MAX152 Evaluation Kit The MAX152 evaluation kit (EV kit) is fully assembled, and provides a proven design and PC board layout for fast, easy evaluation of the MAX152 at sample rates to 400ksps. An oscillator continuously triggers the converter, and an LED displays the conversion results. Several jumpers allow the board to be configured for the various operating modes of the MAX152, and the board includes the low-current shutdown circuit shown in the data sheet. A 16-pin data connector provides easy interface between the MAX152 EV kit and the user's system. The MAX152 EV kit can be used to evaluate the 5V MAX153 at sample rates to 1Msps. ____________________Component List DESIGNATION QTY U1 1 U2 1 U3 1 MAX152CPP 74HCT574 ICM7555CPA C1, C3, C6, C7, C8 5 0.1µF ceramic capacitors C2, C4 2 10µF 16V radial electrolytic capacitors C5 1 D1-D8 8 Q1 1 DESCRIPTION 100pF ceramic capacitor Red LEDs ____________________________Features ♦ High-Speed 8-Bit ADC ♦ Unipolar or Bipolar Input ♦ No Clock Circuit Required ♦ +3V (MAX152) or +5V (MAX153) Operation ♦ Low-Power Shutdown Mode ♦ LED Display of Conversion Results ♦ 3in2 Prototyping Area ♦ 16-Pin Data Connector for Interface to External System ______________Ordering Information PART TEMP. RANGE BOARD TYPE MAX152EVKIT-DIP 0°C to +70°C Through-Hole The MAX152EVKIT may also be used to evaluate the MAX153. To receive a free sample of the MAX153CPP, call 1-800-998-8800. ______________________________EV Kit ME12N06EL Nihon N-channel logic-level MOSFET R1 1 R2, R12 2 R3-R10 8 R11 1 J1, J3 2 300Ω 5% resistor 510kΩ 5% resistors 620Ω 5% resistors 10kΩ 5% resistor 3-pin jumper headers J2, J4, J5, J6, J7, J8 6 2-pin jumper headers None 8 None 1 None 1 None 4 Shunts 16-pin ribbon cable connector 3.50" x 4.00" PC board Rubber feet None 1 MAX152 data sheet and EV kit manual ________________________________________________________________________________________ 13 MAX152 EV Kit _______________General Description MAX152 EV Kit MAX152 Evaluation Kit ___________________Quick Reference The evaluation kit as shipped, is configured for the continuousconversion mode. To verify operation, follow these steps: 1. Verify that the jumpers are configured as described in Table 2. Table 1. Jumper Functions JUMPER CONNECTION 1&2 J1 2. Connect the power supplies (+3V for MAX152, +5V for MAX153) to the power input connector. 2&3 VREF- connected to ground Open Used when connecting a voltage source to the VREF- pad 3. Connect an analog input to AIN input. 4. Read conversion results displayed on the LEDs. J2 _______________General Description Jumper Functions The MAX152 EV kit has several jumpers to alter the configuration. Table 1 lists the jumpers and their functions. Table 2 gives the jumper selection for a free-running mode used for board verification. Note that Table 2's configuration drives both the RD and CS inputs and sets the MODE pin low. The timing diagram for this configuration is shown in the MAX152 or MAX153 data sheet. Refer to the data sheet for more information on the various operating modes. Power Requirements The MAX152 EV kit may be used with either the MAX152 or MAX153. The MAX152 will operate on supplies as low as 2.7V. The MAX153 operates on +5V or ±5V. The positive supply is also connected to the octal latch and ICM7555 timer on the board. The LEDs will cause the positive supply current to approach 60mA when all are on. The VSS input is connected only to the MAX152/MAX153's VSS pin. The VSS pin will draw less than 50µA. Optionally, J4 can be shorted to connect VSS to ground when not using a negative supply. MAX152/MAX153 Reference Voltage The VREF+ and VREF- pins may be connected to any potential between V DD and V SS. For single-supply operation, VREF+ can be connected to VDD and VREFcan be connected to ground. Jumpers (J1 and J2) are provided for this configuration. If a reference voltage other than V DD or ground is desired, connect the source to the VREF+ and/or VREF- pads and set J1 and J2 accordingly. Refer to Table 1 for their use. MAX152/MAX153 Data Output/Display The MAX152/MAX153's output is latched and buffered by a 74HCT574 so it can drive an LED display. The 14 J3 J4 J5 J6 J7 J8 FUNCTION VREF- connected to the drain of Q1 Open Used when connecting a voltage source to the VREF+ pad Short VREF+ shorted to VDD 1&2 CS grounded 2&3 CS driven by the ICM7555 Open Used when an external digital signal is applied to the CS input Open Used when driving VSS with a negative source (-5V or -3V) Short VSS connected to ground Open MODE pin open (internally pulled low) Short MODE pin connected to VDD Open ICM7555 circuit disabled Short ICM7555 circuit enabled Open LED display disabled Short LED