78SR 2 Amp Series www.murata-ps.com 2 Amp, 3.3V & 5V Output, High Efficiency, Synchronous Switching Regulators FEATURES Up to 95% efficiency– no costly heat sinks or fans required 3.3V/2A & 5V/2A models; pin compatible with 1.5A 78xx regulators Wide 8– 32Vdc input voltage range Two package options: 3-pin vertical mount SIP Low profile, horizontal mount SIP No external Input/Output filter capacitors required –40 to +70°C full load operation at 24Vin with no derating Excellent load (±0.25%) and line (±0.35%) regulation Low-cost upgrade for 78HT2, 78SR1, 78ST1, and PT5100 switchers Open frame design minimizes self-heating & pc-board footprint Includes output short-circuit protection and thermal shutdown Low noise output for powering sensitive instrumentation Murata’s 78SR-3.3/2 (3.3V, 2 Amp output) and 78SR-5/2 (5V, 2 Amp output) step-down, switching regulators are ultra high-efficiency, modern replacements for LM78xx series 1.5Amp linear regulators. They are pin- and size-compatible, drop-in replacements for TO-220 style, 3-pin SIP or modular packages which require heat sinks. And, to ensure the lowest installed cost, no messy thermal grease, no mounting hardware and no external components are required for full operation. A 200KHz switching frequency, combined with a synchronous rectifier buck regulator topology, provides for efficiencies exceeding 95%. 78SR switchers can easily drive 2A loads from 12V or 24Vsupplies—at ambient temperatures up to +70°C—without heat sinks, fans, or thermal derating. A thermally efficient 3-pin vertical mount SIP occupies less than 0.09in.2 (58mm2) of pc-board real estate, while a horizontal mount option has an installed height of less than 0.290in. (7.4mm). 78SR Series 2A switching regulators are lower cost, improved-efficiency upgrades for many 78HT2, 78SR1, 78ST1, and PT5100 series switchers. Their higher efficiency ensures significantly lower heat generation and provides increased run time in battery-powered applications, making these regulators ideal for today’s low power “green” applications. TECHNICAL NOTES 1. Input/Output (I/O) Filtering: As shown in the accompanying noise and ripple graphs, 78SR Series regulators exhibit excellent low noise performance with no additional I/O filter components. However, if additional noise reduction is required, be sure to use low ESR capacitors that are rated for continuous operation (with an additional 20% safety margin) at the highest input voltage and ambient temperatures. Adding external output capacitors will improve the unit’s load-transient response. Ordering Information Part No. Output Output Input Voltage CurrentVoltage 78SR-3.3/2-C 78SR-5/2-C 78SRH-3.3/2-C 78SRH-5/2-C 3.3Vdc2.0A 5.0Vdc2.0A 3.3Vdc2.0A 5.0Vdc2.0A 8.0-32Vdc 8.0-32Vdc 8.0-32Vdc 8.0-32Vdc Applications in which 78SR regulators are located more than 24 inches (61cm) from the input power supply should include an external 47uF/50V (or greater) aluminum electrolytic capacitor, connected as close as possible to the regulator’s +Vin and GND terminals (pins 1 and 2). An external input capacitor is particularly important if the input voltage is applied to the regulator via a mechanical switch or relay. Contact bounce at turn-on can produce large inductive current spikes, and these current spikes can generate potentially damaging voltage transients at the regulator’s input terminals. 