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19-3614; Rev 0; 3/05
MAX8620Y Evaluation Kit
General Description
The MAX8620Y evaluation kit (EV kit) is a fully assembled and tested circuit board that evaluates the MAX8620Y power-management IC. The MAX8620Y IC features a 500mA adjustable step-down DC-DC converter, two 300mA low-dropout linear regulators (LDOs), and a reset function. The MAX8620Y EV kit is configured to operate over a 2.7V to 5.5V input range. The MAX8620Y EV kit stepdown converter's output voltage is configured for 1.8V at 500mA, and the two LDOs can be configured through jumpers to nine different output voltages in the 1.8V to 3.3V range. This makes the MAX8620Y suitable for DSP or microprocessor (P) power-management applications in handsets, PDAs, smartphones, and other portable applications.
Features
o 1.8V, 500mA, 2.5MHz Step-Down DC-DC Converter o Up to 92% High-Efficiency Step-Down Converter o Internal Synchronous Rectifier o Two Low-Noise, 300mA LDOs with JumperSelectable Output Voltages o 30ms (min) RESET Output Signal o Demonstrates Hands-Free Enabling o Power Sequencing and On/Off Control Logic o Overcurrent and Thermal Protection o Tiny 3mm x 3mm, 14-Pin TDFN Package o Fully Assembled and Tested
Evaluates: MAX8620Y
Ordering Information
PART MAX8620YEVKIT TEMP RANGE 0C to +70C IC PACKAGE 14 TDFN
Component List
DESIGNATION C1 QTY 1 DESCRIPTION 10F 20%, 6.3V X5R ceramic capacitor (0805) TDK C2012X5R0J106M 4.7F 10%, 6.3V X5R ceramic capacitors (0603) TDK C1608X5R0J475K 2.2F 10%, 6.3V X5R ceramic capacitor (0603) TDK C1608X5R0J225K 150pF 5%, 50V C0G ceramic capacitor (0603) TDK C1608C0G1H151J 0.01F 5%, 25V C0G ceramic capacitor (0603) TDK C1608C0G1E103J DESIGNATION JU1, JU2, JU3 JU4 L1 C2, C3 2 R1 R2 R3 R4, R5, R6 SW1 U1 None None QTY 3 1 1 1 1 1 3 1 1 4 1 DESCRIPTION 3-pin headers 2-pin header 2.2H, 790mA inductor (1210) Murata LQH32CN2R2M53 150k 1% resistor (0603) 75k 1% resistor (0603) 100k 5% resistor (0603) 1M 5% resistors (0603) Momentary pushbutton switch MAX8620YETD (14-pin TDFN with EP) Shunts (JU1-JU4) MAX8620Y EV kit PC board
C4
1
C5
1
C6
1
________________________________________________________________ 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.
MAX8620Y Evaluation Kit Evaluates: MAX8620Y
Component Suppliers
SUPPLIER Murata TDK PHONE 770-436-1300 847-803-6100 FAX 770-436-3030 847-390-4405 WEBSITE www.murata.com www.component.tdk.com
Note: Indicate that you are using the MAX8620Y when contacting these component suppliers.
Quick Start
Recommended Equipment
* 5V, 2A power supply The MAX8620Y EV kit is fully assembled and tested. Follow these steps to verify board operation. Do not turn on the power supply until all connections are completed: 1) Verify that a shunt is installed across pins 2 and 3 of jumper JU1. This configures the PWR_ON pin to be pulled high by VOUT1. 2) Verify that shunts are installed across pins 1 and 2 of jumpers JU2 and JU3. This configures VOUT1 and VOUT2 to provide 3.0V and 2.5V, respectively. 3) Verify that no shunt is installed on jumper JU4 (VOUT2 enabled). 4) Connect the 5V power supply across the IN and GND PC board pads. 5) 6) 7) 8) 9) Turn on the 5V power supply. Momentarily press and release pushbutton switch SW1. Verify that the voltage across the OUT1 and GND pads is 3.0V. Verify that the voltage across the OUT2 and GND pads is 2.5V. Verify that the voltage across the OUT3 and GND pads is approximately 1.8V.
Detailed Description
The MAX8620Y EV kit features a 1.8V, 500mA stepdown converter, two configurable 300mA LDOs and a 30ms (min) delayed reset timer. The LDO outputs OUT1 and OUT2 can be configured through jumpers JU2 and JU3 to nine different output voltages in the 1.8V to 3.3V range. To reconfigure OUT1 and OUT2, the EV kit input power needs to be recycled. The MAX8620Y EV kit demonstrates the hands-free enabling feature of the MAX8620Y through momentary pushbutton switch SW1. Additionally, the EV kit demonstrates the power-on sequencing capability of the MAX8620Y. The step-down converter needs a very small output capacitor (C4) due to its unique feedback network, consisting of feedback resistors R1 and R2 and feedforward capacitor C5. The switching frequency of the MAX8620Y can be reconfigured up to 4MHz by appropriately selecting inductor L1 and capacitor C5. To reconfigure the MAX8620Y switching frequency, refer to the Inductor Selection section in the MAX8620Y data sheet. The MAX8620Y features overcurrent and thermal protection to provide device safety.
PWR_ON Enable
The MAX8620Y can be enabled by asserting a logichigh signal on the PWR_ON pin using jumper JU1. An external controller can also be used to assert logichigh. See Table 1 for jumper JU1 configuration.
