ACT8740 Rev PrB, 25-Feb-08 Advanced Product Information―All Information Subject to Change Six Channel Integrated Power Management IC for Handheld Portable Equipment FEATURES GENERAL DESCRIPTION • Multiple Patents Pending • Li+ Battery Charger with Integrated MOSFET The patent-pending ACT8740 is a complete, cost effective, highly-efficient ActivePMUTM power management solution that is ideal for a wide range of portable handheld equipment. This device integrates one PWM step-down DC/DC converter, one PWM step-up DC/DC converter with over-voltage protection (OVP), three low dropout linear regulators (LDOs) and a full-featured linear-mode Li+ battery charger into a single, thin, space-saving package. An I2C Serial Interface provides programmability for the DC/DC converters, LDOs and battery charger. − Programmable Charge Current up to 1A − ON/OFF Control • Five Integrated Regulators − 350mA PWM Step-Down DC/DC − Step-Up DC/DC with OVP for WLED Bias − 350mA Low Noise LDO − 250mA Low Noise LDO − 250mA Low Noise LDO • I2CTM Compatible Serial Interface REG1 is a fixed-frequency, current-mode PWM step -down DC/DC converter that is optimized for high efficiency and is capable of supplying up to 350mA output current. REG2 is a fixed-frequency, step-up DC/DC converter that safely and efficiently biases a string of up to seven white-LEDs for backlighting. REG3, REG4, and REG5 are low noise, high PSRR linear regulators that are capable of supplying up to 350mA, 250mA, and 250mA, respectively. The battery charger incorporates an internal power MOSFET for constant-current/constant-voltage, thermally regulated charging of a single-cell Li+ battery. All DC/DC converters and LDOs output voltages are programmable and controllable via the I2C interface. − Programmable Output Voltages − Configurable Operating Modes • Minimal External Components • 4x4mm, Thin-QFN (TQFN44-24) Package − Only 0.75mm Height − RoHS Compliant APPLICATIONS • Portable Devices and PDAs • Wireless Handhelds • DMB Enabled Devices The ACT8740 is available in a tiny 4mm x 4mm 24-pin Thin-QFN package that is just 0.75mm thin. • GPS Receivers, etc. SYSTEM BLOCK DIAGRAM VIN CHGLEV Single-Cell Li+ Battery Charger REG1 Step-Down DC/DC nMSTR REG2 nIRQ SCL Step-Up DC/DC System Control SDA REG3 ON1 LDO REG4 LDO ACT8740 PMU REG5 TM Active Innovative Products. Active Solutions. ActivePMUTM is a trademark of Active-Semi. I2CTM is a trademark of Philips Electronics. LDO -1- Battery Programmable Up to 1A OUT1 1.1V to 4.4V Up to 350mA OUT2 WLED Bias OUT3 1.4 to 3.7V Up to 350mA Pb-free OUT4 1.4 to 3.7V Up to 250mA OUT5 1.4 to 3.7V Up to 250mA www.active-semi.com Copyright © 2008 Active-Semi, Inc. ACT8740 Rev PrB, 25-Feb-08 TABLE OF CONTENTS GENERAL INFORMATION ...................................................................................... P. 01 Functional Block Diagram ............................................................................................ p. 03 Ordering Information .................................................................................................... p. 04 Pin Configuration .......................................................................................................... p. 04 Pin Descriptions ........................................................................................................... p. 05 Absolute Maximum Ratings ......................................................................................... p. 07 SYSTEM MANAGEMENT ........................................................................................ P. 08 Register Descriptions ................................................................................................... p. 08 Electrical Characteristics .............................................................................................. p. 09 I2C Interface Electrical Characteristics ......................................................................... p. 10 Typical Performance Characteristics............................................................................ p. 11 Functional Description .................................................................................................. p. 12 STEP-DOWN DC/DC CONVERTERS ..................................................................... P. 14 Electrical Characteristics ............................................................................................. p. 14 Register Descriptions ................................................................................................... p. 15 Typical Performance Characteristics ........................................................................... p. 17 Functional Description .................................................................................................. p. 18 WLED BIAS DC/DC CONVERTER ......................................................................... P. 20 Electrical Characteristics ............................................................................................. p. 20 Register Descriptions ................................................................................................... p. 21 Typical Performance Characteristics ........................................................................... p. 23 Functional Description .................................................................................................. p. 24 LOW-NOISE, LOW-DROPOUT, LINEAR REGULATORS....................................... P. 26 Electrical Characteristics ............................................................................................. p. 26 Register Descriptions ................................................................................................... p. 29 Typical Performance Characteristics............................................................................ p. 31 Functional Description .................................................................................................. p. 32 SINGLE-CELL Li+ BATTERY CHARGER (CHGR) ................................................. P. 33 Electrical Characteristics .............................................................................................. p. 33 Register Descriptions ................................................................................................... p. 34 Typical Performance Characteristics ............................................................................ p. 36 Functional Description .................................................................................................. p. 37 PACKAGE INFORMATION ...................................................................................... P. 40 Innovative Products. Active Solutions. ActivePMUTM is a trademark of Active-Semi. I2CTM is a trademark of Philips Electronics. -2- www.active-semi.com Copyright © 2008 Active-Semi, Inc. ACT8740 Rev PrB, 25-Feb-08 FUNCTIONAL BLOCK DIAGRAM VSYS BODY AND VSYS CONTROL AC Adaptor or USB ACT8740 BAT VIN 4.3V to 6V Li+ Battery + CURRENT SENSE VINUVLO 4.0V VOLTAGE SENSE Charge Control OUT3 PRECONDITION 2.9V THERMAL REGULATION CHGLEV FLOAT 110°C VP1 To Battery SCL SW1 REG1 Serial Interface SDA OUT1 OUT1 GP1 VSYS VINUVLO nMSTR To Battery SW2 PUSH BUTTON OUT2 System Control nIRQ REG2 OVP2 OUT3 FB2 GP2 INL To Battery ON1 LDO REG3 REFBP Reference LDO REG4 OUT3 OUT3 OUT4 OUT4 GA LDO REG5 Innovative Products. Active Solutions. ActivePMUTM is a trademark of Active-Semi. I2CTM is a trademark of Philips Electronics. -3- OUT5 OUT5 www.active-semi.com Copyright © 2008 Active-Semi, Inc. ACT8740 Rev PrB, 25-Feb-08 ORDERING INFORMATIONcd PART NUMBER VOUT1 VOUT3 VOUT4 VOUT5 PACKAGE PINS TEMPERATURE RANGE ACT8740QLEGA-T 1.8V 3.0V 2.5V 3.0V TQFN44-24 24 -40°C to +85°C OUTPUT VOLTAGE CODES C D E F G H 1.2V 1.5V 1.8V 2.5V 3.0V 3.3V c: Output voltage options detailed in this table represent standard voltage options, and are available for samples or production orders. Additional output voltage options, as detailed in the Output Voltage Codes table, are available for production subject to minimum order quantities. Contact Active-Semi for more information regarding semi-custom output voltage combinations. d: All Active-Semi components are RoHS Compliant and with Pb-free plating unless specified differently. The term Pb-free means semiconductor products that are in compliance with current RoHS (Restriction of Hazardous Substances) standards. PIN CONFIGURATION TOP VIEW BAT CHGLEV SW2 GP2 OVP2 FB2 24 23 22 21 20 19 VIN 1 18 REFBP SCL 2 17 GA SDA 3 16 VSYS nIRQ 4 nMSTR 5 OUT3 6 15 ON1 ACT8740 14 GA EP 10 11 12 GP1 SW1 VP1 9 OUT4 INL 8 OUT5 7 13 OUT1 Thin - QFN (TQFN44-24) Innovative Products. Active Solutions. ActivePMUTM is a trademark of Active-Semi. I2CTM is a trademark of Philips Electronics. -4- www.active-semi.com Copyright © 2008 Active-Semi, Inc. ACT8740 Rev PrB, 25-Feb-08 PIN DESCRIPTIONS PIN NAME DESCRIPTION 1 VIN Power Input for the Battery Charger. The Battery Charger, REG1 and REG3 are automatically enabled whenever a valid voltage is present on VIN. Bypass to GA with a high quality ceramic capacitor placed as close as possible to the IC. 2 SCL Clock Input for I2C Serial Interface. Data is read on the rising edge of the clock. 