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MAX152 Evaluation Kit
_______________General Description
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.
____________________________Features
o High-Speed 8-Bit ADC o Unipolar or Bipolar Input o No Clock Circuit Required o +3V (MAX152) or +5V (MAX153) Operation o Low-Power Shutdown Mode o LED Display of Conversion Results o 3in2 Prototyping Area o 16-Pin Data Connector for Interface to External System
MAX152 EV Kit
____________________Component List
DESIGNATION U1 U2 U3 C1, C3, C6, C7, C8 C2, C4 C5 D1-D8 Q1 R1 R2, R12 R3-R10 R11 J1, J3 J2, J4, J5, J6, J7, J8 None None None None None QTY 1 1 1 5 DESCRIPTION
______________Ordering Information
PART MAX152EVKIT-DIP TEMP. RANGE 0C to +70C BOARD TYPE Through-Hole
MAX152CPP 74HCT574 ICM7555CPA 0.1F ceramic capacitors 10F 16V radial electrolytic capacitors 100pF ceramic capacitor Red LEDs ME12N06EL Nihon N-channel logic-level MOSFET 300 5% resistor 510k 5% resistors 620 5% resistors 10k 5% resistor 3-pin jumper headers 2-pin jumper headers Shunts 16-pin ribbon cable connector 3.50" x 4.00" PC board Rubber feet MAX152 data sheet and EV kit manual
The MAX152EVKIT may also be used to evaluate the MAX153. To receive a free sample of the MAX153CPP, call 1-800-998-8800.
2 1 8 1 1 2 8 1 2 6 8 1 1 4 1
______________________________EV Kit
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MAX152 Evaluation Kit MAX152 EV 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. 2. Connect the power supplies (+3V for MAX152, +5V for MAX153) to the power input connector. 3. Connect an analog input to AIN input. 4. Read conversion results displayed on the LEDs.
J2 Open Short 1&2
Table 1. Jumper Functions
JUMPER CONNECTION 1&2 J1 2&3 Open FUNCTION VREF- connected to the drain of Q1 VREF- connected to ground Used when connecting a voltage source to the VREF- pad Used when connecting a voltage source to the VREF+ pad VREF+ shorted to VDD CS grounded CS driven by the ICM7555 Used when an external digital signal is applied to the CS input Used when driving VSS with a negative source (-5V or -3V) VSS connected to ground MODE pin open (internally pulled low) MODE pin connected to VDD ICM7555 circuit disabled ICM7555 circuit enabled LED display disabled LED display enabled Used when an external digital input is applied to the RD input RD driven by the ICM7555
_______________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.
J3
2&3 Open Open Short
J4
J5
Open Short
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 50A. Optionally, J4 can be shorted to connect VSS to ground when not using a negative supply.
J6
Open Short Open Short Open Short
J7
J8
Table 2. Jumper Selection for Free-Running Mode
JUMPER CONNECTION J1 J2 J3 J4 J5 J6 J7 J8 2&3 Short 2&3 Short Open Short Short Short FUNCTION VREF- connected to GND VREF+ connected to VDD CS driven by ICM7555 VSS connected to GND. Leave J4 open if a VSS source is used. MODE pin internally pulled low Enable the ICM7555 Enable the LED display RD driven by ICM7555
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
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MAX152 Evaluation 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. 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 4.7k 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.
Shutdown Modes
The function of the power-down pin (PWRDN) is to drop the MAX152/MAX153's supply current to typically 1A. Note, however, that VREF+ will continue to appear to the source as a 2k 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 510k 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 50A. The actual reading will include the MAX152/MAC153 VDD current, static current for the 74HCT574, and 10A drawn through the 510k resistor R2.
MAX152 EV Kit
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 2.5s 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.
______________________________________________________________________________________
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MAX152 EV Kit
MAX152 Evaluation Kit
Figure 1. MAX152 EV Kit Schematic
C4 + 22F C3 0.1F C1 J4 0.1F
+
16
C2 22F GND VSS J7 R3 620 R4 620 R5 620 R6 620 R7 620 R8 620 R9 620 74HCT574 U2 R10 620 0.1F J2 J6 R2 510k R12 510k D1 D2 D3 D4 D5 D6 D7 D8 R1 300 J5 CS VREF+ C8 O.1F
1 23
VDD
VIN
R13 OPEN
WR/RDY
RD INT
1 2 3 4 5 6 7 8 9 10 2 3 4 5 6 7 8 9 Q0 Q1 Q2 Q3 Q4 Q5 Q6 Q7 19 18 17 16 15 14 13 12 CE CLK D0 D1 D2 D3 D4 D5 D6 D7
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 VREFVREFJ3 4 5 6 7 2 C7 0.1F
J8
1 J1 2 1 Q1 3
23
8 V+ 3 O 1 GND RS CV THR DIS TR ICM7555 U3 R11 10k C5 100pF
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
______________________________________________________________________________________
PWRDN
MAX152 Evaluation Kit MAX152 EV Kit
Figure 2. MAX152 EV Kit Component-Side Layout
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MAX152 Evaluation Kit MAX152 EV Kit
Figure 3. MAX152 EV Kit Solder-Side Layout (Mirror Image)
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MAX152 Evaluation Kit MAX152 EV Kit
Figure 4. MAX152 EV Kit Component Placement Guide
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MAX152 Evaluation Kit MAX152 EV 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 (c) 1993 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

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