SC813ULTRT

SC811 SEMTECH | Alldatasheet

Document overview

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Technical content

Features

Single input charger with three charging modes Constant voltage — 4.2V, 1% regulation Fast-charge current regulation — 15% at 70mA, 9% at 700mA Charging by current regulation, voltage regulation, and thermal limiting Input voltage protection — 30V Current-limited adapter support capability — reduces power dissipation in charger IC USB high and low power modes limit charge current to prevent USB Vbus overload Instantaneous CC-to-CV transition for faster charging Programmable battery-dependent currents (adapter mode fast- and pre-charge, termination) Programmable source-limited currents (USB-high mode fast-charge, and USB-low mode fast- and pre-charge) Independent programming of termination current with dual-mode operation Three termination options — fl oat-charge, automatic re-charge, or forced re-charge to keep the battery topped-off after termination without fl oat-charging Soft-start reduces adapter or USB load transients High operating voltage range of SC811 permits use of unregulated adapters Complies with CCSA YD/T 1591-2006 Space saving 2x2x0.6 (mm) MLPD package WEEE and RoHS compliant

Applications

Description

The SC811 and SC813 are highly versatile single input triple mode (adapter/USB high current, USB low current) linear single-cell Li-ion battery chargers, each in an 8 lead 2x2 MLPD ultra-thin package. The input will survive sus- tained input voltage up to 30V to protect against hot plug overshoot and faulty charging adapters. The SC811 has 9.6V rising, 8.2V falling OVP thresholds for general purpose charging with low cost adaptors. The SC813 has 6V rising, 5.6V falling OVP thresholds for customers utilizing charg- ing adapters with specifi cations that are similar to a USB Vbus supply. The SC811 and SC813 differ only in OVP threshold. Charging begins automatically when an input source is applied to the charging input. Thermal limiting protects against excessive power dissipation. The charger can be programmed to turn off when charging is complete or to continue operating as an LDO regulator while fl oat-charg- ing the battery. Three charging modes are provided: adapter mode, USB low power mode, and USB high power mode. Battery- capacity-dependent and charging source-dependent current programming are independently programmed. Adapter and USB high power modes can charge up to 1A, with the charging adapter operating either in voltage regulation or in current limit to obtain the lowest possible power dissipation. A single current programming pin is used to program pre-charge, termination, and adapter- mode fast-charge currents in fixed proportions. In the USB modes, a second programming pin is used to program low power pre-charge current and low and high power fast-charge currents. This confi guration allows indepen- dent programming of termination current. The two USB modes dynamically limit the charging load if necessary to prevent overloading the USB Vbus supply. Device Load Battery Pack 2.2 μF VADAPTER 2.2 μF MODE SELECT VIN IPUSB IPRGM MODE GND STATB ENB BAT SC811 / SC813 Typical Application Circuit April 7, 2008

© 2008 Semtech Corporation SC811 / SC813 Pin Confi guration Marking Information

Ordering Information

SC811ULTRT(1)(2) MLPD-UT-8 2×2 SC813ULTRT(1)(2) MLPD-UT-8 2×2 SC811EVB Evaluation Board SC813EVB Evaluation Board Notes: (1) Available in tape and reel only. A reel contains 3,000 devices. (2) Lead-free package only. Device is WEEE and RoHS compliant. TOP VIEW T 4 5

8 ENB

MLPD-UT8; 2x2, 8 LEAD θJA = 68°C/W x = 1 or 3 yw = Date Code

© 2008 Semtech Corporation SC811 / SC813 Exceeding the above specifi cations may result in permanent damage to the device or device malfunction. Operation outside of the parameters specifi ed in the Electrical Characteristics section is not recommended. NOTES: (1) Tested according to JEDEC standard JESD22-A114-B. (2) This is the input voltage at which the charger is guaranteed to begin operation. Maximum operating voltage is the maximum Vsupply as defined in EIA/JEDEC Standard No. 78, paragraph 2.11. (3) Calculated from package in still air, mounted to 3 x 4.5 (in), 4 layer FR4 PCB with thermal vias under the exposed pad per JESD51 standards. Absolute Maximum Ratings BAT, IPRGM, IPUSB Short to GND Duration . . . . Continuous ESD Protection Level Recommended Operating Conditions SC811: VIN Adapter Mode Operating Voltage SC813: VIN Adapter Mode Operating Voltage Thermal Information Test Conditions: VVIN = 4.75V to 5.25V; VBAT = 3.7V; Typ values at 25°C; Min and Max at -40°C < TA < 85°C, unless specifi ed. Parameter Symbol Conditions Min Typ Max Units VIN Adapter Mode Rising Threshold VT ADUVLO-R 4.30 4.45 4.60 V VIN Adapter Mode Falling Threshold (1) VTADUVLO-F VVIN > VBAT 2.70 2.85 3.00 V VIN USB Modes Rising Threshold VT USBUVLO-R VVIN > VBAT 4.20 4.35 V VIN USB Modes Falling Threshold VT USBUVLO-F VVIN > VBAT 3.65 4.00 V VIN USB Modes Hysteresis VT USBUVLO-H VTUSBUVLOR - VTUSBUVLOF 100 mV VIN OVP Rising Threshold VT OVP-R All modes, SC811 9.0 9.6 V All modes, SC813 5.85 6.0 VIN OVP Falling Threshold VT OVP-F All modes, SC811 8.2 8.8 V All modes, SC813 5.6 5.75 VIN OVP Hysteresis VT OVP-H VTOVP-R - VTOVP-F , all modes, SC811 50 200 mV VTOVP-R - VTOVP-F , all modes, SC813 50 100

