Application Note 1671 Author: Oscar Mansilla ISL706xRH Evaluation Board User’s Guide Introduction Section 2 The ISL706xRHEVAL1Z evaluation board is a design platform featuring all three versions of the rad hard 3.3V supervisory circuits. It includes all the circuitry needed to characterize critical performance parameters and enables evaluation of basic functional operation and common application implementations. Figures 1 and 2 illustrate the ISL706xRHEVAL1Z in photographic and schematic forms, respectively. The middle position (Section 2), has the ISL706BRH installed and is set-up as a 3.3V window detector. The VDD monitors for UV and the PFI for OV via the R5, R6 divider. The PFO output is inverted and connected to the manual reset input (MR) via U4. Hence, a reset signal is generated when 3.06V < VDD > 3.45V. If J4 is not installed, the PFO will be an OV indicator but no reset signal will be generated. There is also a LED indicator for an overvoltage condition, when VDD > 3.45V PFO is a high and a LED will turn on indicating an OV condition. The active high reset signal for the an UV condition maybe monitored through the RST test point. Section 3 FIGURE 1. ISL706xRHEVAL1Z Evaluation Board Key Features The ISL706xRHEVAL1Z is divided into three sections; each section having one of the three available reset output versions. The left position has the ISL706ARH and is set-up as a +5V and +3.3V UV monitor with reset signal. The middle position features the ISL706BRH set up as 3.3V window detector. The right section contains the ISL706CRH in a bipolar voltage sensing application. Section 1 In the left position (Section 1), the ISL706ARH is configured to monitor undervoltage conditions on a +3.3V supply through the VDD pin and on a +5V supply through the PFI pin. The PFI allows monitoring of any voltage above the 0.6V PFI reference and with a resistor divider is used to monitor the +5V. The rising threshold for the +5V auxiliary voltage is set to 3V via the R1, R2 divider, when this condition is met PFO will be high driving on a green LED. When the +5V auxiliary voltage falls below 3V, PFO is pulled low and a red LED will be turned on. There is an option to add hysteresis to the power fail comparator by adding a resistor on pad R13. The active low reset signal maybe monitored through the RST test point. There is also a MR test point in order to drive the MR low to test its functionality. September 30, 2011 AN1671.0 1 The right position (Section 3), features the ISL706CRH in a negative voltage sensing application. A +3.3V supply is monitored through the VDD pin and a -5V supply is monitored on the PFI pin with use of the R7, R8 resistor divider network. Both pins are sensing for an under voltage condition. When the -5V supply rail drops below -4.5V, PFO will be high driving on the N3904 NPN transistor. As the NPN turns on, the manual reset (MR) pin will be pull low initiating a reset. An UV condition on the +3.3V supply may be monitored on the RST_OD pin, which has a 3.01kΩ pull-up resistor to VDD. Watchdog Timer Functionality All of these positions have independent Watchdog input (WDI) and Watchdog output (WDO) test points to evaluate the functionality the watchdog timer. A waveform generator may be used to apply a square wave signal to the WDI test points and the output monitored through the WDO test points. The WDI may also be left open and WDO is now a low line indicator of the voltage on VDD. Power Supplies External power connections are made through the VDD, 5V, -5V and GND connections on the evaluation board. All three sections share a common VDD test point with a decoupling capacitor C1, C2 and C3 placed close to each IC. The PFI pins in sections 1 and 2 have a unpopulated component pad to add decoupling capacitors C2 and C3 if needed. Reference Documents ISL705xRH Data Sheet, FN7662 CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. Copyright Intersil Americas Inc. 2011. All Rights Reserved. 1-888-INTERSIL or 1-888-468-3774 | 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. Application Note 1671 RST OD SECTION 1 - ISL706ARH SECTION 2 - ISL706BRH SECTION 3 - ISL706CRH FIGURE 2. ISL706xRHEVAL1Z SIMPLIFIED SCHEMATIC Bill of Materials TABLE 1. ISL706XRHEVAL1Z COMPONENTS PARTS LIST DEVICE # DESCRIPTION COMMENTS C1, C3, C5 CAP, SMD, 0603, 0.1µF, 50V, 10%, X7R, ROHS Power Supply Decoupling C2, C4 CAP, SMD, 0603, DNP, ROHS User selectable capacitors - not populated D1, D2, D3 LED, SMD, ROHS Power Fail Indicator Q1, Q3 N-Channel EMF Effect Transistor, SMD, SOT-23,ROHS Power Fail Detector Q2 P-Channel EMF Effect Transistor, SMD, SOT-23,ROHS Power Fail Detector Q4 NPN General Purpose Transistor, SMD, SOT-223, ROHS R1 RES, SMD, 0603, 383kΩ, 1/16W, 1%, ROHS PFI Voltage Divider Network R2, R6 RES, SMD, 0603, 49.9kΩ, 1/10W, 1%, ROHS PFI Voltage Divider Network R3, R4, R12 RES, SMD, 0603, 1kΩ, 1/10W, 1%, ROHS LED Current Limiting Resistor R5 RES, SMD, 0603, 165kΩ, 1/16W, 1%, ROHS PFI Voltage Divider Network R7, R9, R10 RES, SMD, 0603, 100kΩ, 1/16W, 1%, ROHS PFI Voltage Divider Network R11 RES, SMD, 0603, 5.1kΩ, 1/16W, 1%, ROHS ISL705CRH Reset Pull-up Resistor R13 RES, SMD, 0603, DNP Placeholder for Addition of Hysteresis U1 ISL706ARH, 8 Ld Flatpack, 3.3V Supervisory Circuit Supervisory Circuit with Active Low RESET U2 ISL706BRH, 8 Ld Flatpack, 3.3V Supervisory Circuit Supervisory Circuit with Active High RESET U3 ISL706CRH, 8 Ld Flatpack, 3.3V Supervisory Circuit Supervisory Circuit with Open Drain RESET U4 UHS Inverter with Schmitt Trigger Input, SC70, ROHS 2 AN1671.0 September 30, 2011 Application Note 1671 ISL706xEVAL1Z Board Layout FIGURE 3. ISL706xEVAL1Z TOP VIEW FIGURE 4. ISL706xEVAL1Z TOP LAYER 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 the Application Note or Technical Brief is current before proceeding. For information regarding Intersil Corporation and its products, see www.intersil.com 3 AN1671.0 September 30, 2011