3 SDA Data Input for I2C Serial Interface. Data is read on the rising edge of the clock. 4 nIRQ Open-Drain Push-Button Status Output. nIRQ is an open-drain output which sinks current when nMSTR is asserted or when a fault-condition occurs. If interrupts are not masked. 5 nMSTR 6 OUT3 7 INL 8 OUT5 Output voltage for REG5. Capable of delivering up to 250mA of output current. Output has high impedance when disabled. 9 OUT4 Output voltage for REG4. Capable of delivering up to 250mA of output current. Output has high impedance when disabled. 10 GP1 Power Ground for REG1. Connect GA, GP1 and GP2 together at a single point as close to the IC as possible. 11 SW1 Switching Node Output for REG1. Connect this pin to the switching end of the inductor. 12 VP1 Power Input for REG1. Bypass to GP1 with a high quality ceramic capacitor placed as close as possible to the IC. 13 OUT1 Output Feedback Sense for REG1. Connect this pin directly to the output node to connect the internal feedback network to the output voltage. 14,17 GA Analog Ground. Connect GA directly to a quiet ground node. Connect GA, GP1 and GP2 together at a single point as close to the IC as possible. 15 ON1 Enable Control Input for REG1 and REG3. Drive ON1 to VSYS or to a logic high for normal operation, drive to GA or a logic low to disable REG1 and REG3. 16 VSYS Master Enable Input. Drive nMSTR to GA or to a logic low to enable the IC. Output voltage for REG3. Capable of delivering up to 350mA of output current. Output has high impedance when disabled. Power input for REG3, REG4 and REG5. Bypass to GA with a high quality ceramic capacitor placed as close as possible to the IC. Power Bypass for System Management Circuitry. Bypass to GA with a high quality ceramic capacitor placed as close as possible to the IC. VSYS is internally connected to the higher voltage of either VVIN or VBAT. Do not load VSYS with more than 100µA. Innovative Products. Active Solutions. ActivePMUTM is a trademark of Active-Semi. I2CTM is a trademark of Philips Electronics. -5- www.active-semi.com Copyright © 2008 Active-Semi, Inc. ACT8740 Rev PrB, 25-Feb-08 PIN DESCRIPTIONS CONT’D PIN NAME 18 REFBP Reference Noise Bypass. Connect a 0.01µF ceramic capacitor from REFBP to GA. This pin is discharged to GA in shutdown. 19 FB2 Feedback Sense for REG2. Connect this pin to the LED string current sense resistor to sense the LED current. 20 OVP2 Over-Voltage Protection Input for REG2. Connect this pin directly to the output node to sense and prevent over-voltage conditions. 21 GP2 Power Ground for REG2. Connect GP2 directly to a power ground plane. Connect GA, GP1 and GP2 together at a single point as close to the IC as possible. 22 SW2 Switching Node Output for REG2. Connect this pin to the switching end of the inductor. 23 DESCRIPTION Tri-State Charging State Select Input. When ISET1[ ] = [0000], drive CHGLEV to VSYS or to a CHGLEV logic high for high-current charging mode (450mA), and drive to GA or a logic low for lowcurrent charging mode (90mA). Allow CHGLEV to float (|ICHGLEV| < 2µA) to disable the charger. 24 BAT EP EP Output Voltage for the Battery Charger. Connect this pin directly to the battery anode (+ terminal) to sense the battery voltage. Exposed Pad. Must be soldered to ground on PCB. Innovative Products. Active Solutions. ActivePMUTM is a trademark of Active-Semi. I2CTM is a trademark of Philips Electronics. -6- www.active-semi.com Copyright © 2008 Active-Semi, Inc. ACT8740 Rev PrB, 25-Feb-08 ABSOLUTE MAXIMUM RATINGSc PARAMETER VALUE UNIT VP1, SW1 to GP1, VSYS, SCL, SDA, INL, OUT1, OUT2, OUT3, OUT4, OUT5, FB2, BAT, CHGLEV, ON1, nMSTR, nIRQ to GA -0.3 to +6 V SW1 to VP1 -6 to +0.3 V OVP2, SW2 to GP2 -0.3 to +30 V VIN to GA t <1ms and duty cycle <1% Steady State -0.3 to +7 -0.3 to +6 V V -0.3 to +0.3 V 1.8 W -40 to 85 °C Junction Temperature 125 °C Storage Temperature -55 to 150 °C 300 °C GP1, GP2 to GA RMS Power Dissipation (TA = 70°C) Operating Temperature Range Lead Temperature (Soldering, 10 sec) c: Do not exceed these limits to prevent damage to the device. Exposure to absolute maximum rating conditions for long periods may affect device reliability. Innovative Products. Active Solutions. ActivePMUTM is a trademark of Active-Semi. I2CTM is a trademark of Philips Electronics. -7- www.active-semi.com Copyright © 2008 Active-Semi, Inc. ACT8740 Rev PrB, 25-Feb-08 SYSTEM MANAGEMENT REGISTER DESCRIPTIONS Table 1: Global Register Map OUTPUT ADDRESS HEX A7 DATA (DEFAULT VALUE) A6 A5 A4 A3 A2 A1 A0 D7 D6 D5 D4 D3 D2 D1 D0 CHGR 08h 0 0 0 0 1 0 0 0 0 0 0 0 R R R R CHGR 09h 0 0 0 0 1 0 0 1 0 1 R R R R R R CHGR 0Ah 0 0 0 0 1 0 1 0 0 0 0 0 R R R R CHGR 0Bh 0 0 0 0 1 0 1 1 R R R R 1 0 R 0 REG1 10h 0 0 0 1 0 0 0 0 R V V V V V V V REG1 11h 0 0 0 1 0 0 0 1 R R R R R R R 0 REG1 12h 0 0 0 1 0 0 1 0 R R R R R R R R REG1 13h 0 0 0 1 0 0 1 1 R R R R R 0 R 1 REG2 20h 0 0 1 0 0 0 0 0 R R V V V V V V REG2 21h 0 0 1 0 0 0 0 1 R R R R R R R 0 REG2 22h 0 0 1 0 0 0 1 0 R R 0 0 0 0 0 0 REG2 23h 0 0 1 0 0 0 1 1 0 0 0 0 R 0 R 0 REG3 40h 0 1 0 0 0 0 0 0 R R 1 V V V V V REG4 41h 0 1 0 0 0 0 0 1 R R 0 V V V V V REG5 42h 0 1 0 0 0 0 1 0 R R 0 V V V V V REG345CFG 43h 0 1 0 0 0 0 1 1 R R R 0 0 0 0 R KEY: R: Read-Only bit. No Default Assigned. V: Default Values Depend on Voltage Option. Default Values May Vary. Note: Addresses other than those specified in Table 1 may be used for factory settings. Do not access any registers other than those specified in Table 1. Innovative Products. Active Solutions. ActivePMUTM is a trademark of Active-Semi. I2CTM is a trademark of Philips Electronics. -8- www.active-semi.com Copyright © 2008 Active-Semi, Inc. ACT8740 Rev PrB, 25-Feb-08 SYSTEM MANAGEMENT ELECTRICAL CHARACTERISTICS (VVSYS = 3.6V, TA = 25°C, unless otherwise specified.) PARAMETER TEST CONDITIONS VSYS Operating Voltage Range MIN 2.6 VSYS UVLO Threshold VSYS Voltage Rising VSYS UVLO Hysteresis VSYS Voltage Falling 2.25 VSYS Output Resistance Oscillator Frequency VSYS Supply Current TYP 1.35 ON1 = GA, CHGLEV = floating nMSTR Internal Pull-Up Resistance 250 2.4 MAX UNIT 5.5 V 2.55 V 80 mV 10 Ω 1.6 1.85 MHz 1.5 µA 500 kΩ Logic High Input Voltage ON1, nMSTR Logic Low Input Voltage ON1, nMSTR 0.4 V Logic Low Output Voltage nIRQ, ISINK = 5mA 0.3 V Leakage Current nIRQ, VnIRQ = 4.2V 1 µA Thermal Shutdown Temperature Temperature rising 160 °C Thermal Shutdown Hysteresis Temperature falling 20 °C Innovative Products. Active Solutions. ActivePMUTM is a trademark of Active-Semi. I2CTM is a trademark of Philips Electronics. 1.4 -9- V www.active-semi.com Copyright © 2008 Active-Semi, Inc. ACT8740 Rev PrB, 25-Feb-08 SYSTEM MANAGEMENT I2C INTERFACE ELECTRICAL CHARACTERISTICS (VVSYS = 3.6V, TA = 25°C, unless otherwise specified.) PARAMETER TEST CONDITIONS MIN TYP SCL, SDA Low Input Voltage SCL, SDA High Input Voltage MAX UNIT 0.4 V 1.4 V SCL, SDA Leakage Current SDA Low Output Voltage IOL = 5mA SCL Clock Period, tSCL fSCL clock freq = 400kHz 1 µA 0.3 V 2.5 µs SDA Data In Setup Time to SCL High, tSU 100 ns SDA Data Out Hold Time after SCL Low, tHD 300 ns SDA Data Low Setup Time to SCL Low, tST Start Condition 100 ns SDA Data High Hold Time after Clock High, tHP Stop Condition 100 ns Figure 1: I2C Serial Bus Timing tSCL SCL tST SDA IN tSU tSP tHD SDA OUT Innovative Products. Active Solutions. ActivePMUTM is a trademark of Active-Semi. I2CTM is a trademark of Philips Electronics. - 10 - www.active-semi.com Copyright © 2008 Active-Semi, Inc. ACT8740 Rev PrB, 25-Feb-08 SYSTEM MANAGEMENT TYPICAL PERFORMANCE CHARACTERISTICS (VVSYS = 3.6V, TA = 25°C, unless otherwise specified.) Oscillator Frequency vs. Temperature ON1 = GA Supply Current (µA) 1.65 ACT8740-002 1.68 Frequency (MHz) VSYS Current vs. Temperature 3 ACT8740-001 1.71 1.62 1.59 1.56 VVSYS = 4.2V 2 VVSYS = 3.6V VVSYS = 3.2V 1 1.53 1.50 -40 -20 0 20 40 60 0 -40 85 Temperature (°C) 20 40 60 85 Startup Sequence ACT8740-004 ACT8740-003 CH2 0 Temperature (°C) Startup Sequence CH1 -20 CH1 CH2 CH3 CH3 CH4 CH4 CH1: VnMSTR, 5V/div CH2: Power-On Reset (External Signal), 2V/div CH3: VON1, 5V/div CH4: VOUT1, 2V/div CH1: VnMSTR, 5V/div CH2: Power-On Reset (External Signal), 2V/div CH3: VON1, 5V/div CH4: VOUT1, 2V/div TIME: 100ms/div Innovative Products. Active Solutions. ActivePMUTM is a trademark of Active-Semi. I2CTM is a trademark of Philips Electronics. - 11 - TIME: 100ms/div www.active-semi.com Copyright © 2008 Active-Semi, Inc. ACT8740 Rev PrB, 25-Feb-08 SYSTEM MANAGEMENT FUNTIONAL DESCRIPTION General Description The ACT8740 offers an array of system management functions that allow it to provide optimal performance in a wide range of applications. I2C Serial Interface At the core of the ACT8740’s flexible architecture is an I2C interface that permits optional programming capability to enhance overall system performance. To ensure compatibility with a wide range of system processors, the ACT8740 uses standard I2C commands, I2C write-byte commands are used to program the ACT8740 and I2C read-byte commands are used to read the ACT8740’s internal registers. The ACT8740 always operates as a slave device, and is addressed using a 7-bit slave address followed by an eighth bit, which indicates whether the transaction is a read-operation or a write-operation, [1011110x]. SDA is a bi-directional data line and SCL is