SC631 Fixed 4.4V Output Charge Pump Regulator POWER MANAGEMENT Features Description The SC631 is a high-current voltage regulator using Semtech’s proprietary low-noise charge pump technology. Performance is optimized for use in single Li-Ion battery cell applications. The regulator provides the performance of a linear, low drop-out (LDO) voltage regulator when the input is greater than 4.4V. Unlike an LDO, dropout is avoided when the input is less than 4.4V. Instead, a charge pump is activated to provide voltage boost and the head-room needed for voltage regulation. Input voltage range — 2.9V to 5.5V VOUT tolerance — 4.4V ±3% Continuous output current — 250mA Peak output current — 500mA Three charge pump modes: 1x, 1.5x and 2x Output ripple ≤ 30mVPP for IOUT ≤ 400mA Short circuit, over-voltage, and over-temperature protection Soft-start functionality Shutdown current — 0.1μA, typical Ultra thin package — 2 x 2 x 0.6 (mm) Fully WEEE and RoHS compliant Applications Only two 2.2μF bucket capacitors are required to deliver the full output current. The charge pump provides a low EMI solution compared to inductive boost regulators. The SC631’s charge pump has three modes of operation: 2x, 1.5x, and 1x modes. The 2x and 1.5x modes deliver current to the load in each of two phases. The 1x mode turns off the charge pump, delivering current through an LDO. When active, the charge pump provides low-ripple operation at 200kHz, which is typically less than 30mVpp at the output. The SC631 is capable of delivering 250mA continuous current, with peak current to 500mA. A 22μF output capacitor is used for decoupling the load and for smoothing mode transitions. Hysteresis is provided to prevent chatter between charge pump modes. Mobile phones Multi-LED backlit LCDs PMPs Digital video cameras Digital still cameras PDAs LED camera flash Audio amplifier power The micro lead-frame package is both small and thermally efficient, measuring 2 x 2 x 0.6 (mm). Typical Application Circuit CIN 22μF VBAT IN OUT VOUT = 4.4V @ 250mA COUT 22μF SC631 Chip enable EN C1+ C1C2+ GND C2- C1 2.2μF C2 2.2μF Patents Pending July 24, 2008 © 2008 Semtech Corporation 1 SC631 Pin Configuration GND Ordering Information 1 8 C2- TOP VIEW C1+ 2 7 C2+ C1- 3 6 OUT IN 4 5 EN Device Package SC631ULTRT(1)(2) MLPD-UT-8 2x2 SC631EVB 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. T MLPD-UT-8; 2x2, 8 LEAD θJA = 68°C/W Marking Information 631 yw yw = Datecode 2 SC631 Absolute Maximum Ratings Recommended Operating Conditions IN (V) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3 to +6.0 Ambient Temperature Range (°C) . . . . . . . . -40 ≤ TA ≤ +85 OUT (V). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3 to +6.0 IN (V) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.9 ≤ VIN ≤ 5.5 C1+, C2+ (V) . . . . . . . . . . . . . . . . . . . . . . . . . -0.3 to (VOUT + 0.3) Pin Voltage — All Other Pins (V) . . . . . . . . . -0.3 to (VIN + 0.3) OUT pin — Short Circuit Duration . . . . . . . . . . Continuous ESD Protection Level(2) (kV) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Thermal Information Thermal Resistance, Junction to Ambient(1) (°C/W) . . . . 