Electrical Characteristics

© 2008 Semtech Corporation SC811 / SC813 Parameter Symbol Conditions Min Typ Max Units VIN Charging Disabled Quiescent Current IqVIN_DIS VENB = VBAT 23 m A VIN Charging Enabled Quiescent Current IqVIN_EN VENB = 0V, excluding IBAT, IIPRGM, and IIPUSB 23 m A CV Regulation Voltage V CV IBAT = 50mA, -40°C ≤ TJ ≤ 125°C 4.16 4.20 4.24 V CV Voltage Load Regulation V CV_LOAD Relative to VCV @ 50mA, 1mA ≤ IBAT ≤ 1A, -40°C ≤ TJ ≤ 125°C -20 10 mV Re-charge Threshold VT ReQ VCV - VBAT 60 100 140 mV Pre-charge Threshold (rising) VT PreQ 2.85 2.90 2.95 V Battery Leakage Current lBAT_V0 VBAT = VCV, VVIN = 0V 0.1 1 μA lBAT_DIS VBAT = VCV, VVIN = 5V, VENB = 2V 0.1 1 μA lBAT_MON VBAT = VCV, VVIN = 5V; ENB not connected 0.1 1 μA IPRGM Programming Resistor R IPRGM 2.05 29.4 kΩ Fast-Charge Current, Adapter Mode I FQ_AD RIPRGM = 2.94kΩ, VTPreQ < VBAT < VCV 643 694 745 mA Pre-Charge Current, Adapter Mode and USB High Power Mode IPreQ_AD RIPRGM = 2.94kΩ, 1.8V < VBAT < VTPreQ 105 139 173 mA Termination Current, Any Mode I TERM RIPRGM = 2.94kΩ, VBAT = VCV 59 69 80 mA IPUSB Programming Resistor R IPUSB 2.05 29.4 kΩ Fast-Charge Current, USB High Power Mode IFQ_USB RIPUSB = 4.42kΩ, 1.8V < VBAT < VTPreQ 427 462 497 mA Pre-Charge Current and Fast-Charge Current, USB Low Power Mode IPreQ_USB RIPUSB = 4.42kΩ, 1.8V < VBAT < VCV 69 92 116 mA Dropout Voltage V DO IBAT = 700mA, 0°C ≤ TJ ≤ 125°C 0.40 0.60 V IPRGM Fast-charge Regulated Voltage V IPRGM_FQ VVIN = 5.0V, VTPreQ < VBAT < VCV 2.04 V IPRGM Pre-charge Regulated Voltage V IPRGM_PQ 1.8V < VBAT < VTPreQ 0.408 V IPRGM Termination Threshold Voltage VT IPRGM_TERM VBAT = VCV (either input selected) 0.204 V IPUSB Fast-charge Regulated Voltage V IPUSB_FQ VVIN = 0V, VTPreQ < VBAT < VCV 2.04 V IPUSB Pre-charge or USB Low Power Mode Regulated Voltage VIPUSB_PQ VVIN = 0V, VBAT < VTPreQ 0.408 V VIN USB Modes Under-Voltage Load Regulation Limiting Voltage VUVLR 5mA ≤ VIN supply current limit ≤ 500mA, VMODE = 2V, RIPUSB = 3.65kΩ (559mA) 4.45 4.58 4.70 V Electrical Characteristics (continued)

© 2008 Semtech Corporation SC811 / SC813 Electrical Characteristics (continued) Parameter Symbol Conditions Min Typ Max Units Thermal Limiting Threshold Temperature TTL 130 °C Thermal Limiting Rate i T 50 mA/ °C ENB or MODE Input High Voltage Threshold VIH 1.6 V ENB or MODE Input Mid Voltage Range V IM 0.7 1.3 V ENB or MODE Input Low Voltage Threshold VIL 0.3 V ENB Input High-range Threshold Input Current IENB_IH_TH ENB current required to pull ENB from floating midrange into high range 23 50 μA ENB Input High-range Sustain Input Current IENB_IH_SUS Current required to hold ENB in high range, Min VIH ≤ VENB ≤ VBAT, Min VIH ≤ VBAT ≤ 4.2V 0.3 1 μA MODE Input High-range Input Current I MODE_IH VMODE = Min VIH 23 75 μA ENB or MODE Input Mid-range Load Limit IIM Input will float to mid range when this load limit is observed. -5 5 μA ENB or MODE Input Low-range Input Current IIL 0V ≤ (VENB or VMODE) ≤ Max VIL -25 12 μA MODE Input Monitor State Input Current IMODE_MON VMODE = VBAT = 4.2V, VENB = 1V and Charging Terminated 1μ A ENB or MODE Input Leakage I ILEAK VVIN = 0V or VVIN = 5V, VENB and VMODE = VBAT = 4.2V 1μ A STATB Output Low Voltage V STAT_LO ISTAT_SINK = 2mA 0.5 V STATB Output High Current I STAT_HI VSTAT = 5V 1 μA Notes: (1) Sustained operation to VT ADUVLO-F ≤ VVIN is guaranteed only if a current limited charging source applied to VIN is pulled below VTADUVLO-R by the charging load; forced VIN voltage below VTADUVLO-R may in some cases result in regulation errors or other unexpected behavior.