a clock input. The master initiates a transaction by issuing a START condition, defined by SDA transitioning from high to low while SCL is high. Data is transferred in 8-bit packets, beginning with the MSB, and is clocked-in on the rising edge of SCL. Each packet of data is followed by an “Acknowledge” (ACK) bit, used to confirm that the data was transmitted successfully. For more information regarding the I2C 2-wire serial interface, go to the NXP website: http://www.nxp.com System Startup and Shutdown The ACT8740 features a flexible control architecture that supports a variety of software-controlled enable/disable functions that make it a simple yet flexible and highly configurable solution. The ACT8740 is automatically enabled when any of the following conditions exists: 1) A valid supply voltage is present at VIN, 2) nMSTR is asserted low, or 3) ON1 is asserted high. If any of these conditions is true, the ACT8740 enables REG1 and REG3, powering up the system processor so that the startup and shutdown sequences may be controlled via software. Each of these startup conditions are described in detail below. Innovative Products. Active Solutions. ActivePMUTM is a trademark of Active-Semi. I2CTM is a trademark of Philips Electronics. Automatic Enable Due to Valid VIN Supply The ACT8740 battery charger, REG1, and REG3 are automatically enabled when a valid input supply is applied to VIN. Automatically enabling these functions simplifies system design and eliminates the need for external input supply-detection circuitry. Manual Enable Due to Asserting nMSTR Low System startup is initiated when the user presses the push-button, asserting nMSTR low. When this occurs, both REG1 and REG3 are enabled. Once the power-up routine is successfully completed, the microprocessor must assert ON1 so that the ACT8740 remains enabled after the push-button is released by the user. Upon completion of the startup sequence the processor assumes control of the power system and all further operation is softwarecontrolled. Manual Enable Due to Asserting ON1 High The ACT8740 is compatible with applications that do not utilize its push-button control function, and may be enabled by simply driving ON1 to a logichigh. In this case, the signal driving ON1 controls enable/disable timing, although software-controlled enable/disable sequences are still supported if the processor assumes control of the power system once the startup sequence is completed. Shutdown Sequence Once a successful power-up routine is completed, the system processor controls the operation of the power system, including the system shutdown timing and sequence. The ACT8740 asserts nIRQ low when nMSTR is asserted low, providing a simple means of alerting the system processor when the user wishes to shut the system down. Asserting nIRQ interrupts the system processor, initiating an interrupt service routine in the processor which will reveal that the user pressed the push-button. The microprocessor may validate the input, such as by ensuring that the push-button is asserted for a minimum amount of time, then initiates a softwarecontrolled power-down routine, the final step of which is to de-assert the ON1 input, disabling REG1 and REG3 and shutting the system down. - 12 - www.active-semi.com Copyright © 2008 Active-Semi, Inc. ACT8740 Rev PrB, 25-Feb-08 SYSTEM MANAGEMENT nMSTR Enable Input In most applications, connect nMSTR to an active low, momentary push-button switch to utilize the ACT8740’s closed-loop enable/disable functionality. If a momentary-on switch is not used, drive nMSTR to GA or to a logic low to initiate a startup sequence. nIRQ Output The ACT8740 provides an active-low, open-drain push-button status output that sinks current when nMSTR is driven to a logic-low. Connect a pull-up resistor from nIRQ to an appropriate voltage supply. nIRQ is typically used to drive the interrupt input of the system processor, and is useful in a variety of software-controlled enable/disable control routines. Thermal Shutdown The ACT8740 integrates thermal shutdown protection circuitry to prevent damage resulting from excessive thermal stress, as may be encountered under fault conditions. This circuitry disables all regulators if the ACT8740 die temperature exceeds 160°C, and prevents the regulators from being enabled until the IC temperature drops by 20°C (typ). Innovative Products. Active Solutions. ActivePMUTM is a trademark of Active-Semi. I2CTM is a trademark of Philips Electronics. - 13 - www.active-semi.com Copyright © 2008 Active-Semi, Inc. ACT8740 Rev PrB, 25-Feb-08 STEP-DOWN DC/DC CONVERTER ELECTRICAL CHARACTERISTICS (VVP1 = 3.6V, TA = 25°C, unless otherwise specified.) PARAMETER TEST CONDITIONS VP1 Operating Voltage Range MIN 3.1 VP1 UVLO Threshold Input Voltage Rising VP1 UVLO Hysteresis Input Voltage Falling 2.9 Output Voltage Regulation Accuracy ON1 = GA, VVP1 = 4.2V 0.1 c VNOM1 < 1.3V, IOUT1 = 10mA -2.4% VNOM1 VNOM1 ≥ 1.3V, IOUT1 = 10mA -1.2% VNOM1 VVP1 = Max(VNOM1 + 1V, 3.2V) to 5.5V Load Regulation IOUT1 = 10mA to 350mA Current Limit VOUT1 ≥ 20% of VNOM1 UNIT 5.5 V 3.1 V mV 130 Line Regulation Oscillator Frequency 3 MAX 80 Standby Supply Current Shutdown Supply Current TYP 200 µA 1 µA +1.8% +1.8% V 0.15 %/V 0.0017 %/mA 0.45 0.6 A 1.35 1.6 1.85 MHz VOUT1 = 0V 530 PMOS On-Resistance ISW1 = -100mA 0.45 0.75 Ω NMOS On-Resistance ISW1 = 100mA 0.3 0.5 Ω SW1 Leakage Current VVP1 = 5.5V, VSW1 = 5.5V or 0V 1 µA kHz Power Good Threshold 94 %VNOM1 Minimum On-Time 70 ns c: VNOM1 refers to the nominal output voltage level for VOUT1 as defined by the Ordering Information section. Innovative Products. Active Solutions. ActivePMUTM is a trademark of Active-Semi. I2CTM is a trademark of Philips Electronics. - 14 - www.active-semi.com Copyright © 2008 Active-Semi, Inc. ACT8740 Rev PrB, 25-Feb-08 STEP-DOWN DC/DC CONVERTER REGISTER DESCRIPTIONS Note: See Table 1 for default register settings. Table 2: REG1 Control Register Map ADDRESS DATA D7 D6 D5 D4 D3 10h R VRANGE 11h R 12h 13h D2 D1 D0 R R R R R R MODE R R R R R R R R R R R R R W/E OK W/E VSET R: Read-Only bits. Default Values May Vary. W/E: Write-Exact bits. Read/Write bits which must be written exactly as specified in Table 1 . Table 3: REG1 Control Register Bit Descriptions ADDRESS NAME BIT ACCESS FUNCTION DESCRIPTION 10h VSET [5:0] R/W REG1 Output Voltage Selection See Table 4 10h VRANGE [6] R/W REG1 Voltage Range Selection [7] R 10h 11h Min VOUT = 1.1V 1 Min VOUT = 1.25V READ ONLY PWM/PFM 1 Forced PWM R/W 11h [7:1] R READ ONLY 12h [7:0] R READ ONLY 13h [0] W/E WRITE-EXACT [1] R 13h [2] W/E WRITE-EXACT 13h [7:3] R READ ONLY OK Innovative Products. Active Solutions. ActivePMUTM is a trademark of Active-Semi. I2CTM is a trademark of Philips Electronics. Mode Selection 0 [0] 13h MODE 0 REG1 Power-OK - 15 - 0 1 Output is not OK Output is OK www.active-semi.com Copyright © 2008 Active-Semi, Inc. ACT8740 Rev PrB, 25-Feb-08 STEP-DOWN DC/DC CONVERTER REGISTER DESCRIPTIONS CONT’D Table 4: REG1/VSET[ ] Output Voltage Setting REG1/VSET[5:4] REG1/VSET [3:0] REG1/VRANGE[ ] = [0] REG1/VRANGE[ ] = [1] 00 01 10 11 00 01 10 11 0000 N/A N/A 1.455 1.860 1.250 2.050 2.850 3.650 0001 N/A N/A 1.480 1.890 1.300 2.100 2.900 3.700 0010 N/A 1.100 1.505 1.915 1.350 2.150 2.950 3.750 0011 N/A 1.125 1.530 1.940 1.400 2.200 3.000 3.800 0100 N/A 1.150 1.555 1.965 1.450 2.250 3.050 3.850 0101 N/A 1.175 1.585 1.990 1.500 2.300 3.100 3.900 0110 N/A 1.200 1.610 2.015 1.550 2.350 3.150 3.950 0111 N/A 1.225 1.635 2.040 1.600 2.400 3.200 4.000 1000 N/A 1.255 1.660 2.065 1.650 2.450 3.250 4.050 1001 N/A 1.280 1.685 2.090 1.700 2.500 3.300 4.100 1010 N/A 1.305 1.710 2.115 1.750 2.550 3.350 4.150 1011 N/A 1.330 1.735 2.140 1.800 2.600 3.400 4.200 1100 N/A 1.355 1.760 2.165 1.850 2.650 3.450 4.250 1101 N/A 1.380 1.785 2.190 1.900 2.700 3.500 4.300 1110 N/A 1.405 1.810 2.200 1.950 2.750 3.550 4.350 1111 N/A 1.430 1.835 2.245 2.000 2.800 3.600 4.400 (N/A): Not Available Innovative Products. Active Solutions. ActivePMUTM is a trademark of Active-Semi. I2CTM is a trademark of Philips Electronics. - 16 - www.active-semi.com Copyright © 2008 Active-Semi, Inc. ACT8740 Rev PrB, 25-Feb-08 STEP-DOWN DC/DC CONVERTER TYPICAL PERFORMANCE CHARACTERISTICS (ACT8740QLEGA, VVP1 = VVP2 = 3.6V, L = 3.3µH, CVP1 = CVP2 = 2.2µF, COUT1 = COUT2 = 10µF, TA = 25°C, unless otherwise specified.) REG1 Transient Peak Inductor Current REG1 Efficiency vs. Load Current Efficiency (%) 3.6V 80 Peak Inductor Current (mA) 3.2V 90 4.2V 70 60 ACT8740-006 VOUT1 = 1.8V 650 ACT8740-005 100 630 610 590 570 550 50 0.1 1 10 100 3.0 1000 3.5 4.0 Output Current (mA) REG1 MOSFET Resistance Load Regulation Error (%) RDSON (mΩ) 400 NMOS 200 100 3.5 4.0 4.5 5.0 0.0 -0.2 3.6V 4.2V -0.4 -0.6 -0.8 -1.0 5.5 ACT8740-008 0.2 ACT8740-007 PMOS 3.0 5.5 REG1 Load Regulation 500 0 2.5 5.0 VP1 Voltage (V) 600 300 4.5 0 50 100 VP1 Voltage (V) 150 200 250 300 350 400 Output Current (mA) OUT1 Regulation Voltage ACT8740-009 1.812 IOUT1 = 35mA OUT1 Voltage (V) 1.808 1.804 1.800 1.796 1.792 1.788 -40 -20 0 20 40 60 85 Temperature (°C) Innovative Products. Active Solutions. ActivePMUTM is a trademark of Active-Semi. I2CTM is a trademark of Philips Electronics. - 17 - www.active-semi.com Copyright © 2008 Active-Semi, Inc. ACT8740 Rev PrB, 25-Feb-08 STEP-DOWN DC/DC CONVERTER FUNCTIONAL DESCRIPTION General Description Programmable Operating Mode REG1 is a fixed-frequency, current-mode, synchronous PWM step-down converters that achieves a peak efficiency of up to 97%. REG1 is capable of supplying up to 350mA of output current and operates with a fixed frequency of 1.6MHz, minimizing noise in sensitive applications and allowing the use of small external components. REG1 is available with a variety of standard and custom output voltages, and may be software-controlled via the I2C interface by systems that require advanced power management functions. By default, REG1 operates in fixed-frequency PWM mode at medium to heavy loads, then transitions to a proprietary power-saving mode at light loads in order to save power. In applications where low noise is critical, force fixed-frequency PWM operation across the entire load current range, at the expense of light-load efficiency, by setting the REG1/MODE[ ] bit to [1]. 