www.recom-power.com REV.: 5/2019 I-1
Features
Switching
Regulator
R-78AA-1.0
Description
The R-78AAxx-1.0SMD series are adjustable output non-isolated buck converters that meet the
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
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.
DC/DC Converter
1.0 Amp
SMD
Single Output
EN60950-1 certified
IEC60950-1 certified
• Efficiency up to 94%, no need for heatsinks
• High reflow temperature SMD package
• Adjustable output voltage buck converter
• Short circuit protection, thermal shutdown
• Remote on/off control
• Very low shutdown current
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
Model Numbering
Notes:
Note2: add suffix -R for 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
nom. Output Voltage
Output Current
Packaging (2)
Package
R-78AA__-1.0SMD-_
Notes:
Note1: Input voltage ranges valid for nominal output voltages
Vin must be higher than Vout including adjust range and dropout voltage
www.recom-power.com REV.: 5/2019 I-2
DC/DC Converter
Specifications (measured @ Ta= 25°C, 10% minimum load, unless otherwise stated)
R-78AA-1.0
Series
BASIC CHARACTERISTICS
Parameter Condition Min. Typ. Max.
Quiescent Current Vin= min. to max. 5mA 7mA
Internal Power Dissipation 0.4W
Output Voltage Adjustability see calculation
Minimum Load (2) 0%
Start-up time ON/OFF CTRL 50ms
ON/OFF CTRL DC-DC ON
DC-DC OFF
Open or 2.8VDC<Vr<5VDC
GND or 0VDC<Vr<0.8VDC
Input Current of CTRL Pin DC-DC OFF 1.8µA
Standby Current 20µA 35µA
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
Maximum Capacitive Load with normal start-up time, no external components 470µF
with <1 second start-up time + diode protection circuit 6800µF
continued on next page
Notes:
Note3: Operation under no load will not harm the converter, but specifications may not be met.
A minimum load of 10mA is recommended
4.75 7 9 11 13 15 17 18
100
80
60
40
90
70
50
30
20
10
0
Efficiency [%]
Input Voltage [VDC]
5Vout
3.3Vout
2.5Vout
1.8Vout
1.5Vout
4.75 7 9 11 13 15 17 18
50
40
30
20
45
35
25
15
10
5
0
Ripple [mV]
Input Voltage [VDC]
5Vout
3.3Vout
2.5Vout
1.8Vout
1.5Vout
Efficiency vs. Vin (full load) Ripple vs. Vin (full load)
+VIN +VOUT
R1
R2 R3
Rdown
Rup
GND
Vref
GND
Vadj
Controlled IC
Adjustment Resistor Values
R1 R2 R3 Vref(V)
1.8V 10KΩ 21KΩ 5.6KΩ 1.23
2.5V 22KΩ 21KΩ 5.6KΩ 1.23
3.3V 16.9KΩ 10KΩ 5.6KΩ 1.23
5.0V 30.9KΩ 10KΩ 10KΩ 1.23
Trim down Rdown = R2(R1 + R3) x (Vref - Vo) + Vref x R1R3
R2Vo - Vref (R1 + R2)
Trim up Rup = R2R3 (Vref - Vo) + Vref R1 (R2 + R3)
R2 (Vo - Vref) - Vref R1
Output Voltage Adjustability
www.recom-power.com REV.: 5/2019 I-3
DC/DC Converter
Specifications (measured @ Ta= 25°C, 10% minimum load, unless otherwise stated)
R-78AA-1.0
Series
0 10 20 30 40 50 60 70 80 90 100
100
80
60
40
90
70
50
30
20
10
0
Efficiency [%]
Output Load [%]
5Vout
3.3Vout
2.5Vout
1.8Vout
1.5Vout
100 20 30 40 50 60 70 80 90
100
40
30
20
50
45
35
25
15
10
5
0
Ripple [mV]
Output Load [%]
5Vout
3.3Vout
2.5Vout
1.8Vout
1.5Vout
100 20 30 40 50 60 70 80 90
100
40
30
20
50
45
35
25
15
10
5
0
Ripple [mV]
Output Load [%]
5Vout
3.3Vout
2.5Vout
1.8Vout
1.5Vout
0 10 20 30 40 50 60 70 80 90 100
100
80
60
40
90
70
50
30
20
10
0
Efficiency [%]
Output Load [%]
5Vout
3.3Vout
2.5Vout
1.8Vout
1.5Vout
REGULATIONS
Parameter Condition Value
Output Accuracy full load ±2.0% typ. / ±3.0% max.
Line Regulation low line to high line, full load ±0.2% typ. / ±0.4% max.
Load Regulation 10% to 100% load ±0.7% typ. / ±1.0% max.
Transient Response 25mA/µs 100% <-> 50% load ±85mV typ. / ±100mV max.
