Rad-Hard, 5.0V/3.3V µ-Processor Supervisory Circuits ISL705ARH, ISL705BRH, ISL705CRH, ISL706ARH, ISL706BRH, ISL706CRH This family of devices are radiation hardened 5.0V/3.3V supervisory circuits that reduce the complexity required to monitor supply voltages in microprocessor systems. These devices significantly improve accuracy and reliability relative to discrete solutions. Each IC provides four key functions. 1. A reset output during power-up, power-down, and brownout conditions. 2. An independent watchdog output that goes low if the watchdog input has not been toggled within 1.6s. 3. A precision threshold detector for monitoring a power supply other than VDD. 4. An active-low manual-reset input. Specifications for Rad Hard QML devices are controlled by the Defense Supply Center in Columbus (DSCC). The SMD numbers listed in the “Ordering Information” table on page 3 must be used when ordering. Detailed Electrical Specifications for the ISL705ARH, ISL705BRH, ISL705CRH, ISL706ARH, ISL706BRH and ISL706CRH are contained in SMD 5962-11213. A “hot-link” is provided on our website for downloading. Features • Electrically Screened to SMD 5962-11213 • QML Qualified per MIL-PRF-38535 Requirements • Radiation Hardness - High Dose Rate. . . . . . . . . . . . . . . . . . . . . . . . . . 100krad(Si) - SEL/SEB LETTH . . . . . . . . . . . . . . . . . . . . . . 86MeV/mg/cm2 • Precision Supply Voltage Monitor - 4.65V Threshold in the ISL705ARH/BRH/CRH - 3.08V Threshold in the ISL706ARH/BRH/CRH • 200ms (Typ) Reset Pulse Width - Active High, Active Low and Open Drain Options • Independent Watchdog Timer with 1.6s (Typ) Timeout • Precision Threshold Detector - 1.25V Threshold in the ISL705ARH/BRH/CRH - 0.6V Threshold in the ISL706ARH/BRH/CRH • Debounced TTL/CMOS Compatible Manual-Reset Input • Reset Output Valid at VDD = 1.2V Applications Related Literature • Supervisor for µ-Processors, µ-Controllers, FPGAs and DSPs • ISL705RH Voltage Supervisory Circuit Evaluation Board User’s Guide • Critical Power Supply Monitoring • ISL706RH Voltage Supervisory Circuit Evaluation Board User’s Guide • Reliable Replacement of Discrete Solutions 5V POWER SUPPLY 1.4 VCC 49.9k WDO 8 NMI 2 VDD RST 7 RST 3 GND WDI 6 I/O 4 PFI PFO 5 1.2 ISL705xRH 1.0 µP VPFI (V) 165k 1 MR 0.8 0.6 0.4 ISL705ARH ISL706xRH 0.2 5V SUPERVISOR APPLICATION WITH OVERVOLTAGE PROTECTION 0 -80 -60 -40 -20 0 20 40 60 80 100 120 140 TEMPERATURE (°C) FIGURE 1. TYPICAL APPLICATION September 15, 2011 FN7662.0 1 FIGURE 2. PRECISION THRESHOLD DETECTOR TEMPERATURE CHARACTERISTICS CURVE CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. 1-888-INTERSIL or 1-888-468-3774 | Copyright Intersil Americas Inc. 2011. All Rights Reserved Intersil (and design) is a trademark owned by Intersil Corporation or one of its subsidiaries. All other trademarks mentioned are the property of their respective owners. ISL705ARH, ISL705BRH, ISL705CRH, ISL706ARH, ISL706BRH, ISL706CRH Pin Configurations ISL705BRH, ISL706BRH (8 LD FLATPACK) TOP VIEW ISL705ARH, ISL706ARH (8 LD FLATPACK) TOP VIEW MR 1 8 WDO RST VDD 2 7 6 WDI GND 3 5 PFO PFI 4 MR 1 8 WDO VDD 2 7 GND 3 PFI 4 ISL705CRH, ISL706CRH (8 LD FLATPACK) TOP VIEW MR 1 8 WDO RST VDD 2 7 RST_OD 6 WDI GND 3 6 WDI 5 PFO PFI 4 5 PFO Pin Descriptions ISL705ARH ISL706ARH ISL705BRH ISL706BRH ISL705CRH ISL706CRH NAME DESCRIPTION 1 1 1 MR Manual Reset. MR is an active-low, debounced, TTL/CMOS compatible input that may be used to trigger a reset pulse. 2 2 2 VDD Power Supply. VDD is a supply voltage input that provides power to all internal circuitry. This input is also monitored and used to trigger a reset pulse. Reset is guaranteed operable after VDD rises above 1.2V. 3 3 3 GND Ground. GND is a supply voltage return for all internal circuitry. This return establishes the reference level for voltage detection and should be connected to signal ground. 