100% Duty Cycle Operation REG1 is capable of operating at up to 100% duty cycle. During 100% duty-cycle operation, the highside power MOSFET is held on continuously, providing a direct connection from the input to the output (through the inductor), ensuring the lowest possible dropout voltage in battery-powered applications. Synchronous Rectification REG1 features an integrated n-channel synchronous rectifier, which maximizes efficiency and minimizes the total solution size and cost by eliminating the need for an external rectifier. Enabling and Disabling REG1 Enable/disable functionality is typically implemented as part of a controlled enable/disable scheme utilizing nMSTR and other system control features of the ACT8740. REG1 is automatically enabled whenever either of the following conditions are met: 1) nMSTR is driven low, or 2) ON1 is asserted high. When none of these conditions are true, REG1 is disabled, and its quiescent supply current drops to less than 1µA. Programming the Output Voltage By default, REG1 powers up and regulates to its default output voltage. Once the system is enabled, REG1’s output voltage may be programmed to a different value, typically in order to reduce the power consumption of a microprocessor in standby mode. Program the output voltage via the I2C serial interface by writing to the REG1/VSET1[ ] register. Innovative Products. Active Solutions. ActivePMUTM is a trademark of Active-Semi. I2CTM is a trademark of Philips Electronics. Power-OK REG1 features a power-OK status bit that can be read by the system microprocessor. If the output voltage is lower than the power-OK threshold, typically 6% below the programmed regulation voltage, REG1/OK[ ] will clear to 0. Soft-Start REG1 includes internal soft-start circuitry, and enabled its output voltage tracks an internal 80µs softstart ramp so that it powers up in a monotonic manner that is independent of loading. Compensation REG1 utilizes current-mode control and a proprietary internal compensation scheme to simultaneously simplify external component selection and optimize transient performance over its full operating range. No compensation design is required, simply follow a few simple guidelines described below when choosing external components. Input Capacitor Selection The input capacitor reduces peak currents and noise induced upon the voltage source. A 2.2µF ceramic input capacitor is recommended for most applications. Output Capacitor Selection For most applications, a 10µF ceramic output capacitor is recommended. Although REG1 was designed to take advantage of the benefits of ceramic capacitors, namely small size and very-low ESR, low-ESR tantalum capacitors can provide acceptable results as well. Inductor Selection REG1 utilizes current-mode control and a proprietary internal compensation scheme to simultaneously - 18 - www.active-semi.com Copyright © 2008 Active-Semi, Inc. ACT8740 Rev PrB, 25-Feb-08 STEP-DOWN DC/DC CONVERTER simplify external component selection and optimize transient performance over its full operating range. REG1 was optimized for operation with a 3.3µH inductor, although inductors in the 2.2µH to 4.7µH range can be used. Choose an inductor with a low DC-resistance, and avoid inductor saturation by choosing inductors with DC ratings that exceed the maximum output current of the application by at least 30%. PCB Layout Considerations High switching frequencies and large peak currents make PC board layout an important part of stepdown DC/DC converter design. A good design minimizes excessive EMI on the feedback paths and voltage gradients in the ground plane, both of which can result in instability or regulation errors. Stepdown DC/DCs exhibit discontinuous input current, so the input capacitors should be placed as close as possible to the IC, and avoiding the use of vias if possible. The inductor, input filter capacitor, and output filter capacitor should be connected as close together as possible, with short, direct, and wide traces. The ground nodes for each regulator's power loop should be connected at a single point in a star-ground configuration, and this point should be connected to the backside ground plane with multiple vias. The output node should be connected to the OUT1 pin through the shortest possible route, while keeping sufficient distance from switching nodes to prevent noise injection. Finally, the exposed pad should be directly connected to the backside ground plane using multiple vias to achieve low electrical and thermal resistance. Innovative Products. Active Solutions. ActivePMUTM is a trademark of Active-Semi. I2CTM is a trademark of Philips Electronics. - 19 - www.active-semi.com Copyright © 2008 Active-Semi, Inc. ACT8740 Rev PrB, 25-Feb-08 WLED BIAS DC/DC CONVERTER ELECTRICAL CHARACTERISTICS (VVSYS = 3.6V, TA = 25°C, unless otherwise specified.) PARAMETER TEST CONDITIONS c Input Voltage Range MIN TYP 2 5.5 V 3.1 V VSYS Voltage Rising UVLO Voltage Hysteresis VSYS Voltage Falling 80 REG2/ON[ ] = [1], VFB2 = 0.3V 75 150 REG2/ON[ ] = [0], ILOAD = 0mA 0.1 1 255 275 FB2 Feedback Voltage 235 FB2 Input Current 3 UNIT UVLO Voltage Threshold Supply Current 2.9 MAX mV 50 Oscillator Frequency 1.35 Minimum On-Time Maximum Duty Cycle Switch Current Limit Duty = 83%, L = 22µH, COUT2 = 4.7µF Switch On-Resistance ISW2 = 100mA Switch Leakage Current VSW2 = 30V, Regulator Disabled Over Voltage Threshold VSET[ ] = [111111] 1.6 µA mV nA 1.85 MHz 100 ns 85 90 % 500 750 mA 0.67 27.5 28.5 1.1 Ω 10 µA 29.5 V c: As long as VSYS is within the VSYS operating range, this spec refers to the voltage range of the input that the inductor is connected to. Innovative Products. Active Solutions. ActivePMUTM is a trademark of Active-Semi. I2CTM is a trademark of Philips Electronics. - 20 - www.active-semi.com Copyright © 2008 Active-Semi, Inc. ACT8740 Rev PrB, 25-Feb-08 WLED BIAS DC/DC CONVERTER REGISTER DESCRIPTIONS Note: See Table 1 for default register settings. Table 5: REG2 Control Register Map ADDRESS DATA D7 D6 D5 D4 20h R R 21h R R R R 22h R R W/E 23h W/E W/E W/E D3 D2 D1 D0 R R R W/E W/E W/E W/E W/E W/E W/E R W/E OK ON VSET R: Read-Only bits. Default Values May Vary. W/E: Write-Exact bits. Read/Write bits which must be written exactly as specified in Table 1. Table 6: REG2 Control Register Bit Descriptions ADDRESS NAME BIT ACCESS FUNCTION DESCRIPTION 20h VSET [5:0] R/W REG2 Over Voltage Threshold Selection See Table 7 20h [7:6] R READ ONLY 21h [0] W/E WRITE-EXACT 21h [7:1] R READ ONLY 22h [5:0] W/E WRITE-EXACT 22h [7:6] R READ ONLY 0 REG2 Disable 1 REG2 Enable 0 Output is not OK 1 Output is OK 23h ON [0] R/W REG2 Enable 23h OK [1] R REG2 Power-OK 23h [2] W/E WRITE-EXACT 23h [3] R READ ONLY 23h [7:4] W/E WRITE-EXACT Innovative Products. Active Solutions. ActivePMUTM is a trademark of Active-Semi. I2CTM is a trademark of Philips Electronics. - 21 - www.active-semi.com Copyright © 2008 Active-Semi, Inc. ACT8740 Rev PrB, 25-Feb-08 WLED BIAS DC/DC CONVERTER REGISTER DESCRIPTIONS CONT’D Table 7: REG2/VSET[ ] Over Voltage Threshold Setting REG2/VSET[5:3] REG2/VSET [2:0] 000 001 010 011 100 101 110 111 000 5.00 7.00 9.000 11.00 13.00 17.00 21.00 25.00 001 5.25 7.25 9.250 11.25 13.50 17.50 21.50 25.50 010 5.50 7.50 9.500 11.50 14.00 18.00 22.00 26.00 011 5.75 7.75 9.750 11.75 14.50 18.50 22.50 26.50 100 6.00 8.00 10.00 12.00 15.00 19.00 23.00 27.00 101 6.25 8.25 10.25 12.25 15.50 19.50 23.50 27.50 110 6.50 8.50 10.50 12.50 16.00 20.00 24.00 28.00 111 6.75 8.75 10.75 12.75 16.50 20.50 24.50 28.50 Innovative Products. Active Solutions. ActivePMUTM is a trademark of Active-Semi. I2CTM is a trademark of Philips Electronics. - 22 - www.active-semi.com Copyright © 2008 Active-Semi, Inc. ACT8740 Rev PrB, 25-Feb-08 WLED BIAS DC/DC CONVERTER TYPICAL PERFORMANCE CHARACTERISTICS (ACT8740QLEHA, VVSYS = 3.6V, L = 22µH, COUT = 2.2µF, TA = 25°C, unless otherwise specified.) REG2 RDSON REG2 Efficiency vs. Output Current 800 700 RDSON (mΩ) Efficiency (%) 6 LEDs ACT8740-011 4 LEDs 90 900 ACT8740-010 100 80 70 600 500 400 60 300 200 50 1 5 9 13 17 21 25 2.5 31 3.5 4.0 4.5 5.0 5.5 VSYS Voltage (V) Output Current (mA) REG2 Over-Voltage Protection REG2 Startup Waveform ACT8740-013 ACT8740-012 CH1 3.0 CH1 0V REG2/ON[ ] = 1 CH2 0V REG2/ON[ ] = 0 CH1: VOUT3, 10V/div