NDL Series: Isolated 2W Wide Input Single Output DC-DC Converters

Features

• RoHS compliant
• 2:1 wide range voltage input
• Continuous short circuit protection with current foldback
• Operating temperature range -40°C to 85°C
• 0.75% regulation
• 1kVDC isolation
• Efficiency to 83%
• Power density 0.9W/cm³
• 5V, 12V & 24V nominal inputs
• 5V, 9V, 12V & 15V outputs
• No electrolytic capacitors
• Fully encapsulated
• External control
• Low noise

Description

The NDL series comprises high-performance miniature DC-DC converters with regulated outputs across a wide temperature range of -40°C to 85°C. They feature a 2:1 input voltage range, 2 watts of output power, and 1kVDC input-to-output isolation. Continuous short circuit protection, external control, and a very small SIP packaging contribute to their advanced functionality. Standard nominal input voltages include 5, 12, 24, and 48V, with output voltages of 5, 9, 12, and 15V. Custom parts are available upon request. The plastic case is rated to UL94V-0, and the encapsulant to UL94V-1.

Selection Guide

Notes:
1. Refer to power derating graph for operating of 5V input types at 4.5 to 6V.
2. Measured at full load with external input/output capacitors.
3. Please refer to minimum load application notes section on page 3.
4. Calculated using MIL-HDBK-217F with nominal input voltage at full load.
All specifications typical at Ta=25°C, nominal input voltage and rated output current unless otherwise specified.

Input Characteristics

General Characteristics

Output Characteristics

¹ Refer to recommended test circuit for external input/output capacitors.

Isolation Characteristics

Temperature Characteristics

Absolute Maximum Ratings

• Short-circuit protection: Continuous
• Lead temperature 1.5mm from case for 10 seconds: 260°C
• Wave Solder: Wave Solder profile not to exceed the profile recommended in IEC 61760-1 Section 6.1.3. Please refer to application notes for further information.
• Control pin input current: 15mA
• Input voltage 05 types: 10V
• Input voltage 12 types: 20V
• Input voltage 24 types: 40V
• Input voltage 48 types: 80V

Technical Notes

Isolation Voltage

Terms like 'Hi Pot Test', 'Flash Tested', 'Withstand Voltage', 'Proof Voltage', 'Dielectric Withstand Voltage', and 'Isolation Test Voltage' all refer to the same concept: a test voltage applied for a specified duration to verify the integrity of electrical isolation. Murata Power Solutions NDL series DC-DC converters undergo 100% production testing at their stated isolation voltage of 1kVDC for 1 second. For normal operation of parts without specific agency approvals, like the NDL series, both input and output should typically be kept within SELV limits (less than 42.4V peak or 60VDC). The isolation test voltage indicates immunity to transient voltages; the part should not be used as part of a safety isolation system. While the part might function with several hundred volts offset across the isolation barrier, the circuitry on both sides must be considered at an unsafe voltage, requiring additional isolation/insulation systems for user-accessible circuits according to safety standards.

Repeated High-Voltage Isolation Testing

Repeated high-voltage isolation testing can degrade a barrier component's isolation capability, varying with materials, construction, and environment. The NDL series uses an EI ferrite core with no additional insulation between primary and secondary windings of enamelled wire. While parts can withstand multiples of the test voltage, isolation depends on wire insulation, which (typically polyurethane enamel) can degrade chemically under high voltages. Therefore, test frequency should be limited. Murata strongly advises against repeated high-voltage isolation testing, but if necessary, the voltage should be reduced by 20% from the specified test voltage. This advice also applies to agency-approved parts with better-than-functional isolation, where wire enamel is supplemented by physical spacing or barriers.

RoHS Compliant Information

This series is compatible with RoHS soldering systems, supporting a peak wave solder temperature of 260°C for 10 seconds. Refer to application notes for more details. The pin termination finish is Tin Plate, Hot Dipped over Matte Tin with Nickel Preplate. The series is backward compatible with Sn/Pb soldering systems. For more information, visit www.murata.com/en-global/products/power/rohs.

Part Number Structure

The part number structure is as follows:

NDL XXXX XX XX SC

• Series name: NDL
• Input voltage: e.g., 05 (5V), 12 (12V), 24 (24V), 48 (48V)
• Output voltage: e.g., 05 (5V), 09 (9V), 12 (12V), 15 (15V)
• Package type: S - SIP, D - DIP, M - Surface mount, Z - ZIP
• RoHS compliant: SC

Application Notes

External Capacitance

While these converters function without external capacitors, they are essential for achieving full parametric performance across the entire line and load range. All parts have been tested and characterized using the following values and test circuit:

Test Circuit Diagram Description: A schematic shows the input voltage (+VIN, -VIN) connected through an input capacitor (CIN) to the NDL converter. The output (+VOUT, -VOUT) is connected through an output capacitor (COUT) and an output inductor (not explicitly shown but implied by context) to the load. The control pin (CTRL) and a compensation pin (CS) are also shown.