© 2008 Semtech Corporation SC811 / SC813 Typical Characteristics CV Line Regulation CV Load Regulation CV Temperature Regulation CC AD or USB High FQ Line Regulation CC AD or USB High FQ VBAT Regulation CC AD or USB High FQ Temperature Regulation 55 . 566 . 577 . 584.18 4.184 4.188 4.192 4.196 4.2 4.204 VVIN (V) VBAT (V) TA = 25οC, IBAT = 50mA 0 100 200 300 400 500 600 700 8004.18 4.184 4.188 4.192 4.196 4.2 4.204 IBAT (mA) VBAT (V) TA = 25οC, VVI N = 5V -40 -20 0 20 40 60 80 100 1204.18 4.184 4.188 4.192 4.196 4.2 4.204 Ambient Temperature ( o VBAT (V) VVI N = 5V, IBAT = 50mA 4.5 5 5.5 6 6.5 7 7.5 8440 480 520 560 600 640 680 720 RIPRGM or RIPUSB = 2.94kΩ RIPRGM or RIPUSB = 4.42kΩ VVIN (V) IBAT (mA) TA = 25οC, VBAT = 3.7V 440 480 520 560 600 640 680 720 VBAT (V) IBAT (mA) TA = 25οC, VVI N = 5V RIPRGM or RIPUSB = 2.94kΩ RIPRGM or RIPUSB = 4.42kΩ -40 -20 0 20 40 60 80 100 120 440 480 520 560 600 640 680 720 Ambient Temperature ( o IBAT (mA) VVI N = 5V, VBAT = 3.7V RIPRGM or RIPUSB = 2.94kΩ RIPRGM or RIPUSB = 4.42kΩ

© 2008 Semtech Corporation SC811 / SC813 Typical Characteristics CC USB Low Power FQ Line Regulation CC USB Low Power FQ V BAT Regulation CC USB Low Power FQ Temperature Regulation CC PQ Line Regulation CC PQ Temperature Regulation 4 . 555 . 566 . 577 . 5890 100 110 120 130 140 150 160 RIPUSB = 2.94kΩ RIPUSB = 4.42kΩ VVIN (V) IBAT (mA) TA = 25οC, VBAT = 3.7V 100 110 120 130 140 150 160 VBAT (V) IBAT (mA) TA = 25οC, VVI N = 5V RIPUSB = 2.94kΩ RIPUSB = 4.42kΩ 55 . 566 . 577 . 5890 100 110 120 130 140 150 160 VVIN (V) IBAT (mA) TA = 25οC, VBAT = 2.6V RIPRGM or RIPUSB = 2.94kΩ RIPRGM or RIPUSB = 4.42kΩ -40 -20 0 20 40 60 80 100 12090 100 110 120 130 140 150 160 Ambient Temperature ( o IBAT (mA) VVI N = 5V, VBAT = 2.6V RIPRGM or RIPUSB = 2.94kΩ RIPRGM or RIPUSB = 4.42kΩ -40 -20 0 20 40 60 80 100 120 100 110 120 130 140 150 160 Ambient Temperature ( o IBAT (mA) VVI N = 5V, VBAT = 3.7V RIPUSB = 2.94kΩ RIPUSB = 4.42kΩ

© 2008 Semtech Corporation SC811 / SC813 Typical Characteristics IFQ_AD vs. RIPRGM , or IFQ_USB High Power vs. RIPUSB IPQ_AD or IPQ_USB vs. RIPRGM, or IFQ_USB Low Power vs. RIPUSB Charging Cycle Battery Voltage and Current Pre-Charging Battery Voltage and Current CC-to-CV Battery Voltage and Current Re-Charge Cycle Battery Voltage and Current 610 630 650 670 690 710 IBAT (mA) 44 44.5 45 45.5 46 46.5 47 47.5 48 4.16 4.17 4.18 4.19 4.2 4.21 Time (min) VBAT (V) 850mAhr battery, RIPRGM = 2.94kΩ, VVI N = 5.0V, TA = 25οC VBAT IBAT 100 150 200 250 300 350 400 450 IBAT (mA) 0.5 1.5 2.5 3.5 4.5 Time (hrs) VBAT (V), Internal Power Dissipation (W) 850mAhr battery, RIPRGM = 2.94kΩ, VVI N = 5.0V, Load = 10mA VBAT IBAT Discharge hours 2 - 6 omitted. 100 200 300 400 500 600 700 IBAT (mA) Time (hrs) VBAT (V), Internal Power Dissipation (W) 850mAhr battery, RIPRGM = 2.94kΩ, VVI N = 5.0V, TA = 25οC VBAT IBAT 100 200 300 400 500 600 700 800 IBAT (mA) 0 2 4 6 8 1 01 21 41 61 82 02 2.25 2.5 2.75 3.25 3.5 3.75 Time (s) VBAT (V) 850mAhr battery, RIPRGM = 2.94kΩ, VVI N = 5.0V, TA = 25οC VBAT IBAT 2 6 10 14 18 22 26 300 200 400 600 800 1000 RIPRGM or RIPUSB (kΩ) IBAT (mA) VVI N = 5V, VBAT = 3.7V, TA = 25οC 2 6 10 14 18 22 26 300 120 160 200 RIPRGM or RIPUSB (kΩ) IBAT (mA) VVI N = 5V, VBAT = 2.6V, TA = 25οC