CH2: VFB3, 200mV/div TIME: 2ms/div Innovative Products. Active Solutions. ActivePMUTM is a trademark of Active-Semi. I2CTM is a trademark of Philips Electronics. CH1: VOUT2, 10V/div TIME: 100µs/div - 23 - www.active-semi.com Copyright © 2008 Active-Semi, Inc. ACT8740 Rev PrB, 25-Feb-08 WLED BIAS DC/DC CONVERTER FUNCTIONAL DESCRIPTION General Description Inductor Selection REG2 is a highly efficient step-up DC/DC converter that employs a fixed frequency, current-mode, PWM architecture. This regulator is optimized for white-LED bias applications consisting of up to seven white-LEDs. REG2 was designed to provide excellent performance across a wide range of applications, but was optimized for operation with inductors in the 10µH to 22µH range, although larger inductor values of up to 68µH can be used to achieve the highest possible efficiency. Enabling and Disabling REG2 Enable/disable control of REG2 is achieved through the ACT8740’s I2C serial interface. Enable REG2 by setting REG2/ON[ ] to [1], disable REG2 by clearing REG2/ON[ ] to [0]. When disabled, REG2’s quiescent supply current drops to just 1µA. As with all non-synchronous step-up DC/DC converters, REG2’s application circuit produces a DC current path between the input and the output in shutdown mode. Although the forward drop of the WLEDs makes this leakage current very small in most applications, it is important to consider the effect that this may have in your application particularly when using fewer than three WLEDs. Over-Voltage Protection REG2 features internal over-voltage protection (OVP) circuitry which protects the system from LED open-circuit fault conditions. If the voltage at OV ever reaches the over-voltage threshold, REG2 will regulate the top of the LED strong to the OVP threshold voltage. By default, the ACT8740’s OVP threshold is set at 28.5V, although it may be programmed to a lower value by writing to the REG2/VSET[ ] register. Optimizing for Smallest Footprint REG2 is capable of operating with very low inductor values in order to achieve the smallest possible footprint. When solution size is of primary concern, best results are achieved when using an inductor that ensures discontinuous conduction mode (DCM) operation over the full load current range. Optimizing for Highest Efficiency REG2 achieves excellent efficiency in applications that demand the longest possible battery life. When efficiency is the primary design consideration, best results are achieved when using an inductor that results in continuous conduction mode (CCM) operation and achieves very small inductor ripple current. Output Capacitor Selection REG2 was designed to operate with output capacitors ranging from 0.47µF to 10µF, providing design flexibility. A 1µF output capacitor is suitable for most applications, although larger output capacitors may be used to minimize output voltage ripple, if needed. Ceramic capacitors are recommended for most applications. Power-OK Bit REG2 features a Power-OK status bit that can be read by the system microprocessor via the I2C interface. If the voltage at OV is greater than the OVP threshold, REG2/OK[ ] will clear to 0. Compensation and Stability REG2 utilizes current-mode control and an internal compensation network to optimize transient performance, ease compensation, and improve stability over a wide range of operating conditions. REG2 is a flexible regulator, and its external components can be chosen to achieve the smallest possible footprint or to achieve the highest possible efficiency. Innovative Products. Active Solutions. ActivePMUTM is a trademark of Active-Semi. I2CTM is a trademark of Philips Electronics. Rectifier Selection REG2 requires a Schottky diode to rectify the inductor current. Select a low forward voltage drop Schottky diode with a forward current (IF) rating that is sufficient to support the maximum switch current and a sufficient peak repetitive reverse voltage (VRRM) to support the output voltage. Setting the LED Bias Current The LED bias current is set by a resistor connected from FB2 and ground, and the regulator is satisfied when the LED current is sufficient to generate 250mV across this resistor. Once the bias current is programmed, the LED current can be - 24 - www.active-semi.com Copyright © 2008 Active-Semi, Inc. ACT8740 Rev PrB, 25-Feb-08 WLED BIAS DC/DC CONVERTER adjusted using the ACT8740’s Direct-PWM feature. REG2 is also compatible with a variety of well-known LED dimming circuits, such as with a DC control voltage and a filtered PWM signal. PCB Layout Considerations High switching frequencies and large peak currents make PC board layout a very important part of the design. Good design minimizes excessive EMI on the feedback paths and voltage gradients in the ground plane, both of which can result in instability or regulation errors. Step-up DC/DCs exhibit continuous input current, so there is some amount of flexibility in placing vias in the input capacitor circuit. The inductor, input filter capacitor, rectifier, and output filter capacitor should be connected as close together as possible, with short, direct, and wide traces. Connect the ground nodes together in a star configuration, with a direct connection to the exposed pad. Finally, the exposed pad should be directly connected to the backside ground plane using multiple vias to achieve low electrical and thermal resistance. Note that since the LED string is a low, DC-current path, it does not generally require special layout consideration. Innovative Products. Active Solutions. ActivePMUTM is a trademark of Active-Semi. I2CTM is a trademark of Philips Electronics. - 25 - www.active-semi.com Copyright © 2008 Active-Semi, Inc. ACT8740 Rev PrB, 25-Feb-08 LOW-NOISE, LOW-DROPOUT, LINEAR REGULATORS ELECTRICAL CHARACTERISTICS (VINL = 3.6V, COUT3 = 1µF, TA = 25°C, unless otherwise specified.) PARAMETER TEST CONDITIONS INL Operating Voltage Range VINL Input Rising UVLO Hysteresis VINL Input Falling 2.9 V 3.1 V V VNOM3c +2 TA = -40°C to 85°C -2.5 VNOM3 +3 IOUT3 = 1mA to 350mA mV -0.004 %/mA f = 1kHz, IOUT3 = 350mA, COUT3 = 1µF 70 f = 10kHz, IOUT3 = 350mA, COUT3 = 1µF 60 Regulator Enabled 40 Regulator Disabled 0 IOUT3 = 160mA, VOUT3 > 3.1V 100 dB µA 200 350 VOUT3 = 95% of regulation voltage 400 Internal Soft-Start % 0 Output Current Current Limite 5.5 -1.2 Load Regulation Error Dropout Voltaged UNIT TA = 25°C VINL = Max(VOUT3 + 0.5V, 3.6V) to 5.5V Supply Current per Output 3 MAX 0.1 Line Regulation Error Power Supply Rejection Ratio TYP 3.1 INL UVLO Threshold Output Voltage Accuracy MIN mV mA 100 µs Power Good Flag High Threshold VOUT3, hysteresis = -4% 89 % Output Noise COUT3 = 10µF, f = 10Hz to 100kHz 40 µVRMS Stable COUT3 Range Discharge Resistor in Shutdown 1 LDO Disabled, DIS3[ ] = [1] 20 650 µF Ω c: VNOM3 refers to the nominal output voltage level for VOUT3 as defined by the Ordering Information section. d: Dropout Voltage is defined as the differential voltage between input and output when the output voltage drops 100mV below the regulation voltage at 1V differential voltage. e: LDO current limit is defined as the output current at which the output voltage drops to 95% of the respective regulation voltage. Under heavy overload conditions the output current limit folds back by 30% (typ) Innovative Products. Active Solutions. ActivePMUTM is a trademark of Active-Semi. I2CTM is a trademark of Philips Electronics. - 26 - www.active-semi.com Copyright © 2008 Active-Semi, Inc. ACT8740 Rev PrB, 25-Feb-08 LOW-NOISE, LOW-DROPOUT, LINEAR REGULATORS ELECTRICAL CHARACTERISTICS (VINL = 3.6V, COUT4 = 1µF, TA = 25°C, unless otherwise specified.) PARAMETER TEST CONDITIONS INL Operating Voltage Range VINL Input Rising UVLO Hysteresis VINL Input Falling 2.9 V 3.1 V V VNOM4c +2 TA = -40°C to 85°C -2.5 VNOM4 +3 IOUT4 = 1mA to 250mA mV -0.004 %/mA f = 1kHz, IOUT4 = 250mA, COUT4 = 1µF 70 f = 10kHz, IOUT4 = 250mA, COUT4 = 1µF 60 Regulator Enabled 40 Regulator Disabled 0 IOUT4 = 120mA, VOUT4 > 3.1V VOUT4 = 95% of regulation voltage 100 dB µA 200 mV 250 mA 280 Internal Soft-Start % 0 Output Current Current Limite 5.5 -1.2 Load Regulation Error Dropout Voltaged UNIT TA = 25°C VINL = Max(VOUT4 + 0.5V, 3.6V) to 5.5V Supply Current per Output 3 MAX 0.1 Line Regulation Error Power Supply Rejection Ratio TYP 3.1 INL UVLO Threshold Output Voltage Accuracy MIN mA 100 µs Power Good Flag High Threshold VOUT4, hysteresis = -4% 89 % Output Noise COUT4 = 10µF, f = 10Hz to 100kHz 40 µVRMS Stable COUT4 Range Discharge Resistor in Shutdown 1 LDO Disabled, DIS4[ ] = [1] 20 650 µF Ω c: VNOM4 refers to the nominal output voltage level for VOUT4 as defined by the Ordering Information section. d: Dropout Voltage is defined as the differential voltage between input and output when the output voltage drops 100mV below the regulation voltage at 1V differential voltage. e: LDO current limit is defined as the output current at which the output voltage drops to 95% of the respective regulation voltage. Under heavy overload conditions the output current limit folds back by 30% (typ) Innovative Products. Active Solutions. ActivePMUTM is a trademark of Active-Semi. I2CTM is a trademark of Philips Electronics. - 27 - www.active-semi.com Copyright © 2008 Active-Semi, Inc. ACT8740 Rev PrB, 25-Feb-08 