68 Maximum Junction Temperature (°C) . . . . . . . . . . . . . . +150 Storage Temperature Range (°C) . . . . . . . . . . . . -65 to +150 Peak IR Reflow Temperature (10s to 30s) (°C) . . . . . . . +260 Exceeding the above specifications may result in permanent damage to the device or device malfunction. Operation outside of the parameters specified in the Electrical Characteristics section is not recommended. NOTES (1) 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. (2) Tested according to JEDEC standard JESD22-A114-B. Electrical Characteristics Unless otherwise specified: TA = +25°C for Typ, -40°C to +85°C for Min and Max; C1 = C2 = 2.2μF (ESR < 0.03Ω); CIN = COUT = 22μF; VIN = 2.9V to 5.5V Parameter Symbol Condition Min Typ Max Units Output Voltage VOUT VIN = 4.2V, IOUT = 1mA 4.27 4.4 4.53 V Output Voltage Ripple VPP IOUT ≤ 400mA Maximum Output Current IOUT 30 mV Peak Load - thermally limited(1), TJ <150°C, 3.33V ≤ VIN ≤ 5.5V 500 mA Continuous Load, TA ≤ 55°C, 2.92V ≤ VIN ≤ 4.2V 325 mA Continuous Load 250 mA Shutdown Current ISD Shutdown (EN = GND), VIN = 3.6V 0.1 2 μA Total Quiescent Current IQ EN high, IOUT = 1mA 1.5 2.5 mA Charge Pump Frequency fPUMP VIN = 3.2V 200 kHz tSU (EN transitions from low to high), 4.27V ≤ VOUT ≤ 4.53V, No load 400 μs Line Regulation ΔVLINE IOUT = 1mA, 2.85V ≤ VIN ≤ 4.2V 21 mV Load Regulation ΔVLOAD VIN =4.2V, 1mA ≤ IOUT ≤ 400mA 33 mV Start-Up Time 3 SC631 Electrical Characteristics (continued) Parameter Symbol Condition Min EN Input High Threshold VIH VIN = 5.5V 1.6 EN Input Low Threshold VIL VIN = 2.7V 0.4 V EN Input High Current IIH VIN = 5.5V 2 μA EN Input Low Current IIL VIN = 5.5V 2 μA Open-Loop Output Resistance Typ Max Units V 1x mode 0.25 Ω 1.5x mode, VIN = 3.7V 2.85 Ω 2x mode, VIN = 3.1V 2.9 Ω V TRANS 1X IOUT = 200mA 4.41 V V TRANS 1.5X IOUT = 200mA 3.31 V ISC VOUT = 0V, IOUT = IIN 300 600 980 mA VOUT > 2V, 1x mode 0.6 1.2 2.0 A VOUT > 2V, 1.5x and 2x modes 1.2 2.0 2.8 A ROUT Mode Transition Voltage (2) Fault Protection Short-Circuit Current Input Current Limit ILIMIT VOUT ≤ 2V, IOUT = IIN 700 mA TOTP Rising Threshold 165 °C THYS Hysteresis(3) 20 °C Over Temperature Notes: (1) Thermal limitation is dependent upon the thermal performance of the printed circuit board in support of the package standard of 68° C/W. (2) Voltage at the IN pin where a mode transition takes place in the charge pump with VIN falling. (3) Guaranteed by design - not tested in production. 4 SC631 Typical Characteristics Line Regulation Load Regulation TA=25°C 20 TA=85°C 15 10 TA=-40°C 5 0 0 90 VOUT = 4.4V, IOUT = 1mA 25 Output Voltage Variation — ΔV LINE (mV) Output Voltage Variation — ΔVLOAD (mV) 25 VOUT = 4.4V, VIN = 4.2V 180 270 Output Current (mA) 360 20 85°C 15 25°C 10 3.6V, 0mV 0 -5 -10 -15 450 2.7 PSRR versus Frequency — 1.5x Mode 0 -20 -20 -30 -30 -40 -40 -50 -60 4.7 5.1 5.5 VIN = 2.9V, VOUT = 4.4V, IOUT = 50mA -70 -80 -90 -90 -100 10 -100 10 10000 CIN=COUT=22μF (0805) C1=C2=2.2μF (0603) -60 -80 1000 3.9 4.3 Input Voltage (V) -50 -70 Frequency [Hz] 3.5 -10 C1=C2=2.2μF (0603) Gain [dB] Gain [dB] 0 CIN=COUT=22μF (0805) 100 3.1 PSRR versus Frequency — 2x Mode VIN = 3.6V, VOUT = 4.4V, IOUT = 50mA -10 -40°C 5 1000 100 10000 Frequency [Hz] 5 SC631 Typical Characteristics (continued) Efficiency — 10mA 100 Efficiency — 50mA VOUT = 4.4V, IOUT = 10mA 100 VOUT = 4.4V, IOUT = 50mA 1.5x Mode 1.5x Mode 90 Efficiency(%) Efficiency(%) 90 80 70 Mode Transition Hysteresis 60 50 4.2 3.9 3.6 80 Mode Transition Hysteresis 70 2x Mode 2x Mode 3.3 3.0 60 50 4.2 2.7 3.9 3.6 VIN (V) Efficiency — 100mA 100 3.3 3.0 2.7 3.0 