© 2008 Semtech Corporation SC811 / SC813 Typical Characteristics Mode Reselection — USB Low to USB High Mode Reselection — USB High to USB Low Mode Reselection — AD to USB High Mode Reselection — USB High to AD Mode Reselection — AD to USB Low Mode Reselection — USB Low to AD 100μs/div IBAT (100mA/div)) VMODE=0V— VMODE (2V/div) IBAT=0mA— VVIN=5V, VBAT=3.7V 100μs/div IBAT (100mA/div) VMODE=0V— VMODE (2V/div) IBAT=0mA— VVIN=5V, VBAT=3.7V 100μs/div IBAT (100mA/div) VMODE (2V/div) VVIN=5V, VBAT=3.7V 100μs/div IBAT (100mA/div) VMODE (2V/div) VVIN=5V, VBAT=3.7V 100μs/div IBAT (100mA/div) VMODE=0V— VMODE (2V/div) IBAT=0mA— VVIN=5V, VBAT=3.7V 100μs/div IBAT (100mA/div) VMODE=0V— VMODE (2V/div) IBAT=0mA— VVIN=5V, VBAT=3.7V VMODE=0V— IBAT=0mA— VMODE=0V— IBAT=0mA—

© 2008 Semtech Corporation SC811 / SC813 Pin Descriptions Pin # Pin Name Pin Function 1 VIN Supply pin — connect to charging adapter (wall adapter or USB). This pin is protected against damage due to high voltage up to 30V. 2 MODE Charging mode selection (tri-level logical) input — Logical high selects USB high power mode, fl oating selects USB low power mode, ground selects adapter mode. 3S T A T B Status output pin — This open-drain pin is asserted (pulled low) when a valid charging supply is connected to the VIN pin, and a charging cycle begins. It is released when the termination current is reached, indicating that charging is complete. STATB is not asserted for re-charge cycles.

4 GND Ground

5 IPUSB

Fast-charge and pre-charge current programming pin for a USB mode charging source — USB high power mode (100%) and low power mode (20%) fast-charge current are programmed by connecting a resistor from this pin to ground. USB low power mode pre-charge current is equal to the low power mode fast-charge current (20% of USB high power mode fast-charge current).

6 IPRGM

Adapter mode fast-charge, adapter and USB high power modes pre-charge, and all modes termination current programming pin — Connect a resistor from this pin to ground. Pre-charge current is 20% of IPRGM-programmed adapter mode fast-charge current when in adapter mode or USB high power mode. The charging termination current threshold (for adapter or either USB mode selection) is 10% of the IPRGM programmed fast-charge current. 7B A T Charger output — connect to battery positive terminal. Combined device enable/disable — Logic high disables the device. Tie to GND to enable charging with indefi nite fl oat-charging. Float this pin to enable charging without fl oat-charge upon termination. Note that this pin must be grounded if the SC811/3 is to be operated without a battery connected to BAT. T Thermal Pad Pad is for heatsinking purposes — not connected internally. Connect exposed pad to ground plane using multiple vias.

© 2008 Semtech Corporation SC811 / SC813 Block Diagram CC CV Mode Selection Logic Ad/USB select STATB IPRGM GND BAT IPUSB VCV = 4.2V VIREF VIN MODEV_Adapter or V_USB To System Load Lithium- Ion Single Cell Battery Pack RIPRGMRIPUSB Connect to BAT or to regulated supply VVUSB_UV_LIM = 4.575V Precharg, CC/CV & Termination Controller, Logical State Machine CC Feedback Selection (USB only) Termination ENB VTIPRGM_TERM Tri-level Control VTENB_HIGH = ~1.50V VTENB_LOW = ~0.551V Tri-level Control VTMODE_HIGH = ~1.50V VTMODE_LOW = ~0.55 Thermal Limiting Die Temperature VT_CT Regulated System Supply

