SC1454 Dual 150mA Ultra Low Dropout, Low Noise Regulator POWER MANAGEMENT Description Features u u u u u u u The SC1454 has a bypass pin to enable the user to u capacitively decouple the bandgap reference for very low u u output noise (50µVRMS typically). u The SC1454 contains two ultra low dropout voltage regulators (ULDOs). It operates from an input voltage range of 2.25V to 6.5V, and a wide variety of output voltage options are available. One ULDO has a fixed output, and the other is either fixed (SETA pin grounded) or adjustable using external resistors. Each ULDO has an independent enable pin. Designed specifically for battery operated systems, the devices utilize CMOS technology to require very low operating currents (typically 130µA with both outputs supplying 150mA). In addition, the dropout voltage is typically 155mV at 150mA, helping to prolong battery life further. The devices are designed to provide 400mA of peak current for applications which require high initial inrush current. Up to 150mA per regulator output Low quiescent current Low dropout voltage Stable operation with ceramic caps Very low 50µVRMS output noise Wide selection of output voltages Tight load and line regulation Current and thermal limiting Reverse input polarity protection <1.5uA off-mode current Logic controlled enable Applications u u u u u u Cellular telephones Palmtop/Laptop computers Battery-powered equipment Bar code scanners SMPS post regulator/dc to dc modules High efficiency linear power supplies They have been designed to be used with low ESR ceramic capacitors to save cost and PCB area. The SC1454 is available with a wide variety of voltage options as standard. It comes in the tiny 8 lead MSOP surface mount package. Typical Application Circuit U1 SC1454DIMS 1 OUTPUT A: 3.0V 2 OUTPUT B: 3.0V 3 4 C1 1uF OUTA IN OUTB ENA GND BYP SETA ENB 8 VIN 7 ENABLE OUTPUT A 6 5 ENABLE OUTPUT B C2 1uF C3 10nF U1 1 OUTPUT A: 2.5V 2 OUTPUT B: 2.8V 3 R1 100k 4 C4 1uF SC1454CIMS OUTA IN OUTB ENA GND BYP SETA ENB 8 VIN 7 ENABLE OUTPUT A 6 5 ENABLE OUTPUT B R2 100k C1 1uF Revision 1, November 2000 C2 1uF C3 10nF 1 C4 1uF www.semtech.com SC1454 POWER MANAGEMENT Absolute Maximum Ratings Parameter Sy mbol Maximum U nits Input Supply Voltage VIN -5 to +7 V Enable Input Voltage V EN -5 to +VIN V Operati ng Ambi ent Temperature Range TA -40 to +85 °C Operati ng Juncti on Temperature Range TJ -40 to +125 °C Storage Temperature Range TSTG -60 to +150 °C Thermal Impedance Juncti on to Ambi ent(1) q JA 206 °C /W Thermal Impedance Juncti on to Ambi ent(2) q JA 95 °C /W Thermal Impedance Juncti on to C ase q JC 39 °C /W ESD 2 kV ESD Rati ng (Human Body Model) NOTES: (1) Minimum pad size. (2) 1 square inch of FR-4, double sided, 1oz. minimum copper weight. Electrical Characteristics Unless specified: TA = 25°C, VIN = VOUT + 1V, IOUTA = IOUTB = 1mA, CIN = COUT = 1.0 µF, VENA = VENB = VIN. Values in bold apply over full operating temperature range. Parameter Sy mbol C onditions Min Ty p Max U nits 6.50 V 150 µA IN Input Supply Voltage