MCP73827 Single Cell Lithium-Ion Charge Management Controller with Mode Indicator and Charge Current Monitor Features Description • Linear Charge Management Controller for Single Lithium-Ion Cells • High Accuracy Preset Voltage Regulation: + 1% (max) • Two Preset Voltage Regulation Options: - 4.1V - MCP73827-4.1 - 4.2V - MCP73827-4.2 • Programmable Charge Current • Automatic Cell Preconditioning of Deeply Depleted Cells, Minimizing Heat Dissipation During Initial Charge Cycle • Charge Status Output for LED Drive or Microcontroller Interface • Charge Current Monitor Output • Automatic Power-Down when Input Power Removed • Temperature Range: -20°C to +85°C • Packaging: 8-Pin MSOP The MCP73827 is a linear charge management controller for use in space-limited, cost sensitive applications. The MCP73827 combines high accuracy constant voltage, controlled current regulation, cell preconditioning, and charge status indication in a space saving 8-pin MSOP package. The MCP73827 provides a stand-alone charge management solution. Applications • • • • • • Typical Application Circuit 500 mA Lithium-Ion Battery Charger VIN 5V 10 µF 100 mΩ 332Ω 8 100 kΩ NDS8434 + Single Lithium-Ion - Cell 6 7 VSNS VDRV 1 3 VIN VBAT SHDN GND MODE IMON MCP73827 Following the preconditioning phase, the MCP73827 enters the controlled current phase. The MCP73827 allows for design flexibility with a programmable charge current set by an external sense resistor. The charge current is ramped up, based on the cell voltage, from the foldback current to the peak charge current established by the sense resistor. This phase is maintained until the battery reaches the charge-regulation voltage. Then, the MCP73827 enters the final phase, constant voltage. The accuracy of the voltage regulation is better than +1% over the entire operating temperature range and supply voltage range. The MCP73827-4.1 is preset to a regulation voltage of 4.1V, while the MCP73827-4.2 is preset to 4.2V. The charge status output, MODE, indicates when the charge cycle has transitioned to constant voltage mode. The charge cycle can be terminated by a timer that is started when the MODE pin goes to a logic High or by monitoring the charge current monitor output, IMON, for a minimum current. Single Cell Lithium-Ion Battery Chargers Personal Data Assistants Cellular Telephones Hand Held Instruments Cradle Chargers Digital Cameras MA2Q705 The MCP73827 charges the battery in three phases: preconditioning, controlled current, and constant voltage. If the battery voltage is below the internal low-voltage threshold, the battery is preconditioned with a foldback current. The preconditioning phase protects the lithium-ion cell and minimizes heat dissipation. The MCP73827 operates with an input voltage range from 4.5V to 5.5V. The MCP73827 is fully specified over the ambient temperature range of -20°C to +85°C. 5 2 4 10 µF Package Type MSOP 8 VIN SHDN 1 7 VSNS GND 2 MODE 3 IMON 4 © 2007 Microchip Technology Inc. MCP73827 6 VDRV 5 VBAT DS21704B-page 1 SHDN VSNS VIN VIN 0.3V CLAMP CHARGE CURRENT FOLDBACK AMPLIFIER – + 12 kΩ VREF (1.2V) CHARGE CURRENT AMPLIFIER SHUTDOWN, REFERENCE GENERATOR + – Value = 352.5KΩ for MCP73827-4.2 NOTE 1: Value = 340.5KΩ for MCP73827-4.1 37.5 kΩ 112.5 kΩ VREF 1.1 kΩ 500 kΩ CHARGE CURRENT CONTROL AMPLIFIER – + VIN VOLTAGE CONTROL AMPLIFIER VREF MODE COMPARATOR - + 138 kΩ CHARGE CURRENT MONITOR AMPLIFIER – DS21704B-page 2 + 100 kΩ – + 75 kΩ 75 kΩ 352.5 kΩ (NOTE 1) GND VBAT VDRV MODE IMON MCP73827 Functional Block Diagram © 2007 Microchip Technology Inc. MCP73827 1.0 ELECTRICAL CHARACTERISTICS 1.1 Maximum Ratings* PIN FUNCTION TABLE Pin Name 1 SHDN 2 GND Battery Management 0V Reference Current at MODE Pin .............................................. +/-30 mA 3 MODE Charge Status Output IMON Charge Current Monitor VIN ...................................................................... -0.3V to 6.0V All inputs and outputs w.r.t. GND ................-0.3 to (VIN+0.3)V Description Logic Shutdown Current at VDRV .......................................................... +/-1 mA 4 Maximum Junction Temperature, TJ.............................. 150°C 5 VBAT Cell Voltage Monitor Input Storage temperature .....................................