NON-ISOLATED DC/DC CONVERTERS
12 Vdc Input Dec. 03, 2010 Vddq/2 / 8 A Output
Bel Power Inc., a subsidiary of Bel Fuse Inc.
RoHS Compliant
• • • • •
VRAF-08xT50
• • • • • • Non-Isolated High Efficiency Fixed Frequency Low Cost
Rev.J
Under-Voltage Lockout Output Enable OCP/SCP Current Source/Sink Capability Over Voltage Protection (Hiccup Mode)
Tracking a Reference for Output Voltage High Power Density
Description
The Bel VRAF-08xT50 module is a non-isolated, step down dc/dc power converter that operates from a nominal 12 Vdc or wide range 5 Vdc to 13.8 Vdc source. This converter is designed specifically to provide bus termination voltages in applications such as DDR (double data rate) memory where the bus termination voltage must closely track the I/O bus voltage. The converter accepts a reference input and uses this to program its output voltage to 50% of the reference. The unit is packaged in compact single-in-line footprint and provides a maximum 8 A output. Standard features include remote on/off, input under-voltage lockout, output over voltage protection.
Part Selection
Output Voltage 0.9 V 0.9 V Input Voltage 5.0 V - 13.8 V 5.0 V - 13.8 V Max. Output Current 8A 8A Max. Output Power 7.2 W 7.2 W Typical Efficiency 69% 69% Model Number VRAF-08AT50 VRAF-08ET50
Notes: 1. All part numbers above indicate RoHS 6. Change the second letter "R" to "7" for RoHS 5 part numbers. 2. Add “G” suffix at the end of the model numbers listed above to indicate “Tray Packaging”. 3. Part number VRAF-08ET50 is better suited for applications where start up is guaranteed at 5V input.
Absolute Maximum Ratings
Parameter Input Supply Voltage Input Signal Voltage Operating Temperature Storage Temperature Min -0.5 V -0.3 V 0 °C -40 °C Typ Max 15 V 5.25 V 70 °C 85 °C Notes
Note: All specifications are typical at 25 °C unless otherwise stated.
Input Specifications
Parameter Operating Input Voltage VRAF-08AT50 VRAF-08ET50 Input Current (full load) VRAF-08AT50 VRAF-08ET50 Input Current (no load) Reference Voltage Range (Vddq) Remote Off Input Current Min 5.0 V 5.0 V 1.2 V Typ 12 V 12 V 25 mA 1.8 V 7 mA Max 13.8 V 13.8 V 2.2 A 2.2 A 35 mA 1.89 V 10 mA Notes
Bel Fuse Inc. 206 Van Vorst Street, Jersey City, NJ 07302 • Tel 201-432-0463 • Fax 201-432-9542 • www.belfuse.com
NON-ISOLATED DC/DC CONVERTERS
12 Vdc Input Dec. 03, 2010 Vddq/2 / 8 A Output
Bel Power Inc., a subsidiary of Bel Fuse Inc.
Parameter Min 2.6 V 2.4 V Typ 110 mA 25 mA 0.006 A s 2
Input Specifications (continued)
Max 180 mA 60 mA 0.012 A s 3.9 V 3.7 V
2
Input Reflected Ripple Current (pk-pk) Input Reflected Ripple Current (rms) I t Inrush Current Transient Turn on Voltage Threshold Turn off Voltage Threshold
2
Notes With simulated source impedance of 1000 nH, 5 Hz to 20 MHz. Use a 100 uF/25 V Tan cap with ESR=0.025 ohm max, at 100 kHz@25°C.
Notes: 1. All specifications are typical at 25 °C unless otherwise stated. 2. This power module is not internally fused. An input line fuse must always be used.
Output Specifications
Parameter Output Voltage Set Point Tracking Tolerance (Vddq/2-Vout)/Vout Load Regulation Line Regulation Output Current Output DC Current Limit Output Ripple and Noise (pk-pk) Output Ripple and Noise (rms) Short Circuit Surge Transient Turn on Time VRAF-08AT50 VRAF-08ET50 Overshoot at Turn on Output Capacitance Transient Response 50% ~ 100% Max Load Settling Time 100% ~ 50% Max Load Settling Time VO =0.9 V 100 mV 20 uS 100 mV 20 uS 200 mV 50 uS 200 mV 50 uS di/dt=0.3 A/uS; Vin12 V; and with a 22 uF / 6.3 V ceramic capacitor at the output. 0 uF 2.5 mS 5 mS 0% 5 mS 8 mS 3% 2200 uF Start up from ENABLE. Min -1.5% 0A 9.2 A Typ Vddq/2 3 mV 3 mV 25 mV 8 mV 1.1 A s
2
Max 1.5% 6 mV 6 mV 8A 14 A 50 mV 15 mV 2.2 A2s
Notes Vin=12 V, lout=full load
Test conditions: 0-20 MHz BW, with a 22 uF / 6.3 V ceramic capacitor at the output.
Note: All specifications are typical at Vin =12 V, Vddq=1.8 V, Io=8 A, Ta= 25°C unless otherwise stated.
General Specifications
Parameter Efficiency Switching Frequency MTBF Dimensions Inches (L × W × H) Millimeters (L × W × H) Weight 0.65 x 0.41 x 0.40 16.51 x 10.41 x 10.16 2.5 g Min 68% 260 kHz Typ 69% 300 kHz 6,416,286 hours Max 340 kHz Notes Vin=12 V, Vddq=1.8 V, Io=8 A Calculated Per Bell Core SR-332 (IO = 80% load; Vin=12 V; Ta = 25 °C)
-
Note: All specifications are typical at 25 °C unless otherwise stated.
