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
5 V-24 V Input
0.9 V-3.3 V/3 A Output
Non-Isolated
Remote
On/Off
High
Efficiency
Fixed
Frequency
High Power Density
OCP/SCP
Low
Cost
Description
The Bel x7AH-03L1A0 modules are a series of non-isolated, step down dc/dc converters that operate from a
nominal 12 V source. These converters are available in an output voltage range from 0.9 V to 3.3 V. It is
packaged in a compact, overmolded package rated at 3 A. Optional lead forming provides a vertical mount
product for minimal footprint or a surface mount option for a very low profile. The output is closely regulated and
the efficiency for 3.3 V output is typically 88% at full load. Typical features include remote on/off, over current
protection and short circuit protection.
Part Selection
Output
Voltage
Input
Voltage
Max. Output
Current
Max. Output
Power
Typical
Efficiency
Part Number
Surface Mount
Part Number
Vertical Mount
0.9 V - 3.3 V 5.0 V 24 V
3 A
10 W
88%
S7AH-03L1A0
V7AH-03L1A0
Note:
Add "0" suffix at the end of the model number to indicate "Tube Packaging", and "R" for "Reel
Packaging", and "G" for "Tray Packaging".
Absolute Maximum Ratings
Parameter
Min
Typ
Max
Notes
Input Voltage (continuous)
-0.3 V
-
25 V
Output Enable Terminal Voltage
-0.3 V
-
24 V
Ambient Temperature
-40
C
-
85
C
Storage Temperature
-40
C
-
125
C
Input Specifications
Parameter
Min
Typ
Max
Notes
Input Voltage
V
O
=3.3 V
V
O
=2.5 V
V
O
=1.8 V
Vo=1.5 V
Vo=1.2 V
Vo=0.9 V
5 V
5 V
5 V
5 V
5 V
5 V
-
-
-
-
-
-
24 V
24 V
18 V
15 V
12 V
9 V
Input Current (no load)
-
-
100 mA
Input Current (full load)
-
-
3 A
Remote Off Input Current
-
3 mA
10 mA
Input Reflected Ripple Current
(pk-pk) - 200
mA -
Input Reflected Ripple Current
(rms) -
50
mA
-
With simulated source impedance of 500
nH, 5 Hz to 20 MHz. Use one 100 uF/
35 V Tantalum capacitor and one 3.3 uF/
50 V ceramic capacitor at the input
I
2
t Inrush Current Transient
-
0.05 A
2
s
0.1 A
2
s
Turn on Voltage Threshold
-
4.0 V
-
Turn off Voltage Threshold
3.5 V
-
4.9 V
x7AH-03L1A0
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
5 V-24 V Input
0.9 V-3.3 V/3 A Output
Output Specifications
Parameter
Min
Typ
Max
Notes
Output Voltage Set Point
V
O
=3.3 V
V
O
=2.5 V
V
O
=1.8 V
V
O
=1.5 V
V
O
=1.2 V
V
O
=0.9 V
3.200 V
2.425 V
1.746 V
1.470 V
1.176 V
0.882 V
3.3 V
2.5 V
1.8 V
1.5V
1.2 V
0.9 V
3.400 V
2.575 V
1.854 V
1.530 V
1.224 V
0.918 V
Test conditions:
Io=50% full load.
Line Regulation
V
O
=3.3 V
V
O
=2.5 V
V
O
=1.8 V
V
O
=1.5 V
V
O
=1.2 V
V
O
=0.9 V
-
-
-
-
-
-
10 mV
10 mV
5 mV
5 mV
5 mV
3 mV
20 mV
15 mV
10 mV
10 mV
10 mV
7.5 mV
Load Regulation
V
O
=3.3 V
V
O
=2.5 V
V
O
=1.8 V
V
O
=1.5 V
V
O
=1.2 V
V
O
=0.9 V
-
-
-
-
-
-
25 mV
15 mV
10 mV
10 mV
8 mV
5 mV
45 mV
35 mV
25 mV
20 mV
15 mV
13 mV
Regulation Over Temperature (-40
C to +85 C)
V
O
=3.3 V
V
O
=2.5 V
V
O
=1.8 V
V
O
=1.5 V
V
O
=1.2 V
V
O
=0.9 V
-
-
-
-
-
-
30 mV
25 mV
20 mV
15 mV
10 mV
8 mV
60 mV
45 mV
33 mV
27 mV
22 mV
16 mV
Output Current Range
0 A
-
3 A
Output DC Current Limit
4 A
-
8 A
Short Circuit Surge Transient
-
0.8 A
2
s 1.5
A
2
s
Ripple and Noise (rms)
-
30 mV
50 mV
Ripple and Noise (pk-pk)
V
O
=3.3 V
V
O
=2.5 V
V
O
=1.8 V
V
O
=1.5 V
V
O
=1.2 V
V
O
=0.9 V
-
-
-
-
-
-
70 mV
70 mV
60 mV
60 mV
50 mV
50 mV
130 mV
100 mV
100 mV
100 mV
100 mV
100 mV
Test conditions:
0-20 MHz BW, with 1 uF
/16 V ceramic capacitor
at the output.