LOW-NOISE, LOW-DROPOUT, LINEAR REGULATORS ELECTRICAL CHARACTERISTICS (VINL = 3.6V, COUT5 = 1µF, TA = 25°C, unless otherwise specified.) PARAMETER TEST CONDITIONS INL Operating Voltage Range VINL Input Rising UVLO Hysteresis VINL Input Falling 2.9 V 3.1 V V VNOM5c +2 TA = -40°C to 85°C -2.5 VNOM5 +3 IOUT5 = 1mA to 250mA mV -0.004 %/mA f = 1kHz, IOUT5 = 250mA, COUT5 = 1µF 70 f = 10kHz, IOUT5 = 250mA, COUT5 = 1µF 60 Regulator Enabled 40 Regulator Disabled 0 IOUT5 = 120mA, VOUT5 > 3.1V VOUT5 = 95% of regulation voltage 100 dB µA 200 mV 250 mA 280 Internal Soft-Start % 0 Output Current Current Limite 5.5 -1.2 Load Regulation Error Dropout Voltaged UNIT TA = 25°C VINL = Max(VOUT5 + 0.5V, 3.6V) to 5.5V Supply Current per Output 3 MAX 0.1 Line Regulation Error Power Supply Rejection Ratio TYP 3.1 INL UVLO Threshold Output Voltage Accuracy MIN mA 100 µs Power Good Flag High Threshold VOUT5, hysteresis = -4% 89 % Output Noise COUT5 = 10µF, f = 10Hz to 100kHz 40 µVRMS Stable COUT5 Range Discharge Resistor in Shutdown 1 LDO Disabled, DIS5[ ] = [1] 20 650 µF Ω c: VNOM5 refers to the nominal output voltage level for VOUT5 as defined by the Ordering Information section. d: Dropout Voltage is defined as the differential voltage between input and output when the output voltage drops 100mV below the regulation voltage at 1V differential voltage. e: LDO current limit is defined as the output current at which the output voltage drops to 95% of the respective regulation voltage. Under heavy overload conditions the output current limit folds back by 30% (typ) Innovative Products. Active Solutions. ActivePMUTM is a trademark of Active-Semi. I2CTM is a trademark of Philips Electronics. - 28 - www.active-semi.com Copyright © 2008 Active-Semi, Inc. ACT8740 Rev PrB, 25-Feb-08 LOW-NOISE, LOW-DROPOUT, LINEAR REGULATORS REGISTER DESCRIPTIONS Note: See Table 1 for default register settings. Table 8: CFG Control Register Map ADDRESS DATA D7 D6 D5 40h R R ON3 VSET3 41h R R ON4 VSET4 42h R R ON5 VSET5 43h OK5 OK4 OK3 D4 DIS5 D3 DIS4 D2 DIS3 D1 D0 W/E R R: Read-Only bits. Default Values May Vary. W/E: Write-Exact bits. Read/Write bits which must be written exactly as specified in Table 1. Table 9: REG345 Control Register Bit Descriptions ADDRESS NAME BIT ACCESS FUNCTION DESCRIPTION 40h VSET3 [4:0] R/W REG3 Output Voltage Selection See Table 10 40h ON3 [5] R/W REG3 Enable [7:6] R 40h REG3 Disable 1 REG3 Enable READ ONLY 41h VSET4 [4:0] R/W REG4 Output Voltage Selection 41h ON4 [5] R/W REG4 Enable [7:6] R 41h 0 See Table 10 0 REG4 Disable 1 REG4 Enable READ ONLY 42h VSET5 [4:0] R/W REG5 Output Voltage Selection 42h ON5 [5] R/W REG5 Enable 42h [7:6] R READ ONLY 43h [0] R READ ONLY 43h [1] W/E WRITE-EXACT 43h DIS3 [2] R/W REG3 Discharge Enable 43h DIS4 [3] R/W REG4 Discharge Enable Innovative Products. Active Solutions. ActivePMUTM is a trademark of Active-Semi. I2CTM is a trademark of Philips Electronics. - 29 - See Table 10 0 REG5 Disable 1 REG5 Enable 0 Discharge Disable 1 Discharge Enable 0 Discharge Disable 1 Discharge Enable www.active-semi.com Copyright © 2008 Active-Semi, Inc. ACT8740 Rev PrB, 25-Feb-08 LOW-NOISE, LOW-DROPOUT, LINEAR REGULATORS REGISTER DESCRIPTIONS CONT’D Table 9: Control Register Bit Descriptions (Cont’d) ADDRESS NAME BIT ACCESS FUNCTION 43h DIS5 [4] R/W REG5 Discharge Enable 43h OK3 [5] R REG3 Power-OK 43h OK4 [6] R REG4 Power-OK 43h OK5 [7] R REG5 Power-OK DESCRIPTION 0 Discharge Disable 1 Discharge Enable 0 Output is not OK 1 Output is OK 0 Output is not OK 1 Output is OK 0 Output is not OK 1 Output is OK Table 10: REG345CFG/VSETx[ ] Output Voltage Setting REG345CFG/VSETx[2:0] REG345CFG/VSETx[4:3] 00 01 10 11 000 1.4 2.15 2.55 3.0 001 1.5 2.20 2.60 3.1 010 1.6 2.25 2.65 3.2 011 1.7 2.30 2.70 3.3 100 1.8 2.35 2.75 3.4 101 1.9 2.40 2.80 3.5 110 2.0 2.45 2.85 3.6 111 2.1 2.50 2.90 3.7 Innovative Products. Active Solutions. ActivePMUTM is a trademark of Active-Semi. I2CTM is a trademark of Philips Electronics. - 30 - www.active-semi.com Copyright © 2008 Active-Semi, Inc. ACT8740 Rev PrB, 25-Feb-08 LOW-NOISE, LOW-DROPOUT, LINEAR REGULATORS TYPICAL PERFORMANCE CHARACTERISTICS (ACT8740QLEGA, VVIN = 5V, TA = 25°C, unless otherwise specified.) Dropout Voltage vs. Output Current Load Regulation 0.2 Dropout Voltage (mV) Output Voltage (%) 0.3 200 0.1 0.0 -0.1 -0.2 -0.3 25 0 125 REG3 100 75 50 3.1V 3.3V 3.6V 50 75 0 100 125 150 175 200 225 250 50 100 150 200 250 Load Current (mA) Output Current (mA) Output Voltage Deviation vs. Temperature LDO Output Voltage Noise 300 ILOAD = 0mA 0.3 0.2 350 ACT8740-017 ACT8740-016 Output Voltage Deviation (%) 150 0 -0.5 0.4 REG4, REG5 175 25 -0.4 0.5 ACT8740-015 225 ACT8740-014 0.5 0.4 0.1 CH1 0.0 -0.1 -0.2 -0.3 CREF = 10nF -0.4 -0.5 -40 -15 10 35 60 85 CH1: VOUTx, 200µV/div (AC COUPLED) TIME: 200ms/div Temperature (°C) Region of Stable COUT ESR vs. Output Current ACT8740-018 ESR (Ω) 1 0.1 Stable ESR 0.01 0 Innovative Products. Active Solutions. ActivePMUTM is a trademark of Active-Semi. I2CTM is a trademark of Philips Electronics. 50 100 150 - 31 - 200 250 300 350 www.active-semi.com Copyright © 2008 Active-Semi, Inc. ACT8740 Rev PrB, 25-Feb-08 LOW-NOISE, LOW-DROPOUT, LINEAR REGULATORS FUNCTIONAL DESCRIPTION General Description Optional LDO Output Discharge REG3, REG4, and REG5 are low-noise, lowdropout linear regulators (LDOs) that are optimized for low-noise and high-PSRR operation, achieving more than 60dB PSRR at frequencies up to 10kHz. Each of the ACT8740’s LDOs features an optional, independent output voltage discharge feature. When this feature is enabled, the LDO output is discharged to ground through a 1kΩ resistance when the LDO is shutdown. This feature may be enabled or disabled via the I2C interface by writing to the REG345CFG/DISx[ ] bits. LDO Output Voltage Programming All LDOs feature independently-programmable output voltages that are set via the I2C serial interface, increasing the ACT8740’s flexibility while reducing total solution size and cost. Set the output voltage by writing to the REG345CFG/VSETx[ ] registers. Output Current Capability REG3, REG4, and REG5 each supply 250mA of load current. Excellent performance is achieved over each regulator's entire load current ranges. Output Current Limit In order to ensure safe operation under over-load conditions, each LDO features current-limit circuitry with current fold-back. The current-limit circuitry limits the current that can be drawn from the output, providing protection in over-load conditions. For additional protection under extreme over current conditions, current-fold-back protection reduces the current-limit by approximately 30% under extreme overload conditions. Enabling and Disabling the LDOs All LDOs feature independent enable/disable control via the I2C serial interface. Independently enable or disable each output by writing to the appropriate REG345CFG/ONx[ ] bit. Power-OK Each of the LDOs features Power-OK status bit that can be read by the system microprocessor via the I2C interface. If an output voltage is lower than the power-OK threshold, typically 6% below the programmed regulation voltage, the corresponding REG345CFG/OKx[ ] will clear to 0. Reference Bypass Pin The ACT8740 contains a reference bypass pin which filters noise from the reference, providing a low-noise voltage reference to the LDOs. Bypass REF to G with a 0.01µF ceramic capacitor. Innovative Products. Active Solutions. ActivePMUTM is a trademark of Active-Semi. I2CTM is a trademark of Philips Electronics. Output Capacitor Selection REG3, REG4, and REG5 each require only a small ceramic capacitor for stability. For best performance, each output capacitor should be connected directly between the OUTx and G pins as possible, with a short and direct connection. To ensure best performance for the device, the output capacitor should have a minimum capacitance of 1µF, and ESR value between 10mΩ and 200mΩ. High quality ceramic capacitors such as X7R and X5R dielectric types are strongly recommended. PCB Layout Considerations The ACT8740’s LDOs provide good DC, AC, and noise performance over a wide range of operating conditions, and are relatively insensitive to layout considerations. When designing a PCB, however, careful layout is necessary to prevent other circuitry from degrading LDO performance. A good design places input and output capacitors as close to the LDO inputs and output as possible, and utilizes a star-ground configuration for all regulators to prevent noise-coupling through ground. Output traces should be routed to avoid close proximity to noisy nodes, particularly the SW nodes of the DC/DCs. REFBP is a filtered reference noise, and internally has a direct connection to the linear regulator controller. Any noise injected onto REFBP will directly affect the outputs of the linear regulators, and therefore special care should be taken to ensure that no noise is injected to the outputs via REFBP. As with the LDO output capacitors, the REFBP bypass capacitor should be placed as close to the IC as possible, with short, direct connections to the star-ground. Avoid the use of vias whenever possible. Noisy nodes, such as from the DC/DCs, should be routed as far away from REFBP as possible. - 32 - www.active-semi.com Copyright © 2008 