Bel Fuse Inc. 206 Van Vorst Street, Jersey City, NJ 07302 • Tel 201-432-0463 • Fax 201-432-9542 • www.belfuse.com
NON-ISOLATED DC/DC CONVERTERS
12 Vdc Input Dec. 03, 2010 Vddq/2 / 8 A Output
Bel Power Inc., a subsidiary of Bel Fuse Inc.
Control Specifications
Parameter Output Enable ENABLE High ENABLE Low Min 2V 0V Typ Max 5.5 V 0.8 V Notes
Enable Pin open, the module is off.
Efficiency Data
Efficiency Curve 85.0% 80.0% 75.0% 70.0% 65.0% 60.0% 55.0% 50.0% 45.0% 0.8 2.0 4.0 6.0 8.0 Output Current (A)
VRAF-08AT50
Efficiency
10.8 V 12.0 V 13.2 V
Efficiency Curve 85.0% Efficiency 75.0% 65.0% 55.0% 45.0% 0.8 2.0 4.0 6.0 8.0 Output Current (A)
VRAF-08ET50
5.0V 12.0V 13.8V
Bel Fuse Inc. 206 Van Vorst Street, Jersey City, NJ 07302 • Tel 201-432-0463 • Fax 201-432-9542 • www.belfuse.com
NON-ISOLATED DC/DC CONVERTERS
12 Vdc Input Dec. 03, 2010 Vddq/2 / 8 A Output
Bel Power Inc., a subsidiary of Bel Fuse Inc.
Thermal Derating Curve
The thermal reference point Tref is shown above. For reliable operation this temperature should not exceed 115°C. The output power of the module should not exceed the rated power for the module.
Vin=12 V, Vddq=1.8 V
Bel Fuse Inc. 206 Van Vorst Street, Jersey City, NJ 07302 • Tel 201-432-0463 • Fax 201-432-9542 • www.belfuse.com
NON-ISOLATED DC/DC CONVERTERS
12 Vdc Input Dec. 03, 2010 Vddq/2 / 8 A Output
Bel Power Inc., a subsidiary of Bel Fuse Inc.
Ripple and Noise Waveform
Note: Ripple and noise at Vin=12 V, Vddq=1.8 V, Io=8 A, with a 22 uF/6.3 V X5R ceramic capacitor at the output, Ta=25 °C.
Transient Response Waveforms
50% to 100% load step at Vin=12 V, Vddq=1.8 V
100% to 50% load step at Vin=12 V, Vddq=1.8 V
Note: Transient response at di/dt=0.3 A/uS, with 22 uF/6.3 V X5R ceramic capacitor at the output, Ta=25 °C.
Bel Fuse Inc. 206 Van Vorst Street, Jersey City, NJ 07302 • Tel 201-432-0463 • Fax 201-432-9542 • www.belfuse.com
NON-ISOLATED DC/DC CONVERTERS
12 Vdc Input Dec. 03, 2010 Vddq/2 / 8 A Output
Bel Power Inc., a subsidiary of Bel Fuse Inc.
Output Tracking
Test condition: Vin=12 V, Vddq=1.8 V, Io=8 A.
Bel Fuse Inc. 206 Van Vorst Street, Jersey City, NJ 07302 • Tel 201-432-0463 • Fax 201-432-9542 • www.belfuse.com
NON-ISOLATED DC/DC CONVERTERS
12 Vdc Input Dec. 03, 2010 Vddq/2 / 8 A Output
Bel Power Inc., a subsidiary of Bel Fuse Inc.
Mechanical Outline
Pin Connections
Pin 1 2 3 4 5 Function Vin Vddq Vout GND Enable
Bel Fuse Inc. 206 Van Vorst Street, Jersey City, NJ 07302 • Tel 201-432-0463 • Fax 201-432-9542 • www.belfuse.com
NON-ISOLATED DC/DC CONVERTERS
12 Vdc Input Dec. 03, 2010 Vddq/2 / 8 A Output
Bel Power Inc., a subsidiary of Bel Fuse Inc.
Revision History
Date 2010-02-26 2010-12-03 Revision I J Changes Detail Update the input range for VRAF-08AT50 and add note 3 for VRAF08ET50 on first page. Add pin length in the MD. Approval HL XF
RoHS Compliance
Complies with the European Directive 2002/95/EC, calling for the elimination of lead and other hazardous substances from electronic products.
©2010 Bel Fuse Inc. Specifications subject to change without notice. 120310
CORPORATE Bel Fuse Inc. 206 Van Vorst Street Jersey City, NJ 07302 Tel 201-432-0463 Fax 201-432-9542 www.belfuse.com
FAR EAST Bel Fuse Ltd. 8F/ 8 Luk Hop Street San Po Kong Kowloon, Hong Kong Tel 852-2328-5515 Fax 852-2352-3706 www.belfuse.com
EUROPE Bel Fuse Europe Ltd. Preston Technology Management Centre Marsh Lane, Suite G7, Preston Lancashire, PR1 8UD, U.K. Tel 44-1772-556601 Fax 44-1772-888366 www.belfuse.com
