View MAX8568AEVKIT_324871.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

19-3612; Rev 0; 3/05
MAX8568A Evaluation Kit
General Description
The MAX8568A evaluation kit (EV kit) is a fully assembled and tested circuit board that evaluates the MAX8568A and MAX8568B complete backup-management ICs for lithium and NiMH batteries. The MAX8568A EV kit can charge both NiMH and rechargeable lithium battery types; the EV kit default setting is for NiMH charging. Two on-board p-channel MOSFETs allow the evaluation of backup switchover from the primary source. Low-voltage backup cells can be stepped up by the on-chip synchronous-rectified step-up DC-DC converter, which has a default setting of 3.3V on the EV kit and is capable of 50mA output current. A secondary output provided by an on-chip LDO has a 2.5V output voltage for the MAX8568A and is capable of providing 10mA output current. When the main battery is connected, these two voltages are typically provided by a MAX1586/MAX1587 multi-output complete system power supply. The MAX8568A EV kit can also evaluate the MAX8568B. To evaluate the MAX8568B, order a free sample along with this EV kit.
Features
Charges Both NiMH and Rechargeable Lithium Backup Batteries Internal Switch Step-Up DC-DC Converter for 1-Cell NiMH Battery Input Two Backup Output Voltages 3.3V, 50mA Step-Up DC-DC Converter 2.5V, 10mA LDO Programmable Charge Current Programmable Charge Voltage Limit On Board p-Channel MOSFETs for Backup Switchover Fully Assembled and Tested
Evaluates: MAX8568A/MAX8568B
Ordering Information
PART MAX8568AEVKIT TEMP RANGE 0C to +70C IC PACKAGE 16 Thin QFN 3mm x 3mm
Component List
DESIGNATION C1, C4 QTY 2 DESCRIPTION 4.7F 10%, 6.3V X5R ceramic capacitors (0603) Murata GRM188R60J475K 10F 10%, 6.3V X5R ceramic capacitors (0805) Murata GRM219R60J106K 0.22F 10%, 6.3V X5R ceramic capacitor (0402) Murata GRM155R60J224K 3-pin header 10H inductor Murata LQH32CN100K53 -12V, 50m (max), SOT23 Fairchild Semiconductor FDN306P DESIGNATION R1 R2, R7 R3, R4 R5 R6 R8 R9 R10 U1 None None QTY 0 2 2 1 1 1 1 1 1 1 1 DESCRIPTION Open, resistor (0402) 0 resistors (0402) 100k 1% resistors (0402) 169k 1% resistor (0402) 49.9k 1% resistor (0402) 1.2M 5% resistor (0402) 357k 1% resistor (0402) 1M 1% resistor (0402) MAX8568A Shunts MAX8568A PC board
C2, C3
2
C5 JU1 L1 Q1, Q2
1 1 1 2
Component Suppliers
SUPPLIER Fairchild Semiconductor Kamaya Murata COMPONENT MOSFET Resistors Capacitor, Inductor PHONE 972-910-8000 260-489-1533 814-237-1431 WEBSITE www.fairchildsemi.com www.kamaya.com www.murata.com
Note: Indicate that you are using the MAX8568A when contacting these component suppliers. ________________________________________________________________ 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.
MAX8568A Evaluation Kit Evaluates: MAX8568A/MAX8568B
Quick Start
Recommended Equipment
* MAX1586A EV kit * One variable-DC power supply (further referred to as PS1) capable of supplying up to 5.5V at 1A * One variable-DC power supply (further referred to as PS2) capable of supplying up to 5V at 150mA * Two digital multimeters (DMM) * * * * One 75, 1/10W resistor 20mA load 5mA load Ammeter 12) Turn on PS2, and then turn on PS1. 13) Verify that the voltage at BK is approximately 1.3V. Verify that charging current from BK is approximately 10mA. 14) Increase the voltage at BK to 1.5V. Verify that charging current from BK is approximately 1mA. 15) Decrease the voltage at BK to 1.15V. Verify that charging current from BK is approximately 10mA. 16) Increase the voltage at BK to 1.85V. Verify that charging current from BK is approximately 0mA.
Procedure (Backup Switchover)
Follow the steps below to verify board operation: 1) Repeat steps 1 through 8 above (from the Procedure (Charging) section). 2) Connect the positive lead of PS2 to the BK pad and the negative lead of PS2 to the GND pad on the MAX8568A EV kit. 3) Connect the positive lead of one DMM to the I/O OUT pad on the MAX8568A EV kit and connect the negative lead of that DMM to the GND pad on the MAX8568A EV kit. 4) Connect the positive lead of the second DMM to the MEM OUT pad on the MAX8568A EV kit and connect the negative lead of that DMM to the GND pad on the MAX8568A EV kit. 5) Connect the 20mA load from I/O OUT to GND. 6) Connect the 5mA load from MEM OUT to GND. 7) Verify that the shunt on JU1 is in the NI position.
Procedure (Charging)