Table 1. Jumper JU1 Function
SHUNT LOCATION 1 and 2 2 and 3 Not installed PWR_ON PIN CONNECTION Connected to IN Connected to OUT1 Pulled to GND by resistor R6 EV KIT FUNCTION MAX8620Y is enabled by the input IN. MAX8620Y is enabled by the HF_PWR and maintained by the output OUT1. MAX8620Y is in shutdown mode.*
*An external signal can be applied across the PWR_ON and GND PC board pads to enable the MAX8620Y.
2
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MAX8620Y Evaluation Kit Evaluates: MAX8620Y
Table 2. Jumper JU4 Function
SHUNT LOCATION Installed Not installed EN2 PIN CONNECTION Connected to OUT1 Pulled to GND by resistor R4 OUT2 is disabled OUT2 is enabled EV KIT FUNCTION
HF_PWR
The MAX8620Y IC can also be enabled using the HF_PWR pin in conjunction with the PWR_ON pin. Momentarily pressing switch SW1 on the MAX8620Y EV kit emulates a rising edge on the HF_PWR pin. The PWR_ON pin must be asserted high within 1.23 seconds (typ) after a rising edge is detected at the HF_PWR pin. Install a shunt across pins 2 and 3 of jumper JU1 or connect an external signal to the HF_PWR PC board pad to test this feature. See Table 1 for jumper JU1 configuration.
The MAX8620Y's step-down converter operates with inductors in the 1H to 4.7H range. The MAX8620Y can support up to 500mA load current connected to the OUT3 PC board pad. Select an inductor rated for 100mA greater than the desired load current. Ceramic capacitors with a dielectric rating of X5R or X7R type are recommended for the step-down converter's output capacitor C4 on the MAX8620Y EV kit. To achieve optimum load-transient performance and a very low output voltage ripple, the output capacitor's numerical value in F should be equal to or greater than the inductor value in H. For example, the EV kit has a 2.2F capacitor for C4 and thus L1 is a 2.2H inductor. Refer to the MAX8620Y data sheet for additional information on selecting inductor L1 and output capacitor C4.
EN2
The MAX8620Y LDO output OUT2 can be disabled by asserting logic-high on the EN2 pin through jumper JU4 on the MAX8620Y EV kit board. See Table 2 for jumper JU4 configuration.
Setting the Step-Down Converter Output Voltage
The step-down converter output OUT3 voltage can be reconfigured in the 0.6V to 2.5V range by selecting resistors R1 and R2 according to the following equation: V R1 = R2 x OUT3 - 1 0.6 where resistor R2 is typically 100k and VOUT3 is the desired output voltage at the OUT3 PC board pad.
Setting LDO OUT1 and OUT2 Output Voltages
The MAX8620Y EV kit LDO outputs OUT1 and OUT2 can be configured through jumpers JU2 and JU3 to nine different output voltages in the 1.8V to 3.3V range. See Table 3 for jumpers JU2 and JU3 configuration. The EV kit input power needs to be recycled after reconfiguring jumpers JU2 and JU3.
Table 3. LDOs Output Voltage Configuration
JUMPER JU2 SHUNT LOCATION 1 and 2 1 and 2 1 and 2 Not installed Not installed Not installed 2 and 3 2 and 3 2 and 3 JUMPER JU3 SHUNT LOCATION 1 and 2 Not installed 2 and 3 1 and 2 Not installed 2 and 3 1 and 2 Not installed 2 and 3 EV KIT FUNCTION OUT1 (V) 3.00* 2.85 3.00 3.30 2.80 3.30 2.85 2.60 1.80 OUT2 (V) 2.50* 2.85 3.00 2.50 2.60 1.80 2.60 2.60 2.60
*Default Quick Start Setting _______________________________________________________________________________________ 3
MAX8620Y Evaluation Kit Evaluates: MAX8620Y
LDO Output Capacitor Selection and Regulator Stability
The MAX8620Y EV kit is configured for up to 300mA load current at OUT1 and OUT2. To reconfigure the EV kit for other load currents, capacitors C2 and C3 may need replacement. See Table 4 for output capacitors C2 and C3 selection. For additional information, refer to the Capacitor Selection section in the IC data sheet.
Reset Timer
The MAX8620Y features a reset timer that can be used as a system reset signal. The MAX8620Y RESET pin is held low during power-up. The RESET is asserted high 30ms (min) after VOUT1 reaches 87% of its regulation voltage. This delayed reset signal confirms that output voltages must have settled to their final voltages.
Table 4. Capacitors C2 and C3 Selection
OUT1, OUT2 CURRENT (mA) 50 or less 150 or less 300 or less SELECT C2, C3 (F) 1.0 2.2 4.7
11 IN IN GND SW1 HF_PWR C1 10F 12
IN2
EN2
3 R4 1M
IN1
JU4 OUT1
OUT1 6 HF_PWR U1 IN R5 1M
13 C2 4.7F
R3 100k
OUT1
MAX8620Y
RESET 7 PWR_ON 4
RESET GND
PWR_ON
1 2 JU1 3 R6 1M 1 2 3 IN 1 2 3
OUT1
IN OUT2 SEL1 14 C3 4.7F L1 2.2H C4 2.2F OUT2 GND
JU2 1
JU3
2
SEL2
LX
10
OUT3 GND
R1 150k 1% C5 150pF 5 C6 0.01F BP GND 9 FB 8 R2 75k 1%
Figure 1. MAX8620Y EV Kit Schematic 4 _______________________________________________________________________________________
MAX8620Y Evaluation Kit Evaluates: MAX8620Y
Figure 2. MAX8620Y EV Kit Component Placement Guide-- Component Side
Figure 3. MAX8620Y EV Kit PC Board Layout--Component Side
Figure 4. MAX8620Y 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.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 _____________________ 5 (c) 2005 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products, Inc.

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