Active-Semi, Inc. ACT8740 Rev PrB, 25-Feb-08 SINGLE-CELL Li+ BATTERY CHARGER (CHGR) ELECTRICAL CHARACTERISTICS (VVIN = 5V, VBAT = 3.6V, ISET1[ ] = [0000], TA = 25°C, unless otherwise specified.) PARAMETER TEST CONDITIONS VIN Operating Voltage Range MIN TYP 4.3 VIN UVLO Threshold VIN Voltage Rising VIN UVLO Hysteresis VIN Voltage Falling 3.75 6 V 4.25 V mV 300 500 mΩ TA = 25°C 4.179 4.200 4.221 V VVIN = 4.5V to 5.5V, TA = 0°C to 85°C 4.158 4.200 4.242 V Line Regulation VVIN = 4.5V to 5.5V, IBAT = 10mA Load Regulation IBAT = 50mA to 500mA VBAT = 4V, CHGLEV = GA Charge Current UNIT 500 On-Resistance Battery Termination Voltage 4 MAX 0.2 %/V 0.001 %/mA 90 100 mA VBAT = 4V, CHGLEV = VSYS 400 450 500 mA Precondition Charge Current VBAT = 2.7V, CHGLEV = GA or VSYS 30 45 60 mA Precondition Threshold Voltage VBAT Voltage Rising 2.75 2.9 3.05 V Precondition Threshold Hysteresis VBAT Voltage Falling End-of-Charge Current Threshold VBAT = 4.2V, CHGLEV = VSYS 150 20 End-of-Charge Delay Charge Restart Threshold VSET[ ] - VBAT, VBAT Falling Thermal Regulation Threshold BAT Reverse Leakage Current 38 mV 56 mA 4 min 200 mV 110 °C VBAT = 4.2V, VIN = GA or BAT 0.4 VVIN < UVLO Voltage 50 µA SLEEP, SUSPEND or TIMEOUT-FAULT state 200 µA PRECONDITION, FAST-CHARGE, or TOP-OFF state 700 µA Precondition Timeout Period TIMOSET[ ] = [10] 90 min Total Timeout Period TIMOSET[ ] = [10] 4 hr VIN Supply Current CHGLEV Logic High Input Voltage ICHGLEV ≥ 15µA 1.4 c CHGLEV Tri-state Current Threshold CHGLEV Logic Low Input Voltage 2 -2 ICHGLEV ≤ -15µA µA V 2 µA 0.4 V c: Charger is suspended when CHGLEV pin current is within this range Innovative Products. Active Solutions. ActivePMUTM is a trademark of Active-Semi. I2CTM is a trademark of Philips Electronics. - 33 - www.active-semi.com Copyright © 2008 Active-Semi, Inc. ACT8740 Rev PrB, 25-Feb-08 SINGLE-CELL Li+ BATTERY CHARGER (CHGR) REGISTER DESCRIPTIONS Note: See Table 1 for default register settings. Table 11: Battery Charger (CHGR) Control Register Map ADDRESS DATA D7 D6 08h D5 D4 ISET1 09h TIMOSET 0Ah LDOMODE 0Bh R R BATFLT ISET2 R R R D3 D2 D1 D0 R R R R TIMOFLT TEMPFLT CHGSTAT VINPOK R R R R W/E ICHGSET CHGROK SUSCHG R: Read-Only bits. Default Values May Vary. W/E: Write-Exact bits. Read/Write bits which must be written exactly as specified in Table 1. Table 12: Battery Charger (CHGR) Control Register Bit Descriptions ADDRESS NAME 08h BIT ACCESS [3:0] R FUNCTION READ ONLY 08h ISET1 [7:4] R/W ISET1 Charge Current Selection 09h VINPOK [0] R Input Supply Power-OK 09h CHGSTAT [1] R Charging Status 09h TEMPFLT [2] R Temperature Status 09h TIMOFLT [3] R Timeout Fault 09h BATFLT [4] R Battery Removed Fault [5] R 09h 09h TIMOSET 0Ah 0Ah ISET2 [7:6] R/W [3:0] R [6:4] R/W Innovative Products. Active Solutions. ActivePMUTM is a trademark of Active-Semi. I2CTM is a trademark of Philips Electronics. DESCRIPTION See Table 13 0 Input Power is not OK 1 Input Power is OK 0 Not Charging 1 Charging 0 No Temperature Fault 1 Temperature Fault 0 No Timeout Fault 1 Timeout Fault 0 Battery Not Removed 1 Battery Removed READ ONLY Charge Timeout Select 00 60 mins 01 90 mins 10 120 mins 11 No Timeout READ ONLY ISET2 Charger Current Selection - 34 - See Table 14 www.active-semi.com Copyright © 2008 Active-Semi, Inc. ACT8740 Rev PrB, 25-Feb-08 SINGLE-CELL Li+ BATTERY CHARGER (CHGR) REGISTER DESCRIPTIONS CONT’D Table 12: Battery Charger (CHGR) Control Register Bit Descriptions (Cont’d) ADDRESS NAME BIT ACCESS FUNCTION DESCRIPTION 0Ah LDOMODE [7] R/W LDO Mode Enable 0Bh SUSCHG [0] R/W Suspend Charging 0Bh CHGROK [1] R Charge Status 0Bh ICHGSET [2] R/W USB Charge Current Selection 0Bh [3] W/E WRITE-EXACT 0Bh [7:4] R READ ONLY 0 Charger in Normal Mode 1 Charger in LDO Mode 0 Charging Enable 1 Charging Disable 0 Charging Error Occurred 1 Charging OK 0 90mA 1 450mA Table 13: Table 14: ISET1[ ] Charge Current Setting ISET2[ ] Charge Current Setting CHGR/ISET1 [3:0] 0000 FAST CHARGE CURRENT SETTING (mA) CHGR/ISET2[2:0] ISET2 CURRENT SETTING (mA) CHGLEV = 1 450 000 300 CHGLEV = 0 90 001 400 0001 300 010 500 0010 350 011 600 0011 400 100 700 0100 450 101 800 0101 500 110 900 0110 550 111 1000 0111 600 1000 650 1001 700 1010 750 1011 800 1100 850 1101 900 1110 950 1111 1000 Innovative Products. Active Solutions. ActivePMUTM is a trademark of Active-Semi. I2CTM is a trademark of Philips Electronics. - 35 - www.active-semi.com Copyright © 2008 Active-Semi, Inc. ACT8740 Rev PrB, 25-Feb-08 SINGLE-CELL Li+ BATTERY CHARGER (CHGR) TYPICAL PERFORMANCE CHARACTERISTICS (ACT8740QLEGA, VVIN = 5V, TA = 25°C, unless otherwise specified.) Trickle-Charge Threshold Charge Termination Voltage 4.206 4.204 Trickle-Charge Threshold (V) VBAT Voltage Accuracy (V) 4.208 4.202 4.200 4.198 4.196 4.194 4.192 4.190 0 2.9 VBAT RISING 2.8 VBAT FALLING 2.7 2.6 2.5 10 20 30 40 50 60 70 0 10 20 Temperature (°C) SUSPEND Mode Battery Current CHGLEV Drive Current (µA) BAT Current (µA) VVIN = 5V 1 LOGIC HIGH INPUT 3 30 40 50 FLOATING INPUT -3 LOGIC LOW INPUT 60 70 -20 -40 0 Temperature (°C) MOSFET Resistance Max. Charge Current (mA) RDSON (mΩ) 150 100 50 50 60 70 Temperature (°C) Innovative Products. Active Solutions. ActivePMUTM is a trademark of Active-Semi. I2CTM is a trademark of Philips Electronics. 500 CHGLEV = VSYS 400 CHARGE CURRENT LIMITED BY THERMAL CONTROL CIRCUITRY 300 200 CHGLEV = GA 100 0 -40 0 40 85 ACT8740-024 200 30 60 600 ACT8740-023 250 20 40 Maximum Charge Current 300 10 20 Temperature (°C) 350 0 70 0 -6 0 20 60 CHGLEV Drive Current Threshold VIN FLOATING 10 50 ACT8740-022 VIN = GA 0 40 6 ACT8740-021 4 2 30 Temperature (°C) 5 3 ACT8740-020 3.0 ACT8740-019 4.210 -25 5 35 65 95 125 Temperature (°C) - 36 - www.active-semi.com Copyright © 2008 Active-Semi, Inc. ACT8740 Rev PrB, 25-Feb-08 SINGLE-CELL Li+ BATTERY CHARGER (CHGR) FUNCTIONAL DESCRIPTION General Description Charger Status The ACT8740’s internal battery charger is a fullfeatured, intelligent, linear-mode, single-cell charger for Lithium-based cells. This charger provides a complete selection of advanced functions and requires minimum system design effort. During normal operation, the processor can read the status of the input supply by reading CHGR/VINPOK[ ], which is set to [1] when the following conditions are true: The core of the charger is a CC/CV (Constant- Current/Constant-Voltage), linear-mode charge controller with a highly-accurate charge termination threshold. This controller incorporates current and voltage sense circuitry, an internal power MOSFET, a fullfeatured state-machine that implements charge control and safety features, and circuitry that eliminates the reverse-blocking diode required by conventional charger designs. The ACT8740’s charger also features thermal-regulation circuitry that protects it against excessive junction temperature, allowing the fastest possible charging times, as well as proprietary input protection circuitry that makes the charger robust against input voltage transients that can damage other chargers. CC/CV Regulation Loop At the core of the ACT8740’s battery charger is a CC/CV regulation loop, which regulates either current or voltage as necessary to ensure fast and safe charging of the battery. In a normal charge cycle, this loop regulates the charge current to the programmed charge current level and continues charging at this current until the battery cell voltage reaches the charge termination voltage. Once the cell reaches the Charge-Termination Threshold Voltage, the CV loop takes over and charge current is allowed to decrease as necessary to keep the cell voltage at the charge termination voltage. Charger Enable/Disable When a valid input voltage is applied to VIN, the battery charger is automatically enabled in order to simplify system design and eliminate the need for external input supply detection circuitry. Once the charger is enabled, a charge cycle automatically begins unless CHGLEV is floating, CHGR/SUSCHG[ ] is set to [1], or a fault condition has occurred. Innovative Products. Active Solutions. ActivePMUTM is a trademark of Active-Semi. I2CTM is a trademark of Philips Electronics. 