display enabled Open Used when an external digital input is applied to the RD input Short RD driven by the ICM7555 Table 2. Jumper Selection for Free-Running Mode JUMPER CONNECTION J1 2&3 FUNCTION VREF- connected to GND J2 Short VREF+ connected to VDD J3 2&3 CS driven by ICM7555 J4 Short VSS connected to GND. Leave J4 open if a VSS source is used. J5 Open MODE pin internally pulled low J6 Short Enable the ICM7555 J7 Short Enable the LED display J8 Short RD driven by ICM7555 ______________________________________________________________________________________ MAX152 Evaluation Kit The clock signal for the 74HCT574 is taken off the RD input. This latches the MAX152/MAX153 conversion results on the trailing (positive going) edge of the RD signal. This technique works as long as RD pulse is longer than the conversion time of the MAX152/MAX153. The ready (RDY) signal can be observed by configurring the board per Table 2 and inserting a 4.7kΩ pullup resistor in the location marked R13. The RDY signal will appear on the WR/RDY pin. The resistor is normally not installed, in order to keep the pin input current as low as possible. ICM7555 Circuit A simple ICM7555 timer circuit on the board provides a clock for the stand-alone mode. The output can be connected to the CS and RD pins through J3 and J8. It will then trigger a conversion approximately every 2.5µs when J6 is shorted. J6 is provided to disable the ICM7555 when evaluating the shutdown currents. When using external signal sources for CS and RD, leave jumpers J3 and J8 open. Refer to the data sheet for timing specifications with external sources. Shutdown Modes The function of the power-down pin (PWRDN) is to drop the MAX152/MAX153's supply current to typically 1µA. Note, however, that VREF+ will continue to appear to the source as a 2kΩ resistor, and this resistor draws current even when the device is in power-down mode. The addition of MOSFET Q1 opens VREF- to disconnect this internal reference resistor and remove its current drain. A 510kΩ resistor acts as the pull-up for the gate of Q1 and PWRDN. You can evaluate the powerdown mode simply by grounding the PWRDN pad. The other chips on the board will continue to draw current if they are left enabled. Be sure to disable the LED display and the ICM7555 circuits for a true measurement. With the device and LEDs enabled, the supply current may be 60mA. The current drops to less than 15mA with the LEDs disabled. Using PWRDN with VREF- connected to ground will reduce the current to about 3.5mA. Finally, in power-down mode with VREF- disabled by Q1 and the ICM7555 disabled, the supply current will typically be less than 50µA. The actual reading will include the MAX152/MAC153 VDD current, static current for the 74HCT574, and 10µA drawn through the 510kΩ resistor R2. ______________________________________________________________________________________ 15 MAX152 EV Kit LEDs display the output of the MAX152/MAX153 after each conversion. Removing the J7 shunt will disable the LED display and lower the positive supply current. 16 R13 OPEN RD INT WR/RDY VIN VDD J5 J8 R1 300Ω PWRDN C4 + 22µF 1 2 3 4 5 6 7 8 9 10 VREF- 1 MAX152 U1 VDD 20 VIN VSS 19 D0 D1 PWRDN 18 D7 17 D2 D6 16 D3 WR/RDY D5 15 D4 14 MODE 13 CS 12 RD VREF+ 11 INT GND VREF- C3 0.1µF 1 J1 3 2 2 3 Q1 J3 1 C8 O.1F 2 3 R2 510k C1 J4 0.1µF + RS CV THR DIS TR R11 10kΩ 4 5 6 7 2 C5 100pF C7 0.1µF J6 CS VREF+ GND VSS ICM7555 U3 8 V+ 3 O 1 GND J2 C2 22µF DATA CONNECTOR 1 D0 D1 2 3 4 D3 6 5 D2 D5 8 7 D4 D7 10 9 D6 CS WR/RD 11 12 INT RD 13 14 15 VDD VDD 16 GND GND 0.1µF R12 510k 2 3 4 5 6 7 8 9 Q0 Q1 Q2 Q3 Q4 Q5 Q6 Q7 74HCT574 U2 CE CLK D0 D1 D2 D3 D4 D5 D6 D7 J7 19 18 17 16 15 14 13 12 D1 R10 620Ω R9 620Ω R8 620Ω D8 D7 D6 D5 D4 R7 620Ω D3 R6 620Ω D2 R5 620Ω R4 620Ω R3 620Ω MAX152 EV Kit MAX152 Evaluation Kit Figure 1. MAX152 EV Kit Schematic ______________________________________________________________________________________ MAX152 Evaluation Kit MAX152 EV Kit Figure 2. MAX152 EV Kit Component-Side Layout ______________________________________________________________________________________ 17 MAX152 EV Kit MAX152 Evaluation Kit Figure 3. MAX152 EV Kit Solder-Side Layout (Mirror Image) 18 ______________________________________________________________________________________ MAX152 Evaluation Kit MAX152 EV Kit Figure 4. MAX152 EV Kit Component Placement Guide ______________________________________________________________________________________ 19 MAX152 EV Kit MAX152 Evaluation Kit 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. 20 __________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 (408) 737-7600 © 1993 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.