4 4 4 PFI Power Fail Input. PFI is an input to a threshold detector, which may be used to monitor another supply voltage level. The threshold of the detector (VPFI) is 1.25V in the ISL705ARH/BRH/CRH and 0.6V in the ISL706ARH/BRH/CRH. 5 5 5 PFO Power Fail Output. PFO is an active-low, push-pull output of a threshold detector that indicates the voltage at the PFI pin is less than VPFI. 6 6 6 WDI Watchdog Input. WDI is a tri-state input that monitors microprocessor activity. If the microprocessor does not toggle WDI within 1.6s and WDI is not tri-stated, WDO goes low. As long as reset is asserted or WDI is tri-stated, the watchdog timer will stay cleared and will not count. As soon as reset is released and WDI is driven high or low, the timer will start counting. Floating WDI or connecting WDI to a high impedance tri-state buffer disables the watchdog feature. 7 - - RST Reset. RST is an active-low, push-pull output that is guaranteed to be low once VDD reaches 1.2V. As VDD rises, RST stays low. When VDD rises above a 4.65V (ISL705ARH/BRH/CRH) or 3.08V (ISL706ARH/BRH/CRH) reset threshold, an internal timer releases RST after about 200ms. RST pulses low whenever VDD goes below the reset threshold. If a brownout condition occurs in the middle of a previously initiated reset pulse, the pulse will continue for at least 140ms. On power-down, once VDD falls below the reset threshold, RST goes low and is guaranteed low until VDD drops below 1.2V. Reset. RST is an active-high, push-pull output. RST is the inverse of RST. - 7 - RST - - 7 RST_OD Reset. RST_OD is an active-low, open-drain output that goes low when reset is asserted. This pin may be pulled up to VDD with a resistor consistent with the sink and leakage current specifications of the output. Behavior is otherwise identical to the RST pin. 8 8 8 WDO Watchdog Output. WDO is an active-low, push-pull output that goes low if the microprocessor does not toggle WDI within 1.6s and WDI is not tri-stated. WDO is usually connected to the non-maskable interrupt input of a microprocessor. When VDD drops below the reset threshold, WDO will go low whether or not the watchdog timer has timed out. Reset is simultaneously asserted, thus preventing an interrupt. Since floating WDI disables the internal timer, WDO goes low only when VDD drops below the reset threshold, thus functioning as a low line output. 2 FN7662.0 September 15, 2011 ISL705ARH, ISL705BRH, ISL705CRH, ISL706ARH, ISL706BRH, ISL706CRH Ordering Information ORDERING NUMBER PART NUMBER TEMP RANGE (°C) PACKAGE (RoHs Compliant) PKG. DWG. # 5962R1121301QXC ISL705ARHQF (Note 1) -55 to +125 8 Ld Flatpack K8.A 5962R1121301VXC ISL705ARHVF (Note 1) -55 to +125 8 Ld Flatpack K8.A 5962R1121301V9A ISL705ARHVX -55 to +125 Die ISL705ARHF/PROTO ISL705ARHF/PROTO (Note 1) -55 to +125 8 Ld Flatpack ISL705ARHX/SAMPLE ISL705ARHX/SAMPLE -55 to +125 Die 5962R1121302QXC ISL705BRHQF (Note 1) -55 to +125 8 Ld Flatpack K8.A 5962R1121302VXC ISL705BRHVF (Note 1) -55 to +125 8 Ld Flatpack K8.A 5962R1121302V9A ISL705BRHVX -55 to +125 Die ISL705BRHF/PROTO ISL705BRHF/PROTO (Note 1) -55 to +125 8 Ld Flatpack ISL705BRHX/SAMPLE ISL705BRHX/SAMPLE -55 to +125 Die 5962R1121303QXC ISL705CRHQF (Note 1) -55 to +125 8 Ld Flapack K8.A 5962R1121303VXC ISL705CRHVF (Note 1) -55 to +125 8 Ld Flatpack K8.A 5962R1121303V9A ISL705CRHVX -55 to +125 Die ISL705CRHF/PROTO ISL705CRHF/PROTO (Note 1) -55 to +125 8 Ld Flatpack ISL705CRHX/SAMPLE ISL705CRHX/SAMPLE -55 to +125 Die 5962R1121304QXC ISL706ARHQF (Note 1) -55 to +125 8 Ld Flapack K8.A 5962R1121304VXC ISL706ARHVF (Note 1) -55 to +125 8 Ld Flatpack K8.A 5962R1121304V9A ISL706ARHVX -55 to +125 Die ISL706ARHF/PROTO ISL706ARHF/PROTO (Note 1) -55 to +125 8 Ld Flatpack ISL706ARHX/SAMPLE ISL706ARHX/SAMPLE -55 to +125 Die 5962R1121305QXC ISL706BRHQF (Note 1) -55 to +125 8 Ld Flatpack K8.A 5962R1121305VXC ISL706BRHVF (Note 1) -55 to +125 8 Ld Flatpack K8.A 5962R1121305V9A ISL706BRHVX -55 to +125 Die ISL706BRHF/PROTO ISL706BRHF/PROTO (Note 1) -55 to +125 8 Ld Flatpack ISL706BRHX/SAMPLE ISL706BRHX/SAMPLE -55 to +125 Die 5962R1121306QXC ISL706CRHQF (Note 1) -55 to +125 8 Ld Flatpack K8.A 5962R1121306VXC ISL706CRHVF (Note 1) -55 to +125 8 Ld Flatpack K8.A 5962R1121306V9A ISL706CRHVX -55 to +125 Die ISL706CRHF/PROTO ISL706CRHF/PROTO (Note 1) -55 to +125 8 Ld Flatpack ISL706CRHX/SAMPLE ISL706CRHX/SAMPLE -55 to +125 Die ISL705XRHEVAL1Z ISL705XRH Evaluation Board ISL706XRHEVAL1Z ISL706XRH Evaluation Board K8.A K8.A K8.A K8.A K8.A K8.A NOTE: 1. These Intersil Pb-free Hermetic packaged products employ 100% Au plate - e4 termination finish, which is RoHS compliant and compatible with both SnPb and Pb-free soldering operations. 