-65°C to +150°C 6 VDRV Drive Output 7 VSNS Charge Current Sense Input 8 VIN ESD protection on all pins ..................................................≥ 4 kV *Notice: Stresses above those listed under “Maximum Ratings” may cause permanent damage to the device. This is a stress rating only and functional operation of the device at those or any other conditions above those indicated in the operational listings of this specification is not implied. Exposure to maximum rating conditions for extended periods may affect device reliability. Battery Management Input Supply DC CHARACTERISTICS: MCP73827-4.1, MCP73827-4.2 Unless otherwise specified, all limits apply for VIN = [VREG(typ)+1V], RSENSE = 500 mΩ, TA = -20°C to +85°C. Typical values are at +25°C. Refer to Figure 1-1 for test circuit. Sym Min Typ Max Units Supply Voltage Parameter VIN 4.5 — 5.5 V Conditions Supply Current IIN — — 0.5 250 15 560 µA Shutdown, VSHDN = 0V Constant Voltage Mode Regulated Output Voltage VREG 4.059 4.158 4.1 4.2 4.141 4.242 V V MCP73827-4.1 only MCP73827-4.2 only Line Regulation ΔVBAT -10 — 10 mV VIN = 4.5V to 5.5V, IOUT = 75 mA Load Regulation ΔVBAT -1 +0.1 1 mV IOUT=10 mA to 75 mA ILK — 8 — µA VIN=Floating, VBAT=VREG Gate Drive Current IDRV — 0.08 — — 1 — mA mA Sink, CV Mode Source, CV Mode Gate Drive Minimum Voltage VDRV — 1.6 — V Voltage Regulation (Constant Voltage Mode) Output Reverse Leakage Current External MOSFET Gate Drive Current Regulation (Controlled Current Mode) Current Sense Gain ACS — 100 — dB Δ(VSNS-VDRV) / ΔVBAT Current Limit Threshold VCS 40 53 75 mV (VIN-VSNS) at IOUT K — 0.43 — A/A Foldback Current Scale Factor Charge Status Indicator - MODE Threshold Voltage VTH — VREG — V Low Output Voltage VOL — — 400 mV ISINK = 10 mA Leakage Current ILK — — 1 µA ISINK=0 mA, VMODE=5.5V Input High Voltage Level VIH 40 — — %VIN Input Low Voltage Level VIL — — 25 %VIN Input Leakage Current ILK — — 1 µA VSHDN=0V to 5.5V AIMON — 26 — V/V ΔVIMON / Δ(VIN-VSNS) Shutdown Input - SHDN Charge Current Monitor - IMON Charge Current Monitor Gain © 2007 Microchip Technology Inc. DS21704B-page 3 MCP73827 TEMPERATURE SPECIFICATIONS Unless otherwise specified, all limits apply for VIN = 4.5V-5.5V Parameters Symbol Min Typ Max Units Conditions Temperature Ranges Specified Temperature Range TA -20 — +85 °C Operating Temperature Range TA -40 — +125 °C Storage Temperature Range TA -65 — +150 °C θJA — 206 — °C/W Package Thermal Resistance Thermal Resistance, 8L-MSOP VIN = 5.1V (MCP73827-4.1) VIN = 5.2V (MCP73827-4.2) NDS8434 RSENSE Single Layer SEMI G42-88 Standard Board, Natural Convection IOUT 22 µF 8 100 kΩ 100 kΩ 1 3 VOUT 7 6 VSNS VDRV VBAT VIN SHDN GND MODE IMON 5 2 22 µF 4 MCP73827 FIGURE 1-1: MCP73827 Test Circuit. DS21704B-page 4 © 2007 Microchip Technology Inc. MCP73827 2.0 TYPICAL PERFORMANCE CHARACTERISTICS Note: The graphs and tables provided following this note are a statistical summary based on a limited number of samples and are provided for informational purposes only. The performance characteristics listed herein are not tested or guaranteed. In some graphs or tables, the data presented may be outside the specified operating range (e.g., outside specified power supply range) and therefore outside the warranted range. Note: Unless otherwise indicated, IOUT = 10 mA, Constant Voltage Mode, TA = 25°C. Refer to Figure 1-1 for test circuit. 4.205 300 4.204 Supply Current (μA) Output Voltage (V) 4.203 4.202 4.201 4.200 4.199 4.198 4.197 280 260 240 220 4.196 4.195 200 0 200 400 600 800 1000 0 200 Output Current (mA) FIGURE 2-1: Output Voltage vs. Output Current (MCP73827-4.2). FIGURE 2-4: 4.205 600 800 1000 Supply Current vs. Output Current. 300 IOUT = 1000 mA IOUT = 1000 mA 4.204 Supply Current (μA) 4.203 Output Voltage (V) 400 Output Current (mA) 4.202 4.201 4.200 4.199 4.198 4.197 280 260 240 220 4.196 4.195 200 4.5 4.6 4.7 4.8 4.9 5.0 5.1 5.2 5.3 5.4 5.5 4.5 4.6 4.7 4.8 Input Voltage (V) 4.9 5.0 5.1 5.2 FIGURE 2-2: Output Voltage vs. Input Voltage (MCP73827-4.2) 4.205 FIGURE 2-5: 5.4 5.5 Supply Current vs. Input Voltage. 