SC1458 Dual Output Low Noise LDO Linear Regulator POWER MANAGEMENT Features Description The SC1458 is a family of dual output, ultra-low dropout linear voltage regulators designed for use in battery powered wireless applications. Both versions of the SC1458 require an input voltage level between 2.5V and 5.5V. The SC1458A supplies 2.5V on OUTA and 1.8V on OUTB, while SC1458B supplies 2.85V on both outputs. (For other voltage options see the SC560). Input voltage range — 2.5 to 5.5V Output voltages — 2.8V and 1.8V (SC1458A), 2.85V and 2.85V (SC1458B) Maximum output current — 300mA (each LDO) Low 200mV maximum dropout at 200mA load Quiescent current — 100μA (both LDOs enabled) Shutdown current — 100nA Output noise < 50μVRMS (SC1458B) PSRR > 65dB at 1kHz (SC1458B) Space saving package — MLPD-W6, 3mm x 3mm Over-temperature protection Short-circuit protection Under-voltage lockout Reset monitor for output A (SC1458A) Applications The SC1458A provides a PGOOD output to hold a processor in reset when the voltage on OUTA is not in regulation. The SC1458B provides superior low-noise performance by using an external bypass capacitor to filter the bandgap reference. Both versions have a single enable pin that controls both LDO outputs. The startup sequence delays the start of OUTB by 128μs after OUTA is enabled. Each version also provides protection circuitry such as current limiting, under-voltage lockout, and thermal protection to prevent device failures. Stability is maintained by using 1μF capacitors on the output pins. The MLPD package and 0402 ceramic capacitors minimize the required PCB area. PDAs and cellular phones GPS devices Palmtop computers and handheld instruments TFT/LCD applications Wireless handsets Digital cordless phones and PCS phones Personal communicators Two-way pagers Wireless LAN Typical Application Circuit SC1458A VIN VIN From μP September 12, 2007 To μP PGOOD EN OUTA OUTA 2.5V, 300mA GND OUTB OUTB 1.8V, 300mA CIN COUTA COUTB 2.2μF 1μF 1μF 1 SC1458 Pin Configuration 1 Ordering Information TOP VIEW 2 3 6 5 T Device Package SC1458AWLTRT(1)(2) MLPD-W6 3x3 SC1458BWLTRT(1)(2) MLPD-W6 3x3 SC1458AEVB Evaluation Board SC1458BEVB Evaluation Board Notes: (1) Available in tape and reel only. A reel contains 3,000 devices. (2) Available in lead-free package only. Device is WEEE and RoHS compliant. 4 MLPD-W6; 3x3, 6 LEAD θJA = 50°C/W Marking Information BROn yyww xxxx Voltage Options Device Marking ID VLDOA VLDOB SC1458A BROA 2.5V 1.8V SC1458B BROB 2.85V 2.85V BROn = See Voltage Options Table for Details yyww = Datecode xxxx = Semtech Lot Number 2 SC1458 Absolute Maximum Ratings Recommended Operating Conditions VIN (V) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3 to +6.5 Ambient Temperature Range (°C) . . . . . . . . -40 < TA < +85 VEN (V) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3 to (VIN + 0.3) VIN (V) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.5 < VIN < 5.5 VPGOOD (V) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3 to (VIN + 0.3) Pin Voltage — All Other Pins (V) . . . . . . . . . -0.3 to (VIN + 0.3) VOUTA, VOUTB, Short Circuit Duration . . . . . . . . . .Continuous Thermal Information ESD Protection Level(1) (kV) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Thermal Resistance, Junction to Ambient(2) (°C/W) . . . . 50 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) Tested according to JEDEC standard JESD22-A114-B. (2) Calculated from package in still air, mounted to 3” x 4.5”, 4 layer FR4 PCB with thermal vias under the exposed pad per JESD51 standards. Electrical Characteristics Unless otherwise noted VIN = 3.6V, CIN = 2.2μF, COUTA = COUTB = 1μF, VEN = VIN, TA = -40 to +85°C. Typical values are at TA = 25°C. All specifications apply to both LDOs unless otherwise noted. Parameter Input Supply Voltage Range Symbol Conditions VIN Typ Max Units 2.5 5.5 V -3 3 % Output Voltage Accuracy ΔVOUT Maximum Output Current IMAX Dropout Voltage(1) VD IOUT = 200mA, VOUT = 2.5V 100 200 mV Shutdown Current ISD TA = 25°C 