R-78AA3.3-1.0SMD - Audio/video converter Recom - Free user manual and instructions

Product Type	Non-isolated buck converter (DC/DC)
Brand	RECOM
Model	R-78AA3.3-1.0SMD
Input Voltage Range	4.75 – 18 VDC
Output Voltage	3.3 VDC (adjustable 3.0 – 5.5 VDC)
Output Current	1.0 A
Efficiency (typical)	Up to 94% (at 3.3 Vout, full load)
Dimensions (L x W x H)	15.3 x 9.6 x 8.8 mm
Weight	1.7 g (typical)
Operating Temperature Range	-40°C to +85°C
Protections	Short circuit (continuous, auto recovery), thermal shutdown
Remote On/Off Control	Yes (CTRL pin, active high >2.8 VDC)
Output Ripple & Noise	30 mVp-p maximum (20 MHz BW)
Switching Frequency	385 kHz typical
Package Type	SMD (surface mount, reflow compatible)
Certifications	IEC/EN 60950-1, RoHS 2+
MTBF	13,338 x 10³ hours @ 25°C (MIL-HDBK-217F)
Storage Temperature	-55°C to +125°C

Frequently Asked Questions - R-78AA3.3-1.0SMD Recom

What is the input voltage range for the R-78AA3.3-1.0SMD?

The input voltage range is from 4.75 VDC to 18 VDC. Note that the input must be higher than the output voltage plus dropout.

Can the output voltage be adjusted?

Yes, the output voltage can be adjusted from 3.0 VDC to 5.5 VDC using external resistors connected to the Vadj pin. The default output is 3.3 VDC.

Does this converter require a heatsink?

No, due to its high efficiency (up to 94%), the R-78AA3.3-1.0SMD does not require a heatsink under normal operating conditions.

How do I enable the remote on/off function?

Apply a voltage of 2.8 VDC or higher to the CTRL pin to turn the converter on. Connect the CTRL pin to GND or leave it open to turn it off. The shutdown current is very low, typically 1.8 µA.

Is the converter protected against short circuits?

Yes, it features continuous short circuit protection with automatic recovery. The input current during a short circuit is limited to typically 120 mA at 12 V input.

What is the maximum capacitive load I can use?

With normal startup, the maximum capacitive load is 470 µF. Using an optional diode protection circuit, it can be increased to 6800 µF with startup time under 1 second.

What are the storage temperature and humidity limits?

The storage temperature range is -55°C to +125°C with a maximum humidity of 95% RH (non-condensing).

Does the converter meet any safety certifications?

Yes, it is certified to IEC/EN 60950-1 (Safety of Information Technology Equipment) and complies with RoHS 2+ (2011/65/EU + AM2015/863).

Can I use this converter for battery-powered applications?

Yes, the very low quiescent current (5 mA typical) and shutdown current (1.8 µA) make it suitable for battery-powered, industrial, medical, and automotive applications.

What is the recommended soldering profile for reflow?

The SMD package is designed for high reflow temperatures associated with vapor phase soldering. Follow the standard lead-free reflow profile with peak temperature up to 260°C.

USER MANUAL R-78AA3.3-1.0SMD Recom

• 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

Switching Regulator

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 vapor 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.

Selection Guide

Part Number	Input Voltage Range	Output Voltage [VDC]	Vout Adjust Range [VDC]	Output Current @ min Vin [VDC]	Efficiency @ max. Vin [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

Notes:

Note2: add suffix -R for tape & reel packaging

Ordering Examples:

R-78AA5.0-1.0SMD-R = 5.0VDC Output Voltage, 1.0A, SMD, tape and reel packaging R-78AA2.5-1.0SMD = 2.5VDC Output Voltage, 1.0A, SMD, tube

RECOM

DC/DC Converter

R-78AA-1.0

1.0 Amp

SMD

Single Output

EN60950-1 certified IEC60950-1 certified

Specifications (measured @ Ta= 25°C, 10% minimum load, unless otherwise stated)

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 ONDC-DC OFF	Open or 2.8VDC
		GND or 0VDC
Input Current of CTRL Pin DC-DC OFF			1.8μA
Standby Current			20μA 35μA
CTRL Theshold Voltage		2.4VDC 2.6VDC 2.8VDC
CTRL Voltage Hysteresse			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

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

	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)+VrefxR1R3/R2Vo-Vref(R1+R2)

Trim up Rup = R2R3(Vref-Vo)+VrefR1(R2+R3)/R2(Vo-Vref)-VrefR1

Efficiency vs. Vin (full load)

Ripple vs. Vin (full load)

continued on next page

Specifications (measured @ Ta= 25°C, 10% minimum load, unless otherwise stated)

Efficiency vs. Load (max. Vin)

Ripple vs. Load (max. Vin)

Efficiency vs. Load (min. Vin)

Ripple vs. Load (min. Vin)

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.

Specifications (measured @ Ta= 25°C, 10% minimum load, unless otherwise stated)

PROTECTIONS

Parameter Condition Value
Short Circuit Protection (SCP) continuous, automatic recovery
Short Circuit Input Current nom. Vin= 12VDC 120mA max.

Optional Diode Protection Circuit

Optional Protection 1: Optional Protection 2:

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).

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 103hours3880 - 6769 x 103hours

Derating Graph

Specifications (measured @ Ta= 25°C, 10% minimum load, unless otherwise stated)

SAFETY AND CERTIFICATIONS

Certificate Type (Safety) Report / File Number Standard
Information Technology Equipment, General Requirements for Safety	1603123	IEC60950-1:2005, 2nd Edition + AM 2:2013EN60950-1:2006 + 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

DIMENSION AND PHYSICAL CHARACTERISTICS

Parameter	Type	Value
Material	casePCB	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.

Dimension Drawing (mm)

Pinning information

Pin #	Single
1,2	+Vin
3,7,8,9	GND
4,5	+Vout
6	Vadj
10	CTRL

Recommended Footprint Details

Tolerance:

xx.x=0.5mm

xx.xx=±0.25mm

Specifications (measured @ Ta= 25°C, 10% minimum load, unless otherwise stated)

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.