© 2008 Semtech Corporation SC811 / SC813 Charger Operation The SC811/3 is a single input tri-mode stand-alone Li-ion battery charger. (The SC811 diff ers from the SC813 only in the input voltage Over Voltage Protection threshold.) It provides selections of adapter mode and USB high and low power mode charging. The device is independently programmed for battery capacity dependent currents (adapter fast-charge current and termination current) using the IPRGM pin. Charging currents from the USB Vbus supply, which has a maximum load specifi cation, are programmed using the IPUSB pin when either of the USB modes is selected. When an input supply is fi rst detected, a charge cycle is initiated and the STATB open-drain output goes low. If the battery voltage is less than the pre-charge threshold voltage, the pre-charge current is supplied. Pre-charge current is 20% of the IPRGM (adapter or USB high power modes) or IPUSB (USB low power mode) programmed fast-charge current. When the battery voltage exceeds the pre-charge thresh- old, typically within seconds for a standard battery with a starting cell voltage greater than 2V, the fast-charge Constant Current (CC) mode begins. The charge current soft-starts in three steps (20%, 60%, and 100% of pro- grammed fast-charge current) to reduce adapter load transients. CC current is programmed by the IPRGM resis- tance to ground when adapter mode is selected and by the IPUSB resistance to ground when either USB mode is selected. In USB low power mode, the CC current is held at 20% of the IPUSB programmed fast-charge current. The charger begins Constant Voltage (CV) regulation when the battery voltage rises to the fully-charged single- cell Li-ion regulation voltage (V CV), nominally 4.2V. In CV regulation, the output voltage is regulated, and as the battery charges, the charge current gradually decreases. The STATB output goes high when I BAT drops below the termination threshold current, which is 10% of the IPRGM pin programmed fast-charge current regardless of the mode selected. This is known as charge termination. Optional Float-charging or Monitoring Depending on the state of the ENB input, upon termina- tion the SC811/3 either operates indefi nitely as a voltage regulator (known as float-charging) or it turns off its output. If the output is turned off upon termination, the device enters the monitor state. In this state, the output remains off until the BAT pin voltage decreases by the re- charge threshold (VT ReQ). A re-charge cycle then begins automatically and the process repeats. A forced re- charge cycle can also be periodically commanded by the processor to keep the battery topped-off without fl oat- charging. See the Monitor State section for details. Re-charge cycles are not indicated by the STATB pin. Charging Input Pin Mode Dependencies The UVLO rising and falling thresholds are adjusted with the charging mode selected. In adapter mode, if the charging current loads the adapter beyond its current limit, the input voltage will be pulled down to just above the battery voltage. The adapter mode UVLO falling threshold is set close to the battery voltage pre-charge threshold to permit low-dissipation charging from a current limited adapter. The USB modes provide a higher UVLO falling threshold applicable to the USB specifi cation. The USB modes also provide Under-Voltage Load Regulation (UVLR), in which the charging current is reduced if needed to prevent overloading of the USB Vbus supply. UVLR can serve as a low-cost alternative to directly programming the USB low power charge current. This can be beneficial for charging small batteries, for which the USB high power fast-charge current must be programmed to less than 500mA. The fi xed 20% USB low power mode fast-charge current would be less than 100mA and, therefore, is unsuitable for minimum charge-time applications. UVLR can also be used where there is no signal available to indicate whether USB low or high power mode should be selected. All modes use the same input Over-Voltage Protection (OVP) threshold as defi ned in the Electrical Characteristics section for the device being used. Constant Current Mode Fast-charge Current Programming Constant Current (CC) regulation is active when the battery voltage is above VT PreQ and less than V CV. When adapter mode is selected, the programmed CC regula- tion fast-charge (FQ) current is inversely proportional to Applications Information

