19-2508; Rev 0; 7/02 MAX1894/MAX1924 Evaluation Kit The MAX1894 evaluation kit (EV kit) is a fully assembled and tested circuit board. It uses the MAX1894 lithiumion (Li+) battery-pack protector to protect four series Li+ cell battery packs against overvoltage, undervoltage, excessive charge/discharge currents, and battery pack-short conditions. Three external P-channel MOSFETs control the charge and discharge paths of the battery pack. The MAX1894 EV kit provides two inputs, which can be used by a microcontroller (µC) to control the protection MOSFETs or put the MAX1894 in shutdown mode. The EV kit also evaluates the MAX1924. Features ♦ Protects Against Cell Overvoltage ♦ Protects Against Cell Undervoltage ♦ Protects Against Excessive Charge/Discharge Currents and Pack-Short Conditions ♦ 0.8µA (typ) Shutdown Supply Current Prevents Deep Discharge of Cells ♦ Low Operating Supply Current, 30µA (typ) ♦ Small 16-Pin QSOP Package ♦ Fully Assembled and Tested Ordering Information PART TEMP RANGE MAX1894EVKIT 0°C to +70°C IC PACKAGE 16 QSOP Component List DESIGNATION C1 QTY 1 DESIGNATION QTY 4.7µF ±20%, 6.3V X7R ceramic capacitor (0805) Taiyo Yuden JMK212BJ475MG J1, J2 2 Nonisolated banana jacks JU1, JU2, JU3 3 3-pin headers JU4, JU5 2 2-pin headers P1 1 -0.13A, -50V, P-channel MOSFET, SOT23 Fairchild Semiconductor BSS84 DESCRIPTION C2, C12 2 0.1µF ±10%, 50V X7R ceramic capacitors (0805) Taiyo Yuden UMK212BJ104KG C3, C4 0 0.1µF to 1µF ±20%, 50V X7R ceramic capacitors (0805), not installed C5 1 1µF ±10%, 6.3V X5R ceramic capacitor (0603) TDK C1608X5R0J105K C6, C7, C8 C9 C10, C11, C13, C14 D1 3 1 0 1 0.1µF ±10%,16V X7R ceramic capacitors (0603) Taiyo Yuden EMK107BJ104KA 2.2µF ±10%, 25V X7R ceramic capacitor (1206) TDK C3216X7R1E225K 0.1µF ±10%, 50V X7R ceramic capacitors (0805) Taiyo Yuden UMK212BJ104KG, not installed 100mA, 30V, Schottky diode, SOT23 Central Semiconductor CMPSH-3 DESCRIPTION 8A, -30V, P-channel MOSFETs , 8-pin SO Vishay Siliconix Si4435DY or International Rectifier Si4435DY P2, P3 2 R1 1 510Ω ±5% resistor (2512) R2 1 0.02Ω ±1%, 2W resistor (2512) IRC LRC-LRF 2512-01-R020-F R3 1 51Ω ±5% resistor (0805) R4, R5, R6 3 1kΩ ±5% resistors (0805) R7 1 10Ω ±5% resistor (0805) TB1 1 5-pin terminal block U1 1 MAX1894XEEE, 16-pin QSOP U2 1 MAX1615EUK-T, 5-pin SOT23 None 5 Shunts (JU1–JU5) None 1 MAX1894 PC board None 1 MAX1894 data sheet None 1 MAX1894 EV kit data sheet ________________________________________________________________ Maxim Integrated Products 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. 1 Evaluates: MAX1894/MAX1924 General Description Evaluates: MAX1894/MAX1924 MAX1894/MAX1924 Evaluation Kit Component Suppliers PHONE FAX Fairchild Semiconductor SUPPLIERS 888-522-5372 972-910-8023 www.fairchildsemi.com WEBSITE International Rectifier 310-322-3331 310-726-8721 www.irf.com IRC 361-992-7900 361-992-3377 www.irctt.com Taiyo Yuden 800-348-2496 847-925-0899 www.t-yuden.com TDK 847-803-6100 847-390-4405 www.component.tdk.com Vishay Siliconix 408-988-8000 408-567-8979 www.vishay.com Note: Please indicate that you are using the MAX1894 or MAX1924 when contacting these component suppliers. Quick Start The MAX1894 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. + TB1 MAX1894 Recommended Equipment PACK+ • Current-limited 25V power supply (or Li+ charger) • One voltmeter • Four Li+ cells (2.3V to 4.35V) Warning: Exercise caution when handling loose Li+ cells. Obey all manufacturer guidelines for handling Li+ cells. For test purposes, floating power supplies can be substituted for the Li+ cells. CELL 4 - POWER SUPPLY + - B4P + B3P - CELL 3 B2P PACK - B1P + BN - CELL 2 + CELL1 - Jumper Setting and Connecting the Li+ Cells 1) Install a shunt across pins 1 and 2 of jumper JU1. 2) Install a shunt across pins 2 and 3 of jumpers JU2 and JU3. 3) Install a shunt across jumper JU4, and remove the shunt from jumper JU5. 4) See Figure 1 for connecting the Li+ cells (steps 5 to 12). 5) Connect the negative terminal of Li+ cell 1 to BN of terminal block TB1. 6) Connect the positive terminal of Li+ cell 1 to B1P of terminal block TB1. 7) Connect the negative terminal of Li+ cell 2 to B1P of terminal block TB1. 