Control Pin

The NDL converters feature a shutdown function to enter a low power state. The control pin connects to the base of an internal NPN transistor. Forward biasing this transistor switches the converter OFF. If the pin is left open (high impedance), the converter remains ON. A control voltage with sufficient drive current switches the converter OFF. A suitable application circuit is shown:

Application Circuit Diagram Description: A circuit diagram shows the control pin (CTRL) connected via a resistor (R1) and a diode (D1) to the base of an NPN transistor (Q). The emitter of Q is connected to -VIN, and the collector is connected to a voltage source (e.g., 5V) through a resistor (R2). The diode D1 (e.g., 1N4001) is used for high impedance when the signal is low. The calculation for R1 is provided: R₁ = (V_source - V_BE - V_diode) / I_drive. Assuming V_source=5V, V_BE=0.7V, and V_diode=1V, and a recommended drive current of 10mA, R1 is calculated as (5 - 0.7 - 1.0) / (10 x 10⁻³) = 330Ω.

Pin 8 (CS)

This pin serves as a connection point for the main reservoir capacitor. Additional capacitance can be added between this pin and pin 7. Lower ESR capacitors can improve ripple and noise reduction. Connecting capacitance here, before the output filter inductor, offers benefits over simple additional output capacitance. Maximum external capacitance depends on output voltage, converter load, and desired ripple, with values up to 100µF being possible.

Minimum Load

For correct operation, a minimum load of 25% of the full rated load is required across the specified input voltage range. Lighter loads may lead to increased output ripple and temporary overshooting of the output voltage during power-down when the input voltage also drops below its minimum rating.

NDL05 Power Derating Curve

Graph Description: A line graph titled "NDL05 POWER DERATING CURVE". The X-axis represents "Isolation voltage (V)" ranging from 4.5 to 9. The Y-axis represents "Output Power (W)" ranging from 0 to 2.5. The curve shows that for NDL05 series, output power is derated as isolation voltage increases, starting from approximately 2.0W at 5V and decreasing to about 1.75W at 9V.

Package Specifications

Mechanical Dimensions

Diagram Description: A diagram shows the physical dimensions of the NDL series converter in a SIP (Single In-line Package) format. Key dimensions are provided in millimeters with tolerances, such as length (21.80±0.25 mm), width (9.20±0.25 mm), height (11.10±0.25 mm), and pin pitch (2.54 mm). The diagram also shows the pinout with numbers 1, 2, 3, 5, 6, 7, 8. Pin 5 is marked with an asterisk and noted as internally connected, not for external connection.

Weight: 5.0g

Pin Connections

* This pin is internally connected and must have no external connection. External connection will result in converter failure.

Tube Outline Dimensions

Diagram Description: A diagram illustrates the dimensions for packaging the converters in a tube. Key dimensions include tube width (5.00 mm / 0.197 in), tube height (6.00 mm / 0.236 in), and tube length (14.20 mm / 0.559 in). The diagram also shows the placement of components within the tube and specifies the tube length as 520mm ±2mm (20.47±0.079 in) with a Tube Quantity of 23.

Recommended Footprint Details

Diagram Description: A diagram shows the recommended PCB footprint for the NDL series converter. It indicates the placement of seven holes with a diameter of 1.15 mm (Ø 1.00) on a 2.54 mm grid, corresponding to the converter's pins.

Disclaimer

Unless otherwise stated, all products are designed for standard commercial and industrial applications and are NOT intended for safety-critical or life-critical applications. For applications that may endanger life, cause bodily harm, severe damage to equipment/property, or harm the environment, prior explicit written approval from Murata is strictly required. Unauthorized use of Murata standard products in such applications is deemed unauthorized use.

Examples of applications where explicit approval is required include, but are not limited to:

• Aircraft equipment
• Aerospace equipment
• Undersea equipment
• Power plant control equipment
• Medical equipment
• Transportation equipment (automobiles, trains, ships, etc.)
• Traffic signal equipment
• Disaster prevention / crime prevention equipment
• Data Processing equipment

Murata makes no warranties regarding suitability, fitness for purpose, or compatibility with buyer applications. Murata assumes no liability for unauthorized use. The buyer is responsible for ensuring suitability, fitness, and compatibility. The buyer agrees to indemnify Murata against damages arising from unauthorized use in safety-critical or life-critical applications.

Murata in this context refers to Murata Manufacturing Company and its affiliated companies, including Murata Power Solutions.

Operating Requirements: This product is subject to specific operating requirements and the Life and Safety Critical Application Sales Policy. Refer to: https://www.murata.com/en-eu/products/power/requirements.

Murata Power Solutions (Milton Keynes) Ltd. makes no representation regarding patent rights or licenses for circuits described herein. Specifications are subject to change without notice. ©2025 Murata Power Solutions (Milton Keynes) Ltd.