300 IOUT = 10 mA IOUT = 10 mA 4.204 Supply Current (μA) 4.203 Output Voltage (V) 5.3 Input Voltage (V) 4.202 4.201 4.200 4.199 4.198 280 260 240 220 4.197 4.196 4.195 200 4.5 4.6 4.7 4.8 4.9 5.0 5.1 5.2 5.3 5.4 5.5 4.5 4.6 Input Voltage (V) FIGURE 2-3: Output Voltage vs. Input Voltage (MCP73827-4.2) © 2007 Microchip Technology Inc. 4.7 4.8 4.9 5.0 5.1 5.2 5.3 5.4 5.5 Input Voltage (V) FIGURE 2-6: Supply Current vs. Input Voltage. DS21704B-page 5 MCP73827 12 300 VIN = Floating VSHDN = VOUT 10 275 o 85 C o 8 25 C o -20 C 6 4 Supply Current (μA) Output Reverse Leakage Current (μA) Note: Unless otherwise indicated, IOUT = 10 mA, Constant Voltage Mode, TA = 25°C. Refer to Figure 1-1 for test circuit. 250 225 200 175 2 150 0 2.0 2.5 3.0 3.5 4.0 -20 4.5 -10 0 10 20 50 60 70 80 FIGURE 2-10: Supply Current vs. Temperature. 1.6 4.206 VIN = Floating VSHDN = GND 1.4 4.204 o 85 C 1.2 o 25 C o 1.0 -20 C 0.8 0.6 0.4 Output Voltage (V) Output Reverse Leakage Current (μA) 40 o FIGURE 2-7: Output Reverse Leakage Current vs. Output Voltage. 4.202 4.200 4.198 4.196 4.194 4.192 0.2 4.190 0.0 2.0 2.5 3.0 3.5 4.0 -20 4.5 -10 0 10 20 30 40 50 60 70 80 o Temperature ( C) Output Voltage (V) FIGURE 2-8: Output Reverse Leakage Current vs. Output Voltage. FIGURE 2-11: Output (MCP73827-4.2). 4.500 4.5 4.000 4.0 3.500 3.5 Output Voltage (V) Output Voltage (V) 30 Temperature ( C) Output Voltage (V) 3.000 2.500 2.000 1.500 1.000 Voltage vs. Temperature 3.0 2.5 2.0 1.5 1.0 0.500 Power Down Power Up 0.5 0.000 0 20 40 60 80 100 120 0.0 0 Output Current (mA) FIGURE 2-9: Current Limit Foldback. DS21704B-page 6 1 2 3 4 5 64 73 8 2 9 1 10 0 Input Voltage (V) FIGURE 2-12: Power-Up / Power-Down. © 2007 Microchip Technology Inc. MCP73827 Note: Unless otherwise indicated, IOUT = 10 mA, Constant Voltage Mode, TA = 25°C. Refer to Figure 1-1 for test circuit. FIGURE 2-13: Line Transient Response. FIGURE 2-15: Load Transient Response. FIGURE 2-14: Line Transient Response. FIGURE 2-16: Load Transient Response. © 2007 Microchip Technology Inc. DS21704B-page 7 MCP73827 3.0 PIN DESCRIPTION The descriptions of the pins are listed in Table 3-1. Pin Name 1 SHDN 2 GND Description Logic Shutdown Battery Management 0V Reference Cell Voltage Monitor Input (VBAT) Voltage sense input. Connect to positive terminal of battery. Bypass to GND with a minimum of 10 µF to ensure loop stability when the battery is disconnected. A precision internal resistor divider regulates the final voltage on this pin to VREG. 3.6 Drive Output (VDRV) 3 MODE 4 IMON Charge Current Monitor Direct output drive of an external P-channel MOSFET pass transistor for current and voltage regulation. 5 VBAT Cell Voltage Monitor Input 3.7 6 VDRV Drive Output 7 VSNS Charge Current Sense Input 8 VIN TABLE 3-1: 3.1 Charge Status Output 3.5 Battery Management Input Supply Pin Function Table. Logic Shutdown (SHDN) Input to force charge termination, initiate charge, or initiate recharge. 3.2 Battery Management 0V Reference (GND) Charge Current Sense Input (VSNS) Charge current is sensed via the voltage developed across an external precision sense resistor. The sense resistor must be placed between the supply voltage (VIN) and the source of the external pass transistor. A 50 mΩ sense resistor produces a fast charge current of 1 A, typically. 3.8 Battery Management Input Supply (VIN) A supply voltage of 4.5V to 5.5V is recommended. Bypass to GND with a minimum of 10 µF. Connect to negative terminal of battery. 3.3 Charge Status Output (MODE) Open-drain drive for connection to an LED for charge status indication. Alternatively, a pull-up resistor can be applied for interfacing to a microcontroller. A low impedance state indicates foldback current limit or controlled current phase. A high impedance indicates constant voltage phase or battery cell disconnected. 3.4 Charge Current Monitor (IMON) Amplified output of the voltage difference between VIN and VSNS. A host microcontroller can monitor this output with an A/D converter. DS21704B-page 8 © 2007 Microchip Technology Inc. MCP73827 4.0 DEVICE OVERVIEW The MCP73827 is a linear charge management controller. Refer to the functional block diagram on page 2 and the typical application circuit, Figure 6-1. 