8) Connect the positive terminal of Li+ cell 2 to B2P of terminal block TB1. 9) Connect the negative terminal of Li+ cell 3 to B2P of terminal block TB1. 10) Connect the positive terminal of Li+ cell 3 to B3P of terminal block TB1. 11) Connect the negative terminal of Li+ cell 4 to B3P of terminal block TB1. 2 Figure 1. Connecting the Li+ Cell, Power Supply, and Voltmeter 12) Connect the positive terminal of Li+ cell 4 to B4P of terminal block TB1. Connecting the Power Supply 1) See Figure 1 for connecting the power supply (steps 2 and 4 below). The power supply should be current limited to no more than the C rate of the battery pack. 2) Using short banana leads, connect the negative terminal of the power supply to J2 (PACK-). 3) Turn on the power supply and set the power-supply voltage to 4.2V x the number of cells in series. Momentarily connect the positive terminal of the power supply to J1 (JACK+). 4) Remove the positive terminal of the power supply from PACK+, and verify that the DSO, CGO, and TKO pads are pulled low. 5) Momentarily short the PACK+ and PACK- pads with a short banana lead. Verify that the DSO, CGO, and TKO pads are pulled high. 6) Reconnect the positive terminal of the power supply to J1 (PACK+). _______________________________________________________________________________________ MAX1894/MAX1924 Evaluation Kit Note: Short leads are less than 6in long. Detailed Description The MAX1894 EV kit protects Li+ battery cells against charge/discharge faults. The EV kit is designed for both 3- and 4-cell applications. It is configured from the factory for a 4-cell application with the MAX1894X installed. For a 3-cell application, replace the MAX1894X with the MAX1924V and reconfigure jumper JU5 (see Table 5). The EV kit monitors the voltage across each cell to provide protection against undervoltage and overvoltage conditions. The EV kit also monitors the voltage across the current-sense resistor (R2) to protect against excessive charge and discharge current, and pack short conditions. The MAX1894 EV kit also features a MAX1615 lowpower linear regulator, configurable for 3.3V or 5V to power a µC. The linear regulator can provide 30mA for VIN up to 28V. The charge and discharge paths of the battery pack are controlled by three P-channel MOSFETs: the trickle-charge MOSFET P1, the overdischarge MOSFET P2, and the overcharge MOSFET P3. In the event of a fault condition, some or all of these protection MOSFETs are turned off to disconnect the battery pack from the current path. The MAX1894 EV kit provides two logic-level inputs, which can be connected to general-purpose input/output (GPIO) lines from a µC. These inputs can be used to turn off all three protection MOSFETs, or put the MAX1894 in shutdown mode for minimizing the current consumption during pack storage. Trickle-Charge Operation When the MAX1894 is in an undervoltage or deep discharge state (VCC < 4.5V typ), the circuit operates in trickle-charge mode. During trickle-charge operation, MOSFETs P2 and P3 are turned off and MOSFET P1 is turned on to provide a lower current charge path for the battery pack. Refer to the Fast and Trickle-Charge Paths section in the MAX1894 data sheet. Normal Operation When all cell voltages are greater than 2.36V, the MAX1894 EV kit operates in normal mode and can readily charge and discharge. During normal operation, all three MOSFETs (P1, P2, and P3) are turned on to provide a current path for the battery pack. The voltage across the current-sense resistor (R2) monitors the charge and discharge current during normal operation. Shutdown The MAX1894 EV kit goes into shutdown mode when an undervoltage fault occurs or when a logic high is applied to the shutdown pad (SHDN). During shutdown mode, the quiescent current is 0.8µA (typ). Control The control pad (CTL) on the MAX1894 EV kit can be connected to one of the GPIO lines of a µC to turn off all the protection MOSFETs simultaneously. Discharge Current Protection When the discharge current exceeds 7.25A (IOD_TH = VOD_TH/R2) for more than 3ms, all protection MOSFETs are turned off, disconnecting the battery pack from the current path. Charge-Current Protection When the charge current exceeds 5A (I OC_TH = V OC_TH /R2) for more than 