Application Note 1906 ISL71091SEHXXEV1Z User’s Guide Introduction Features The ISL71091SEHXXEV1Z evaluation boards are designed to measure the performance of the radiation hardened ultra low noise, high precision ISL71091SEH voltage reference family. There are four output voltage options in the reference family, and they have a wide input voltage range up to 30V and an initial accuracy of 0.05%. With ultra low voltage noise of 3.3µVP-P in the 0.1Hz to 10Hz range (2.048V option), a maximum output voltage temperature coefficient of 6ppm/°C, and excellent radiation performance, the ISL71091SEH is ideal for space applications. • Small, compact design • Multiple connectors to easily monitor VIN and VOUT • Four output voltage options Reference Documents • ISL71091SEH20 Datasheet • ISL71091SEH33 Datasheet • ISL71091SEH40 Datasheet Specifications • ISL71091SEH10 Datasheet The boards are designed to operate at the following conditions: Ordering Information • Input voltage range: - 2.048V option = 4.2V to 30V - 3.3V option = 4.6V to 30V - 4.096V option = 6V to 30V - 10V option = 12V to 30V ISL71091SEH20EV1Z 2.048 Evaluation Board ISL71091SEH33EV1Z 3.3 Evaluation Board ISL71091SEH40EV1Z 4.096 Evaluation Board • Output current capability: Source 10mA, Sink 5mA ISL71091SEH10EV1Z 10.0 Evaluation Board ORDERING NUMBER OUTPUT VOLTAGE (V) TYPE • Operating temperature range: -55°C to +125°C ISL71091SEHXX 1 2 VIN 0.1µF COMP 3 1nF GND 4 DNC DNC VIN DNC COMP GND VOUT TRIM 8 7 VOUT 6 5 VOUT TRIM 1µF DNP GND FIGURE 1. ISL71091SEHXXEV1Z BLOCK DIAGRAM May 28, 2014 AN1906.1 1 CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. 1-888-INTERSIL or 1-888-468-3774 | Copyright Intersil Americas LLC 2013, 2014. 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. Application Note 1906 Functional Description The schematic of the evaluation board is shown on page 4. The ISL71091SEHXXEV1Z contains the ISL71091SEH voltage reference (U1), input decoupling capacitor (C1), compensation capacitor (C2), and load capacitor (C4). Component values are listed in Table 1. The power supply leads attach to TP1 and TP2 (VIN, GND). The output is measured at test points TP8 and TP9 (VOUT, GND), and is best measured with a high quality voltmeter in DC conditions. In addition, there is a BNC connector on VOUT to aid in taking measurements such as voltage noise. The SP1 (VIN), SP2 (GND), and SP3 (VOUT) are oscilloscope probe test points for easy connection to an oscilloscope. When testing the output voltage of the device under load, it is recommended to attach the load to the test point turret or BNC connector and monitor the voltage from the oscilloscope test point. If smaller transient overshoot is desired, increase C4 to 10µF and C2 to 10nF. However, note that the settling time also increases. TRIM 1-3 The TRIM1, TRIM2, and TRIM3 pins are for factory use only. Do not connect these to the circuit in any way. It will adversely effect the performance of the reference. Device Performance The following plots show the performance of the voltage reference that can be expected on the evaluation board. VIN = 8V unless otherwise specified. 4.099 4.101 4.100 -55°C 4.098 4.099 +25°C 4.098 4.097 VOUT (V) VOUT (V) +125°C 4.096 4.095 4.097 4.096 4.094 4.095 4.093 4.092 4.094 4.091 -65 -45 -25 -5 15 35 55 75 95 115 135 6 10 14 TEMPERATURE (°C) 22 26 30 FIGURE 3. LINE REGULATION vs VOUT OVER TEMPERATURE FIGURE 2. VOUT vs TEMPERATURE 4.099 80 60 -55°C 4.098 AMPLITUDE (mV) +25°C VOUT (V) 18 VIN (V) 4.097 4.096 +125°C 4.095 40 20 VOUT 0 -20 -40 -60 4.094 -5.0 -2.5 SINKING 0 2.5 ILOAD (mA) 5.0 7.5 SOURCING FIGURE 4. LOAD REGULATION vs VOUT OVER TEMPERATURE Submit Document Feedback 2 10 -80 0 0.25 0.5 0.75 1.00 1.25 1.5 1.75 2.00 TIME (ms) FIGURE 5. LOAD TRANSIENT (IL = 1mA) AN1906.1 May 28, 2014 Application Note 1906 TABLE 1. COMPONENTS PARTS LIST REFERENCE VALUE BNC1 Coaxial Cable PCB Mount Receptacle C1 0.1µF C2 1nF C3 DNP C4 1µF SP1 - SP3 Bypass Capacitor 0805, X7R, 50V, 10% Compensation Capacitor 0805, X7R, 50V, 10% Load Capacitor 0805, X7R, 50V, 10% Scope Probe Test Point PCB Mount TP1, TP2, TP4, TP5, TP8, TP9 1514-2 Test Point Turret TP3, TP7, TP8 DNP U1 ISL71091SEHXX FIGURE 6. VOLTAGE REFERENCE EVALUATION BOARD (FRONT) Submit Document Feedback DESCRIPTION 3 Radiation Hardened Ultra Low Noise, Precision Voltage Reference FIGURE 7. VOLTAGE REFERENCE EVALUATION BOARD (BACK) AN1906.1 May 28, 2014 1 2 TP6 1000PF TP4 4 8 2 7 7 3 6 6 5 5 4 TP7 4 SP2 VOUT TP8 TRIM TP5 ISL7109XSEH OPEN GND 3 8 1 C3 COMP C2 0.1UF C1 TP1 2 TRIM3 VOUT 3 3 1 1 2 1 2 GND 4 SP3 GND TP9 Application Note 1906 U1 3 1 2 VIN TP2 5BNC1 TRIM2 SP1 4 GND VOUT 3 4 TP3 1UF 4 TRIM1 C4 Submit Document Feedback ISL71091SEHXXEV1Z Schematic AN1906.1 May 28, 2014 Application Note 1906 Voltage Reference Evaluation Board Layout FIGURE 9. BOTTOM LAYER (VIEWED FROM TOP) FIGURE 8. TOP LAYER VOUT TRIM FIGURE 10. TOP SILKSCREEN 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 document is current before proceeding. For information regarding Intersil Corporation and its products, see www.intersil.com Submit Document Feedback 5 AN1906.1 May 28, 2014