0.1 1 μA Quiescent Current IQ IOUTA = IOUTB = 0mA, TA = 25°C 100 Load Regulation VLOAD IOUT = 1mA to IMAX Line Regulation VLINE IOUT = 1mA Current Limit ILIM Noise(2) eN VIN = VOUT + 0.3V to 5.5V, IOUT = 0 to 300mA Min 300 mA μA 20 mV -6 6 mV 350 850 mA VIN = 3.7V, IOUT = 50mA , 10Hz < f < 100kHz, CBYP = 22nF 50 μVRMS VIN = 3.7V, IOUT = 50mA , 10Hz < f < 100kHz 300 μVRMS 3 SC1458 Electrical Characteristics (continued) Parameter Power Supply Rejection Ratio(2) PGOOD Delay(3) PGOOD Threshold(3) Symbol Conditions 65 PSRR VIN = 3.7V, IOUT = 50mA, f = 1kHz, CBYP = 22nF VIN = 3.7V, IOUT = 50mA, f = 1kHz 40 tPGOOD Min Typ Max Units dB 160 200 240 ms 82 87 92 % V TH(PGOOD) VOUT(LDOA) falling tSU From OFF to 87% VOUT, IOUT = 50mA, CBYP = 22nF 1 ms Power Up Delay Between LDOA and LDOB tDELAY Delay between 0.87VOUTA and VOUTB start-up 128 μs Under Voltage Lockout VUVLO VIN Rising Start-Up Time UVLO Hysteresis Over Temperature Protection Threshold Over Temperature Hysteresis 2.15 VUVLO-HYS TOT Rising threshold TOT-HYS 2.25 2.35 V 100 mV 160 °C 20 °C Digital Inputs Logic Input High Threshold VIH VIN = 5.5V 1.25 V Logic Input Low Threshold VIL VIN = 2.5V 0.4 V Logic Input High Current IIH VIN = 5.5V 1 μA Logic Input Low Current IIL VIN = 5.5V 1 μA VOL ISINK = 500μA, VIN = 3.7V 20 mV Digital Outputs PGOOD Output Voltage Low 7 Notes: (1) Dropout voltage is defined as VIN - VOUT, when VOUT is 100 mV below the value of VOUT for VIN = VOUT +0.5V. (2) SC1458B only (3) SC1458A only 4 SC1458 Typical Characteristics Load Regulation LDOA 4 Load Regulation LDOB VOUTA = 2.5V, VIN = 3.6V 4 3.5 Output Voltage Variation (mV) Output Voltage Variation (mV) 3.5 3 TA=85°C 2.5 2 TA=25°C 1.5 TA=-40°C 1 3 TA=85°C 2.5 2 TA=25°C 1.5 TA=-40°C 1 0.5 0.5 0 VOUTB = 2.85V, VIN = 3.6V 0 0 50 100 150 Output Current (mA) 200 250 0 50 100 Line Regulation LDOA 1 VOUTA = 2.5V, IOUTA = 1mA 1.2 250 VOUTB = 2.85V, IOUTB = 1mA 1 0.8 Output Voltage Variation (mV) 0.6 0.4 0.2 0 -0.2 TA=-40°C -0.4 TA=25°C -0.6 TA=85°C -0.8 -1 2.7 2.9 3.1 3.3 3.5 3.7 0.6 0.4 0.2 TA=-40°C 0 TA=25°C -0.2 -0.4 -0.6 TA=85°C -0.8 3.9 4.1 4.3 4.5 4.7 Input Voltage (V) 4.9 5.1 5.3 -1 2.7 5.5 2.9 3.1 Dropout Voltage LDOA 3.3 3.5 3.7 3.9 4.1 4.3 4.5 Input Voltage (V) 4.7 4.9 5.1 5.3 5.5 Dropout Voltage LDOB VOUTA = 2.5V, IOUTA = 200mA 300 VOUTB = 2.85V, IOUTB = 200mA 250 250 T=85°C TA=85°C 200 150 TA=25°C VIN - VOUT (mV) VIN - VOUTA (mV) Output Voltage Variation (mV) 200 Line Regulation LDOB 0.8 300 150 Output Current (mA) TA=-40°C 100 150 T=25°C T=-40°C 100 50 50 0 2.2 200 2.25 2.3 2.35 2.4 2.45 2.5 2.55 Input Voltage (V) 2.6 2.65 2.7 2.75 2.8 0 2.2 2.25 2.3 2.35 2.4 2.45 2.5 2.55 2.6 2.65 2.7 2.75 2.8 Input Voltage (V) 5 SC1458 Typical Characteristics (continued) PSRR vs. Frequency 0 -10 -10 -20 -20 -30 -40 -30 -40 -50 -50 -60 -60 -70 10 VOUT = 2.85V, IO = 50mA, CBYP=22nF 0 PSRR (dB) PSRR (dB) PSRR vs. Frequency VOUT = 2.5V, IOUT = 50mA 100 1000 10000 -70 10 100 Output Noise vs. Load Current 350 TA=85°C 300 TA=25°C 90 VOUTB = 2.85V, IO = 50mA, CBYP=22nF 80 TA=-40°C 250 10000 Output Noise vs. Load Current VOUT = 2.5V, VIN = 3.6V, no CBYP Output Voltage Noise (uV) Output Voltage Noise (uV) 400 1000 Frequency (Hz) Frequency (Hz) 200 150 100 T=85°C 70 T=25°C 60 50 T=-40°C 40 30 20 50 10 0 0 50 100 150 200 250 0 0 50 Load Transient Response (Rising Edge) 100 150 200 250 Output Current (mA) Output Current (mA) Load Transient Response (Falling Edge) VOUT = 2.5V, VIN = 3.6V VOUT = 2.5V, VIN = 3.6V (0.1A/div) (0.1A/div) (20mV/div) (20mV/div) Time (1ms/div) Time (1ms/div) 6 SC1458 Pin Descriptions Pin # Pin Name Pin Function SC1458A SC1458B 1 1 OUTB 2 2 VIN 3 3 OUTA Output for LDOA 4 4 GND Analog and digital ground 5 5 EN 6 T PGOOD 6 BYP T Thermal Pad Output for LDOB Input supply voltage terminal Logic Input — active high enables the SC1458. Open drain logic output — monitors output of LDOA, switches low when the output drops out of regulation. LDO bypass output — bypass with a 22nF capacitor. Pad is for heatsinking purposes — not connected