4.1 Charge Qualification and Preconditioning Upon insertion of a battery or application of an external supply, the MCP73827 verifies the state of the SHDN pin. The SHDN pin must be above the logic High level. If the SHDN pin is above the logic High level, the MCP73827 initiates a charge cycle. The charge status output, MODE, is pulled low throughout throughout the preconditioning and controlled current phases (see Table 5-1 for charge status outputs). If the cell is below the preconditioning threshold, 2.4V typically, the MCP73827 preconditions the cell with a scaled back current. The preconditioning current is set to approximately 43% of the fast charge peak current. The preconditioning safely replenishes deeply depleted cells and minimizes heat dissipation in the external pass transistor during the initial charge cycle. 4.2 4.3 Constant Voltage Regulation When the cell voltage reaches the regulation voltage, VREG, constant voltage regulation begins. The MCP73827 monitors the cell voltage at the VBAT pin. This input is tied directly to the positive terminal of the battery. The MCP73827 is offered in two fixed-voltage versions for battery packs with either coke or graphite anodes: 4.1V (MCP73827-4.1) and 4.2V (MCP73827-4.2). 4.4 Charge Cycle Completion The charge cycle can be terminated by a host microcontroller when the output of the charge current monitor, IMON, has diminished below approximately 10% of the peak output voltage level. Alternatively, the transition of the charge status output, MODE, can be used to initialize a timer to terminate the charge. The charge is terminated by pulling the shutdown pin, SHDN, to a logic Low Level. Controlled Current Regulation - Fast Charge Preconditioning ends and fast charging begins when the cell voltage exceeds the preconditioning threshold. Fast charge utilizes a foldback current scheme based on the voltage at the VSNS input developed by the drop across an external sense resistor, RSENSE, and the output voltage, VBAT. Fast charge continues until the cell voltage reaches the regulation voltage, VREG. © 2007 Microchip Technology Inc. DS21704B-page 9 MCP73827 5.0 DETAILED DESCRIPTION 5.2 Digital Circuitry Refer to the typical application circuit, Figure 6-1. 5.2.1 SHUTDOWN INPUT (SHDN) 5.1 Analog Circuitry 5.1.1 CHARGE CURRENT MONITOR (IMON) The shutdown input pin, SHDN, can be used to terminate a charge anytime during the charge cycle, initiate a charge cycle, or initiate a recharge cycle. The IMON pin provides an output voltage that is proportional to the battery charging current. It is an amplified version of the sense resistor voltage drop that the current loop uses to control the external P-channel pass transistor. This voltage signal can be applied to the input of an A/D Converter and used by a host microcontroller to display information about the state of the battery or charge current profile. 5.1.2 CELL VOLTAGE MONITORED INPUT (VBAT) The MCP73827 monitors the cell voltage at the VBAT pin. This input is tied directly to the positive terminal of the battery. The MCP73827 is offered in two fixed-voltage versions for single cells with either coke or graphite anodes: 4.1V (MCP73827-4.1) and 4.2V (MCP73827-4.2). 5.1.3 GATE DRIVE OUTPUT (VDRV) The MCP73827 controls the gate drive to an external P-channel MOSFET, Q1. The P-channel MOSFET is controlled in the linear region, regulating current and voltage supplied to the cell. The drive output is automatically turned off when the input supply falls below the voltage sensed on the VBAT input. 5.1.4 Applying a logic High input signal to the SHDN pin, or tying it to the input source, enables the device. Applying a logic Low input signal disables the device and terminates a charge cycle. In shutdown mode, the device’s supply current is reduced to 0.5 µA, typically. 