1) The voltage at VIN is greater than the voltage at BAT, and 2) The voltage at VIN is greater than the VIN UVLO threshold. Alternatively, the processor can read the status of the charger by reading the CHGR/CHGROK[ ] bit, which is set to [1] when the following conditions are true: 1) The voltage at VIN is greater than the voltage at BAT, and 2) The voltage at VIN is greater than the VIN UVLO threshold, and 3) No fault has occurred. Finally, the status of a charge cycle can be determine by reading the CHGR/CHGSTAT[ ] bit or by evaluating the state of the nSTAT output. nSTAT is an open-drain output that has an internal 8mA current limit, and is capable of directly driving LEDs for a visual charge-status indication without the need of current-limiting resistors or other external circuitry. To drive an LED, simply connect the LED between an appropriate supply, typically VIN, and nSTAT. When a logic-level charge status indicator is desired, simply connect a pull-up resistor of 10kΩ or more from nSTAT to OUT2 or another suitable supply. CHGR/CHGSTAT[ ] is set to [1] and nSTAT sinks current when any of the following conditions are true: 1) The charger is operating in the PRECONDITION state, or 2) The charger is operating in the FAST-CHARGE state, or 3) The charger is operating in the TOP-OFF state. When none of these conditions are true, CHGR/ CHGSTAT[ ] is cleared to [0] and nSTAT goes into a high-Z state. - 37 - www.active-semi.com Copyright © 2008 Active-Semi, Inc. ACT8740 Rev PrB, 25-Feb-08 SINGLE-CELL Li+ BATTERY CHARGER (CHGR) FUNCTIONAL DESCRIPTION CONT’D Input Capacitor Selection VIN is the power input pin for the ACT8740 battery charger. The battery charger is automatically enabled whenever a valid voltage is present on VIN. In most applications, VIN is connected to either a wall adapter or a USB port. Under normal operation, the input of the charger will often be “hot-plugged” directly to a powered USB or a wall adapter cable, and supply voltage ringing and overshoot may appear at the VIN pin and can potentially be large enough to damage the charger input. In most applications, a capacitor connected from VIN to GA, placed as close as possible to the IC, is sufficient to absorb the energy. The VIN pin is designed for enhanced robustness and has an absolute maximum transient voltage rating of +7V, and attention must be given to bypass techniques to ensure operation within this limit. Charge Current Programming The charger was designed for maximum flexibility, and charge current programming is performed using the CHGR/ISET1[ ] and CHGR/ISET2[ ] registers and (optionally) the multifunction CHGLEV input. For applications that desire a combination of pin-control and I2C control, the CHGLEV input provides charge current selection between the current settings defined by CHGR/ISET1[ ] and CHGR/ISET2[ ]. Alternatively, when complete I2C control is desired, simply connect CHGLEV to G and utilize the CHGR/ICHGSET[ ] bit. The two methods are functionally equivalent, select the charge current programmed by CHGR/ISET1[ ] by driving CHGLEV to a logic low or by clearing CHGR/ICHGSET[ ] to [0], and select the charge current programmed by CHGR/ISET2[ ] by driving CHGLEV to a logic high or by setting CHGR/ICHGSET[ ] to [1]. The charger's default settings of CHGR/ISET1[ ] =[0000] and CHGR/ISET2[ ]=[0000] ensure compatibility with lower-current input supplies, such as USB ports. In the default configuration, drive CHGLEV to a logic-low for a 90mA charge current, and drive CHGLEV to a logic-high for 450mA charge current. If different charge current settings are desired, the charge current associated with either CHGLEV state is easily modified via the I2C serial interface. For example, in order to maintain compatibility with USB’s high-current mode as well as charge at a higher current if an AC adapter is available, simply reprogram Innovative Products. Active Solutions. ActivePMUTM is a trademark of Active-Semi. I2CTM is a trademark of Philips Electronics. CHGR/ISET1[ ] to select the desired charge current, then select this charge current by driving CHGLEV to a logic low or clear CHGR/ICHGSET[ ] to [0]. Charge Safety Timer The ACT8740 features a programmable charge safety timer that is utilized during operation in the PRECONDITION state. The safety timer has a default timeout period of 60 minutes, although it may be programmed to either 90 minutes or 120 minutes by writing to the CHGR/TIMOSET[ ] register. This register also provides a timer-disable function, for applications that do not require a charge safety timer function. Thermal Regulation The ACT8740 features an internal thermal feedback loop that reduces the charging current as necessary to ensure that the die temperature does not exceed the thermal regulation threshold of 110°C. This feature protects the ACT8740 against excessive junction temperature and makes the ACT8740 more accommodating of aggressive thermal designs without risk of damage. Note, however, that attention to good thermal design is required to achieve the shortest possible charge time. Reverse Leakage Current The ACT8740 includes internal circuitry that eliminates the need for series blocking diodes, reducing solution size and cost as well as dropout voltage relative to conventional battery chargers. When the input supply is removed, when VVIN goes below its under-voltage-lockout (UVLO) voltage, or when VVIN drops below VBAT, the ACT8740 automatically goes into SUSPEND mode and reconfigures its power switch to minimize current drain from the battery. Charger State Machine PRECONDITION State A new charging cycle begins in the PRECONDITION state. In this state, the cell is charged at a reduced current of either 45mA or 10% of the selected maximum fast-charge current, whichever is greater. During a normal charge cycle, charging continues at this rate until VBAT reaches the Precondition Threshold Voltage, at which point the state machine jumps to the FAST-CHARGE state. If VBAT - 38 - www.active-semi.com Copyright © 2008 Active-Semi, Inc. ACT8740 Rev PrB, 25-Feb-08 SINGLE-CELL Li+ BATTERY CHARGER (CHGR) FUNCTIONAL DESCRIPTION CONT’D does not reach the Precondition Threshold Voltage before the Precondition Charge Timeout period expires, then a damaged cell is detected and the state machine jumps to the TIMEOUT-FAULT state. FAST-CHARGE State In the FAST-CHARGE state the charger operates in Constant-Current (CC) mode and charges the cell at the programmed charge current. During a normal charge cycle, constant-current charging continues until VBAT reaches the charge termination voltage, at which point the state machine jumps to the TOPOFF state. TOP-OFF State In the TOP-OFF state the cell is charged in Constant-Voltage (CV) mode with the charge current limited by the internal chemistry of the cell, decreasing as the cell charges. A normal charging cycle continues until the charge current decreases to below the End-Of-Charge (EOC) threshold. In order to improve immunity to conditions that can result in false-EOC detection, the charging continues until the EOC condition persists for 4 consecutive minutes. Once this condition is met, the charge cycle is terminated and the state machine jumps to the SLEEP state. SUSPEND State When in the SUSPEND state, the charger is disabled and the charger presents a high-impedance to the battery, but the charge-control circuitry remains functional. When exiting the SUSPEND state, the charge timer is reset and the state machine jumps to the PRECONDITION state. TIMEOUT-FAULT State When a TIMEOUT-FAULT occurs, charging is suspended, CHGR/TIMOFLT[ ] is set to [1], and the charger presents a high-impedance to the battery. To maximize safety, there is no direct path to resume charging from the TIMEOUT-FAULT state. A new charging cycle may only be initiated if the state machine first jumps to the SUSPEND state then each of the conditions necessary to enter the PRECONDITION state are satisfied. SLEEP State In the SLEEP state the ACT8740 presents a highimpedance to the battery, allowing the cell to “relax” and minimizing battery leakage current. The ACT8740 continues to monitor the cell voltage, however, so that it can reinitiate a charging cycle as necessary to ensure that the cell remains fully charged. Charge Restart After a charge cycle successfully terminates, the ACT8740 jumps to its SLEEP state to minimize battery drain, but continues to actively monitor the cell voltage. A new charging cycle begins when the cell voltage has dropped by 200mV (typ), keeping the cell fully charged. This charge restart process minimizes cycle-life degradation of the cell by allowing it to “relax” between charges, while ensuring that the cell remains fully-charged while connected to a power source. Innovative Products. Active Solutions. ActivePMUTM is a trademark of Active-Semi. I2CTM is a trademark of Philips Electronics. - 39 - www.active-semi.com Copyright © 2008 Active-Semi, Inc. ACT8740 Rev PrB, 25-Feb-08 PACKAGE INFORMATION PACKAGE OUTLINE TQFN44-24 PACKAGE OUTLINE AND DIMENSIONS D D/2 SYMBOL E/2 E PIN #1 INDEX AREA DIMENSION IN MILLIMETERS DIMENSION IN INCHES MIN MAX MIN MAX A 0.700 0.800 0.028 0.031 A1 0.000 0.050 0.000 0.002 A3 0.200 REF 0.008 REF D/2 x E/2 A A3 A1 0.180 0.300 0.007 0.012 D 3.850 4.150 0.152 0.163 E 3.850 4.150 0.152 0.163 D2 2.500 2.800 0.098 0.110 E2 2.500 2.800 0.098 0.110 e D2 L b b L R e K 0.500 BSC 0.350 0.450 0.200 TYP 0.200 --- 0.020 BSC 0.014 0.018 0.008 TYP 0.008 --- E2 PIN #1 INDEX AREA D/2 x E/2 K R Active-Semi, Inc. reserves the right to modify the circuitry or specifications without notice. Users should evaluate each product to make sure that it is suitable for their applications. Active-Semi products are not intended or authorized for use as critical components in lifesupport devices or systems. Active-Semi, Inc. does not assume any liability arising out of the use of any product or circuit described in this datasheet, nor does it convey any patent license. Active-Semi and its logo are trademarks of Active-Semi, Inc. For more information on this and other products, contact [email protected] or visit http://www.active-semi.com. For other inquiries, please send to: 1270 Oakmead Parkway, Suite 310, Sunnyvale, California 94085-4044, USA Innovative Products. Active Solutions. ActivePMUTM is a trademark of Active-Semi. I2CTM is a trademark of Philips Electronics. - 40 - www.active-semi.com Copyright © 2008 Active-Semi, Inc.