word section). In addition, Bit 2 in the UPDCFG register (Address 0x90) must be set to 1. WRITE OPERATIONS ADM1166 Because a page consists of 32 bytes, only the three MSBs of the address low byte are important for page erasure. The lower five bits of the EEPROM address low byte specify the addresses within a page and are ignored during an erase operation. • Unlike some EEPROM devices that limit block writes to within a page boundary, there is no limitation on the start address when performing a block write to EEPROM, except when • To write a single byte of data to the EEPROM. In this case, the command byte is the high byte of EEPROM Address 0xF8 to EEPROM Address 0xFB. The first data byte is the low byte of the EEPROM address, and the second data byte is the actual data, as shown in Figure 43. 2 3 4 5 6 7 8 • Note that the ADM1166 features a clock extend function for writes to the EEPROM. Programming an EEPROM byte takes approximately 250 μs, which limits the SMBus clock for repeated or block write operations. The ADM1166 pulls SCL low and extends the clock pulse when it cannot accept any more data. 9 10 EEPROM EEPROM ADDRESS ADDRESS A A DATA A P S SLAVE W A LOW BYTE HIGH BYTE ADDRESS (0x00 TO 0xFF) (0xF8 TO 0xFB) 09332-043 1 There must be at least N locations from the start address to the highest EEPROM address (0xFBFF) to avoid writing to invalid addresses. An address crosses a page boundary. In this case, both pages must be erased before programming. Figure 43. Single Byte Write to the EEPROM READ OPERATIONS Block Write The ADM1166 uses the following SMBus read protocols. In a block write operation, the master device writes a block of data to a slave device. The start address for a block write must have been set previously. In the ADM1166, a send byte operation sets a RAM address, and a write byte/word operation sets an EEPROM address, as follows: Receive Byte In a receive byte operation, the master device receives a single byte from a slave device, as follows: 1. 2. The master device asserts a start condition on SDA. The master sends the 7-bit slave address followed by the write bit (low). 3. The addressed slave device asserts an ACK on SDA. 4. The master sends a command code that tells the slave device to expect a block write. The ADM1166 command code for a block write is 0xFC (1111 1100). 5. The slave asserts an ACK on SDA. 6. The master sends a data byte that tells the slave device how many data bytes are being sent. The SMBus specification allows a maximum of 32 data bytes in a block write. 7. The slave asserts an ACK on SDA. 8. The master sends N data bytes. 9. The slave asserts an ACK on SDA after each data byte. 10. The master asserts a stop condition on SDA to end the transaction. 1. 2. 2 3 4 3. 4. 5. 6. 1 2 S SLAVE ADDRESS R 3 4 5 6 A DATA A P 09332-045 In the ADM1166, the receive byte protocol is used to read a single byte of data from a RAM or EEPROM location whose address has previously been set by a send byte or write byte/word operation, as shown in Figure 44. Figure 44. Single Byte Read from the EEPROM or RAM 5 6 7 8 9 10 SLAVE COMMAND 0xFC BYTE DATA DATA DATA A A A P S ADDRESS W A (BLOCK WRITE) A COUNT A 1 2 N Figure 45. Block Write to the EEPROM or RAM Rev. 0 | Page 30 of 32 09332-044 1 The master device asserts a start condition on SDA. The master sends the 7-bit slave address followed by the read bit (high). The addressed slave device asserts an ACK on SDA. The master receives a data byte. The master asserts a NACK on SDA. The master asserts a stop condition on SDA, and the transaction ends. ADM1166 Block Read Error Correction In a block read operation, the master device reads a block of data from a slave device. The start address for a block read must have been set previously. In the ADM1166, this is done by a send byte operation to set a RAM address, or a write byte/word operation to set an EEPROM address. The block read operation itself consists of a send byte operation that sends a block read command to the slave, immediately followed by a repeated start and a read operation that