© 2008 Semtech Corporation SC811 / SC813 Applications Information (continued) which is the safest default mode with the lowest fast- charge current. Enable Input The ENB pin is a tri-level logical input that allows selection of the following behaviors: charging enabled with fl oat-charging after ter- mination (ENB = low range) charging enabled with fl oat-charging disabled and battery monitoring at termination (ENB = mid range) charging disabled (ENB = high range). If the ENB input voltage is permitted to fl oat to mid-range, the charger is enabled but it will turn off its output follow- ing charge termination and will enter the monitor state. This state is explained in the next section. Mid-range can be selected either by floating the input (sourcing or sinking less than 5μA) or by being externally forced such that V ENB falls within the midrange limits specifi ed in the Electrical Characteristics table. When driven low (V ENB < Max VIL), the charger is enabled and will continue to float-charge the battery following termination. If the charger is already in monitor state fol- lowing a previous termination, it will exit the monitor state and begin fl oat-charging. When ENB is driven high (V ENB > Min V IH), the charger is disabled and the ENB input pin enters a high impedance state, suspending tri-level functionality. The specified high level input current I IH is required only until a high level is recognized by the SC811/3 internal logic. The tri- level float circuitry is then disabled and the ENB input becomes high impedance. Once forced high, the ENB pin will not fl oat to mid range. To restore tri-level operation, the ENB pin must fi rst be pulled down to mid or low range (at least to V ENB < Max V IM), then, if desired, released (by reconfi guring the GPIO as an input) to select mid-range. If the ENB GPIO has a weak pull-down when confi gured as an input, then it is unnecessary to drive ENB low to restore tri-level operation; simply confi gure the GPIO as an input. When the ENB selection changes from high-range to mid- or low-range, a new charge cycle begins and STATB goes low. Note that if a GPIO with a weak pull-up input confi gura- tion is used, its pull-up current will fl ow from the GPIO into the ENB pin while it is fl oating to mid-range. Since the GPIO is driving a 1V equivalent voltage source through a resistance (looking into ENB), this current is small — pos- sibly less than 1 μA. Nevertheless, this current is drawn from the GPIO peripheral power supply and, therefore, from the battery after termination. (See the next section, Monitor State.) For this reason, it is preferable that the GPIO chosen to operate the ENB pin should provide a true high impedance (CMOS) configuration or a weak pull- down when confi gured as an input. When pulled below the fl oat voltage, the ENB pin output current is sourced from VIN, not from the battery. Monitor State If the ENB pin is fl oating, the charger output and STATB pin will turn off and the device will enter the monitor state when a charge cycle is complete. If the battery voltage falls below the re-charge threshold (V CV - VReQ) while in the monitor state, the charger will automatically initiate a re- charge cycle. The battery leakage current during monitor state is no more than 1μA over temperature and typically less than 0.1μA at room temperature. While in the monitor state, the ENB tri-level input pin remains fully active, and although in midrange, is sensitive to both high and low levels. The SC811/3 can be forced from the monitor state (no fl oat-charging) directly to fl oat- charging operation by driving ENB low. This operation will turn on the charger output, but will not assert the STATB output. If the ENB pin is again allowed to float to mid- range, the charger will remain on only until the output current becomes less than the termination current, and charging terminates. The SC811/3 turns off its charging output and returns to the monitor state within a millisec- ond. This forced re-charge behavior is useful for periodically testing the battery state-of-charge and topping-off the battery, without float-charging and without requiring the battery to discharge to the auto- matic re-charge voltage. ENB should be held low for at least 1ms to ensure a successful forced re-charge. Forced re-charge can be requested at any time during the charge cycle, or even with no charging source present, with no detrimental effect on charger operation. This allows the host processor to schedule a forced re-charge

© 2008 Semtech Corporation SC811 / SC813 Applications Information (continued) at any desired interval, without regard to whether a charge cycle is already in progress, or even whether a charging source is present. Forced re-charge will neither assert nor release the STATB output. Status Output The STATB pin is an open-drain output. It is asserted (driven low) as charging begins after a valid charging input is applied and the VIN voltage is greater than the UVLO level and less than the OVP level of the selected mode. STATB is also asserted as charging begins after the ENB input returns to either of the enable voltage ranges (mid or low voltage) from the disable (high voltage) range. STATB is subsequently released when the termination current is reached to indicate end-of-charge, when the ENB input is driven high to disable charging, or when the input voltage is removed. If the battery is already fully charged when a charge cycle is initiated, STATB is asserted, and will remain asserted for approximately 750μs before being released. The STATB pin is not asserted for auto- matic re-charge cycles. The STATB pin may be connected to an interrupt input to notify a host controller of the charging status or it can be used as an LED driver. Logical CC-to-CV Transition The SC811/3 diff ers from monolithic linear single cell Li- ion chargers that implement a linear transition from CC to CV regulation. The linear transition method uses two simultaneous feedback signals — output voltage and output current — to the closed-loop controller. When the output voltage is sufficiently below the CV regulation voltage, the infl uence of the voltage feedback is negligible and the output current is regulated to the desired current. As the battery voltage approaches the CV regulation voltage (4.2V), the voltage feedback signal begins to infl u- ence the control loop, which causes the output current to decrease although the output voltage has not reached 4.2V. The output voltage limit dominates the controller when the battery reaches 4.2V and eventually the control- ler is entirely in CV regulation. The soft transition eff ectively reduces the charge current below that which is permitted for a portion of the charge cycle, which increases charge time. In the SC811/3, a logical transition is implemented from CC to CV to recover the charge current lost due to the soft transition. The controller regulates only current until the output voltage exceeds the transition threshold voltage. It then switches to CV regulation. The transition voltage from CC to CV regulation is typically 5mV higher than the CV regulation voltage, which provides a sharp and clean transition free of chatter between regulation modes. The diff erence between the transition voltage and the regula- tion voltage is termed the CC/CV overshoot. While in CV regulation, the output current sense remains active. If the output current exceeds by 5% the mode-dependent pro- grammed fast-charge current, the controller reverts to current regulation. The logical transition from CC to CV results in the fastest possible charging cycle that is compliant with the speci- fi ed current and voltage limits of the Li-ion cell. The output current is constant at the CC limit, then decreases abruptly when the output voltage steps from the overshoot voltage to the regulation voltage at the transition to CV control. Thermal Limiting Device thermal limiting is the third output constraint of the Constant Current, Constant Voltage, “Constant” Temperature (CC/CV/CT) control. This feature permits a higher input OVP threshold, and thus the use of higher voltage or poorly regulated adapters. If high input voltage results in excessive power dissipation, the output current is reduced to prevent overheating of the SC811/3. The thermal limiting controller reduces the output current by i T ≈ 50mA/ºC for any junction temperature TJ > TTL. When thermal limiting is inactive, TJ = TA + VΔ IFQ θJA, where VΔ is the voltage difference between the VIN pin and the BAT pin. However, if TJ computed this way exceeds TTL, then thermal limiting will become active and the thermal limiting regulation junction temperature will be TJTL = TA + VΔ I(TJTL) θJA, where I(TJTL) = IFQ − iT (TJTL − TTL).