Turn on Time
-
7 mS
10 mS
Overshoot at Turn on
-
0%
3%
Output Capacitance
0 uF
-
1200 uF
Transient Response
Overshoot
-
150 mV
200 mV
50% ~ 100%
Max Load
Settling Time
-
50 uS
100 uS
Overshoot
-
150 mV
200 mV
100% ~ 50%
Max Load
Settling Time
3.3 V
-
50 uS
100 uS
Overshoot
-
100 mV
150 mV
50% ~ 100%
Max Load
Settling Time
-
50 uS
100 uS
Overshoot
-
100 mV
150 mV
100% ~ 50%
Max Load
Settling Time
0.9 V-2.5 V
-
50 uS
100 uS
Test conditions:
di/dt = 0.5 A/us, with
220 uF external
capacitor at the output.
Note:
All specifications are typical at nominal input, full load 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
5 V-24 V Input
0.9 V-3.3 V/3 A Output
General Specifications
Parameter
Min
Typ
Max
Notes
Efficiency
V
O
=3.3 V
V
O
=2.5 V
V
O
=1.8 V
V
O
=1.5 V
V
O
=1.2 V
Vo=0.9 V
85%
82%
79%
77%
74%
72%
88%
85%
82%
80%
77%
75%
-
-
-
-
-
-
Vin=12.0V; lo=lo, max
Switching Frequency
250 kHz
300 kHz
360 kHz
MTBF
9,900,543 hours
Calculated Per Bell Core TR-332
(Vin=12 V; Vo=3.3 V; I
O
=2.4 A; T
a
=
25
C)
Dimensions (surface mount)
Inches (L W H)
Millimeters (L W H)
0.78 x 0.7 x 0.32
19.81 x 17.78 x 8.13
Dimensions (vertical)
Inches (L W H)
Millimeters (L W H)
0.7 x 0.308 x 0.65
17.78 x 7.82 x 16.51
Weight -
4.9
g
-
Control Specifications
Parameter
Min
Typ
Max
Notes
Remote On/Off
Signal Low (Unit Off)
-0.3 V
-
1 V
Signal High (Unit On)
2.8 V
-
24 V
Remote on/off pin open, Unit On
Output Trim Equations
Equations for calculating the trim resistor (in k) given the desired adjusted voltage (Vadj) and the nominal
output voltage of the converter (Vo) are shown below. The Trim Up resistor should be connected between the
Trim pin and Ground. Only one of the resistors should be used for any given application.
1
928
.
6
-
-
=
-
o
adj
up
trim
V
V
R
Note:
Output voltage Vo=0.902 V when Rtrim_up is not connected.
Vout
Trim
GND
Rtrim-up
Module
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
5 V-24 V Input
0.9 V-3.3 V/3 A Output
Efficiency Data
3.3V module
40.0%
50.0%
60.0%
70.0%
80.0%
90.0%
100.0%
0.3A
0.75A
1.5A
2.25A
3A
Output current
Ef
f
i
c
i
e
n
c
y
5V
12V
24V
1.8V module
40.0%
50.0%
60.0%
70.0%
80.0%
90.0%
100.0%
0.3A
0.75A
1.5A
2.25A
3A
Output current
E
f
f
i
ci
enc
y
5V
12V
18V
0.9V module
40.0%
50.0%
60.0%
70.0%
80.0%
90.0%
100.0%
0.3A
0.75A
1.5A
2.25A
3A
Output current
Ef
f
i
c
i
e
n
c
y
5V
7V
9V
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
5 V-24 V Input
0.9 V-3.3 V/3 A Output
Thermal Derating Curve
x7AH-03L1A0
.
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