Follow the steps below to verify board operation: 1) Preset the variable-DC power supply, PS1, to 4.2V. Turn off the power supply. Do not turn on the power supply until all connections are complete: 2) Preset the variable-DC power supply, PS2, to 1.3V. Turn off the power supply. Do not turn on the power supply until all connections are complete: 3) Connect the 75 resistor from the positive lead of PS2 to the negative lead of PS2. This allows PS2 to sink current to simulate a rechargeable backup battery. 4) Connect the positive lead of PS1 to the VIN pad on the MAX1586A EV kit and connect the negative lead of PS1 to the GND pad on the MAX1586A EV kit. 5) Connect the VIN pad of the MAX1586A EV kit, as shown in Figure 1, to the MAIN pad of the MAX8568A EV kit. 6) Connect the VCC_I/O pad of the MAX1586A EV kit to the I/O IN pad of the MAX8568A EV kit. 7) Connect the VCC_MEM pad of the MAX1586A EV kit to the MEM IN pad of the MAX8568A EV kit. 8) Connect the GND pad of the MAX1586A EV kit to the GND pad of the MAX8568A EV kit. 9) Connect the positive lead of the ammeter (50mA setting/capability) to the BK pad on the MAX8568A EV kit. Connect the negative lead of the ammeter to the positive lead of PS2. Connect the negative lead of PS2 to the GND pad on the MAX8568A EV kit. 10) Connect the positive lead of a DMM to the BK pad on the MAX8568A EV kit and connect the negative lead of that DMM to the GND pad on the MAX8568A EV kit. 11) Verify that the shunt on JU1 is in the NI position.
2
DC POWER SUPPLY (PS1) NEGATIVE POSITIVE
VIN MAX1586A VCC_MEM EV KIT VCC_I/O GND MEM IN I/O IN GND
MAIN MAX8568A EV KIT BK
A NEGATIVE POSITIVE *REMOVE AMMETER FOR BACKUP SWITCHOVER TEST PROCEDURE
DC POWER SUPPLY (PS2)
Figure 1. Quick-Start Wiring Diagram
_______________________________________________________________________________________
MAX8568A Evaluation Kit
8) Turn on PS2, and then turn on PS1. 9) Verify that the voltage at I/O OUT is approximately 3.3V. Verify that the voltage at MEM OUT is approximately 2.5V. 10) Turn off PS1. 11) Verify that the voltage at I/O OUT is approximately 3.3V. Verify that the voltage at MEM OUT is approximately 2.5V. BK voltage where trickle-charge begins: VBK(NIHI) = 1.163 x VTERMV BK voltage where all charging stops: VBK(NIMAX) = 1.493 x VTERMV Figure 2 shows the connection of R6, R7, and R8. Select R8 in the 100k to 2M range. The equations for the two upper divider-resistors are: VBK (NIHI) R7 = R8 x - 1 1.163 x VBK (NILO) 1.163 x V REF - 1 R6 = (R7 + R8 ) x VBK(NIHI) where VREF is 1.25V. The MAX8568A/MAX8568B data sheet discusses using a NiMH backup battery in more detail.
Evaluates: MAX8568A/MAX8568B
Detailed Description
Evaluating the MAX8568A EV Kit Without the MAX1586A
To evaluate the MAX8568A without the MAX1586A, four power supplies are required. These supply MAIN (4.2V), BK (1.3V), I/O IN (3.3V), and MEM IN (2.5V). Note that the backup-battery boost converter will not operate unless I/O IN has been activated at least one time. The typical power removal sequence for testing is 1) main battery goes low, then 2) MEM IN and I/O IN go low.
Setting the Charge Current
Charge current is set by a resistor connected from CHGI to GND, R5 in Figure 2. The acceptable resistor range is from 50k to 1800k. Charge current is calculated by the following: 41.2 x ( VIN - VBK ) + 679.4 RCHGI (k) = ICHG (mA)
1.1641
Evaluating Rechargeable Lithium Backup Batteries
The MAX8568A EV kit can charge a lithium-type backup battery from the main battery connected at MAIN. Connect a shunt on jumper JU1 to the pins labeled LI for lithium backup-battery charging. The lithium charger acts like a current-limited voltage source. The MAX8568A/MAX8568B data sheet discusses using a lithium backup battery in more detail.
where VBK is the nominal voltage of the charged backup battery. This is the fast-charge current for both NiMH and lithium batteries. For NiMH batteries, the trickle-charge is 10% of the fast-charge current.
Evaluating the MAX8568B
For evaluating the MAX8568B, carefully remove the MAX8568A and install the MAX8568B. All other components can remain the same.
Setting the Fast-Charge-to-Trickle-Charge Transition Points
One 3-resistor-divider can be used to set the BK voltage where fast-charge begins (VBK(NILO)) and the BK voltage where trickle-charge begins (VBK(NIHI)) independently. VBK(NILO), VBK(NIHI), and the BK voltage where all charging stops (VBK(NIMAX)) are defined as follows: BK voltage where fast-charge begins: VBK(NILO) = VSTRTV
_______________________________________________________________________________________
3
MAX8568A Evaluation Kit Evaluates: MAX8568A/MAX8568B
MAIN C1 4.7F BK C2 10F
1
IN REF 16 C5 0.22F 15 R7 0 STRTV 14 R8 1.2M MAIN R9 357k INOK 11 R10 1M R6 49.9k
2
BK U1
L1 10H I/O OUT
TERMV
4 5 R1 OPEN Q1 R3 100k R2 0 C3 10F 3 10
MAX8568A LX BKSU PGND BKV GND 13
I/O IN
7 MEM OUT C4 4.7F 6
OD1 LDO
MEM IN
Q2 R4 100k
I/O OUT NI/LI CHGI 8 OD2 9 12 R5 169k JU1 * DEFAULT: SHUNT CONNECTS TO I/O OUT
Figure 2. MAX8568A EV Kit Schematic
4
_______________________________________________________________________________________
MAX8568A Evaluation Kit Evaluates: MAX8568A/MAX8568B
Figure 3. MAX8568A EV Kit Component Placement Guide-- Component Side
Figure 4. MAX8568A EV Kit PC Board Layout--Component Side
Figure 5. MAX8568A 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.

▲Up To Search▲

Price & Availability of MAX8568AEVKIT

	To Download MAX8568AEVKIT Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .