19-0997; Rev 0; 9/07 MAX4208 Evaluation Kit The MAX4208 evaluation kit (EV kit) simplifies evaluation of the MAX4208 ultra-low offset/drift, adjustable gain, precision instrumentation amplifier in a MAX(R) package. The MAX4208 features high-impedance differential inputs optimized for small voltages (100mV max) and provides rail-to-rail output. The MAX4208 EV kit is configured for a gain of 148V/V. The EV kit operates from a single-supply voltage between 2.85V and 5.5V, or dual supplies providing 1.425V to 2.75V. The MAX4208 EV kit can also be used to evaluate the MAX4209 fixed-gain amplifiers. The MAX4208 IC temperature range is -40C to +125C. The MAX4209 EV kit, available separately, evaluates the 100V/V fixed-gain MAX4209 amplifier without external gain-setting resistors. Note: To evaluate a MAX4209 IC featuring internal gain-setting resistors, order a MAX4209EVKIT+ or request a free sample of the MAX4209 IC along with the MAX4208EVKIT+. See the Part Selection Table for IC ordering information. Features o Single- or Dual-Supply Operation 2.85V to 5.5V Single-Supply Operation 1.425V to 2.75V Dual-Supply Operation o Adjustable Voltage Gain Configured to 148V/V o Rail-to-Rail Output o Configurable Reference Voltage: Externally or Internally Buffered o Optional Current-Sense Mode o Fully Assembled and Tested Ordering Information Component List DESIGNATION QTY DESCRIPTION 2 10F 10%, 10V X5R ceramic capacitors (0805) Murata GRM21BR61A106K KEMET C0805C106K8PAC C2, C4, C5 3 0.1F 10%, 10V X5R ceramic capacitors (0402) Murata GRM155R61A104K KEMET C0402C104K8RACTU C6, C7 0 Not installed, capacitors (0603) 1 1000pF 10%, 16V X5R ceramic capacitor (0402) Murata GRM155R61C102K C1, C3 C8 JU1 1 4-pin header JU2, JU3 2 2-pin headers R1 1 R2 1 R3, R4 2 PART TYPE MAX4208EVKIT+ EV Kit +Denotes lead-free and RoHS-compliant Part Selection Table PART MAX4208AUA+ GAIN (V/V) Adjustable MAX4209TAUA+ 10 MAX4209HAUA+ 100 MAX4209KAUA+ 1000 1k 0.1% resistor (0805) IRC PCF-W0805LF-03-1001-B 147k 0.1% resistor (0805) IRC PCF-W0805LF-03-1473-B 4.99k 1% resistors (0603) R5, R6 0 Not installed, resistors--short (0603) R7 0 Not installed, resistor (1206) U1 1 MAX4208AUA+ (8-pin MAX) -- 3 Shunts -- 1 PCB: MAX4208 Evaluation Kit+ MAX is a registered trademark of Maxim Integrated Products, Inc. ________________________________________________________________ Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim's website at www.maxim-ic.com. 1 Evaluates: MAX4208/MAX4209 General Description Evaluates: MAX4208/MAX4209 MAX4208 Evaluation Kit Component Suppliers SUPPLIER IRC PHONE WEBSITE 361-992-7900 www.irctt.com KEMET Corp. 864-963-6300 www.kemet.com Murata Mfg. Co., Ltd. 770-436-1300 www.murata.com Note: Indicate that you are using the MAX4208 or MAX4209 when contacting these component suppliers. Quick Start Detailed Description Recommended Equipment The MAX4208 EV kit evaluates the MAX4208 instrumentation amplifier that features adjustable gain with gainsetting resistors R1 and R2, low offset voltage, and low offset voltage drift. The output-voltage range is from VSS + 100mV, to VDD - 100mV. The MAX4208 EV kit voltage gain is configured to 148V/V. The EV kit operates from a single-supply voltage between 2.85V and 5.5V or from a dual-supply voltage providing 1.425V to 2.75V. The MAX4208 EV kit can evaluate the fixed-gain MAX4209 ICs in the 8-pin MAX package by replacing the MAX4208 IC U1 and removing resistors R1 and R2. Before beginning, the following equipment is needed: * 5V, 1A-rated DC power supply * Function generator * Oscilloscope Procedure The MAX4208 EV kit is fully assembled and tested. Follow the steps below to verify board operation. Caution: Do not turn on the power supply until all connections are completed. 