3 FN7662.0 September 15, 2011 ISL705ARH, ISL705BRH, ISL705CRH, ISL706ARH, ISL706BRH, ISL706CRH Functional Block Diagrams VDD VDD VDD RST RST_OD POR RST POR +- VREF +- VREF MR +- VREF MR MR PB PB PB WDO WDI POR WDO WDT PFI PF PFI PFO +- VREF WDO WDT WDI WDI PF +- VREF GND ISL705ARH, ISL706ARH PFO WDT PFI PF +- VREF GND ISL705BRH, ISL706BRH PFO GND ISL705CRH, ISL706CRH Timing Diagrams VRST VDD 1.2V >tMR MR tRST tRST tRST RST <tMD RST FIGURE 3. RST, RST, MR AND WDO TIMING DIAGRAM VRST VDD 1.2V < tWD < tWD < tWD WDI tWD >tWP tWD WDO tRST RST tRST FIGURE 4. WATCHDOG TIMING DIAGRAM 4 FN7662.0 September 15, 2011 ISL705ARH, ISL705BRH, ISL705CRH, ISL706ARH, ISL706BRH, ISL706CRH Absolute Maximum Ratings Thermal Information Supply Voltage Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to 6.5V Voltage on All Other Inputs . . . . . . . . . . . . . . . . . . . . . . . -0.3V to VDD + 0.3V ESD Rating Human Body Model (Tested per MIL-PRF-883 3015.7). . . . . . . . . .3.0kV Machine Model (Tested per JESD22-A115C) . . . . . . . . . . . . . . . . . . 300V Charged Device Model (Tested per JESD22-C110D) . . . . . . . . . . . .1.0kV Latch Up (Tested per JESD-78C) . . . . . . . . . . . . . . . . . . . . . . Class 2, Level A Thermal Resistance (Typical) θJA (°C/W) θJC (°C/W) 8 Ld Flatpack Package (Notes 2, 3). . . . . . 140 15 Maximum Junction Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . .+175°C Storage Temperature Range. . . . . . . . . . . . . . . . . . . . . . . .-65°C to +150°C Recommended Operating Conditions Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .-55°C to +125°C Supply Voltage ISL705ARH/BRH/CRH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.75V to 5.5V ISL706ARH/BRH/CRH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.15V to 3.6V CAUTION: Do not operate at or near the maximum ratings listed for extended periods of time. Exposure to such conditions may adversely impact product reliability and result in failures not covered by warranty. NOTES: 2. θJA is measured with the component mounted on a low effective thermal conductivity test board in free air. See Tech Brief TB379 for details. 3. For θJC, the “case temp” location is the center of the package underside. Electrical Specifications Unless otherwise specified VDD = 4.75V to 5.5V for the ISL705ARH/BRH/CRH, VDD = 3.15V to 3.6V for the ISL706ARH/BRH/CRH TA = -55°C to +125°C. Boldface limits apply over the ambient operating temperature range, -55°C to +125°C. SYMBOL PARAMETER CONDITIONS MIN (Note 4) TYP MAX (Note 5) (Note 4) UNITS POWER SUPPLY SECTION VDD IDD Operating Supply Voltage (Note 6) Operating Supply Current ISL705ARH/BRH/CRH 1.2 5 5.5 V ISL706ARH/BRH/CRH 1.2 3.3 3.6 V ISL705ARH/BRH/CRH 530 µA ISL706ARH/BRH/CRH 400 µA RESET SECTION VRST VHYS Reset Threshold Voltage Reset Threshold Voltage Hysteresis tRST Reset Pulse Width VOUT Reset Output Voltage ISL705ARH/BRH/CRH 4.50 4.65 4.75 V ISL706ARH/BRH/CRH 3.00 3.08 3.15 V ISL705ARH/BRH/CRH 20 40 mV ISL706ARH/BRH/CRH 20 30 mV 140 200 ISL705ARH/BRH, ISOURCE = 800µA VDD - 1.5 ISL705ARH/BRH/CRH, ISINK = 3.2mA ISL706ARH/BRH, ISOURCE = 500µA Reset Output Leakage Current 5 ms V 0.4 0.8 x VDD V V ISL706ARH/BRH/CRH, ISINK = 1.2mA 0.3 V ISL70XARH/CRH, VDD = 1.2V, ISINK = 100µA 0.3 V ISL70XBRH, VDD = 1.2V, ISOURCE = 4µA ILEAK 280 0.9 V ISL705CRH, VOUT = VDD 1 µA ISL706CRH, VOUT = VDD 1 µA FN7662.0 September 15, 2011 ISL705ARH, ISL705BRH, ISL705CRH, ISL706ARH, ISL706BRH, ISL706CRH Electrical Specifications Unless otherwise specified VDD = 4.75V to 5.5V for the ISL705ARH/BRH/CRH, VDD = 3.15V to 3.6V for the ISL706ARH/BRH/CRH TA = -55°C to +125°C. Boldface limits apply over the ambient operating temperature range, -55°C to +125°C. (Continued) SYMBOL PARAMETER CONDITIONS MIN (Note 4) TYP MAX (Note 5) (Note 4) UNITS WATCHDOG SECTION tWD Watchdog Time-Out Period tWP Watchdog