internally. Connect exposed pad to ground using multiple vias. 7 SC1458 Block Diagram VIN 2 Power On And Control Logic 5 EN 6 BYP or PGOOD 3 OUTA 1 OUTB Bandgap SC1458B Reference SC1458A ENA LDOA ENB GND 4 LDOB 8 SC1458 Applications Information General Description Active Shutdown The SC1458 is a dual output linear regulator intended for applications where low dropout voltage, low supply current, and low output noise are critical. The device provides a very simple, low cost solution for two separate regulated outputs using very little PCB area due to its small package size and the need for only three external capacitors. The SC1458 has internal active shutdown circuitry included for both LDOs. Shutdown behavior is controlled by discharging the output capacitor on the LDO output by an on-chip FET when the LDO is disabled. Protection Circuitry Both linear regulators are powered from a single input voltage supply rail, and each provides 300mA of output current. Output voltages are set internally, eliminating the need for external resistors. The device provides the following protection features to ensure that no damage is incurred in the event of a fault condition. Under-Voltage Lockout Over-Temperature Protection Short-Circuit Protection An active high enable pin (EN) controls operation of both regulators. Pulling this pin low causes the device to enter a very low power shutdown mode, where it typically draws 100nA from the input supply. Under-Voltage Lockout The Under-Voltage LockOut (UVLO) circuit protects the device from operating in an unknown state if the input voltage supply is too low. The device is available in two versions: SC1458A and SC1458B. The SC1458A version has pin 6 configured as a power good signal (PGOOD), which monitors the output of LDOA. The SC1458B device has pin 6 configured as an external bypass pin (BYP). This is suitable for applications which require low output noise and excellent PSRR characteristics. When the VIN drops below the UVLO threshold, the LDOs are disabled and discharged — PGOOD is held low (SC1458A only). When VIN is increased above the hysteresis level, the LDOs are enabled into their previous states (timing described in Figure 1), provided EN has remained high. When powering-up with VIN below the UVLO threshold, the LDOs will remain off and PGOOD will be held low (SC1458A only). • • • Power-On Control When EN transitions high, the output of LDOA is enabled. After a delay of 128μs, the output of LDOB is enabled. In the case of the SC1458A, when the output voltage of LDOA reaches 87% of its regulation point, the delay timer starts and the PGOOD signal transitions high after a delay of 200ms. The power up/down sequence is shown in Figure 1. EN 87% OUTA 200 ms PGOOD 128μs OUTB Figure 1 — Timing Diagram 87% Over-Temperature Protection An internal over-temperature (OT) protection circuit is provided that monitors the internal junction temperature. When the temperature exceeds the OT threshold as defined in the Electrical Characteristics section, the OT protection disables all the LDO outputs and holds the PGOOD signal low. When the junction temperature drops below the hysteresis level, the LDOs are re-enabled into their previous states and PGOOD is set high, provided EN has remained high (SC1458A only). Short-Circuit Protection Each LDO output has short-circuit protection. If the output current exceeds the current limit, the output voltage will drop and the output current will be limited until the short is removed. If a short-circuit occurs on the output of LDOA, the output of LDOB will also be disabled 9 SC1458 Applications Information (continued) 1.8 Component Selection A capacitance of 1μF or larger on each output is recommended to ensure stability. Ceramic capacitors of type X5R or X7R should be used because of their low ESR and stable temperature coefficients. It is also recommended that the input be bypassed with a 2.2μF, low ESR X5R or X7R capacitor to minimize noise and improve transient response. Note: Tantalum and Y5V