BEL VRAF

NON-ISOLATED DC/DC CONVERTERS
12 Vdc Input
Vddq/2 / 8 A Output
VRAF-08xT50
RoHS Compliant
Rev.H

Non-Isolated

Under-Voltage Lockout

High Efficiency

Output Enable

Fixed Frequency

OCP/SCP

Low Cost

Current Source/Sink Capability

Tracking a Reference for
Output Voltage

Over Voltage Protection
(Hiccup Mode)

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
Input Voltage
Max. Output
Current
Max. Output
Power
Typical
Efficiency
Model Number
0.9 V
10.8 V - 13.2 V
8A
7.2 W
69%
VRAF-08AT50
0.9 V
5.0 V - 13.8 V
8A
7.2 W
69%
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”.
Absolute Maximum Ratings
Parameter
Input Supply Voltage
Min
-0.5 V
Input Signal Voltage
-0.3 V
Operating Temperature
Storage Temperature
Typ
-
Max
15 V
Notes
5.25 V
0 C
-
70 C
-40 C
-
85 C
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
Typ
Max
10.8 V
5.0 V
12 V
12 V
13.2 V
13.8 V
-
-
1.05 A
2.2 A
-
25 mA
35 mA
1.2 V
1.8 V
1.89 V
-
7 mA
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
Vddq/2 / 8 A Output
Input Specifications (continued)
Parameter
Min
Typ
Max
Input Reflected Ripple Current (pk-pk)
-
110 mA
180 mA
Input Reflected Ripple Current (rms)
-
25 mA
60 mA
I t Inrush Current Transient
-
0.006 A s
0.012 A s
Turn on Voltage Threshold
2.6 V
-
3.9 V
Turn off Voltage Threshold
2.4 V
-
3.7 V
2
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
[email protected]°C.
2
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
Min
-
Typ
Vddq/2
Max
-
-1.5%
-
1.5%
-
3 mV
6 mV
Line Regulation
-
3 mV
6 mV
Output Current
0A
-
8A
9.2 A
-
14 A
Output Ripple and Noise (pk-pk)
-
25 mV
50 mV
Output Ripple and Noise (rms)
-
8 mV
15 mV
-
2
1.1 A s
2.2 A s
-
2.5 mS
5 mS
5 mS
8 mS
-
0%
3%
0 uF
-
2200 uF
Output DC Current Limit
Short Circuit Surge Transient
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.
2
Turn on Time
VRAF-08AT50
VRAF-08ET50
Overshoot at Turn on
Output Capacitance
Start up from ENABLE.
Transient Response
50% ~ 100% Max Load
Settling Time
100% ~ 50% Max Load
VO =0.9 V
Settling Time
-
100 mV
200 mV
-
20 uS
50 uS
-
100 mV
200 mV
-
20 uS
50 uS
di/dt=0.3 A/uS; Vin12 V; and
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
Min
68%
260 kHz
MTBF
Typ
69%
300 kHz
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)
6,416,286 hours
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
-
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
Vddq/2 / 8 A Output
Control Specifications
Parameter
Output Enable
Min
Typ
Max
Notes
ENABLE High
2V
-
5.5 V
ENABLE Low
0V
-
0.8 V
Enable Pin open, the module is off.
Efficiency Data
Efficiency
Efficiency Curve
85.0%
80.0%
75.0%
70.0%
65.0%
60.0%
55.0%
50.0%
45.0%
10.8 V
12.0 V
13.2 V
0.8
2.0
4.0
6.0
8.0
Output Current (A)
VRAF-08AT50
Efficiency Curve
Efficiency
85.0%
75.0%
5.0V
12.0V
13.8V
65.0%
55.0%
45.0%
0.8
2.0
4.0
6.0
8.0
Output Current (A)
VRAF-08ET50
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
Vddq/2 / 8 A Output
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
Vddq/2 / 8 A Output
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
Vddq/2 / 8 A Output
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
Vddq/2 / 8 A Output
Mechanical Outline
Pin Connections
Pin
Function
1
Vin
2
Vddq
3
Vout (Vtt)
4
GND
5
Enable
RoHS Compliance
Complies with the European Directive 2002/95/EC, calling for the elimination of lead and
other hazardous substances from electronic products.
2009 Bel Fuse Inc. Specifications subject to change without notice. 042709
CORPORATE
FAR EAST
EUROPE
Bel Fuse Inc.
206 Van Vorst Street
Jersey City, NJ 07302
Tel 201-432-0463
Fax 201-432-9542
www.belfuse.com
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
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