Input (WDI) Pulse Width VIL Watchdog Input (WDI) Threshold Voltage 1.00 ns ISL706ARH/BRH/CRH, VIL = 0.4V, VIH = 0.8 x VDD 100 ns ISL705ARH/BRH/CRH VIL ISL706ARH/BRH/CRH ISL706ARH/BRH/CRH Watchdog Input (WDI) Current 0.8 3.5 Watchdog Output (WDO) Voltage ISL705ARH/BRH/CRH, ISOURCE = 800µA V 100 µA V -100 µA 5 µA -5 µA VDD - 1.5 V ISL705ARH/BRH/CRH, ISINK = 1.2mA ISL706ARH/BRH/CRH, ISOURCE = 500µA 0.6 0.7 x VDD ISL706ARH/BRH/CRH, WDI = VDD ISL706ARH/BRH/CRH, WDI = 0V V V ISL705ARH/BRH/CRH, WDI = VDD ISL705ARH/BRH/CRH, WDI = 0V VWDO s 50 ISL705ARH/BRH/CRH VIH 2.25 ISL705ARH/BRH/CRH, VIL = 0.4V, VIH = 0.8 x VDD VIH IWDI 1.60 0.4 0.8 x VDD V V ISL706ARH/BRH/CRH, ISINK = 500µA 0.3 V MANUAL RESET SECTION IMR tMR VIL Manual Reset (MR) Pull-up Current Manual Reset (MR) Pulse Width Manual Reset (MR) Input Threshold Voltage ISL705ARH/BRH/CRH, MR = 0V -500 -100 µA ISL706ARH/BRH/CRH, MR = 0V -250 -25 µA ISL705ARH/BRH/CRH 150 ns ISL706ARH/BRH/CRH 150 ns ISL705ARH/BRH/CRH VIH 2.0 VIL 0.6 0.7 x VDD Manual Reset (MR) to Reset Out Delay V V ISL706ARH/BRH/CRH VIH tMD 0.8 V V ISL705ARH/BRH/CRH 100 ns ISL706ARH/BRH/CRH 100 ns THRESHOLD DETECTOR SECTION VPFI IPFI VPFO Power Fail Input (PFI) Input Threshold Voltage ISL705ARH/BRH/CRH 1.20 1.25 1.30 V ISL706ARH/BRH/CRH 0.576 0.6 0.624 V 10 nA 0.4 V Power Fail Input (PFI) Input Current Power Fail Output (PFO) Output Voltage -10 ISL705ARH/BRH/CRH, ISOURCE = 800µA VDD - 1.5 V ISL705ARH/BRH/CRH, ISINK = 3.2mA ISL706ARH/BRH/CRH, ISOURCE = 500µA 0.8 x VDD V ISL706ARH/BRH/CRH, ISINK = 1.2mA tRPFI 0.3 V PFI Rising Threshold Crossing to PFO Delay ISL705ARH/BRH/CRH 7 15 µs ISL706ARH/BRH/CRH 11 20 µs 6 FN7662.0 September 15, 2011 ISL705ARH, ISL705BRH, ISL705CRH, ISL706ARH, ISL706BRH, ISL706CRH Electrical Specifications Unless otherwise specified VDD = 4.75V to 5.5V for the ISL705ARH/BRH/CRH, VDD = 3.15V to 3.6V for the ISL706ARH/BRH/CRH TA = -55°C to +125°C. Boldface limits apply over the ambient operating temperature range, -55°C to +125°C. (Continued) SYMBOL PARAMETER tFPFI MIN (Note 4) CONDITIONS TYP MAX (Note 5) (Note 4) UNITS PFI Falling Threshold Crossing to PFO Delay ISL705ARH/BRH/CRH 20 35 µs ISL706ARH/BRH/CRH 25 40 µs NOTES: 4. Compliance to datasheet limits is assured by one or more methods: production test, characterization and/or design. 5. Typical values shown reflect TA = TJ = +25°C operation and are not guaranteed. 6. Reset is the only parameter operable within 1.2V and the minimum recommended operating supply voltage. Typical Performance Curves 550 5.0 500 4.5 450 VRST (V) IDD (µA) 350 300 3.5 3.0 ISL706xRH ISL706xRH 2.5 250 200 -80 ISL705xRH 4.0 ISL705xRH 400 -60 -40 -20 0 20 40 60 80 100 120 140 2.0 -80 -60 TEMPERATURE (°C) -40 -20 0 20 40 60 80 100 120 140 TEMPERATURE (°C) FIGURE 5. IDD vs TEMPERATURE FIGURE 6. VRST vs TEMPERATURE 1.4 1.2 VDD ISL705xRH VPFI (V) 1.0 0.8 RST 0.6 0.4 ISL706xRH RST 0.2 0 -80 -60 -40 -20 0 20 40 60 80 100 120 140 TEMPERATURE (°C) FIGURE 7. VPFI vs TEMPERATURE 7 FIGURE 8. ISL705xRH RESET and RESET ASSERTION FN7662.0 September 15, 2011 ISL705ARH, ISL705BRH, ISL705CRH, ISL706ARH, ISL706BRH, ISL706CRH Typical Performance Curves (Continued) VDD VDD RST RST RST RST FIGURE 9. ISL706xRH RESET AND RESET ASSERTION FIGURE 10. ISL705xRH RESET AND RESET DEASSERTION VDD PFO RST PFI RST FIGURE 11. ISL706xRH RESET AND RESET DEASSERTION FIGURE 12. ISL705xRH PFI TO PFO RESPONSE PFO PFI FIGURE 13. ISL706xRH PFI TO PFO RESPONSE 8 FN7662.0 September 15, 2011 ISL705ARH, ISL705BRH, ISL705CRH, ISL706ARH, ISL706BRH, ISL706CRH Post Radiation Characteristics Unless otherwise specified, VDD = 4.75V to 5.5V for the ISL705ARH/BRH/CRH, VDD = 3.15V to 3.6V for the ISL706ARH/BRH/CRH TA = +25°C. This data is parameter deltas post radiation exposure at a rate of 50 to 300rad(Si)/s. This data is intended to show typical parameter shifts due to high dose radiation. These are not limits nor are they guaranteed. SYMBOL PARAMETER CONDITIONS 0 - 25kRad 0 - 50kRad 0 - 75kRad 0 - 100kRad UNITS ISL705ARH/BRH/CRH -2 -2.44 -3.86 -4.88 µA ISL706ARH/BRH/CRH -4.79 -7.47 -6.93 -8.88 µA ISL705ARH/BRH/CRH -8.1 -13.1 -17.5 -18.1 mV ISL706ARH/BRH/CRH -1 -3.25 -5.38 -7.25 mV ISL705ARH/BRH/CRH -3.75 -1.9 -5 -3.12 mV ISL706ARH/BRH/CRH 0.375 0.25 0.625 0.625 mV -2.13 -2.18 -2.39 -2.35 ms -56 -72 -81 -80 ms ISL705ARH/BRH/CRH 0.028 0.146 0.274 0.368 ns ISL706ARH/BRH/CRH 0.305 0.605 0.793 0.956 ns 0.94 0.31 0 -0.62 mV POWER SUPPLY SECTION IDD Operating Supply Current RESET SECTION VRST Reset Threshold Voltage VHYS Reset Threshold Voltage Hysteresis tRST Reset Pulse Width WATCHDOG SECTION tWD Watchdog Time-Out Period MANUAL RESET SECTION tMD Manual Reset (MR) to Reset Out Delay THRESHOLD DETECTOR SECTION VPFI Power Fail Input (PFI) Input Threshold Voltage ISL705ARH/BRH/CRH ISL706ARH/BRH/CRH -1.56 -2.5 -2.5 -2.5 mV tRPFI PFI Rising Threshold Crossing to PFO Delay ISL705ARH/BRH/CRH -0.026 -0.047 -0.085 -0.068 µs ISL706ARH/BRH/CRH 0.028 -0.058 0.11 -0.11 µs PFI Falling Threshold Crossing to PFO Delay ISL705ARH/BRH/CRH -0.397 -0.77 -1.17 -2.88 µs ISL706ARH/BRH/CRH -0.35 -0.782 -1.516 -2.087 µs tFPFI 9 FN7662.0 September 15, 2011 ISL705ARH, ISL705BRH, ISL705CRH, ISL706ARH, ISL706BRH, ISL706CRH Functional Overview The ISL705xRH and ISL706xRH provide the functions needed for monitoring critical voltages in high reliability applications such as microprocessor systems. Functions of the these supervisors include power-on reset control; supply voltage supervisions; power-fail detection; manual-reset assertion and a watch dog timer. The integration of all these functions along with their high threshold accuracy, low power consumption, and radiation tolerance make these devices ideal for critical supply monitoring. Reset Output Reset control has long been a critical aspect of embedded control design. Microprocessors require a reset signal during power up to ensure that the system environment is stable before initialization. The reset signal provides several benefits: • It prevents the system microprocessor from starting to operate with insufficient voltage. R1 VIN PFI R2 ISL705xRH/ISL706xRH FIGURE 14. CUSTOM V TH WITH RESISTOR DIVIDER ON PFI Manual Reset The manual reset input (MR) allows designers to add manual system reset capability via a push button switch (see Figure 15). The MR input is an active low debounced input which asserts reset if the MR pin is pulled low to less than VIL for at least 150ns. After MR is released, the reset output remains asserted for tRST and then released. MR is a TTL/CMOS logic compatible, so it can be driven by external logic. By connecting WDO to MR, one can force a watchdog time out to generate a reset pulse. • It prevents the processor from operating prior to stabilization of the oscillator. 20k • It ensures that the monitored device is held out of operation until internal registers are initialized. MR • It allows time for an FPGA to perform its self configuration prior to initialization of the circuit. On power-up, once VDD reaches 1.2V, RST is guaranteed logic low. As VDD rises, RST stays low. When VDD rises above the reset threshold (VRST), an internal timer releases RST after 200ms (typ). RST pulses low whenever VDD degrades to below VRST (see Figure 3). If a brownout condition occurs in the middle of a previously initiated reset pulse, the pulse is lengthened 200ms (typ). On power-down, once VDD falls below the reset threshold, RST stays low and is guaranteed to be low until VDD drops below 1.2V. The ISL705BRH and ISL706BRH active-high RST output is simply the complement of the RST output, and is guaranteed to be valid with VDD down to 1.2V. The ISL705CRH and ISL706CRH active-low open-drain reset output is functionally identical to RST. Power Failure Monitor Besides monitoring VDD for reset control, these devices have a Power-Failure Monitor feature that supervises an additional critical voltage on the Power-Fail Input (PFI) pin. For example, the PFI pin could be used to provide an early power-fail warning, overvoltage detection or monitor a power supply other than VDD. PFO goes low whenever PFI is less than VPFI. The threshold detector can be adjusted using an external resistor divider network to provide custom voltage monitoring for voltages greater than VPFI, according to Equation 