2. Input Fusing: 78SR switching regulators are not internally fused. If fusing their input and/or output terminals is required, use the data shown in the Efficiency Curves as a guide to select an appropriate slow-blow fuse. For full details go to www.murata-ps.com/rohs www.murata-ps.com/support MPM_78SR-2A_B03 Page 1 of 5 78SR 2 Amp Series 2 Amp, 3.3V & 5V Output, High Efficiency, Synchronous Switching Regulators Performance/Functional Specifications TECHNICAL NOTES (continued) Typical at TA = +25°C & VIN = 12V, unless otherwise noted Input/Output Models 78SR-3.3/2 78SR-5/2 Output Voltage 3.3Vdc5.0Vdc Rated Output Current2.0A 2.0A Output Voltage Accuracy ±2% Input Voltage Range 8.0-32Vdc8.0-32Vdc Line Regulation (100% load) ±0.35% ±0.35% Load Regulation (0-100% load) ±0.2% ±0.2% Quiescent Current (mAdc) 25 typ., 30 max Input Current vs. Input Voltage ±2% 20 typ., 35max See Efficiency Curves Efficiency See Efficiency Curves Transient Response See Performance Curves Input & Output Noise See Performance Curves Output Short Circuit Protection ➀ Continuous Input/Output Isolation None Overvoltage Protection None Undervoltage Protection None Environmental Models 78SR-3.3/2 Operating Temperature 78SR-5/2 –40 to +70°C Storage Temperature 3. Input-Output Isolation: 78SR regulators’ internal input and output circuits share a common connection (GND, pin 2), there is no electrical isolation between their INPUT (pin 1) and OUTPUT (pin 3) terminals. 4. Overvoltage Protection: 78SR switching regulators do not provide input or output overvoltage protection. In the extremely rare situation where a catastrophic failure occurs, the output voltage may rise to excessively high levels. If the load circuit must be protected against all possible overvoltage situations, voltage-limiting circuitry must be provided externally. 5. Soldering & Handling Precautions: All units are designed to be hand soldered to pc-boards, using lead-free no-clean solders (+260°C, 5 seconds max.). See the Mechanical Specifications section for pin 1 orientation and recommended pc-board hole dimensions. 78SR series regulators have limited built-in ESD protection; therefore they should always be treated as ESD susceptible devices. 6. Horizontal-Pin Models (78SRH): 78SRH switching regulators are pincompatible replacements for TO-220 style LM78xx linear regulators which are installed with their metal tabs or heat sinks laying flat on the surface of the pc-board. In replacement applications, 78SRH units must be soldered to the pc-board such that the insulating body of diode D1 lies flat and in contact with the pc-board’s surface. –40 to +85°C Cooling ③ Free Air Convection Humidity (Non-condensing) 0 to 85% Physical Mechanical See Mechanical Specifications Package Pins Weight Pin Soldering Open-frame SIP 0.025” (0.64mm) square, tin-plated bronze 0.15 ounces (4.2g) +260°C for 5 seconds Absolute Maximum Ratings ➁ Input Voltage: +36Vdc Operating Temperature +85°C Output Current 3.0 Amps ➀78SR Series regulators can withstand a continuous short-circuit across their output terminals. However, extended short-circuit operation will decrease the unit’s long-term reliability. ➁These are stress ratings only; Exposure of devices to any of these conditions may adversely affect long-term reliability. Proper operation under conditions other than those listed in the Performance/Functional Specifications Table is not implied. ③See derating chart for more information. www.murata-ps.com/support MPM_78SR-2A_B03 Page 2 of 5 78SR 2 Amp Series 2 Amp, 3.3V & 5V Output, High