reads out multiple data bytes, as follows: The ADM1166 provides the option of issuing a packet error correction (PEC) byte after a write to the RAM, a write to the EEPROM, a block write to the RAM/EEPROM, or a block read from the RAM/EEPROM. This option enables the user to verify that the data received by or sent from the ADM1166 is correct. The PEC byte is an optional byte sent after the last data byte has been written to or read from the ADM1166. The protocol is the same as a block read for Step 1 to Step 12 and then proceeds as follows: The master device asserts a start condition on SDA. The master sends the 7-bit slave address followed by the write bit (low). The addressed slave device asserts an ACK on SDA. The master sends a command code that tells the slave device to expect a block read. The ADM1166 command code for a block read is 0xFD (1111 1101). The slave asserts an ACK on SDA. The master asserts a repeat start condition on SDA. The master sends the 7-bit slave address followed by the read bit (high). The slave asserts an ACK on SDA. The ADM1166 sends a byte-count data byte that tells the master how many data bytes to expect. The ADM1166 always returns 32 data bytes (0x20), which is the maximum allowed by the SMBus Version 1.1 specification. The master asserts an ACK on SDA. The master receives 32 data bytes. The master asserts an ACK on SDA after each data byte. The master asserts a stop condition on SDA to end the transaction. 13. The ADM1166 issues a PEC byte to the master. The master checks the PEC byte and issues another block read, if the PEC byte is incorrect. 14. A NACK is generated after the PEC byte to signal the end of the read. 15. The master asserts a stop condition on SDA to end the transaction. 5. 6. 7. 8. 9. 10. 11. 12. 13. 1 S 2 3 4 Note that the PEC byte is calculated using CRC-8. The frame check sequence (FCS) conforms to CRC-8 by the polynomial C(x) = x8 + x2 + x1 + 1 See the SMBus Version 1.1 specification for details. An example of a block read with the optional PEC byte is shown in Figure 47. 5 6 7 8 9 10 11 12 SLAVE W A COMMAND 0xFD A S SLAVE R A BYTE A DATA A ADDRESS (BLOCK READ) ADDRESS COUNT 1 13 DATA A 32 P 09332-046 3. 4. Figure 46. Block Read from the EEPROM or RAM 1 S 2 3 4 5 6 7 8 9 10 11 12 SLAVE W A COMMAND 0xFD A S SLAVE R A BYTE A DATA A ADDRESS (BLOCK READ) ADDRESS COUNT 1 13 14 15 DATA 32 A PEC A P Figure 47. Block Read from the EEPROM or RAM with PEC Rev. 0 | Page 31 of 32 09332-047 1. 2. ADM1166 OUTLINE DIMENSIONS 6.10 6.00 SQ 5.90 31 1 0.50 BSC TOP VIEW 0.80 0.75 0.70 4.60 SQ 4.50 10 11 20 BOTTOM VIEW 0.20 MIN FOR PROPER CONNECTION OF THE EXPOSED PAD, REFER TO THE PIN CONFIGURATION AND FUNCTION DESCRIPTIONS SECTION OF THIS DATA SHEET. 0.05 MAX 0.02 NOM COPLANARITY 0.08 0.20 REF SEATING PLANE *4.70 EXPOSED PAD 21 0.45 0.40 0.35 PIN 1 INDICATOR 40 30 02-02-2010-A PIN 1 INDICATOR 0.30 0.25 0.18 COMPLIANT TO JEDEC STANDARDS MO-220-WJJD-5 WITH EXCEPTION TO EXPOSED PAD DIMENSION. Figure 48. 40-Lead Lead Frame Chip Scale Package [LFCSP_WQ] 6 mm × 6 mm Body, Very Thin Quad (CP-40-7) Dimensions shown in millimeters 0.75 0.60 0.45 1.20 MAX 9.00 BSC SQ 37 36 48 1 PIN 1 1.05 1.00 0.95 0.15 0.05 SEATING PLANE 0.20 0.09 7° 3.5° 0° 0.08 MAX COPLANARITY 7.00 BSC SQ TOP VIEW 0° MIN (PINS DOWN) 12 13 25 24 VIEW A VIEW A 0.50 0.27 BSC 0.22 LEAD PITCH 0.17 ROTATED 90° CCW COMPLIANT TO JEDEC STANDARDS MS-026ABC Figure 49. 48-Lead Thin Plastic Quad Flat Package [TQFP] (SU-48) Dimensions shown in millimeters ORDERING GUIDE Model 1 ADM1166ACPZ ADM1166ACPZ-REEL ADM1166ASUZ ADM1166ASUZ-REEL EVAL-ADM1166TQEBZ 1 Temperature Range −40°C to +85°C −40°C to +85°C −40°C to +85°C −40°C to +85°C Package Description 40-Lead Lead Frame Chip Scale Package [LFCSP_WQ] 40-Lead Lead Frame Chip Scale Package [LFCSP_WQ] 48-Lead Thin Plastic Quad Flat Package [TQFP] 48-Lead Thin Plastic Quad Flat Package [TQFP] Evaluation Kit [TQFP] Z = RoHS Compliant Part. ©2010 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D09332-0-12/10(0) Rev. 0 | Page 32 of 32 Package Option CP-40-7 CP-40-7 SU-48 SU-48