1 (see Figure 14). R1 + R2 VIN = V PFI ⎛ ----------------------⎞ ⎝ R2 ⎠ (EQ. 1) 10 PB ISL705xRH/ISL706xRH FIGURE 15. CONNECTING A MANUAL RESET PUSH-BUTTON Watch Dog Timer The watchdog time circuit checks for coherent program execution by monitoring the WDI pin. If the processor does not toggle the watchdog input within tWD (1.0s min), WDO will go low. As long as reset is asserted or the WDI pin is tri-stated, the watchdog timer will stay cleared and not count. As soon as reset is released and WDI is driven high or low, the timer will start counting. Pulses as short as 50ns can be detected on the ISL705xRH, on ISL706xRH pulses as short as 100ns can be detected. Whenever there is a low-voltage VDD condition, WDO goes low. Unlike the reset outputs, however, WDO goes high as soon as VDD rises above its voltage trip point (see Figure 4). With WDI open or connected to a tri-stated high impedance input, the Watchdog Timer is disabled and only pulls low when VDD < VRST. Applications Information Negative Voltage Sensing This family of devices can be used to sense and monitor the presence of both a positive and negative rail. VDD is used to monitors the positive supply while PFI monitors the negative rail. PFO is high when the negative rail degrades below a VTRIP value and remains low when the negative rail is above the Vtrip value. As the differential voltage across the R1, R2 divider is increased, the resistor values must be chosen such that the PFI node is <1.25V when the -V supply is satisfactory and the positive supply FN7662.0 September 15, 2011 ISL705ARH, ISL705BRH, ISL705CRH, ISL706ARH, ISL706BRH, ISL706CRH is at its maximum specified value. This allows the positive supply to fluctuate within its acceptable range without signaling a reset when configured as shown in Figure 16. R1 ( VPFI – Vtrip ) R2 = --------------------------------------------VDD – VPFI (EQ. 2) RST In Figure 16, the ISL705ARH is monitoring +5V through VDD and -5V through PFI. In this example, the trip point (V TRIP) for the negative supply rail is set for -4.5V. Equation 2 can be used to select the appropriate resistor values. R1 is selected arbitrarily as 100kΩ, VDD = 5V, VPFI = 1.25V, and V TRIP = (-4.5V). By plugging the values into Equation 2 as shown in Equation 3 it can be seen a resistor of 153.3kΩ is needed. The closest 1% resistor value is 154kΩ. 100k ( 1.25 – ( – 4.5 ) ) R2 = ------------------------------------------------------ = 153.3kΩ 5 – 1.25 (EQ. 3) +5V 100k VDD R1 MR 100k 2N3904 100kΩ ISL705ARH, ISL706ARH FIGURE 17. RST VALID TO GROUND CIRCUIT Assuring a Valid RST Output On the ISL705BRH and ISL706BRH, when VDD falls below 1.2V, the RST output can no longer source enough current to track VDD. As a result, this pin can drift to undetermined voltages if left undriven. By adding a pull-up resistor to the RST pin as shown in Figure 18, RST will track VDD below 1.2V. The resistor value (R1) is not critical however, it should be large enough not to exceed the sink capability of RST pin at 1.2V. A 300kΩ resistor would suffice, assuming there is no load on the RST pin during that time. PFO PFI R2 VDD RST -5V VDD R1 300kΩ RST ISL705ARH FIGURE 16. ±5V MONITORING Figure 4 also has a general purpose NPN transistor in which the base is connected to the PFO pin through a 100kΩ resistor. The emitter is tied to ground and the collector is tied to MR signal. This configuration allows the negative voltage sense circuit to initiate a reset if it is not within its regulation window. A pull-up on the MR ensures no false reset triggering when the negative voltage is within its regulation window. Assuring a Valid RST Output When VDD falls below 1.2V, the RST output can no longer sink current and is essentially an open circuit. As a result, this pin can drift to undetermined voltages if left undriven. By adding a pull-down resistor to the RST pin as shown in Figure 17, any stray charge or leakage currents will be drained to ground and keep RST low when VDD falls below 1.2V. The resistor value (R1) is not critical however, it should be large enough not to load RST and small enough to pull RST to