3ms, the trickle-charge MOSFET P1 and the overcharge MOSFET P3 are turned off, disconnecting the battery pack from the current path. Pack-Short Current Protection When the discharge current exceeds a second higher current limit, 20A (IPS_TH = VPS_TH/R2) for more than 450µs, all protection MOSFETs are turned off, disconnecting the battery pack from the current path. Jumper Selection VDD Enable Jumper JU4 enables the VDD power supply by connecting the input of the MAX1615 to B4_P. Install a shunt on JU4 to enable VDD. Remove the shunt from JU4 to disable VDD. See Table 4 for shunt positions. VDD Selection Jumper JU1 selects the output voltage of VDD. To set VDD to +5V, install a shunt across pins 1 and 2 of JU1. To set VDD to +3.3V, install a shunt across pins 2 and 3 of JU1. See Table 1 for shunt positions. MAX1894 EV Kit Shutdown Jumper JU2 selects the shutdown mode. To shut down the part, install a shunt across pins 1 and 2 of JU2. To enable the part, install a shunt across pins 2 and 3 of JU2. The shutdown mode can also be driven by an external µC connected to the SHDN pad. To use an external µC for the shutdown mode, remove the shunt from JU2 and connect the output of the µC to the SHDN pad. See Table 2 for shunt positions. _______________________________________________________________________________________ 3 Evaluates: MAX1894/MAX1924 7) Verify that the DSO, CGO, and TKO pads are pulled low. Evaluates: MAX1894/MAX1924 MAX1894/MAX1924 Evaluation Kit Table 1. JU1 Jumper Selection JUMPER JU1 SHUNT POSITION VDD OUTPUT VOLTAGE (V) 1-2* VDD = +5 2-3* VDD = +3.3 *A shunt must be installed on one of these selections. 3-Cell/4-Cell Selection Jumper JU5 selects between the 3-cell and the 4-cell battery pack applications for the MAX1894 EV kit. The MAX1894 EV kit is set at the factory for 4-cell applications. For 3-cell battery pack applications, install a shunt across JU5, and replace U1 with the MAX1924V. See Table 5 for shunt positions. Table 2. JU2 Jumper Selection JUMPER JU2 SHUNT POSITION EV KIT FUNCTION 1-2 Shutdown mode enabled 2-3 Shutdown mode disabled None Shutdown mode controlled by an external controller Table 3. JU3 Jumper Selection JUMPER SHUNT POSITION 1-2 JU3 2-3 None EV KIT FUNCTION Control mode enabled (FETs OFF) Control mode disabled Table 4. JU4 Jumper Selection JUMPER JU4 SHUNT POSITION VDD FUNCTION Installed MAX1615 enabled None MAX1615 disabled Table 5. JU5 Jumper Selection JUMPER JU5 SHUNT POSITION EV KIT FUNCTION Installed 3 series cells None 4 series cells Control mode controlled by an external controller Control Jumper JU3 selects the logic state of the control pin of the MAX1894. To force a logic high on the control pin, install a shunt across pins 1 and 2 of JU3. To force a logic low on the control pin, install a shunt across pins 2 and 3 of JU3. The control mode can also be driven by an external µC. Remove the shunt from jumper JU3 and connect the output of the µC to the CTL pad. See Table 3 for shunt positions. 4 _______________________________________________________________________________________ MAX1894/MAX1924 Evaluation Kit 3 BN VDD D1 1 Evaluates: MAX1894/MAX1924 C12 0.1µF B4_P 2 CTL 1 JU3 2 11 VCC TKO CTL TKO 13 PACK+ 3 VDD SHDN 1 JU2 2 12 DSO SHDN 3 C9 2.2µF U1 PACK- SRC C13 OPEN C14 OPEN 2 1 CGO C4 OPEN 4 PACK+ 6 8 IC2 B4P 9 BN R3 51Ω 1 B1P 3 5 7 2 3 C11 OPEN 56 8 R4 1kΩ C2 0.1µF P1 1 JU4 1 IN SHDN R1 510Ω 2 GND U2 MAX1615 VDD JU5 5 7 VDD 3 PKN B2P P3 CGO C5 1µF IC1 R2 0.02Ω 4 B4_P B3P 10 14 IC3 C10 OPEN P2 BN R7 10Ω 16 J1 BANANA 32 1 C3 OPEN J2 BANANA 6 5 4 15 MAX1894 PACK- 7 8 DSO PACK+ TB1-1 TB1-2 B4_P B3_P C6 R5 0.1µF 1kΩ 3 OUT B2_P TB1-4 B1_P TB1-5 BN C7 R6 0.1µF 1kΩ 4 C1 PACK- 4.7µF 1 TB1-3 5/3 (FB) 3 2 JU1 C8 0.1µF BN Figure 2. MAX1894 EV Kit Schematic _______________________________________________________________________________________ 5 Evaluates: MAX1894/MAX1924 MAX1894/MAX1924 Evaluation Kit Figure 3. MAX1894 EV Kit Component Placement Guide— Component Side Figure 4. MAX1894 EV Kit PC Board Layout—Component Side Figure 5. MAX1894 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. 6 _____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 2002 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.