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19-2701; Rev 0; 12/02
MAX1993 Evaluation Kit
General Description
The MAX1993 evaluation kit (EV kit) demonstrates the MAX1993's standard 4A application circuit. This DC-toDC converter steps down high-voltage batteries and/or AC adapters, generating a precision, low-voltage rail for use as chipset, DRAM, and other low-voltage supplies. The MAX1993 EV kit provides a dynamically adjustable 1.0V/1.5V output voltage from 7V to 24V battery input range. It delivers up to 4A output current with greater than 90% efficiency. The EV kit operates at 300kHz switching frequency and has superior line- and loadtransient response. This EV kit is a fully assembled and tested circuit board. It also allows the evaluation of other dynamically adjustable output voltages in the 0.7V to 5.5V range by changing R6, R7, and R8 resistors. This EV kit can also be used to evaluate the MAX1992, which has preset 1.8V/2.5V output voltages.
Features
o 7V to 24V Input Voltage Range o Preset 1.8V/2.5V Output Voltages (Adjustable from 0.7V to 5.5V, MAX1992) o Dynamically Selectable Output Voltages 1.0V/1.5V (Adjustable from 0.7V to 5.5V, MAX1993) o 4A Output Current o 300kHz Switching Frequency o Selectable Inductor Saturation Protection o Power-Good Output o Selectable Overvoltage/Undervoltage Protection o Low-Profile Components o Fully Assembled and Tested
Evaluates: MAX1992/MAX1993
Ordering Information
PART MAX1993EVKIT TEMP RANGE 0C to +70C IC PACKAGE 24 Thin QFN 4mm x 4mm
Component List
DESIGNATION QTY C1 1 DESCRIPTION 10F, 25V ceramic capacitor (1812) Taiyo Yuden TMK432BJ106KM or TDK C4532X5R1E106M 270F, 2.5V, 9m low-ESR capacitor Sanyo 2R5TPE220M9 1F, 10V X5R ceramic capacitors (0805) Taiyo Yuden LMK212BJ105KG or TDK C2012X5R105M 0.1F ceramic capacitor (0603) 470pF ceramic capacitor (0603) 0.22F, 16V X5R ceramic capacitor (0805) Taiyo Yuden EMK212BJ224KG 1000pF ceramic capacitor (0603) 10F, 6.3V X5R ceramic capacitor (0805) TDK C2012X5R0J106M or Taiyo Yuden AMK212BJ106MG Not installed (0603) 1A, 30V Schottky diode Nihon EP10QY03 or Nihon EC10QS03 100mA, 30V Schottky diode Central Semiconductor CMPSH-3 3-pin headers R19 U1 None None None 0 1 4 4 1 DESIGNATION QTY JU4 L1 N1A, N1B R1, R11, R12, R22 R2, R3, R13-R17, R20, R21 R4 R5 R6, R7 R8 R9 R10 R18 1 1 2 4 DESCRIPTION 4-pin header 2.5H, 7.5A power inductor Sumida CDRH104R-2R5 Dual N-channel MOSFETs Fairchild FDS6982A 0 resistors (0603)
C2
1
C3, C7 C4 C5 C6 C8
2 1 1 1 1
0 1 1 2 1 1 1 1
Not installed (0603) 100k 1% resistor (0603 49.9k 1% resistor (0603) 75k 1% resistors (0603) 150k 1% resistor (0603) 100k 5% resistor (0603) 20 5% resistor (0805) 0.015 1%, 1/2W resistor (2010) IRC LR2010-01-R015-F or Dale WSL-2010-R015F Not installed (short PC trace) (0805) MAX1993ETG (24-pin thin QFN) Shunts Rubber feet MAX1993 PC board
C9
1
C10, C11, C12 D1 D2 JU1, JU2, JU3
0 1 1 3
________________________________________________________________ Maxim Integrated Products
1
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.
MAX1993 Evaluation Kit Evaluates: MAX1992/MAX1993
Component Suppliers
SUPPLIER Central Semiconductor Dale-Vishay IRC Fairchild Nihon Taiyo Yuden TDK Sanyo Sumida PHONE 516-435-1110 402-564-3131 361-992-7900 408-721-2181 847-843-7500 408-573-4150 847-390-4373 619-661-6835 708-956-0666 FAX 516-435-1824 402-563-6296 361-992-3377 408-721-1635 847-843-2798 408-573-4159 847-390-4428 619-661-1055 708-956-0702 WEBSITE www.centralsemi.com www.vishay.com www.irctt.com www.fairchildsemi.com www.niec.co.jp www.t-yuden.com www.component.tdk.com www.sanyovideo.com www.sumida.com
Note: Please indicate that you are using the MAX1993 when contacting these component suppliers.
Required Equipment
* 7V to 24V, power supply, battery, or notebook AC adapter * DC bias power supply, 5V at 100mA * Dummy load capable of sinking 4A * Digital multimeter (DMM) * 100MHz dual-trace oscilloscope
Table 1. Jumper JU1 Functions (Shutdown Mode)
JU1 1 and 2 (default) 2 and 3 SHDN PIN Connected to VCC Connected to GND SHDN must be driven by an external signal; connected to SHDN pad MAX1993 OUTPUT MAX1993 enabled Shutdown mode MAX1993 operation depends on the external SHDN signal levels
Not installed
Quick Start
1) Ensure that the circuit is connected correctly to the supplies and dummy load prior to applying any power. 2) Verify that the shunts are across JU1 pins 1 and 2 (SHDN high), JU2 pins 1 and 2 (forced PWM), JU3 pins 2 and 3 (1.5V output), and JU4 pins 1 and 2 (OVP/UVP enabled). 3) Turn on battery power prior to +5V bias power; otherwise, the output UVLO timer times out and the FAULT latch is set, disabling the regulator until +5V power is cycled or shutdown is toggled. 4) Observe the 1.5V output with the DMM and/or oscilloscope. Look at the LX switching node and MOSFET gate-drive signals while varying the load current.
Table 2. Jumper JU2 Functions (Low-Noise Mode)
JU2 1 and 2 (default) SKIP PIN Connected to VCC OPERATIONAL MODE Low-noise mode, forcedPWM operation Normal operation; allows automatic PWM/PFM switchover for pulse skipping at light load, resulting in highest efficiency
2 and 3
Connected to GND
Detailed Description
Jumper Settings Evaluating Other Dynamic Output Voltages
The EV kit output is preset to 1.0V/1.5V. However, the output voltage can also be adjusted between 0.7V and 2V (FB = OUT) by selecting R6, R7, and R8 values. The
2
MAX1993 regulates FB to the voltage set at REFIN. By changing the voltage at REFIN, the MAX1993 can be used in applications that require dynamic output-voltage changes between two set points. Using the GATE signal and open-drain output (OD), a resistor can be switched in and out of the REFIN resistor-divider, changing the voltage at REFIN. A logic high on GATE turns on the internal N-channel MOSFET, forcing OD to a low-impedance state. A low logic on GATE disables the N-channel MOSFET, so OD is high impedance. The
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MAX1993 Evaluation Kit Evaluates: MAX1992/MAX1993
Table 3. Jumper JU3 Functions (GATE-- MAX1993 Only)
JU3 GATE PIN MAX1993 OUTPUT A logic high on GATE turns on the internal MOSFET, pulling OD to ground, VOUT = 1.0V. A logic low on GATE turns off the internal MOSFET so that OD appears as a high impedance, VOUT = 1.5V.
Table 5. Jumper JU5 Functions (Switching-Frequency Selection)
JU5 1 and 2 1 and 3 1 and 4 Not installed (default) TON PIN Connected to VCC Connected to REF Connected to GND Floating FREQUENCY (kHz) 200 450 600 300 (as shipped)
1 and 2
Connected to VCC
2 and 3 (default)
Connected to GND
Not installed
GATE must be driven by an VOUT depends on the external signal; external GATE signal connected to GATE levels. pad
Note: Do not change the operating frequency without first recalculating component values, because the frequency has a significant effect on preferred inductor value, peak current-limit level, MOSFET heating, PFM/PWM switchover point, output noise, efficiency, and other critical parameters.
Refer to the MAX1993 data sheet for selection of output capacitor and inductor values for output voltages greater than 2V.
Evaluating the MAX1992
Table 4. Jumper JU4 Functions (Overvoltage/Undervoltage Protection Selection)
JU4 OVP/UVP PIN UVP UVP is enabled; UVP threshold is 70% of nominal. UVP is enabled. UVP is disabled. UVP is disabled. OVP/DISCHARGE MODE
This EV kit can also be used to evaluate the MAX1992 by following these steps: 1) Remove the MAX1993 and install the MAX1992. 2) Short pin 21 (AGND) to pin 20 (PGND) at the IC pins. 3) Remove the shunt from JU3 (GATE open). 4) Install resistors R1 and R2 for the desired output voltage. The MAX1992 provides a fixed 1.8V output when FB is connected to VCC (R3 = short, R1 and R2 = open) or a fixed 2.5V output when FB is connected to GND (R2 = short, R1 and R3 = open). The output voltage can also be adjusted from 0.7V to 5.5V using a resistive voltage-divider formed by R1 and R2. The MAX1992 regulates FB to a fixed reference voltage (0.7V). The adjusted output voltage is: VOUT = VFB (1 + R1/R2) where VFB = 0.7V. Refer to the MAX1992 data sheet for selection of output capacitor and inductor values for different output voltages.
1 and 2 (default)
Connected to VCC
OVP is enabled; OVP threshold is 116% of nominal.
1 and 3 1 and 4 Not installed
Connected to REF Connected to GND Floating
OVP and discharge mode are disabled. OVP and discharge mode are disabled. OVP and discharge mode are enabled.
Note: The MAX1993 detects and latches the discharge mode state set by OVP/UVP on startup.
two output voltages (FB = OUT) are determined by the following equations: VOUT(LOW) = VREF (R7/(R6 + R7)) VOUT(HIGH) = VREF (R7 + R8)/(R6 + R7 + R8) where VREF = 2.0V.
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MAX1993 Evaluation Kit Evaluates: MAX1992/MAX1993
C7 1F 10V REF R20 R14 OPEN OPEN R13 OPEN 3 22 VCC LSAT 19 VDD BST 17 R19 SHORT (PC TRACE) D2 CMPSH-3
VCC R10 20
VDD VBIAS +5V C3 1F 10V GND
R9 100k
PGOOD VCC SHDN VCC 1 2 3 1 2 3
4
PGOOD
V+
14 5 6 C1 10F 25V
VIN 7V TO 24V GND
JU1
23
SHDN
U1
DH
15
N1-B 4 3 C4 0.1F
SKIP
JU2 REF 450kHz VCC JU5 2 3 4 200kHz 1
MAX1993 13 SKIP (MAX1992)
LX
16 7 8
L1 2.5H
R18 0.015 1% C2 270F 2.5V C9 10F 6.3V
1.0V/1.5 AT 4A VOUT
REF C8 1000pF R6 75k 1% R7 75k 1% VCC 1 2 3
1
TON
FLOAT = 300kHz 600kHz 7 REFIN (N.C.)
DL
18
N1-A 2 1
D1
GND
(PGND) GND
20
R8 150k 1%
8
OD (N.C.)
CSP
11 C10 OPEN
R11 0
GATE
JU3 REF R15 OPEN VCC
21
GATE (AGND)
CSN
12
R12 0
R21 R16 OPEN OPEN
2
FBLANK (N.C.)
OUT
10 C12 OPEN
R22 0 VCC R1 0
C6 0.22F
REF 6 VCC R4 100k 1% R17 OPEN 5 R5 49.9k 1% ILIM OVP/UVP 24 REF FB 9 VCC 2 1 4
R3 OPEN
R2 OPEN
C11 OPEN
C5 470pF
JU4 REF 3
Figure 1. MAX1993 EV Kit Schematic 4 _______________________________________________________________________________________
MAX1993 Evaluation Kit Evaluates: MAX1992/MAX1993
Figure 2. MAX1993 EV Kit Component Placement Guide-- Component Side
Figure 3. MAX1993 EV Kit PC Board Layout--Component Side
Figure 4. MAX1993 EV Kit PC Board Layout--GND Layer 2
Figure 5. MAX1993 EV Kit PC Board Layout--GND Layer 3
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MAX1993 Evaluation Kit Evaluates: MAX1992/MAX1993
Figure 6. MAX1993 EV Kit PC Board Layout--Solder Side
Figure 7. MAX1993 EV Kit Component Placement Guide-- 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) 2002 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

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