5.2.2 CHARGE STATUS OUTPUT (MODE) A charge status output, MODE, provides information on the state of charge. The open drain output can be used to illuminate an external LED. Optionally, a pull-up resistor can be used on the output for communication with a microcontroller. Table 5-1 summarizes the state of the charge status output during a charge cycle. Charge Cycle State Mode Qualification OFF Preconditioning ON Controlled Current Fast Charge ON Constant Voltage OFF Disabled - Sleep mode OFF Battery Disconnected OFF TABLE 5-1: Charge Status Output. CURRENT SENSE INPUT (VSNS) Fast charge current regulation is maintained by the voltage drop developed across an external sense resistor, RSENSE, applied to the VSNS input pin. The following formula calculates the value for RSENSE: V CS RSENSE = -----------I OUT Where: VCS is the current limit threshold IOUT is the desired peak fast charge current in amps. The preconditioning current is scaled to approximately 43% of IPEAK. 5.1.5 SUPPLY VOLTAGE (VIN) The VIN input is the input supply to the MCP73827. The MCP73827 automatically enters a power-down mode if the voltage on the VIN input falls below the voltage on the VBAT pin. This feature prevents draining the battery pack when the VIN supply is not present. DS21704B-page 10 © 2007 Microchip Technology Inc. MCP73827 6.0 APPLICATIONS The MCP73827 is designed to operate in conjunction with a host microcontroller or in stand-alone applications. The MCP73827 provides the preferred charge algorithm for Lithium-Ion cells, controlled current fol- lowed by constant voltage. Figure 6-1 depicts a typical stand-alone application circuit and Figure 6-2 depicts the accompanying charge profile. VOLTAGE REGULATED WALL CUBE MA2Q705 RSENSE Q1 NDS8434 IOUT PACK+ 332 Ω 10 µF 100 mΩ 10 µF 22 kΩ SHDN 8 1 GND 7 2 MODE 100 kΩ IMON MCP73827 3 6 4 5 VIN VSNS + VDRV - VBAT PACKSINGLE CELL LITHIUM-ION BATTERY PACK FIGURE 6-1: Typical Application Circuit. PRECONDITIONING PHASE REGULATION VOLTAGE (VREG) CONTROLLED CURRENT PHASE CONSTANT VOLTAGE PHASE CHARGE VOLTAGE REGULATION CURRENT (IOUT(PEAK)) TRANSITION THRESHOLD PRECONDITION CURRENT CHARGE CURRENT 5V MODE - CHARGE STATUS OUTPUT 0V 1.5V IMON - CHARGE CURRENT MONITOR 0V FIGURE 6-2: Typical Charge Profile. © 2007 Microchip Technology Inc. DS21704B-page 11 MCP73827 6.1 Application Circuit Design Due to the low efficiency of linear charging, the most important factors are thermal design and cost, which are a direct function of the input voltage, output current and thermal impedance between the external P-channel pass transistor, Q1, and the ambient cooling air. The worst-case situation is when the output is shorted. In this situation, the P-channel pass transistor has to dissipate the maximum power. A trade-off must be made between the charge current, cost and thermal requirements of the charger. 6.1.1 EXTERNAL PASS TRANSISTOR The external P-channel MOSFET is determined by the gate to source threshold voltage, input voltage, output voltage, and peak fast charge current. The selected Pchannel MOSFET must satisfy the thermal and electrical design requirements. Thermal Considerations The worst case power dissipation in the external pass transistor occurs when the input voltage is at the maximum and the output is shorted. In this case, the power dissipation is: COMPONENT SELECTION Selection of the external components in Figure 6-1 is crucial to the integrity and reliability of the charging system. The following discussion is intended as a guide for the component selection process. 22.214.171.124 126.96.36.199 PowerDissipation = V INMAX × I OUT × K Where: VINMAX is the maximum input voltage SENSE RESISTOR IOUT is the maximum peak fast charge current The preferred fast charge current for Lithium-Ion cells is at the 1C rate with an absolute maximum current at the 2C rate. For example, a 500 mAH battery pack has a preferred fast charge current of 500 mA. Charging at this rate provides the shortest charge cycle times without degradation to the battery pack performance or life. The current sense resistor, RSENSE, is calculated by: V CS RSENSE = -----------I OUT Where: VCS is the current limit threshold voltage IOUT is the desired fast charge current For the 500 mAH battery pack example, a standard value 100 mΩ, 1% resistor provides a typical peak fast charge current of 530 mA and a maximum peak fast charge current of 758 mA. Worst case power dissipation in the sense resistor is: 2 PowerDissipation = 100mΩ × 758mA = 57.5mW A Panasonic ERJ-L1WKF100U 100 mΩ, 1%, 1 