1) Verify that a shunt is installed across pins 1-4 of jumper JU1 (on-board buffered-reference mode). 2) Verify that a shunt is installed on jumper JU2 (singlesupply operation). 3) Verify that a jumper is not installed on jumper JU3 (buffered-reference mode). 4) Set the DC power-supply output to 5V and disable the output. 5) Set the function generator output to a 10mV P-P, 200Hz, 0V DC offset sine wave. Terminate the function generator as needed. 6) Connect the power-supply positive output to the VDD PCB pad on the EV kit. Power Supply The MAX4208 EV kit jumper JU2 must be configured properly for single-supply or dual-supply operation. For single-supply operation, a single power supply is connected to VDD and GND. For dual-supply operation, connect a positive supply to VDD, a negative supply to VSS, and supply ground to GND. See Table 1 to configure jumper JU2. Table 1. Power-Supply Configuration (Jumper JU2) SHUNT POSITION VSS PIN 8) Connect the function generator output across the differential input PCB pads, IN+ and IN-. Installed Connected to GND Single-supply operation. Power only VDD. 9) Connect the IN- PCB pad to the GND PCB pad with a wire. Not installed Not connected Dual-supply operation. Power VDD and VSS. 7) Connect the power-supply ground to the GND PCB pad next to VDD on the EV kit. EV KIT FUNCTION 10) Connect the oscilloscope to the OUT PCB pad and the oscilloscope ground clip to the GND PCB pad. 11) Enable the DC power supply and the function generator. 12) Verify that the oscilloscope measures a 1.48VP-P, 200Hz, 2.5V DC offset sine wave. 2 _______________________________________________________________________________________ MAX4208 Evaluation Kit REF Input The EV kit's jumper JU3 must be configured properly for appropriate reference-voltage operation. In direct reference mode, install a shunt on jumper JU3 to connect REF to the on-board ground (GND), or remove the shunt to connect a user reference voltage to the REF input PCB pad. For either buffered-reference mode, REF must not be connected to a reference voltage; thus, the shunt on jumper JU3 must not be installed. See Table 2 for jumper JU3 configurations. Optional capacitor C6 can be used for reference-voltage stability/filtering. Choose an appropriate value as needed. On-Board Current Sensing The MAX4208 EV kit can be configured for on-board current sensing by installing a surface-mount 1206 sense resistor at R7, located between the IN+ and INPCB pads. Use the following equation to select the value for resistor R7: R4 VREFIN/MODE = VDD x R3 + R4 where VDD is the input supply voltage to the EV kit. In buffered-reference mode, the MAX4208 internally buffers the REFIN/MODE voltage onto REF. Note: Do not connect an external source to the REF PCB pad in buffered-reference mode. See Table 2 for jumper JU1 configurations. R7 = 30mV IIN where IIN is the maximum current flowing across resistor R7 and 30mV is a suggested sense voltage. 30mV x 148V/V gives a 4.4V output swing. Refer to the Table 2. Jumpers JU1 and JU3 Configurations JU1 SHUNT POSITION MODE Direct-reference-mode operation 1-2 REFIN/MODE PIN JU3 SHUNT POSITION REF PIN Installed Connected to GND JU1 disables the internal REF buffer. JU3 sets the REF voltage to GND. Not installed Connected to user reference voltage JU1 disables the internal REF buffer. JU3 allows the user to set the REF voltage directly. Apply a user reference voltage to the REF PCB pad in the 0V and VDD - 1.6V range. Connected to VSS EV KIT FUNCTION Shutdown mode 1-3 Connected to VDD -- -- Buffered-referencemode operation (on-board reference) 1-4 Connected to VDD / 2 Not installed Not connected The IC buffers the on-board VDD / 2 onto REF. Do