Application Note 1532 ISL28006 Evaluation Board User’s Guide Introduction The ISL28006 evaluation board is a design platform containing all the circuitry needed to characterize critical performance parameters of the ISL28006 in either a high side or low-side current sense application. The ISL28006 is available in fixed 100V/V, 50V/V, 20V/V and adjustable gains. Reference Documents • ISL28006 Data Sheet, FN6548 Evaluation Board Schematic The ISL2800XEVAL1Z evaluation board is configured with either the ISL28006-100, ISL28006-50, ISL28006-20 or the ISL28006-ADJ device (adjustable gain via external resistors R11 and R14). Note: When using the adjustable part, V-REF (J1) needs to be grounded. J13 is provided to enable accurate voltage measurements across the sense resistor R3. Figure 1 shows the basic application circuit and optional protection components for the fixed gain parts. Figure 2 shows the basic application circuit and optional protection components for the adjustable gain part. Figure 3 shows the complete schematic for the ISL2800XEVAL1Z evaluation board. Components shown in red in both Figures 1 and 2 are optional transient protection and not required for clean environments. Note: The evaluation board comes equipped with the transient protection devices. Optional Transient Protection For applications where the load and the power source are permanently connected, transient protection is not required and only an external current sense resistor (R3) is needed. For applications where fast transients can generate voltage spikes that can overdrive the amplifier input and drive the output of the amplifier into the rails, a long overload recovery time will result. Common mode capacitors C7, C9 and differential capacitor C8 are used to filter the common mode and differential voltage spikes. For switching applications or where fast transients are caused by hot plugging the source or load, external protection components may be needed. The external April 12, 2010 AN1532.1 1 current limiting resistor (R6) in Figure 1 will limit the peak current through the internal ESD diodes to <20mA. This condition can occur in applications that experience high levels of in-rush current causing high peak voltages that can damage the internal ESD diodes of the ISL28006. If the current limiting resistor is required, it needs to be placed on the RS- input (R6). Placing it on the RS+ input side (R7) will result in a much larger error voltage due to the ISL28006 taking its supply current from the sense current in high-side applications. For example: Current limiting resistor R6 with a value of 100Ω will provide protection for a 2V transient with the maximum of 20mA flowing through the input while adding only an additional 13µV (worst case over-temperature) of VOS as shown in Equation 1. Note: Worst case over-temperature input bias current on the RS- input is 130nA. R 6 × I RS- = 100Ω × 130nA = 13μV (EQ. 1) Current limiting resistor R7 with value of 100Ω will provide the same transient protection, but with an error voltage of 800µV. Note: Worst case over-temperature input bias current on the RS+ input is 8µA as shown in Equation 2. R 7 × I RS+ = 100Ω × 8μA = 800μV (EQ. 2) R7 is a carry-over from our characterization board and was used to measure input bias current. The evaluation board is populated with a zero ohm resistor for R7. Power Supplies External power connections are made through the VS+ and Ground connections on the evaluation board. Capacitors C2 and C4 perform two duties, de-coupling the supplies and filtering of the power supply noise with R15. Anti-reverse diodes D1 and D3 protect the circuit in the case of accidental polarity reversal of the supply. Resistor R12 is used to connect ground to the fixed gain parts. ISL2800XEVAL1Z and BOM Figure 4 shows the top view of the ISL2800XEVAL1Z evaluation board. The evaluation board Bill of Materials is given in Table 2. CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. 