Efficiency vs. Load (max. Vin)
Efficiency vs. Load (min. Vin)
Ripple vs. Load (max. Vin)
Ripple vs. Load (min. Vin)
www.recom-power.com REV.: 5/2019 I-4
DC/DC Converter
Specifications (measured @ Ta= 25°C, 10% minimum load, unless otherwise stated)
R-78AA-1.0
Series
PROTECTIONS
Parameter Condition Value
Short Circuit Protection (SCP) continuous, automatic recovery
Short Circuit Input Current nom. Vin= 12VDC 120mA max.
Optional Diode Protection Circuit
+Vin +Vout
+Vout
Trim output voltage
up 1 diode drop
GNDGND
R-78AAxx
-1.0SMD
R-78AAxx
-1.0SMD
CTRL
+Vin +Vout
GND Vadj
CTRL
+Vin +Vout
GNDCTRL
CTRL
+Vin
GNDGND
+V
in
+V
out
+V
out
Trim output voltage
up 1 diode drop
GNDGND
R-78AAxx
-1.0SMD
R-78AAxx
-1.0SMD
CTRL
+V
in
+V
out
GND V
adj
CTRL
+V
in
+V
out
GNDCTRL
CTRL
+V
in
GNDGND
Add a blocking diode to Vout if
current can flow backwards into
the output, as this can damage the
converter when it is powered down.
The diode can either be fitted
across the device if the source is
low impedance or fitted in series
with the output (recommended).
Optional Protection 1: Optional Protection 2:
-40 -20 0 20 40 70
85
60-30 -10 10 30 50 80 90 100
100
80
60
40
90
70
50
30
20
10
0
Output Load [%]
Ambient Temperature [°C]
ENVIRONMENTAL
Parameter Condition
Value
Operating Temperature Range with derating (see graph) -40°C to +85°C
Maximum Case Temperature +100°C
Temperature Coefficient ±0.015%/°C
Thermal Impedance 0.1m/s, horizontal 70°C/W
Operating Altitude 2000m
Operating Humidity non-condensing 5% - 95% RH max.
Pollution Degree PD2
MTBF according to MIL-HDBK-217F, G.B. +25°C
+ 71°C
13338 - 21070 x 103 hours
3880 - 6769 x 103 hours
Derating Graph
www.recom-power.com REV.: 5/2019 I-5
DC/DC Converter
Specifications (measured @ Ta= 25°C, 10% minimum load, unless otherwise stated)
R-78AA-1.0
Series
DIMENSION AND PHYSICAL CHARACTERISTICS
Parameter
Type
Value
Material case
PCB
non-conductive black plastic, (UL94 V-2)
FR4, (UL94 V-1)
Dimension (LxWxH) 15.3 x 9.6 x 8.8mm
Weight 1.7g typ.
SAFETY AND CERTIFICATIONS
Certificate Type (Safety) Report / File Number Standard
Information Technology Equipment, General Requirements for Safety
1603123 IEC60950-1:2005, 2nd Edition + AM 2:2013
EN60950-1:2006 + AM 2:2013
EAC RU-AT.49.09571 TP TC 004/2011 TP TC 004/2011
RoHS 2+ RoHS 2011/65/EU + AM2015/863
EMC Compliance Condition Standard / Criterion
Electromagnetic compatibility of multimedia equipment -
Emission requirements with external filter EN55032, Class B
ESD Electrostatic discharge immunity test Air ±8kV; Contact ±4kV EN61000-4-2
Radiated, radio-frequency, electromagnetic field immunity test 3V/m EN61000-4-3
10 9 8 7 6
10 9 8 7 6
12345
12345
Bottom View Top View
0.50±0.05
15.3
15.0
2.54 x 4
9.4
9.68.812.35
9.24
13.00
1.30 1.202.54
1.80
Dimension Drawing (mm)
Recommended Footprint Details
Pinning information
Pin # Single
1,2 +Vin
3,7,8,9 GND
4,5 +Vout
6 Vadj
10 CTRL
Tolerance:
xx.x= 0.5mm
xx.xx= ±0.25mm
www.recom-power.com REV.: 5/2019 I-6
DC/DC Converter
Specifications (measured @ Ta= 25°C, 10% minimum load, unless otherwise stated)
R-78AA-1.0
Series
PACKAGING INFORMATION
Parameter Type Value
Packaging Dimension (LxWxH) tube
tape and reel (carton)
530.0 x 17.0 x 13.0mm
355.0 x 342.0 x 36.0mm
Packaging Quantity tube
tape and reel
33pcs
250pcs
Tape Width 24mm
Storage Temperature Range -55°C to +125°C
Storage Humidity 95% RH max.
The product information and specifications may be subject to changes even without prior written notice.The product has been designed for various applications; its suitability lies in the responsibility of each customer.
The
products are not authorized for use in safety-critical applications without RECOM’s explicit written consent. A safety-critical application is an application where a failure may reasonably be expected to endanger or
cause
loss of life, inflict bodily harm or damage property. The applicant shall indemnify and hold harmless RECOM, its affiliated companies and its representatives against any damage claims in connection with the
unauthorized
use of RECOM products in such safety-critical applications.
