Data Sheet

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-0.5
Series
BASIC CHARACTERISTICS
Parameter Condition Min. Typ. Max.
Absolute Maximum Input Voltage 34VDC
Quiescent Current Vin= min. to max.
5mA 7mA
Internal Power Dissipation
0.4W
Output Voltage Adjustability
see calculation
Minimum Load
(3)
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 30µA
CTRL Thereshold Voltage
2.4VDC 2.6VDC 2.8VDC
CTRL Voltage Hysterese
250mV
Internal Operating Frequency
280kHz 330kHz 380kHz
Output Ripple and Noise 20MHz BW
1.5VDC tp 6.5VDC
9VDC to 15VDC
20mVp-p
30mVp-p
30mVp-p
40mVp-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 6mA is recommended
+V
in
+V
out
R1
R2
R3
R
down
R
up
GND
Vref
GND
V
adj
Controlled IC
Adjustment Resistor Values
Output Voltage Adjustability
V0 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
6.5V 43kΩ 10kΩ 10kΩ 1.23
9V 63.4kΩ 10kΩ 22.1kΩ 1.23
12V 88.7kΩ 10kΩ 22.1kΩ 1.23
Rdown =
R2(R1 + R3) x (Vref - Vo) + Vref x R1R3
R2Vo - Vref (R1 + R2)
Rup =
R2R3 (Vref - Vo) + Vref R1 (R2 + R3)
R2 (Vo - Vref) - Vref R1