ground. A 100kΩ resistor would suffice, assuming there is no load on the RST pin during that time. ISL705BRH, ISL706BRH FIGURE 18. RST VALID TO GROUND CIRCUIT Selecting Pull-Up Resistor Values The ISL705CRH and ISL706CRH have open drain active low reset outputs (RST_OD). A pull-up resistor is needed to ensure RST_OD is high when VDD is in a valid state (Figure 19). The resistor value must be chosen in order not to exceed the sink capability of the RST_OD pin. The ISL705ARH has a sink capability of 3.2mA and the ISL706CRH has a sink capability of 1.2mA. Equation 4 may be used to select resistor RPULL based on the pull-up voltage VPULL. It is also important that the pull-up voltage does not exceed VDD. VPULL VDD RPULL RST_OD ISL706CRH, ISL705CRH FIGURE 19. RST_OD PULL-UP CONNECTION 11 FN7662.0 September 15, 2011 ISL705ARH, ISL705BRH, ISL705CRH, ISL706ARH, ISL706BRH, ISL706CRH V PULL R PULL = ---------------I SINK (EQ. 4) Adding Hysteresis to the PFI Comparator The PFI comparator has no built in hysteresis, however the designer may add hysteresis by connecting a resistor from the PFO pin to the PFI pin, essentially adding positive feedback to the comparator (see Figure 20). with VHB selected at 100mV. The closest standard value for R1 is 124kΩ. Then next step is select the rising trip voltage (VTR) such that: VHB VTR > V PFI ⎛ 1 + -----------⎞ ⎝ V DD ⎠ (EQ. 6) The rising threshold voltage is selected at 3.0V and R2 is calculated by Equation 7. 1 VTR 1 R2 = 1 ⁄ ⎛ ------------------------------⎞ – ⎛ -------⎞ – ⎛ -------⎞ ⎝ (V × R1 )⎠ ⎝ R1⎠ ⎝ R3⎠ (EQ. 7) PFI Plugging in all the variables R2 in this example is 90.9kΩ again this is choosing the closest 1% resistor. The final step is verify the trip voltages. VDD RST R1 PFO PFI R2 ISL705ARH FIGURE 20. POSITIVE FEEDBACK FOR HYSTERISIS The following procedure allows the system designer to calculate the components based on the requirements and on given data, such as supply rail voltages, hysteresis band voltage (VHB), and reference voltage (VPFI). The comparator only has two states of operation. When it is low, the current through R3 is IR3 = VPFI/R3. When the output is high, IR3 = (VDD - VPFI)/R3. The feedback current needs to be very small so it does not induce oscillations; 200nA is a good starting point. Now two values of R3 can be calculated with VDD = 5V and VPFI = 1.25V; R3 = 6.25MΩ or 11.25MΩ, select the lowest value of the two. With R3 selected as 6.2MΩ (closest standard 1% resistor), R1 can be calculated as: (EQ. 5) 12 (EQ. 8) R1 × VDD VTF = VTR – ⎛ --------------------------⎞ ⎝ ⎠ R3 (EQ. 9) The rising voltage, VTR is calculated as 2.98V and the falling voltage VTF is calculated as 2.88V so 100mV hysteresis is achieved. R3 VHB R1 = R3 ⎛ -----------⎞ = 124kohms ⎝V ⎠ DD 1 1 1 VTR = ( V PFI ) × R1 ⎛ -------⎞ + ⎛ -------⎞ + ⎛ -------⎞ ⎝ R1⎠ ⎝ R2⎠ ⎝ R3⎠ An additional item to consider is that the output voltage is equal to VDD, however according to the “Electrical Specifications” on page 6, the output of the PFI comparator is guaranteed to be at least (VDD-1.5) volts. When you take this worst case into account, the hysteresis can be as low at 70mV. Special Application Considerations Using good decoupling practices will prevent transients (i.e., due to switching noises and short duration droops in the supply voltage) from causing unwanted resets and reduce the power-fail circuit’s sensitivity to high-frequency noise on the line being monitored. When the WDI input is left unconnected, it is recommended to place a 10µF capacitor to ground to reduce single event transients from arising in the WDO pin. As described in the “Electrical Specifications” Table on page 7, there is a delay on the PFO pin whenever PFI crosses the threshold. This delay is due to internal filters on the PFI comparator circuitry which were added to mitigate single event transients. If the PFI input transitions below or above the threshold and the duration of the transition is less than the delay, the PFO pin will not change states. FN7662.0 September 15, 2011 ISL705ARH, ISL705BRH, ISL705CRH, ISL706ARH, ISL706BRH, ISL706CRH Weight Characteristics Weight