VIN Qui escent C urrent IQ 2.25 100 VENA = 0V, VENB = VIN, IOUTB = 150mA or 200 VENB = 0V, VENA = VIN, IOUTA = 150mA VENA = VENB = VIN, IOUTA = IOUTB = 150mA 130 200 µA 250 VIN = 6.5V, VENA = VENB = 0V (OFF) 0.2 1.0 µA 1.5 OU TA, OU TB Output Voltage(1) Li ne Regulati on(1) VOUT REG(LINE) IOUT = 1mA -1% 0mA £ IOUT £ 150mA, VOUT + 1V £ VIN £ 5.5V -2% VOUT + 1V £ VIN £ 5.5V, IOUT = 1mA VOUT +1% V +2% 2.5 10 mV 12 Load Regulati on(1) REG(LOAD) 0.1mA £ IOUT £ 150mA -5 -20 mV -30 ã 2000 Semtech Corp. 2 www.semtech.com SC1454 POWER MANAGEMENT Electrical Characteristics Unless specified: TA = 25°C, VIN = VOUT + 1V, IOUTA = IOUTB = 1mA, CIN = COUT = 1.0 µF, VENA = VENB = VIN. Values in bold apply over full operating temperature range. Parameter Sy mbol C onditions Min Ty p VD IOUT = 1mA 1 IOUT = 50mA 52 Max U nits OU TA, OU TB (C ont.) D ropout Voltage(1)(2) mV 70 90 IOUT = 150mA 155 210 270 C urrent Li mi t Ri pple Rejecti on Output Voltage Noi se 400 ILIM mA PSRR f = 120Hz, C BYP = 10nF 60 dB en f = 10Hz to 100kHz, IOUT =50mA, C BYP = 10nF, C OUT = 2.2µF 50 µVRMS f = 10Hz to 1MHz, IOUT =50mA, C BYP = 10nF, C OUT = 2.2µF 55 E N A, E N B Enable Input Threshold 1.6 VIH V VIL Enable Input Bi as C urrent(3) 0.4 IEN 0V £ VENA/B £ VIN tr C BYP = 10nF -0.5 0.5 µA B YP Start-Up Ri se Ti me 1.25 ms SETA Sense/Select Threshold SETA Reference Voltage SETA Input Leakage C urrent(3) 20 40 80 mV VIN = 2.5V, IOUT = 1mA -1% 1.250 +1% V 0mA £ IOUT £ 150mA, 2.5V £ VIN £ 5.5V -2% VTH VSETA ISETA VSETA = 1.3V +2% 0.015 50 nA Ov er Temperature Protection Hi gh Tri p Level Hysteresi s THI 150 °C THYST 20 °C NOTES: (1) Low duty cycle pulse testing with Kelvin connections required. (2) Defined as the input to output differential at which the output drops 100mV below the value measured at a differential of 1V. Not measurable on 1.5V and 1.8V outputs due to minimum VIN constraints. (3) Guaranteed by design. ã 2000 Semtech Corp. 3 www.semtech.com SC1454 POWER MANAGEMENT Pin Configuration Voltage Options Replace X in the part number (SC1454XIMS) by the letter shown below for the corresponding voltage option: (Top View) MSOP-8 Ordering Information X VOUTA (V) VOUTB (V) A 1.8 1.8 B 2.5 2.5 C 2.8 2.8 D 3.0 3.0 E 3.3 3.3 Part N umbers P ackag e F 3.0 2.5 SC 1454XIMSTR(1)(2) MSOP-8 G 3.0 1.8 H 3.0 2.8 J 3.3 2.5 K 3.3 2.8 Notes: (1) Where X denotes voltage options - see Voltage Options table. (2) Only available in tape and reel packaging. A reel contains 2500 devices. Pin Descriptions Pin # Pin N ame Pin Function 1 OUTA Regulator A output. 2 OUTB Regulator B output. 3 GND Ground pi n. 4 SETA C onnecti ng thi s pi n to ground results i n the i nternally preset value for VOUT. C onnecti ng to an external resi stor di vi der changes VOUTA to: R1 V OUTA = 1 . 250 • 1 + R 2 5 ENB Acti ve hi gh enable pi n for output B. C MOS compati ble i nput. C onnect to IN i f not bei ng used. 6 BYP Bypass pi n for bandgap reference. C onnect a 10nF capaci tor, C BYP, between thi s pi n and ground for low noi se operati on. 7 ENA Acti ve hi gh enable pi n for output A. C MOS compati ble i nput. C onnect to IN i f not bei ng used. 8 IN ã 2000 Semtech Corp. Input pi n for both regulators. 