2.7 Efficiency — 200mA VOUT = 4.4V, IOUT = 100mA 100 1.5x Mode 90 VIN (V) VOUT = 4.4V, IOUT = 200mA 90 Efficiency(%) Efficiency(%) 1.5x Mode 80 70 Mode Transition Hysteresis 80 70 2x Mode 60 60 Mode Transition Hysteresis 2x Mode 50 4.2 50 3.6 3.9 3.3 3.0 2.7 4.2 3.9 3.6 Efficiency — 300mA 100 Efficiency — 400mA VOUT = 4.4V, IOUT = 300mA 100 VOUT = 4.4V, IOUT = 400mA 90 90 1.5x Mode Efficiency(%) Efficiency(%) 1.5x Mode 80 Mode Transition Hysteresis 70 80 70 60 60 2x Mode 50 4.2 3.3 VIN (V) VIN (V) 2x Mode 50 3.9 3.6 3.3 VIN (V) 3.0 2.7 4.2 3.9 3.6 VIN (V) 3.3 3.0 2.7 6 SC631 Typical Characteristics (continued) Ripple — 1.5x Mode Ripple — 1x Mode VIN = 4.2V, VOUT= 4.4V, IOUT = 400mA VIN = 5.2V, VOUT = 4.4V, IOUT = 400mA VIN -PP (100mV/div) VIN -PP (20mV/div) VOUT -PP (20mV/div) IOUT (200mA/div) VOUT -PP (100mV/div) 400mA 400mA IOUT (200mA/div) CIN=COUT=22μF (0805) CIN=COUT=22μF (0805) C1=C2=2.2μF (0603) 0mA 0mA C1=C2=2.2μF (0603) Time (10μs/div) Time (10μs/div) Startup (No Load) Ripple — 2x Mode VIN = 3.2V, VOUT = 4.4V, IOUT = 400mA VIN = 3.6V, IOUT = 0mA VIN -PP (50mV/div) VEN (2V/div)– 0V— VOUT -PP (50mV/div) IOUT (200mA/div) 400mA VOUT (2V/div)– CIN=COUT=22μF (0805) 0V— CIN=COUT=22μF (0805) 0V— C1=C2=2.2μF (0603) 0mA C1=C2=2.2μF (0603) IOUT (200mA/div) Time (200μs/div) Time (10μs/div) Quiescent Current Startup (400mA) VOUT = 5V, IOUT = 1mA VIN = 3.6V, IOUT = 400mA 2.5 85C 25C 2.0 VEN (2V/div)– IQ (mA) 0V — 1.5 -45C VOUT (2V/div)– 0V— 0V— IOUT (200mA/div)– 1.0 CIN=COUT=22μF (0805) C1=C2=2.2μF (0603) Time (200μs/div) 0.5 4.20 3.94 3.68 3.42 3.16 2.90 VIN (V) 7 SC631 Pin Descriptions Pin Pin Name Pin Function 1 GND Ground — connect to ground plane with multiple vias 2 C1+ Positive terminal of bucket capacitor 1 3 C1- Negative terminal of bucket capacitor 1 4 IN Input supply voltage 5 EN Chip enable — active-high 6 OUT Output 7 C2+ Positive terminal of bucket capacitor 2 8 C2- Negative terminal of bucket capacitor 2 T Thermal Pad This pad is for heat sinking and is not connected internally. It must be connected to a ground plane using multiple vias. 8 SC631 Block Diagram IN 4 LDO 2 C1+ 200kHz 3 C17 C2+ EN 5 Logic Control Reference Voltage Generator CHARGE PUMP 8 C26 OUT 1 GND 9 SC631 Applications Information The SC631 is a 4.4V output charge pump regulator designed to support up to 325mA (TA ≤ 55°C, 2.92V ≤ VIN ≤ 5.5V) and 250mA (TA ≤ 85°C, 2.90V ≤ VIN ≤ 5.5V) of continuous current. SC631 applications include power for LEDs and audio amplifiers in portable handheld equipment. SC631 may be used in conjunction with regulated current sink devices such as the SC620 Octal LED Driver or with ballast resistors. The SC631 has three operating modes — 1x, 1.5x, and 2x. The 1x mode is a linear series regulation mode with a low open-loop output resistance of only 250mΩ. The 1x mode functions as a low-noise linear regulator. The 1.5x and 2x modes are a low noise, constant frequency, constant duty cycle switch mode, using two bucket capacitors. One bucket supports the full output current while the other bucket charges from the input. The two buckets exchange roles in the next phase, supplying continuous output current in both phases and reducing the need for a large output decoupling capacitor. The constant frequency, constant duty cycle operation also produces predictable constant frequency harmonics. Mode Transition Hysteresis