Efficiency, Synchronous Switching Regulators Typical Performance Curves TA = +25°C, VIN as indicated Noise and Ripple - 10% and 100% Load, 20 MHz Bandwidth 78SR-3.3/2 78SR-5/2 Vin = 12V, ILOAD = 0.2A Vin = 12V, ILOAD = 0.2A 78SR-3.3/2 78SR-5/2 Vin = 12V, ILOAD = 2.0A Vin = 12V, ILOAD = 2.0A 78SR-3.3/2 78SR-5/2 Vin = 24V, ILOAD = 2.0A Vin = 24V, ILOAD = 2.0A Transient Response - 50% Load Step 78SR-3.3/2 25% to 75% Load Step 78SR-3.3/2 25% to 75% Load Step Vin = 12V 78SR-3.3/2 75% to 25% Load Step Vin = 24V CH1: Vout, 50mV/div. Vin = 12V CH1: Vout, 50mV/div. CH1: Vout, 50mV/div. CH2: Load Current 1A/div. CH2: Load Current 1A/div. CH2: Load Current 1A/div. 25%75% 25%75% 75%25% 78SR-5/2 40µsec/div. 25% to 75% Load Step 40µsec/div. 78SR-5/2 25% to 75% Load Step Vin = 12V 78SR-5/2 40µsec/div. 75% to 25% Load Step Vin = 24V CH1: Vout, 50mV/div. Vin = 12V CH1: Vout, 50mV/div. CH1: Vout, 50mV/div. CH2: Load Current 1A/div. CH2: Load Current 1A/div. CH2: Load Current 1A/div. 25%75% 25%75% 75%25% 40µsec/div. 40µsec/div. 40µsec/div. www.murata-ps.com/support MPM_78SR-2A_B03 Page 3 of 5 78SR 2 Amp Series 2 Amp, 3.3V & 5V Output, High Efficiency, Synchronous Switching Regulators 78SR-3.3/2-C Input Current 78SR-5/2-C Input Current 1.0 1.4 2.0A LOAD 2.0A LOAD 1.2 INPUT CURRENT (AMPS) INPUT CURRENT (AMPS) 0.8 0.6 1.0A LOAD 0.4 1.0 0.8 0.6 1.0A LOAD 0.4 0.5A LOAD 0.2 0.5A LOAD 0.2 0.0 0.0 0 5 10 15 20 25 30 35 0 5 10 INPUT VOLTAGE 78SR-3.3/2-C Efficiency 95 90 90 85 85 EFFICIENCY (%) 95 EFFICIENCY (%) 100 Vin = 8V 75 Vin = 12V 70 Vin = 15V 65 Vin = 24V Vin = 28V 60 80 0.50 0.75 1.00 1.25 25 30 35 Vin = 8V 75 Vin = 12V 70 Vin = 15V 65 Vin = 24V Vin = 28V 60 Vin = 32V 55 0.25 20 78SR-5/2-C Efficiency 100 80 15 INPUT VOLTAGE Vin = 32V 1.50 1.75 2.00 LOAD CURRENT (AMPS) 55 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 LOAD CURRENT (AMPS) Thermal Derating Curve OUTPUT CURRENT (AMPS) 2.00 60ºC 65ºC 1.75 70ºC 1.50 1.25 8 12 15 24 28 INPUT VOLTAGE 32 36 www.murata-ps.com/support MPM_78SR-2A_B03 Page 4 of 5 78SR 2 Amp Series 2 Amp, 3.3V & 5V Output, High Efficiency, Synchronous Switching Regulators MECHANICAL DIMENSIONS: Inches (mm) TOLERANCES: 2 PL DEC ±0.02 (±0.51) 3 PL DEC ±0.010 (±0.254) Standard Package 0.16 (4.1) 0.80 (20.3) D1 103 L1 Pins: 0.025 (0.64) sq. 0.100 (2.54) centers L1 0.85 (21.6) PC-Board Hole: 0.037 - 0.043 (0.94 - 1.09) Dia. DATEL 78SR-5/2-C 0.095 (2.4) 1 0.15 (3.8) Min. 3 OUTPUT (+VOUT) GND INPUT (+VIN) 0.23 (5.7) 2 Horizontal Package (H Pin Option) 0.07 (1.8) L1 L1 L1 1 0.280 (7.1) D1 3 OUTPUT (+VOUT) ISO 9001 and 14001 REGISTERED GND INPUT (+VIN) Murata Power Solutions, Inc. 11 Cabot Boulevard, Mansfield, MA 02048-1151 U.S.A. 2 0.30 (7.6) min. Pins: 0.025 (0.64) sq. 0.100 (2.54) centers PC-Board Hole: 0.037 - 0.043 (0.94 - 1.09) Dia. This product is subject to the following operating requirements and the Life and Safety Critical Application Sales Policy: Refer to: http://www.murata-ps.com/requirements/ Murata Power Solutions, Inc. makes no representation that the use of its products in the circuits described herein, or the use of other technical information contained herein, will not infringe upon existing or future patent rights. The descriptions contained herein do not imply the granting of licenses to make, use, or sell equipment constructed in accordance therewith. Specifications are subject to change without notice. © 2015 Murata Power Solutions, Inc. www.murata-ps.com/support MPM_78SR-2A_B03 Page 5 of 5