4 www.semtech.com SC1454 POWER MANAGEMENT Block Diagram Marking Information # = Voltage option (Example: 454F) yyww = Datecode (Example: 0008) XXXX = Lot number (Example: E90101-1) ã 2000 Semtech Corp. 5 www.semtech.com SC1454 POWER MANAGEMENT Applications Information Theory Of Operation The SC1454 includes thermal shutdown circuitry to turn off the device if T J exceeds 150°C (typical), with the device remaining off until TJ drops by 20°C (typical). Reverse battery protection circuitry ensures that the device cannot be damaged if the input supply is accidentally reversed, limiting the reverse current to less than 1.5mA. The SC1454 is intended for applications where very low dropout voltage, low supply current and low output noise are critical. Furthermore, the SC1454, by combining two ultra Descriptions low dropout (ULDO) regulators, along with enable PIN controls and output voltage adjustability for one output, provides a very space efficient solution for multiple supply requirements. Component Selection - General The SC1454 contains two ULDOs, both of which are supplied by one input supply, between IN and GND. Each ULDO has its own active high enable pin (ENA/ENB). Pulling this pin low causes that specific ULDO to enter a very low power shutdown state. Output capacitor - Semtech recommends a minimum capacitance of 1µF at the output with an equivalent series resistance (ESR) of < 1W over temperature. While the SC1454 has been designed to be used with ceramic capacitors, it does not have to be used with ceramic capacitors, allowing the designer a choice. Increasing the bulk capacitance will further reduce output noise and improve the overall transient response. The SC1454 contains an internal bandgap reference which is fed into the inverting input of two error amplifiers, one for each output. The output voltage of each regulator is divided down internally using a resistor divider and compared to the bandgap voltage. The error amplifier drives the gate of a low R DS(ON) P-channel MOSFET pass device. Input capacitor - Semtech recommends the use of a 1µF ceramic capacitor at the input. This allows for the device being some distance from any bulk capacitance on the rail. Additionally, input droop due to load transients is reduced, improving overall load transient response. Output A has both a fixed and adjustable output voltage mode. Grounding the SETA pin (pulling it below the Sense/ Select threshold of 40mV) will connect the internal resistor divider to the error amplifier resulting with the internally preset output voltage. If SETA is pulled above this threshold, then the Sense/Select switch will connect the SETA pin to the error amplifier. Output A will then be regulated such that the voltage at SETA will equal VSETA, the SETA reference voltage (typically 1.250V). Bypass capacitor - Semtech recommends the use of a 10nF ceramic capacitor to bypass the bandgap reference. Increasing this capacitor to 100nF will further improve power supply rejection. Reducing this capacitor below 1nF may result in output overshoot at turn-on. Component Selection - Externally Setting Output U1 SC1454CIMS A bypass pin (BYP) is provided to decouple the bandgap reference to reduce output noise (on both outputs) and also to improve power supply rejection. 