of Packaged Device 0.31 Grams typical BACKSIDE FINISH Silicon PROCESS 0.6µM BiCMOS Junction Isolated Die Characteristics ASSEMBLY RELATED INFORMATION Die Dimensions Substrate Potential 2030µm x 2030µm (79.9 mils x 79.9 mils) Thickness: 483µm ± 25.4µm (19.0 mils ± 1 mil) Unbiased ADDITIONAL INFORMATION Interface Materials Worst Case Current Density GLASSIVATION < 2 x 105 A/cm2 Type: Silicon Oxide and Silicon Nitride Thickness: 0.3µm ± 0.03µm to 1.2µm ± 0.12µm TOP METALLIZATION Transistor Count 25030 Layout Characteristics Type: AlCu (99.5%/0.5%) Thickness: 2.7µm ±0.4µm Step and Repeat TOP METALLIZATION 2030µm x 2030µm Type: Silicon Metallization Mask Layout MR WDO VDD RST, RST, RST_OD GND WDI PFI 13 PFO FN7662.0 September 15, 2011 ISL705ARH, ISL705BRH, ISL705CRH, ISL706ARH, ISL706BRH, ISL706CRH Revision History The revision history provided is for informational purposes only and is believed to be accurate, but not warranted. Please go to web to make sure you have the latest Rev. DATE REVISION 9/15/11 FN7662.0 CHANGE Initial release Products Intersil Corporation is a leader in the design and manufacture of high-performance analog semiconductors. The Company's products address some of the industry's fastest growing markets, such as, flat panel displays, cell phones, handheld products, and notebooks. Intersil's product families address power management and analog signal processing functions. Go to www.intersil.com/products for a complete list of Intersil product families. To report errors or suggestions for this datasheet, please go to www.intersil.com/askourstaff For additional products, see www.intersil.com/product_tree Intersil products are manufactured, assembled and tested utilizing ISO9000 quality systems as noted in the quality certifications found at www.intersil.com/design/quality Intersil products are sold by description only. Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time without notice. Accordingly, the reader is cautioned to verify that data sheets are current before placing orders. Information furnished by Intersil is believed to be accurate and reliable. However, no responsibility is assumed by Intersil or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Intersil or its subsidiaries. For information regarding Intersil Corporation and its products, see www.intersil.com 14 FN7662.0 September 15, 2011 ISL705ARH, ISL705BRH, ISL705CRH, ISL706ARH, ISL706BRH, ISL706CRH Package Outline Drawing K8.A 8 LEAD CERAMIC METAL SEAL FLATPACK PACKAGE Rev 2, 12/10 0.015 (0.38) 0.008 (0.20) PIN NO. 1 ID OPTIONAL 1 2 0.050 (1.27 BSC) 0.005 (0.13) MIN 4 PIN NO. 1 ID AREA 0.022 (0.56) 0.015 (0.38) 0.115 (2.92) 0.070 (1.18) 0.265 (6.73) 0.245 (6.22) TOP VIEW 0.045 (1.14) 0.026 (0.66) 0.09 (0.23) 0.04 (0.10) 6 0.265 (6.75) 0.245 (6.22) -D- -H- -C0.180 (4.57) 0.170 (4.32) SEATING AND BASE PLANE 0.370 (9.40) 0.250 (6.35) 0.03 (0.76) MIN SIDE VIEW 0.007 (0.18) 0.004 (0.10) NOTES: LEAD FINISH BASE METAL 0.009 (0.23) 1. Index area: A notch or a pin one identification mark shall be located adjacent to pin one and shall be located within the shaded area shown. The manufacturer’s identification shall not be used as a pin one identification mark. Alternately, a tab may be used to identify pin one. 0.004 (0.10) 2. If a pin one identification mark is used in addition to a tab, the limits of the tab dimension do not apply. 0.019 (0.48) 0.015 (0.38) 0.0015 (0.04) MAX 0.022 (0.56) 0.015 (0.38) 4. Measure dimension at all four corners. 3 SECTION A-A 3. The maximum limits of lead dimensions (section A-A) shall be measured at the centroid of the finished lead surfaces, when solder dip or tin plate lead finish is applied. 5. For bottom-brazed lead packages, no organic or polymeric materials shall be molded to the bottom of the package to cover the leads. 6. Dimension shall be measured at the point of exit (beyond the meniscus) of the lead from the body. Dimension minimum shall be reduced by 0.0015 inch (0.038mm) maximum when solder dip lead finish is applied. 7. Dimensioning and tolerancing per ANSI Y14.5M - 1982. 8. Controlling dimension: INCH. 15 FN7662.0 September 15, 2011