Efficiency up to 94%, no need for heatsinks Features High reflo w temperature SMD package DC/DC Converter Adjustable output voltage buck converter Short circuit protection, thermal shutdown Switching Remote on/off control Regulator Very low shutdown current R-78AA-1.0 Description 1.0 Amp The R-78AAxx-1.0SMD series are adjustable output non-isolated buck converters that meet the SMD requirements for RoHS 10/10 as well as the reflow soldering temperatures associated with va- por phase soldering, making these high efficiency switching regulators ideally suited to modern pick-and-place mass production. The efficiency of up to 97% means that very little energy Single Output is wasted as heat. The additional features of remote on/off control, continuous short circuit protection and adjustable output voltages will find many uses in the battery-powered, industrial, medical and automotive markets. Selection Guide Part Input Output Vout Output Efficiency Number Voltage Range Voltage Adjust Range Current min Vin max. Vin VDC VDC VDC A % % R-78AA1.5-1.0SMD 4.75 - 18 1.5 fixed 1.0 77 73 R-78AA1.8-1.0SMD 4.75 - 18 1.8 1.5 - 3.0 1.0 82 76 R-78AA2.5-1.0SMD 4.75 - 18 2.5 1.5 - 3.0 1.0 87 81 R-78AA3.3-1.0SMD 4.75 - 18 3.3 3.0 - 5.5 1.0 90 84 R-78AA5.0-1.0SMD 6.5 - 18 5.0 3.0 - 5.5 1.0 94 89 Notes: Note1: Input voltage ranges valid for nominal output voltages Vin must be higher than Vout including adjust range and dropout voltage Model Numbering EN60950-1 certified IEC60950-1 certified R-78AA -1.0SMD- (2) nom. Output Voltage Packaging Output Current Package Notes: Note2: add suffix -R f or tape & reel packaging Ordering Examples: R-78AA5.0-1.0SMD-R = 5.0VDC Output Volage, 1.0A, SMD, tape and reel packaging R-78AA2.5-1.0SMD = 2.5VDC Output Volage, 1.0A, SMD, tube www.recom-power.com REV.: 5/2019 I-1R-78AA-1.0 DC/DC Converter Series Specifications (measured Ta= 25C, 10% minimum load, unless otherwise stated) BASIC CHARACTERISTICS Parameter Condition Min. Typ. Max. 5mA 7mA Quiescent Current Vin= min. to max. 0.4W Internal Power Dissipation see calculation Output Voltage Adjustability (2) Minimum Load 0% Start-up time ON/OFF CTRL 50ms DC-DC ON Open or 2.8VDC<Vr<5VDC ON/OFF CTRL DC-DC OFF GND or 0VDC<Vr<0.8VDC 1.8A Input Current of CTRL Pin DC-DC OFF 20A 35A Standby Current CTRL Thereshold Voltage 2.4VDC 2.6VDC 2.8VDC CTRL Voltage Hysterese 250mV Internal Operating Frequency 335kHz 385kHz 435kHz Output Ripple and Noise 20MHz BW 20mVp-p 30mVp-p with normal start-up time, no external components 470F Maximum Capacitive Load with <1 second start-up time + diode protection circuit 6800F Notes: Note3: Operation under no load will not harm the converter, but specifications may not be met. A minimum load of 10mA is recommended Output Voltage Adjustability Adjustment Resistor Values +V +V R1 R2 R3 Vref(V) IN OUT 1.8V 10K 21K 5.6K 1.23 R down 2.5V 22K 21K 5.6K 1.23 R1 3.3V 16.9K 10K 5.6K 1.23 Controlled IC V adj 5.0V 30.9K 10K 10K 1.23 R3 R2 R up R2(R1 + R3) x (Vref - Vo) + Vref x R1R3 GND GND Trim down Rdown = R2Vo - Vref (R1 + R2) Vref R2R3 (Vref - Vo) + Vref R1 (R2 + R3) Trim up Rup = R2 (Vo - Vref) - Vref R1 Efficiency vs. Vin (full load) Ripple vs. Vin (full load) 100 50 5Vout 3.3Vout 90 45 2.5Vout 80 1.8Vout 40 1.5Vout 70 35 60 30 50 25 40 20 5Vout 30 15 3.3Vout 2.5Vout 20 10 1.8Vout 10 5 1.5Vout 0 0 4.75 7 9 11 13 15 17 18 4.75 7 9 11 13 15 17 18 Input Voltage VDC Input Voltage VDC continued on next page www.recom-power.com REV.: 5/2019 I-2 Efficiency % Ripple mV