Hysteresis is provided to prevent chatter between charge pump modes for input steps of up to 120mV. For optimum transient performance, it is recommended for the supply decoupling capacitance be large enough to prevent steps greater than 120mV. Normally CIN = 22uF is sufficient to minimize supply transients during the charge pump mode transitions. Thermal Resistance The SC631 package is thermally efficient when the circuit board layout connects the thermal pad through multiple vias to the ground plane. The thermal resistance rating is dependent upon the connection between the thermal pad and the ground plane. A layout that is done correctly should keep the junction temperature below the over- temperature limit while operating the SC631 within the specified electrical conditions. A poor layout may allow the junction temperature to reach the over temperature limit, so it is important to maintain adequate ground plane around the device to maximize heat transfer to the PCB. Temperature Derating The VIN supply range and ambient temperature range of the application should be compared with the following derating curve to determine the maximum safe continuous load current. The DC operating points beneath each curve are in the safe operating temperature range of the MLP package. 450 400 Derating for VIN < 4.2V 350 IOUT (mA) General Description 300 Derating for VIN < 5.5V 250 200 150 35 45 55 65 Ambient Temp (°C) 75 85 Maximum Continuous Output Protection Circuitry The SC631 also provides protection circuitry that prevents the device from operating in an unspecified state. These functions include: • • • Over-Current Protection (OCP) Short-Circuit Current Protection (SCCP) Over-Temperature Protection (OTP) 10 SC631 Applications Information (continued) Over-Current Protection Over-current protection is provided to limit the output current. When VOUT is greater than 2V, OCP limits the output to 1A typical. The 2V threshold allows the device to recover from excessive voltage droop during an overcurrent event. Short-Circuit Current Protection Short-circuit current protection is provided to limit the current that can be sourced when the output is shorted to ground. When a short circuit forces VOUT to drop below 2V, the SCCP detects the condition and limits the output current to 600mA (typical). Over-Temperature Protection The over-temperature circuit helps prevent the device from overheating and experiencing a catastrophic failure. When the junction temperature exceeds 165°C, the device is disabled. It remains disabled until the junction temperature drops below this threshold. Hysteresis is included that prevents the device from re-enabling until the junction temperature is reduced by 20°C. Capacitor Selection The SC631 is designed to use low-ESR ceramic capacitors for the input and output bypass capacitors as well as the charge pump bucket capacitors. Ideal performance is achieved when the bucket capacitors are exactly equal. The value of input and output decoupling capacitors will vary with system requirements. For best ripple performance CIN and COUT are normally 22μF and the bucket capacitors C1 and C2 are 2.2μF. For low profile designs, two 10μF capacitors may be used in place of each 22μF. When selecting capacitors for the application, the DC voltage characteristic of the capacitor should be considered. The value of capacitance at