2 OUTPUT B: 2.8V 3 R1 100k 4 OUTA IN OUTB ENA GND BYP SETA ENB 8 VIN 7 ENABLE OUTPUT A 6 5 ENABLE OUTPUT B R2 100k Each regulator has its own current limit circuitry to ensure that the output current will not damage the device during output short, overload or start-up. The current limit is guaranteed to be greater than 400mA to allow fast charging of the output capacitor and high initial currents for DSP initialization. C1 1uF C2 1uF C3 10nF C4 1uF Referring to the circuit above, the output voltage of output A can be externally adjusted anywhere within the range from 1.25V to (VIN(MAX) - VD(MAX)). The output voltage will be in accordance with the following equation: R1 VOUTA = 1.250 • 1 + R 2 The SC1454 has a fast start-up circuit to speed up the initial charging time of the bypass capacitor to enable the output voltage to come up quicker. ã 2000 Semtech Corp. 1 OUTPUT A: 2.5V 1% tolerance resistors are recommended. The values of 6 www.semtech.com SC1454 POWER MANAGEMENT Applications Information (Cont.) R1 and R2 should be selected such that the current flowing through them is ³ 10µA (thus R2 £ 120kW). impedance allowable to maintain TJ £ 125°C: θJA (MAX ) = Thermal Considerations = The worst-case power dissipation for this part is given by: PD(MAX ) = (VIN(MAX ) − VOUTA (MIN ) ) • IOUTA (MAX ) + (VIN(MAX ) − VOUTB (MIN ) ) • IOUTB (MAX ) (1) (2) (125 − 85) 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. 1) Attaching the part to a larger copper footprint will enable better heat transfer from the device, especially on PCBs where there are internal ground and power planes. 2) Place the input, output and bypass capacitors close to the device for optimal transient response and device behaviour. 3) Connect all ground connections directly to the ground plane. If there is no ground plane, connect to a common local ground point before connecting to board ground. Looking at a typical application: VIN(MAX) = 4.2V VOUTA = 3V - 2% (worst case) = 2.94V VOUTB = 3.3V - 2% (worst case) = 3.234V IOUTA = IOUTB = 150mA TA = 85°C Inserting these values into equation (2) above gives us: PD(MAX ) = (4.2 − 2.94 ) • 0.15 + (4.2 − 3.234 ) • 0.15 = 0.189 + 0.145 = 0.334 W Using this figure, we can calculate the maximum thermal ã 2000 Semtech Corp. − TA (MAX ) ) PD(MAX ) This target value can be achieved by using one square inch of board copper connected to the GND pin (pin 3), which connects directly to the device substrate. Increasing this area or the use of multi layer boards will lower the junction temperature and improve overall output voltage accuracy. For all practical purposes, equation (1) can be reduced to the