capacitors are not recommended. A bypass capacitor (minimum of 22nF) should be connected between the BYP and GND pins to meet all noise-sensitive requirements. Increasing the capacitance to 100nF will further improve PSRR and output noise (SC1458B only). Thermal Considerations Although each of the two LDOs in the SC1458 can provide 300mA of output current, the maximum power dissipation in the device is restricted by the miniature package size. The graphs in Figure 2 and Figure 3 can be used as a guideline to determine whether the input voltage, output voltages, output currents, and ambient temperature of the system result in power dissipation within the operating limits or if further thermal relief is required. 1.5 TJ(Max)=150°C 1.2 TJ(Max)=125°C 0.9 0.6 0.3 0 -40 -20 0 20 40 60 80 100 Ambient Temperature (oC) Figure 3 — Maximum PD vs. TA The following procedure can be followed to determine if the thermal design of the system is adequate. The junction temperature of the SC1458 can be determined in known operating conditions using the following equation: TJ = TA +(PD x θJA) where TJ = Junction Temperature (°C) TA = Ambient Temperature (°C) PD = Power Dissipation (W) θJA = Thermal Resistance Junction to Ambient (°C/W) Example An SC1458A is used to provide outputs of 2.5V, 150mA from LDOA and 1.8V, 200mA from LDOB. The input voltage is 4.2V, and the ambient temperature of the system is 60°C. 0.5 PD= 0.15(4.2 – 2.5) + 0.2(4.2 – 1.8) = 0.74W 0.4 0.3 0.2 0.1 ______ TA=+25°C, PD(MAX)= 1.9W - - - - TA=+85°C, PD(MAX)= 1.0W 0 3 3.5 4 4.5 Input Voltage (V) and Maximum Recommended Input Voltage Maximum Total Output Current (A) 0.6 Maximum Power Dissipation (W) until the fault is removed and the load current returns to a specified level. 5 5.5 Figure 2 — Safe Operating Limit TJ = 60 + (0.74 x 50) = 97°C 6 Figure 3 shows that the power dissipation is within limits at TA = 60°C and calculation of TJ shows that it is within the specified limit of 150°C. This means that operation of the SC1458 under these conditions is within the specified limits and the device would not require further thermal relief measures. 10 SC1458 Applications Information (continued) PCB Layout Considerations • While layout for linear devices is generally not as critical as for a switching application, careful attention to detail will ensure reliable operation. • • • Connect all ground connections directly to the ground plane whenever possible to minimize ground potential differences on the PCB. Ensure that the feedback resistors are placed as close as possible to the feedback pins. Attach the part to a large copper footprint, particularly the thermal pad on the underside of the device, to enable better heat transfer, particularly on PCBs where there are internal power and ground planes. Place the input, output, and bypass capacitors close to the device for optimal transient response and device behavior. COUTB CIN SC1458B CBYP COUTA 11 SC1458 Outline Drawing — MLPD-W6 3x3 A D B DIM A A1 A2 b D E D1 E1 e L N aaa bbb E PIN 1 INDICATOR (LASER MARK) A aaa C SEATING PLANE C A2 A1 DIMENSIONS INCHES MILLIMETERS MIN NOM MAX MIN NOM MAX .028 .030 .031 0.70 0.75 0.80 .000 .001 .002 0.00 0.02 0.05 (0.20) (.008) .012 .016 .018 0.30 0.40 0.45 .114 .118 .122 2.90 3.00 3.10 .114 .118 .122 2.90 3.00 3.10 .087 .091 .094 2.20 2.30 2.40 .055 .059 .063 1.40 1.50 1.60 .037 BSC 0.95 BSC .012 .014 .016 0.30 0.35 0.40 6 6 .003 0.08 .004 0.10 D1 1 2 LxN E/2 E1 N bxN e bbb C A B D/2 NOTES: 1. CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES). 2. COPLANARITY APPLIES TO THE EXPOSED PAD AS WELL AS TERMINALS. 3. REFERENCE JEDEC STANDARD VARIATION WEEA-2. 12 SC1458 Land Pattern — MLPD-W6 3x3 DIMENSIONS H (C) G K Y X P Z DIM INCHES MILLIMETERS C (.116) (2.95) G .087 2.20 H .094 2.40 K .063 1.60 0.95 P .037 R .009 0.225 X .018 0.45 Y .030 0.75 Z .146 3.70 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 Mangement Products Division 200 Flynn Road, Camarillo, CA 93012 Phone: (805) 498-2111 Fax: (805) 498-3804 www.semtech.com 13