the DC operating voltage may be considerably lower than the rated value. The following table lists recommended capacitor values which have been chosen to minimize the impact of this limitation. Table 1 — Recommended Capacitors Capacitor Value μF Case Size Notes Typical output VPP ≤ 20mV in all charge pump modes CIN , COUT 22 0805 CBUCKET 2.2 0603 Required for the full rated output current CBUCKET 2.2 0402 Useful for load current up to 300mA Typical input ripple ≤ 100mV in all charge pump modes NOTE: Use only X5R type capacitors, with a 6.3V rating or higher The highest capacitance values in the smallest package sizes tend to have poor DC voltage characteristics. The highest value 0402 size capacitor retains as little as 35% of its rated value at 5VDC. The same value chosen in the next larger package size (0603) retains about 60% of its rated value at 5VDC. 11 SC631 Applications Information (continued) PCB Layout Considerations Poor layout can degrade the performance of the regulator and can be a contributory factor in EMI problems, ground bounce, thermal issues, and resistive voltage losses. Poor regulation and instability can result. The following design rules are recommended: 1. Place the bucket capacitors as close to the device as possible and on the same side of the board. Use short wide copper areas between the capacitor pins and the device pins. 2. Place the input and output decoupling capacitors as close as possible to the device and connect these capacitors’ ground pads together to the ground plane using multiple vias through a short wide copper area. 3. Connect pin 1 directly to the copper area under the thermal pad. 4. The thermal pad at the center of the device is not electrically connected. Connect this pad to the ground plane using multiple vias. 5. Use a ground plane to further reduce noise interference on sensitive circuit nodes. SC631 C2- C1 C1+ GND GND C2 C2+ C1- VOUT VIN EN COUT CIN EN 12 SC631 Outline Drawing — MLPD-UT-8 2x2 B D A DIMENSIONS DIM E PIN 1 INDICATOR (LASER MARK) A SEATING PLANE aaa C A2 A1 C A A1 A2 b D D1 E E1 e L N aaa bbb MILLIMETERS INCHES MIN .020 .000 NOM - MAX .024 .002 (.006) .010 .012 .079 .083 .067 .071 .079 .083 .031 .035 .020 BSC .014 .016 .012 8 .003 .004 .007 .075 .061 .075 .026 MIN 0.50 0.00 NOM - (0.1524) 0.18 0.25 1.90 2.00 1.55 1.70 1.90 2.00 0.65 0.80 0.50 BSC 0.30 0.35 8 0.08 0.10 MAX 0.60 0.05 0.30 2.10 1.80 2.10 0.90 0.40 D1 1 2 LxN E/2 E1 N bxN bbb e C A B e/2 D/2 NOTES: 1. CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES). 2. COPLANARITY APPLIES TO THE EXPOSED PAD AS WELL AS THE TERMINALS. 13 SC631 Land Pattern — MLPD-UT-8 2x2 H DIMENSIONS R (C) K G Z Y P DIM INCHES MILLIMETERS C (.077) (1.95) G .047 1.20 H .067 1.70 K .031 0.80 P .020 0.50 R .006 0.15 X .012 0.30 Y .030 0.75 Z .106 2.70 X NOTES: 1. CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES). 2. THIS LAND PATTERN IS FOR REFERENCE PURPOSES ONLY. CONSULT YOUR MANUFACTURING GROUP TO ENSURE YOUR COMPANY'S MANUFACTURING GUIDELINES ARE MET. 3. THERMAL VIAS IN THE LAND PATTERN OF THE EXPOSED PAD SHALL BE CONNECTED TO A SYSTEM GROUND PLANE. FAILURE TO DO SO MAY COMPROMISE THE THERMAL AND/OR FUNCTIONAL PERFORMANCE OF THE DEVICE. Contact Information Semtech Corporation Power Management Products Division 200 Flynn Road, Camarillo, CA 93012 Phone: (805) 498-2111 Fax: (805) 498-3804 www.semtech.com 14