following expression: + (VIN ( MAX ) − VOUTB ( MIN ) ) • IOUTB (MAX ) J( MAX ) 0.334 = 120°C / W + VIN(MAX ) • IQ(MAX ) PD (MAX ) = (VIN (MAX ) − VOUTA (MIN ) ) • IOUTA ( MAX ) (T 7 www.semtech.com SC1454 POWER MANAGEMENT Typical Characteristics Output Voltage vs. Output Current Output Voltage vs. Junction Temperature vs. Junction Temperature, VOUT = 2.8V vs. Output Current, VOUT = 2.8V 10.0 10.0 VIN = 3.8V VOUT = 2.8V VIN = 3.8V VOUT = 2.8V 7.5 5.0 VOUT Deviation (mV) VOUT Deviation (mV) 7.5 Top to bottom: TA = 125°C TA = 25°C TA = -40°C 2.5 0.0 -2.5 -5.0 Top to bottom: IOUT = 1mA IOUT = 50mA IOUT = 100mA IOUT = 150mA 5.0 2.5 0.0 -2.5 -5.0 -7.5 -7.5 -10.0 -10.0 0 25 50 75 100 125 -50 150 -25 0 25 50 100 Output Voltage vs. Junction Temperature Output Voltage vs. Junction Temperature vs. Output Current, VOUT = 1.5V vs. Output Current, VOUT = 5.5V 10.0 125 40 VIN = 2.5V VOUT = 1.5V 7.5 VIN = 6.5V VOUT = 5.5V 30 5.0 20 2.5 10 IOUT = 1mA VOUT (V) VOUT (V) 75 TJ (°C) IOUT (mA) 0.0 -2.5 IOUT = 1mA 0 -10 IOUT = 150mA -5.0 -20 IOUT = 150mA -7.5 -30 -10.0 -40 -50 -25 0 25 50 75 100 125 -50 -25 0 25 TJ (°C) 50 75 100 125 TJ (°C) SETA Reference Voltage vs. Junction Temperature SETA Reference Voltage vs. Junction Temperature vs. Output Current, VIN = 2.5V vs. Output Current, VIN = 6.5V 1.275 1.270 1.275 VIN = 2.5V 1.270 1.265 1.265 1.260 1.260 IOUT = 1mA 1.255 VSET (V) VSET (V) VIN = 6.5V 1.250 1.245 IOUT = 150mA 1.250 IOUT = 150mA 1.245 1.240 1.240 1.235 1.235 1.230 1.230 1.225 IOUT = 1mA 1.255 1.225 -50 -25 0 25 50 75 100 125 -50 TJ (°C) ã 2000 Semtech Corp. -25 0 25 50 75 100 125 TJ (°C) 8 www.semtech.com SC1454 POWER MANAGEMENT Typical Characteristics (Cont.) Dropout Voltage vs. Output Current Dropout Voltage vs. Junction Temperature vs. Junction Temperature vs. Output Current 200 200 175 175 150 150 125 125 VD (mV) VD (mV) IOUT = 150mA 100 75 75 Top to bottom: TJ = 125°C TJ = 25°C TJ = -40°C 50 25 100 50 IOUT = 50mA 25 0 0 0 25 50 75 100 125 150 -50 -25 0 25 IOUT (mA) Line Regulation vs. Load Regulation vs. Junction Temperature Junction Temperature 10 75 100 125 75 100 125 100 125 10 IOUT = 1mA 9 VIN = VOUT + 1V IOUT = 0.1mA to 150mA 9 8 8 VIN = VOUT + 1V to 6.5V REG(LOAD) (mV) 7 REG(LINE) (mV) 50 TJ (°C) 6 5 4 3 7 6 5 4 3 2 2 VIN = VOUT + 1V to 5.5V 1 1 0 0 -50 -25 0 25 50 75 100 125 -50 -25 0 TJ (°C) 25 50 TJ (°C) Current Limit vs. Junction Temperature Off-State Quiescent Current vs. Input Voltage vs. Junction Temperature 800 400 750 350 VIN = 6.5V VENA = VENB = 0V 300 650 250 IQ (nA) ILIM (mA) VIN = 6.5V 700 600 550 200 150 VIN = 3.8V 500 100 450 50 400 0 -50 -25 0 25 50 75 100 125 -50 TJ (°C) ã 2000 Semtech Corp. -25 0 25 50 75 TJ (°C) 9 www.semtech.com SC1454 POWER MANAGEMENT Typical Characteristics (Cont.) Quiescent Current vs. Junction Temperature Quiescent Current vs. Junction Temperature vs. Output Current vs. Input Voltage 200 200 IOUTA = IOUTB = 150mA IOUTA = IOUTB = 150mA 175 175 150 150 125 125 IQ (µA) IQ (µA) VIN = 6.5V 100 IOUTA or IOUTB = 150mA 75 75 50 50 25 25 0 Top to bottom: VIN = 6.5V VIN = 5V VIN = 3.8V 100 0 -50 -25 0 25 50 75 100 125 -50 -25 0 25 TJ (°C) 50 75 100 125 TJ (°C) Enable Input Voltage vs. Junction Temperature Sense/Select Threshold Voltage vs. vs. Input Voltage Junction Temperature vs. Input Voltage 1.6 80 VIH @ VIN = 6.5V 70 1.4 1.0 VIN = 6.5V VTH (mV) VEN (V) 60 VIH @ VIN = 4V 1.2 VIL @ VIN = 6.5V 50 40 VIN = 3.8V 30 0.8 VIL @ VIN = 4V 20 0.6 10 0 0.4 -50 -25 0 25 50 75 100 -50 125 -25 0 25 50 75 100 125 TJ (°C) TJ (°C) Bypass Start-up Rise Time vs. Junction Temperature Output Spectral Noise Density vs. Frequency vs. Input Voltage vs. Bypass Capacitance 2.00 10000 CBYP = 10nF VIN = 2.8V VOUT = 1.8V IOUT = 50mA CIN = 1µF COUT = 2.2µF TA = 25°C 1.75 1.50 CBYP = 10nF VIN = 3.8V 1000 en (nV/√Hz) tr (ms) 1.25 1.00 VIN = 6.5V 0.75 100 0.50 CBYP = 100nF 0.25 0.00 -50 -25 0 25 50 75 100 10 1.E+01 125 TJ (°C) ã 2000 Semtech Corp. 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 f (Hz) 10 www.semtech.com SC1454 POWER MANAGEMENT Typical Characteristics (Cont.) Output Spectral Noise Density vs. Frequency vs. Output Capacitance 10000 en (nV/√Hz) 1000 COUT = 2.2µF 100 10 VIN = 2.8V VOUT = 1.8V IOUT = 50mA CIN = 1µF CBYP = 10nF TA = 25°C 1 1.E+01 COUT = 10µF 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 f (Hz) Evaluation Board Schematic J1 ENA J4 RIPPLE A J2 ENB J5 RIPPLE B 1 2 3 4 5 J3 VIN JP1 1 2 3 1 2 3 4 5 JP2 ON OFF OUTA ENABLE J6 1 2 3 ON OFF OUTB ENABLE U1 SC1454xIMS 1 2 OUTA 3 1 J7 R2 2 4 OUTA IN OUTB ENA GND BYP SETA ENB 8 7 6 R1 5 R3 OUTB JP3 3 C1 R4 C2 1 2 + C3 IQ MON C4 C5 220uF JP4 EXT INT 1 2 3 OUTA SET R5 R6 J8 OUTB LOAD DRV U2 8 7 6 5 D D D D S S S G 1 2 3 4 JP5 1 2 3 EN OFF OUTB LOAD Si4410 J9 OUTA LOAD DRV U3 8 7 6 5 D D D D S S S G 1 2 3 4 J11 GND ã 2000 Semtech Corp. J12 GND J13 GND J14 GND 1 2 3 EN OFF OUTA LOAD Si4410 J10 GND JP6 J15 GND 11 www.semtech.com SC1454 POWER MANAGEMENT Evaluation Board Gerber Plots Top Copper Bottom Copper Top Assembly ã 2000 Semtech Corp. 12 www.semtech.com SC1454 POWER MANAGEMENT Evaluation Board Bill Of Materials Quantity R eference Part/D escription Vendor N otes 2 C 1, C 2 2.2µF cerami c Murata GRM42-6X7R225K16 1 C3 10nF cerami c Vari ous 1 C4 1µF cerami c Murata 1 C5 220µF, 10V Vari ous 2 J1 , J2 Test pi n Vari ous Whi te 3 J3 , J6 , J7 Test pi n Vari ous Red 2 J4 , J5 BNC socket Vari ous VOUT ri pple moni tor 2 J8 , J9 Test pi n Vari ous Orange 6 J1 0 - J1 5 Test pi n Vari ous Black 5 JP 1 , JP 2 , JP 4 - JP 6 Header, 3 pi n Vari ous 1 JP 3 Header, 2 pi n Vari ous 2 R1, R3 10kW, 1/10W Vari ous 1 R2 250kW, 25T Bourns 1 R4 62kW, 1/10W Vari ous 2 R5, R6 150mA load Vari ous 1 U1 SC 1454xIMS Semtech 2 U2, U3 S i 4410 Vi shay ã 2000 Semtech Corp. 13 GRM42-6X7R105K25 Tri mmer potenti ometer 1W, may not be same value www.semtech.com SC1454 POWER MANAGEMENT Outline Drawing - MSOP-8 Land Pattern - MSOP-8 Contact Information Semtech Corporation Power Management Products Division 652 Mitchell Rd., Newbury Park, CA 91320 Phone: (805)498-2111 FAX (805)498-3804 ã 2000 Semtech Corp. 14 www.semtech.com