not install JU3 or connect an external source to the REF PCB pad. Not connected The IC buffers a user reference voltage onto REF. Apply a user reference voltage to the REFIN/MODE PCB pad in the range of VSS + 200mV and VDD 1.6V. Do not install JU3 or connect an external source to the REF PCB pad. Buffered-referencemode operation (user reference) Not installed Connected to user reference voltage Not installed Entire IC is in shutdown. ICC < 5A. _______________________________________________________________________________________ 3 Evaluates: MAX4208/MAX4209 REFIN/MODE Operation Modes The EV kit jumper JU1 configures the MAX4208 for direct reference, buffered reference, or shutdown mode. The reference voltage at REF sets the output voltage DC signal, OUT, when the differential input signal VIN+ - VINequals zero. In direct-reference-mode operation, connect a user reference voltage directly to the REF PCB pad. In buffered-reference-mode operation, connect a user reference voltage to the REFIN/MODE input PCB pad or use the resistor-divider network R3 and R4 to provide a reference voltage for REFIN/MODE, scaled from VDD. The network is configured to scale the voltage at REFIN/MODE to one-half of VDD. Replace resistors R3 and R4 to modify the voltage applied to REFIN/MODE using the following equation: Evaluates: MAX4208/MAX4209 MAX4208 Evaluation Kit MAX4208/MAX4209 IC data sheet for application details. Verify that the selected resistor is rated for the appropriate current and power levels. For high-power applications, use the IN+ and IN- PCB pads as sense connections to an off-board currentsense resistor. high-precision, surface-mount 0805 resistors can change the gain. Tolerance of 0.1% or better is recommended for optimum performance. Use the following equation to select values for resistors R1 and R2: R2 = R1 x (Gain - 1) where R1 1k and the sum of R1 + R2 is 10k (R1 + R2) 500k. Differential Input Filter The MAX4208 EV kit features an optional balanced-differential resistor-capacitor filter across the MAX4208 IN+ and IN- input pins. Use the surface-mount 0603 PCB pads for installing resistors R5, R6, and capacitor C7, which form the filter. Before installing resistors R5 and R6, cut open the shorting PCB trace located at the respective pads. Evaluating the MAX4209 The MAX4208 EV kit can be used to evaluate the fixedgain MAX4209 IC in the 8-pin MAX package by replacing the MAX4208 IC U1 and removing resistors R1 and R2. The MAX4209 IC features fixed gains of 10V/V, 100V/V, or 1000V/V. See the Part Selection Table for ordering information. The MAX4209 EV kit is also available separately. Gain Setting The MAX4208 EV kit gain is configured to 148V/V by resistors R1 and R2. Replacing these resistors with VDD C1 10F R3 4.99k 1% GND VSS 2 3 JU1 4 1 REFIN/MODE R4 4.99k 1% 1 REFIN/MODE VDD C5 0.1F GND R5 SHORT C2 0.1F 2 IN- INR7 OPEN R6 SHORT C7 OPEN IN+ 8 U1 OUT 7 MAX4208 3 IN+ FB 6 C8 1000pF GND R1 1k 0.1% VSS 4 VSS JU2 OUT R2 147k 0.1% C3 10F C4 0.1F VSS REF 5 REF C6 OPEN GND Figure 1. MAX4208 EV Kit Schematic 4 _______________________________________________________________________________________ JU3 MAX4208 Evaluation Kit Evaluates: MAX4208/MAX4209 Figure 2. MAX4208 EV Kit Component Placement Guide-- (Component Side) Figure 3. MAX4208 EV Kit PCB Layout--Component Side _______________________________________________________________________________________ 5 Evaluates: MAX4208/MAX4209 MAX4208 Evaluation Kit Figure 4. MAX4208 EV Kit PCB Layout--Solder Side Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. 6 _____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 (c) 2007 Maxim Integrated Products is a registered trademark of Maxim Integrated Products, Inc.