© 2008 Semtech Corporation SC811 / SC813 Applications Information (continued) Combining these two equations and solving for T JTL, the steady state junction temperature during active thermal limiting is JAT JATLTx_FQA JTL iV1 TiIVTT T T Although the thermal limiting controller is able to reduce output current to zero, this does not happen in practice. Output current is reduced to I(T JTL), reducing power dissi- pation such that die temperature equilibrium T JTL is reached. While thermal limiting is active, all charger functions remain active and the charger logical state is preserved. Operating a Charging Adapter in Current Limit In high charging current applications, charger power dis- sipation can be greatly reduced by operating the charging adapter in current limit. The SC811/3 adapter mode sup- ports adapter-current-limited charging with a low UVLO falling threshold and with internal circuitry designed for low input voltage operation. To operate an adapter in current limit, R IPRGM is chosen such that the adapter input programmed fast-charge current IFQ_AD exceeds the current limit of the charging adapter IAD-LIM. Note that if IAD-LIM is less than 20% of IFQ_AD, then the adapter voltage can be pulled down to the battery voltage while the battery voltage is below the pre-charge threshold. In this case, care must be taken to ensure that the adapter will maintain its current limit below 20% of I FQ_AD at least until the battery voltage exceeds the pre-charge thresh- old. Failure to do so could permit charge current to exceed the pre-charge current while the battery voltage is below the pre-charge threshold. This is because the low input voltage will also compress the pre-charge threshold inter- nal reference voltage to below the battery voltage. This will prematurely advance the charger logic from pre- charge current regulation to fast-charge regulation, and the charge current will exceed the safe level recom- mended for pre-charge conditioning. The low UVLO falling threshold ( VTADUVLO-F ) permits the adapter voltage to be pulled down to just above the battery voltage by the charging load whenever the adapter current limit is less than the programmed fast- charge current. The SC811/3 should be operated with adapter voltage below the rising selection threshold (VT ADUVLO-R ) only if the low input voltage is the result of adapter current limiting. This implies that the VIN voltage first exceeds VTADUVLO-R to begin charging and is subse- quently pulled down to just above the battery voltage by the charging load. Interaction of Thermal Limiting and Current Limited Adapter Charging To permit the charge current to be limited by the adapter, it is necessary that the adapter mode fast-charge current be programmed greater than the maximum adapter current, (I AD-LIM). In this confi guration, the CC regulator will operate with its pass device fully on (in saturation, also called “dropout”). The voltage drop from VIN to BAT is determined by the product of the minimum R DS-ON of the pass device multiplied by the adapter supply current. In dropout, the power dissipation in the SC811/3 is PILIM = (minimum R DS-ON) x (I AD-LIM)2. Since minimum R DS-ON does not vary with battery voltage, dropout power dissi- pation is constant throughout the CC portion of the charge cycle while the adapter remains in current limit. The SC811/3 junction temperature will rise above ambient by P ILIM x θJA. If the device temperature rises to the tem- perature at which the thermal limiting control loop limits charging current (rather than the current being limited by the adapter), the input voltage will rise to the adapter regulation voltage. The power dissipation will increase so that the thermal limit regulation will further limit charge current. This will keep the adapter in voltage regulation for the remainder of the charge cycle. To ensure that the adapter remains in current limit, the internal device temperature must never rise to T TL. This implies that θJA must be kept small enough to ensure that TJ = TA + (PILIM × θJA) < TTL. Under-Voltage Load Regulation in USB Modes VIN pin UVLR in either USB mode prevents the battery charging current from overloading the USB Vbus network, regardless of the programmed fast-charge value. When USB High Power or USB Low Power mode is selected, the SC811/3 monitors the input voltage (V VIN) and reduces the charge current as necessary to keep V VIN at or above the UVLR limit (VUVLR). UVLR operates like a fourth output con-

without the battery present, for example, factory testing. zero-volt capacitance rating. connecting to board ground near the GND pin. ing. The external circuit is illustrated in Figure 5. Figure 5. External programming of arbitrary USB high power and low power charge currents.