W resistor is more than sufficient for this application. A larger value sense resistor will decrease the peak fast charge current and power dissipation in both the sense resistor and external pass transistor, but will increase charge cycle times. Design trade-offs must be considered to minimize space while maintaining the desired performance. K is the foldback current scale factor. Power dissipation with a 5V, +/-10% input voltage source, 100 mΩ, 1% sense resistor, and a scale factor of 0.43 is: PowerDissipation = 5.5V × 758mA × 0.43 = 1.8W Utilizing a Fairchild NDS8434 or an International Rectifier IRF7404 mounted on a 1in2 pad of 2 oz. copper, the junction temperature rise is 90°C, approximately. This would allow for a maximum operating ambient temperature of 60°C. By increasing the size of the copper pad, a higher ambient temperature can be realized or a lower value sense resistor could be utilized. Alternatively, different package options can be utilized for more or less power dissipation. Again, design tradeoffs should be considered to minimize size while maintaining the desired performance. Electrical Considerations The gate to source threshold voltage and RDSON of the external P-channel MOSFET must be considered in the design phase. The worst case, VGS provided by the controller occurs when the input voltage is at the minimum and the charge current is at the maximum. The worst case, VGS is: VGS = V DRVMAX – ( V INMIN – IOUT × R SENSE ) Where: VDRVMAX is the maximum sink voltage at the VDRV output DS21704B-page 12 © 2007 Microchip Technology Inc. MCP73827 VINMIN is the minimum input voltage source IOUT is the maximum peak fast charge current RSENSE is the sense resistor Worst case, VGS with a 5V, +/-10% input voltage source, 100 mΩ, 1% sense resistor, and a maximum sink voltage of 1.6V is: V GS = 1.6V – ( 4.5V – 758mA × 99mΩ ) = – 2.8 V At this worst case VGS, the RDSON of the MOSFET must be low enough as to not impede the performance of the charging system. The maximum allowable RDSON at the worst case VGS is: VINMIN – I PEAK × R SENSE – V BATMAX RDSON = ---------------------------------------------------------------------------------------------I OUT If a reverse protection diode is incorporated in the design, it should be chosen to handle the peak fast charge current continuously at the maximum ambient temperature. In addition, the reverse leakage current of the diode should be kept as small as possible. 188.8.131.52 In the stand-alone configuration, the shutdown pin is generally tied to the input voltage. The MCP73827 will automatically enter a low power mode when the input voltage is less than the output voltage reducing the battery drain current to 8 µA, typically. By connecting the shutdown pin as depicted in Figure 6-1, the battery drain current may be further reduced. In this application, the battery drain current becomes a function of the reverse leakage current of the reverse protection diode. 184.108.40.206 R DSON 4.5V – 758mA × 99mΩ – 4.242V = -------------------------------------------------------------------------------- = 242mΩ 758mA The Fairchild NDS8434 and International Rectifier IRF7404 both satisfy these requirements. 220.127.116.11 EXTERNAL CAPACITORS The MCP73827 is stable with or without a battery load. In order to maintain good AC stability in the constant voltage mode, a minimum capacitance of 10 µF is recommended to bypass the VBAT pin to GND. This capacitance provides compensation when there is no battery load. In addition, the battery and interconnections appear inductive at high frequencies. These elements are in the control feedback loop during constant voltage mode. Therefore, the bypass capacitance may be necessary to compensate for the inductive nature of the battery pack. Virtually any good quality output filter capacitor can be used, independent of the capacitor’s minimum ESR (Effective Series Resistance) value. The actual value of the capacitor and its associated ESR depends on the forward trans conductance, gm, and capacitance of the external pass transistor. A 10 µF tantalum or aluminum electrolytic capacitor at the output is usually sufficient to ensure stability for up to a 1 A output current. 18.104.22.168 SHUTDOWN INTERFACE CHARGE STATUS INTERFACE The charge status indicator, MODE, can be utilized to illuminate an LED when the MCP73827 is in the controlled current phase. When the MCP73827 transitions to constant voltage mode, the MODE pin will transition to a high impedance state. A current limit resistor should be used in series with the LED to establish a nominal LED bias current of 10 mA. The maximum allowable sink current of the MODE pin is 30 mA. 6.2 PCB Layout Issues For optimum voltage regulation, place the battery pack as close as possible to the device’s VBAT and GND pins. It is recommended to minimize voltage drops along the high current carrying PCB traces. If the PCB layout is used as a heatsink, adding many vias around the external pass transistor can help conduct more heat to the back-plane of the PCB, thus reducing the maximum junction temperature. REVERSE BLOCKING PROTECTION The optional reverse blocking protection diode depicted in Figure 6-1 provides protection from a faulted or shorted input or from a reversed polarity input source. Without the protection diode, a faulted or shorted input would discharge the battery pack through the body diode of the external pass transistor. © 2007 Microchip Technology Inc. DS21704B-page 13 MCP73827 7.0 PACKAGING INFORMATION 7.1 Package Marking Information Example: 8-Lead MSOP 738271 e3 XXXXXX YWWNNN Legend: XX...X Y YY WW NNN e3 * Note: DS21704B-page 14 712NNN Part Number Code MCP73827-4.1VUA 738271 MCP73827-4.2VUA 738272 Customer-specific information Year code (last digit of calendar year) Year code (last 2 digits of calendar year) Week code (week of January 1 is week ‘01’) Alphanumeric traceability code Pb-free JEDEC designator for Matte Tin (Sn) This package is Pb-free. The Pb-free JEDEC designator ( e3 ) can be found on the outer packaging for this package. In the event the full Microchip part number cannot be marked on one line, it will be carried over to the next line, thus limiting the number of available characters for customer-specific information. © 2007 Microchip Technology Inc. MCP73827 8-Lead Plastic Micro Small Outline Package (MS or UA) [MSOP] Note: For the most current package drawings, please see the Microchip Packaging Specification located at http://www.microchip.com/packaging D N E E1 NOTE 1 1 2 e b A2 A c φ L L1 A1 Units Dimension Limits Number of Pins MILLIMETERS MIN N NOM MAX 8 Pitch e Overall Height A – 0.65 BSC – Molded Package Thickness A2 0.75 0.85 0.95 Standoff A1 0.00 – 0.15 Overall Width E Molded Package Width E1 3.00 BSC Overall Length D 3.00 BSC Foot Length L Footprint L1 1.10 4.90 BSC 0.40 0.60 0.80 0.95 REF Foot Angle φ 0° – 8° Lead Thickness c 0.08 – 0.23 Lead Width b 0.22 – 0.40 Notes: 1. Pin 1 visual index feature may vary, but must be located within the hatched area. 2. Dimensions D and E1 do not include mold flash or protrusions. Mold flash or protrusions shall not exceed 0.15 mm per side. 3. Dimensioning and tolerancing per ASME Y14.5M. BSC: Basic Dimension. Theoretically exact value shown without tolerances. REF: Reference Dimension, usually without tolerance, for information purposes only. Microchip Technology Drawing C04-111B © 2007 Microchip Technology Inc. DS21704B-page 15 MCP73827 NOTES: DS21704B-page 16 © 2007 Microchip Technology Inc. MCP73827 APPENDIX A: REVISION HISTORY Revision B (February 2007) This revision includes updates to the packaging diagrams. © 2007 Microchip Technology Inc. DS21704B-page 17 MCP73827 PRODUCT IDENTIFICATION SYSTEM To order or obtain information, e.g., on pricing or delivery, refer to the factory or the listed sales office. PART NO. -X.X X XX Device Output Voltage Temperature Range Package Examples: a) MCP73827-4.1VUA: Linear Charge Man- b) MCP73827-4.2VUA: Linear Charge Man- agement Controller, 4.1V agement Controller, 4.2V Device: MCP73827: Linear Charge Management Controller Output Voltage: MCP73827-4.2VUATR: Linear Charge Management Controller, 4.2V, in tape and reel 4.1 = 4.1V 4.2 = 4.2V Temperature Range: V Package: UA = Plastic Micro Small Outline (MSOP), 8-lead DS21704B-page 18 c) = -20°C to +85°C © 2007 Microchip Technology Inc. Note the following details of the code protection feature on Microchip devices: • Microchip products meet the specification contained in their particular Microchip Data Sheet. • Microchip believes that its family of products is one of the most secure families of its kind on the market today, when used in the intended manner and under normal conditions. • There are dishonest and possibly illegal methods used to breach the code protection feature. All of these methods, to our knowledge, require using the Microchip products in a manner outside the operating specifications contained in Microchip’s Data Sheets. Most likely, the person doing so is engaged in theft of intellectual property. • Microchip is willing to work with the customer who is concerned about the integrity of their code. • Neither Microchip nor any other semiconductor manufacturer can guarantee the security of their code. Code protection does not mean that we are guaranteeing the product as “unbreakable.” Code protection is constantly evolving. We at Microchip are committed to continuously improving the code protection features of our products. Attempts to break Microchip’s code protection feature may be a violation of the Digital Millennium Copyright Act. If such acts allow unauthorized access to your software or other copyrighted work, you may have a right to sue for relief under that Act. Information contained in this publication regarding device applications and the like is provided only for your convenience and may be superseded by updates. It is your responsibility to ensure that your application meets with your specifications. MICROCHIP MAKES NO REPRESENTATIONS OR WARRANTIES OF ANY KIND WHETHER EXPRESS OR IMPLIED, WRITTEN OR ORAL, STATUTORY OR OTHERWISE, RELATED TO THE INFORMATION, INCLUDING BUT NOT LIMITED TO ITS CONDITION, QUALITY, PERFORMANCE, MERCHANTABILITY OR FITNESS FOR PURPOSE. Microchip disclaims all liability arising from this information and its use. Use of Microchip devices in life support and/or safety applications is entirely at the buyer’s risk, and the buyer agrees to defend, indemnify and hold harmless Microchip from any and all damages, claims, suits, or expenses resulting from such use. No licenses are conveyed, implicitly or otherwise, under any Microchip intellectual property rights. Trademarks The Microchip name and logo, the Microchip logo, Accuron, dsPIC, KEELOQ, microID, MPLAB, PIC, PICmicro, PICSTART, PRO MATE, PowerSmart, rfPIC, and SmartShunt are registered trademarks of Microchip Technology Incorporated in the U.S.A. and other countries. AmpLab, FilterLab, Migratable Memory, MXDEV, MXLAB, SEEVAL, SmartSensor and The Embedded Control Solutions Company are registered trademarks of Microchip Technology Incorporated in the U.S.A. Analog-for-the-Digital Age, Application Maestro, CodeGuard, dsPICDEM, dsPICDEM.net, dsPICworks, ECAN, ECONOMONITOR, FanSense, FlexROM, fuzzyLAB, In-Circuit Serial Programming, ICSP, ICEPIC, Linear Active Thermistor, Mindi, MiWi, MPASM, MPLIB, MPLINK, PICkit, PICDEM, PICDEM.net, PICLAB, PICtail, PowerCal, PowerInfo, PowerMate, PowerTool, REAL ICE, rfLAB, rfPICDEM, Select Mode, Smart Serial, SmartTel, Total Endurance, UNI/O, WiperLock and ZENA are trademarks of Microchip Technology Incorporated in the U.S.A. and other countries. SQTP is a service mark of Microchip Technology Incorporated in the U.S.A. All other trademarks mentioned herein are property of their respective companies. © 2007, Microchip Technology Incorporated, Printed in the U.S.A., All Rights Reserved. Printed on recycled paper. Microchip received ISO/TS-16949:2002 certification for its worldwide headquarters, design and wafer fabrication facilities in Chandler and Tempe, Arizona, Gresham, Oregon and Mountain View, California. The Company’s quality system processes and procedures are for its PIC® MCUs and dsPIC DSCs, KEELOQ® code hopping devices, Serial EEPROMs, microperipherals, nonvolatile memory and analog products. In addition, Microchip’s quality system for the design and manufacture of development systems is ISO 9001:2000 certified. © 2007 Microchip Technology Inc. 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