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19-2570; Rev 0; 8/02
MAX1982 Evaluation Kit
General Description
The MAX1982 evaluation kit (EV kit) provides a regulated 1.2V output voltage while operating on input voltages from 1.25V to 5.5V. It delivers a 0.3A output current from a 1.25V to 2.5V input, with less than 300mV dropout. Operation with higher input voltages (up to 5.5V) is possible as long as the maximum power dissipation across the internal pass transistor is less than 727mW. The MAX1982 EV kit is a fully assembled and tested surface-mount printed circuit (PC) board. The board is shipped with a fixed 1.2V output MAX1982 IC, and can also be used to evaluate the MAX1983 (adjustable output). Additional pads are provided on the board's component side to accommodate the external components used with the MAX1983. o 1.25V to 5.5V Input Supply Range o 1.2V Fixed Output Voltage o Up to 0.3A Output Current o <5A Shutdown Supply Current o Power-Good (PGOOD) Open-Drain Output with 1ms Rising Edge Propagation Delay (MAX1982) o Surface-Mount Construction o Fully Assembled and Tested
Features
Evaluates: MAX1982/MAX1983
Ordering Information
PART MAX1982EVKIT TEMP RANGE 0C to +70C IC PACKAGE 6 SOT23
Note: To evaluate the MAX1983, request a MAX1983EUT free sample with the MAX1982EVKIT.
Component List
DESIGNATION QTY C1 1 DESCRIPTION 0.1F 20%, X7R ceramic capacitor (1206) TDK C3216X7R2A104M 10F 20%, X5R ceramic capacitors (1210) TDK C3225X7R1C106M Not installed (0805) 3-pin header 2-pin header DESIGNATION QTY R1 R2, R3 U1 None None None None 1 2 1 2 1 1 1 DESCRIPTION 100k 5% resistor (0805) Not installed (0805) MAX1982EUT (6-pin SOT23) Top mark = ABEA Shunts MAX1982 PC board MAX1982 data sheet MAX1982 EV kit data sheet
C2, C3 C4 JU1 JU2
1 1 1 1
Component Suppliers
SUPPLIER TDK PHONE 847-803-6100 FAX 847-390-4405 WEBSITE www.component.tdk.com
Note: Please indicate that you are using the MAX1982 when contacting this component supplier.
________________________________________________________________ Maxim Integrated Products
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For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim's website at www.maxim-ic.com.
MAX1982 Evaluation Kit Evaluates: MAX1982/MAX1983
Quick Start
Recommended Equipment
* * * One variable DC power supply capable of supplying between 1.25V and 5.5V at 0.5A One fixed DC power supply capable of supplying 5V at 10mA Two voltmeters
Shutdown Control
The MAX1982 has an active-low shutdown control input to enable/disable its output. The 3-pin header JU1 selects the shutdown mode. Remove the shunt when driving shutdown with an external signal. Table 1 lists the jumper selectable options.
Evaluating the MAX1983
The MAX1982 can be replaced with a MAX1983 to generate an adjustable output voltage (0.8V to 2V) with an output current up to 0.3A. The modifications required are as follows: 1) Replace the IC (U1). 2) Remove R1. 3) Add R2 and R3 (located on the board's component side). 4) Insert a shunt across JU2 To set the output voltage, choose R2 as follows: V R2 = R3 x OUT - 1 VREF where: VOUT = desired output voltage VREF = 0.8V R3 40k
Procedure
The MAX1982 EV kit is fully assembled and tested. Follow the steps below to verify board operation. Do not turn on the power supply until all connections are completed: 1) Set the variable DC power supply to 2.5V. 2) Ensure that the variable DC power supply is turned off. 3) Ensure that the fixed 5V DC power supply is turned off. 4) Connect the variable DC power supply to the pad marked VIN. Connect the ground return of the power supply to the GND pad located across from VIN. 5) Connect the fixed 5V DC power supply to the pad marked BIAS. Connect the ground return of the power supply to the GND pad located across from VIN. 6) Connect a voltmeter and load (if any) to the pad marked VOUT. Connect the ground return of the voltmeter and load to the GND pad located across from the VOUT pad. 7) Connect a voltmeter to the pad marked PGOOD. Connect the ground return of the voltmeter to the GND user pad located across from the VOUT pad. 8) Turn on the variable DC power supply. 9) Turn on the fixed 5V DC power supply. 10) Verify that the PGOOD voltage is 5V. 11) Verify that the output voltage is 1.2V.
Adjusting PGOOD timing
The MAX1982 EV kit allows the user to extend the PGOOD propagation delay by adding capacitor C4. To set the propagation delay use the following equation: C4 = tPGprop - t R1 x 1 VPGOOD ln 1VBIAS
Detailed Description
The MAX1982 EV kit is a 300mA low-dropout (LDO) regulator capable of supplying a fixed 1.2V output from a variable 1.25V to 5.5V input. The EV kit comes equipped with on-board shutdown control, as well as additional pads for evaluating the MAX1983 (adjustable) LDO.
where: tPGprop = PGOOD propagation delay = 2ms (typ) VBIAS = 5V VPGOOD = 4.5V R1 = 100k t = desired propagation delay Note: t must be greater than tPGprop.
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MAX1982 Evaluation Kit Evaluates: MAX1982/MAX1983
Table 1. Shutdown Selection
JUMPER JU1 JU1 SHUNT POSITION 1-2 2-3 SHDN PIN Connected to BIAS Connected to GND DESCRIPTION MAX1982 enabled, VOUT = 1.2V Shutdown mode, VOUT = 0V
BIAS
1 C4 R1 OPEN 100k C1 0.1F
BIAS
IN
6 C2 10F
VIN
GND
U1 MAX1982 2 GND OUT 5 C3 10F VOUT
GND
SHDN
1 3
JU1 2
3
SHDN
PGOOD
4
R2 OPEN
PGOOD
JU2
R3 OPEN
Figure 1. MAX1982 EV Kit Schematic
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MAX1982 Evaluation Kit Evaluates: MAX1982/MAX1983
1.0"
1.0"
Figure 2. MAX1982 EV Kit Component Placement Guide-- Component Side
Figure 3. MAX1982 EV Kit PC Board Layout--Component Side
1.0"
Figure 4. MAX1982 EV Kit PC Board 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.
4 _____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 (c) 2002 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

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