DC/DC Converter

ECO-2

REV.: 2/2017

www.recom-power.com

REC20-Z

Series

BASIC CHARACTERISTICS

Parameter

Condition

Min.

Typ.

Max.

Input Voltage Range

nom. Vin= 24V

nom. Vin= 48V

9VDC

18VDC

36VDC

75VDC

Start/up Time

10ms

Under Voltage Lockout

nom. Vin= 24V

DC-DC ON

DC-DC OFF

9VDC

7.5VDC

nom. Vin= 48V

DC-DC ON

DC-DC OFF

18VDC

16VDC

Output Voltage Trimming

see calculation below

±10%

Remote ON/OFF

DC-DC ON

DC-DC OFF

Open or 2.5V<Vr<12V

Short or 0V<Vr<1.2V

Operating Frequency

300kHz

Minimum Load

0%

100mVp-p

continued on next page

Notes:

Note1: Ripple and Noise is measured with a 20MHz bandwidth and a 0.1µF ceramic capacitor.

Output Voltage Trimming

Trim Calculation

Trim UP

Trim DOWN

Vref

+Vout

Trim

R1

R3

R2

Vref

-Vout

Trim

R1

R3

R2

Vref

+Vout

Trim

R1

R3

R2

Vref

-Vout

Trim

R1

R3

R2

Vout

3.4V

5.1V

12V

15V

R1

4.71 k

Ω

2.3 k

Ω

19.43 k

Ω 25.6 kΩ

R2

2.7 k

Ω

2.2 k

Ω

5.1 k

Ω

R3

15 k

Ω

9.1 k

Ω

36 k

Ω

Vref

1.24 V

2.5 V

q a*R2 r-R3=kΩ

DVout = Output Voltage Trim

R2 - a

= trim up resistor

q b*R1 r- R3=kΩ

a

= trim up factor

R1 - b

b

= trim down factor

a =

q Vref r*R1=kΩ

DVout - Vref

b =

qDVout -Vrefr*R2=kΩ

Vref

Practical Example:

a =

q 2.5V r*2.3kΩ=1.849kΩ

5.61V - 2.5V

q 1.849kΩ*2.2kΩ r-9.1= 3.411kΩ

2.2kΩ - 1.849kΩ

Trim Up:

Vout = 5.1V,

DVout = 10% (5.61V), Vref= 2.5V

Trim down:

Vout = 5.1V,

DVout = -10% (4.59V), Vref= 2.5V

b =

q4.59V -2.5Vr*2.2kΩ= 1.839kΩ

2.5V

q1.839kΩ*2.3kΩr- 9.1kΩ=0.075kΩ

2.3k

Ω - 1.839kΩ