1-888-INTERSIL or 1-888-468-3774 | Intersil (and design) is a registered trademark of Intersil Americas Inc. Copyright Intersil Americas Inc. 2010. All Rights Reserved All other trademarks mentioned are the property of their respective owners. Application Note 1532 I-SENSE- I-SENSE+ J4 J5 D3 0 C8 1000pF 0 0 R7 C7 R23 100 R6 0.10 R18 S1AB R3 C9 1000pF 0.01µF D2 OPTIONAL TRANSIENT PROTECTION DNP J13 J6 OPEN C10 I-SENSE OUT 0 R9 R26 0 DNP R13 U1 V-REF 1 J1 2 3 5 ISL28006 4 0 R12 SOT23_5 C2 1µF C4 0.01µF D1 J3 0 J2 R15 S1AB GND VS+ FIGURE 1. SIMPLIFIED ISL2800XEVAL1Z SCHEMATIC DIAGRAM FOR FIXED GAIN PARTS 2 AN1532.1 April 12, 2010 Application Note 1532 I-SENSE- I-SENSE+ J4 J5 D3 0 C8 0 0 R7 C7 R23 100 R6 0.10 R18 C9 0.01µF 1000pF S1AB R3 1000pF D2 OPTIONAL TRANSIENT PROTECTION DNP J13 J6 1k R14 2 100k 3 OPEN C10 R26 6 ISL28006 SOT23_6 5 4 0 1 C2 1µF C4 0.01µF D1 0 J3 R15 S1AB J2 J1 U1 R11 R10 V-REF I-SENSE OUT 0 R8 0 DNP R13 GND VS+ FIGURE 2. SIMPLIFIED ISL2800XEVAL1Z SCHEMATIC DIAGRAM FOR ADJUSTABLE GAIN PARTS 3 AN1532.1 April 12, 2010 Application Note 1532 R16-R20 AND R21-R25 ARE FOR KELVIN CONNECTIONS R1 DNP R2 I-SENSE+ 1 J5 1 DNP R3 D3 0.10 R4 2 DNP R5 S1AB I-SENSE1 J4 C8 1000pF DNP DNP R21 0 R22 DNP R23 0 DNP R24 R25 DNP R20 DNP R7 C7 100 R6 0 R19 DNP R18 DNP R17 R16 DNP C9 1000pF 0.01µF D2 DNP J13 2 3 DNP *R12 100k C20 C2 1µF C4 ISL28006 4 TABLE 1. 100 R15 Fixed Gain J3 1 3 4 OPEN C10 5 S1AB J2 J6 I-SENSE 5 OUT *Resistor values shown are for the ISL28006-ADJ. See Table 1 0.01µF 2 D1 1 GND 1 2 6 SOT23_6 OPEN DNP *R14 1k 0 1 0 *R9 J1 U1 1 *R11 *R10 V-REF *R8 R26 0 DNP R13 VS+ Variable Gain (i.e., AV = 101) R8 R9 R10 R11 R12 R14 DNP 0 DNP DNP 0 DNP 0 DNP 0 1k DNP 100k FIGURE 3. ISL2800XEVAL1Z SCHEMATIC DIAGRAM 4 AN1532.1 April 12, 2010 Application Note 1532 FIGURE 4. ISL2800XEVAL1Z TOP VIEW TABLE 2. ISL2800XEVAL1Z COMPONENTS PARTS LIST DEVICE # C2 C4, C8 C7, C9 C10, C20 D1, D3 DESCRIPTION COMMENTS CAP, SMD, 0805, 1µF, 50V, 20%, X7R, ROHS Power Supply Decoupling and Input Filter CAP, SMD, 0603, 0.01µF, 50V, 10%, X7R, ROHS Power Supply Decoupling/Input Filter and Differential Current Sense Filter CAP, SMD, 0603, 1000pF, 50V, 10%, X7R, ROHS Common Mode Current Sense Filter CAP, SMD, 0603, DNP-Place Holder, ROHS User Selectable Capacitors - Not Populated Diode-Rectifier, SMD, S1AB, 50V, ROHS Reverse Power Protection U1 (ISL28006-100EVAL1Z) ISL28006FH100Z-T7, SOT-23, ROHS U1 (ISL28006-50EVAL1Z) ISL28006FH50Z-T7, SOT-23, ROHS U1 (ISL28006-20EVAL1Z) ISL28006FH20Z-T7, SOT-23, ROHS U1 (ISL28006-ADJEVAL1Z) ISL28006FHADJZ-T7-T7, SOT-23, ROHS R16, R17, R19, R20, R21, Resistor, SMD, 0603, MF, DNP-Place Holder R22, R24, R25 R26 R3 R1, R2, R4, R5 R6, R7, R13, R18, R23 User Selectable Kelvin Connection Not Populated Resistor, SMD, 0603, MF, DNP-Place Holder User Selectable Output Load Resistor Not Populated Resistor, SMD, 2512, 0.1Ω, 1W, 1%, TF, ROHS SENSE resistor Resistor, SMD, 2512, DNP-Place Holder User Selectable SENSE Resistors - Not Populated Resistor, SMD, 0603, 0Ω, 1/10W, TF, ROHS Zero Ohm User Selectable Resistors R15 Resistor, SMD, 0603, 100Ω, 1/10W, TF, ROHS Current Limiting Resistors R11 Resistor, SMD, 0603, 1kΩ, 1/10W, 1%, TF, ROHS (Variable Gain) RES, SMD, 0603, DNP-Place Holder (Fixed Gain) Gain and Other User Selectable Resistors R14 Resistor, SMD, 0603, 100kΩ, 1/10W, 1%, TF, ROHS (Variable Gain) Gain and Other User Selectable RES, SMD, 0603, DNP-Place Holder (Fixed Gain) Resistors R8, R10 Resistor, SMD, 0603, 0Ω, 1/10W, 1%, TF, ROHS (Variable Gain) Resistor, SMD, 0603, DNP-Place Holder (Fixed Gain) Gain and Other User Selectable Resistors R9, R12 Resistor, SMD, 0603, DNP-Place Holder (Variable Gain) Resistor, SMD, 0603, 0Ω, 1/10W, 1%, TF, ROHS (Fixed Gain) Gain and Other User Selectable Resistors 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 5 AN1532.1 April 12, 2010