© 2008 Semtech Corporation SC811 / SC813 For USB low power mode charging, the external transistor is turned off . The transistor is turned on when high power mode is desired. The eff ect of the switched parallel IPUSB resistor is to reduce the eff ective programming resistance and thus raise the fast-charge current. An open-drain GPIO can be used directly to engage the parallel resistor RIPUSB_HI. Care must be taken to ensure that the R DS-ON of the GPIO is considered in the selection of RIPUSB_HI. Also important is the part-to-part and tempera- ture variation of the GPIO RDS-ON, and their contribution to the USB High Power charge current tolerance. Note also that IPUSB will be pulled up briefl y to as high as 3V during startup to check for an IPUSB static pinshort to ground. A small amount of current could, potentially, flow from IPUSB into the GPIO ESD structure through R IPUSB_HI during this event. While unlikely to do any harm, this eff ect must also be considered. The 300mAh battery example can be used to illustrate how this system works. The adapter mode and USB high power mode fast-charge currents should both be set to 300mA max. The USB input low power fast-charge current is 100mA max. Refer to the circuit in Figure 5 and the data of Figures 1a and 1b. For I FQ_AD = 300mA max, use RIPRGM = 7.50kΩ. A fi xed IPUSB resistor of RIPUSB = 23.2kΩ programs IFQ_USB = 100mA max for USB low power charging. When a parallel resistor RIPUSB_HI = 11.0kΩ resistor is switched in, the equivalent IPUSB resistor is 7.50kΩ, for I FQ_USB = 300mA max. USB Low Power Mode Alternative Where a USB mode selection signal is not available, or for a low capacity battery where system cost or board space make USB low power mode external current program- ming impractical, USB low power charging can be supported indirectly. The IPUSB pin resistance can be selected to obtain the desired USB high power charge current. Then, with the MODE pin always confi gured for USB high power mode, the UVLR feature will ensure that the charging load on the VIN pin will never pull the USB Vbus supply voltage below V UVLR regardless of the host or hub supply limit. The UVLR limit voltage guarantees that the voltage of the USB Vbus supply will not be loaded below the low power voltage specifi cation limit, as seen by any other low power devices connected to the same USB host or hub. Independent Programming of Termination Current The USB high power mode fast-charge current is limited to 1000mA, twice the USB high power load limit, and so this mode may also be used for general purpose adapter charging. The IPRGM pin resistance to ground determines the USB high power mode pre-charge current, and the termination threshold current for all modes. If adapter mode will not be used in the application, R IPRGM can be selected to program only the termination threshold current independently of the fast-charge current, which is programmed with R IPUSB. Note that USB high power mode invokes Under-Voltage Load Regulation, so if charging with an adapter in current limit, the input voltage can be pulled down no lower than V UVLR. USB-only Charging of Very Large Batteries The SC811/3 can support the charging of very large capac- ity batteries as high as 2Ah using a USB-only charging source. The IPRGM resistance lower limit of 2.05kΩ is intended to limit the fast-charge current while charging in adapter mode to less than 1A. If only USB charging modes will be used, then the IPRGM resistor can be chosen as low as 1kΩ. This extended programming range allows setting the USB high power mode pre-charge current as high as 400mA (still below the USB specifi cation limit), and the charge termination current as high as 200mA. (Both of these currents are determined by R IPRGM.) Note that with RIPRGM < 2.05kΩ, adapter mode should not be used, as this can result in potentially destructive fast-charge current. The USB high power and USB low power fast-charge cur- rents and the USB low power pre-charge current are determined by the resistance between IPUSB and GND to comply with USB specifi ed current limits, and so are unaf- fected by the IPRGM resistor. Termination detection requires that the charger be in CV regulation. If the IPRGM-determined termination threshold current is set higher than the USB low power mode fast-charge current, for example, then charge termination will occur the instant that the battery voltage rises to V CV. Thus USB low power charging will behave as if trickle-charging until fully charged, a perfectly safe and acceptable, although slow, charging scenario. Applications Information (continued)

© 2008 Semtech Corporation SC811 / SC813 2.00.079 PIN 1 INDICATOR (LASER MARK) SEATING PLANE C BA aaa C N E 2.10 2.10 1.90 1.90 .083 .083 .075 .075 D e/2 e bxN bbb C A B COPLANARITY APPLIES TO THE EXPOSED PAD AS WELL AS THE TERMINALS.2. D/2 E/2 E LxN INCHES .020 BSC b .007 bbb aaa N L e D .012 DIM A MIN .000 .020 0.400.30 .004 .003 .014 .079 .016 0.08 0.10 0.35 2.00

0.50 BSC

0.05 0.60 DIMENSIONS MIN 0.00 NOM (.006) MAX .002 .024 NOM 0.50 (0.1524) CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES). NOTES: A Outline Drawing — MLPD-UT8 2x2

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Phone: (805) 498-2111 Fax: (805) 498-3804 www.semtech.com Contact Information SC811 / SC813 Land Pattern — MLPD-UT8 2x2 INCHES DIMENSIONS P Z X Y C G DIM MILLIMETERS FAILURE TO DO SO MAY COMPROMISE THE THERMAL AND/OR FUNCTIONAL PERFORMANCE OF THE DEVICE. SHALL BE CONNECTED TO A SYSTEM GROUND PLANE. THERMAL VIAS IN THE LAND PATTERN OF THE EXPOSED PAD3. H .067 1.70 K .031 0.80 R .006 0.15 Y R G Z P X (C) 1. CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES). H K .030 .106 (.077) .047 0.75 2.70 (1.95) 1.20 0.30 0.50.020 .012 THIS LAND PATTERN IS FOR REFERENCE PURPOSES ONLY. CONSULT YOUR MANUFACTURING GROUP TO ENSURE YOUR COMPANY'S MANUFACTURING GUIDELINES ARE MET. NOTES: