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
3.3V Input
0.9V-2.5V/3A Output
Non-Isolated
OCP/SCP
High
Efficiency
Wide Range Trim
Low
Cost
Remote
On/Off
Excellent Thermal Performance
Industrial
Temperature
Range
Input Under Voltage Lockout
Description
The Bel x7AH-03C1A0 modules are a series of non-isolated, step down DC/DC converters that operate from a
nominal 3.3V source. These converters are available in a range of output voltages from 0.9V to 2.5V. It is
packaged in a compact, overmolded package rated at 3A. 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 2.5 V output is typically 93% at full load. Typical features include remote on/off, input under
voltage lockout, 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
0.9-2.5V 3.3V
3A
7.5W 93% S7AH-03C1A0
V7AH-03C1A0
2.5V 3.3V 3A 7.5W 93%
S7AH-03C250
V7AH-03C250
1.8V 3.3V 3A 5.4W 89%
S7AH-03C180
V7AH-03C180
1.5V 3.3V 3A 4.5W 87%
S7AH-03C150
V7AH-03C150
1.2V 3.3V 3A 3.6W 84%
S7AH-03C120
V7AH-03C120
0.9 V
3.3V
3A
2.7W
81%
S7AH-03C090
V7AH-03C090
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)
-0.3V
-
6V
Output Enable Terminal Voltage
-0.3V
-
6V
Ambient Temperature
-40
C
-
85
C
Storage Temperature
-55
C
-
125
C
Input Specifications
Parameter
Min
Typ
Max
Notes
Input Voltage
3V
-
3.6V
Input Current (no load)
-
-
110mA
Input Current (full load)
V
O
=2.5V
V
O
=1.8V
V
O
=1.5V
V
O
=1.2V
V
O
=0.9V
-
-
-
-
-
-
-
-
-
-
3.1A
2.3A
1.9A
1.6A
1.2A
Remote Off Input Current
-
7mA
14mA
x7AH-03C1A0 Series
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
3.3V Input
0.9V-2.5V/3A Output
Input Specifications (continued)
Parameter
Min
Typ
Max
Notes
Input Reflected Ripple Current (pk-pk)
-
50mA
100mA
Input Reflected Ripple Current (RMS)
-
15mA
25mA
With simulated source
impedance of 500nH, 5Hz
to 20MHz; use a
270uF/6.3V capacitor with
ESR=0.03 ohm max, at
100KHz.
I
2
t Inrush Current Transient
-
0.01A
2
s 0.02A
2
s
Turn on Voltage Threshold
-
2.7V
-
Turn off Voltage Threshold
-
2.4V
-
Note
: All specifications are typical at 25
C
unless otherwise stated.
Output Specifications
Parameter
Min
Typ
Max
Notes
Output Voltage Set Point
V
O
=2.5V
V
O
=1.8V
V
O
=1.5V
V
O
=1.2V
V
O
=0.9V
2.450V
1.764V
1.470V
1.176V
0.882V
2.5V
1.8V
1.5V
1.2V
0.9V
2.550V
1.836V
1.530V
1.224V
0.918V
Test conditions:
Vin=3.3V, Io= full load
Line Regulation
V
O
=2.5V
V
O
=1.8V
V
O
=1.5V
V
O
=1.2V
V
O
=0.9V
-
-
-
-
-
1mV
1mV
1mV
1mV
1mV
5mV
5mV
5mV
5mV
5mV
Load Regulation
V
O
=2.5V
V
O
=1.8V
V
O
=1.5V
V
O
=1.2V
V
O
=0.9V
-
-
-
-
-
1mV
1mV
1mV
1mV
1mV
5mV
5mV
5mV
5mV
5mV
Regulation Over Temperature
(-40
C to +85C)
V
O
=2.5V
V
O
=1.8V
V
O
=1.5V
V
O
=1.2V
V
O
=0.9V
-
-
-
-
-
10mV
10mV
10mV
10mV
10mV
20mV
20mV
20mV
20mV
20mV
Output Current
0A - 3A
Current Limit Threshold
5A - 9A
Short Circuit Surge Transient
V
O
=2.5V
V
O
=1.8V
V
O
=1.5V
V
O
=1.2V
V
O
=0.9V
-
-
-
-
-
0.04A
2
s
0.04A
2
s
0.04A
2
s
0.04A
2
s
0.04A
2
s
0.08A
2
s
0.08A
2
s
0.08A
2
s
0.08A
2
s
0.08A
2
s
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
3.3V Input
0.9V-2.5V/3A Output
Output Specifications (continued)
Parameter
Min
Typ
Max
Notes
Ripple and Noise (RMS)
V
O
=2.5V
V
O
=1.8V
V
O
=1.5V
V
O
=1.2V
V
O
=0.9V
-
-
-
-
-
10mV
10mV
10mV
10mV
10mV
20mV
20mV
20mV
20mV
20mV
Ripple and Noise (pk-pk)
V
O
=2.5V
V
O
=1.8V
V
O
=1.5V
V
O
=1.2V
V
O
=0.9V
-
-
-
-
-
45mV
45mV
45mV
45mV
45mV
70mV
70mV
70mV
70mV
70mV
Test conditions:
0-20MHz BW; 0.1uF
ceramic capacitor and 10uF
tantalum capacitor at the
output.
Turn on Time
-
7mS
15mS
Overshoot at Turn on
-
0%
1%
Output Capacitance
0uF
-
1200uF
Transient Response
Overshoot
-
100mV
130mV
50% ~ 100%
Max Load
Settling Time
-
30uS 60uS
Overshoot
-
100mV
130mV
100% ~ 50%
Max Load
Settling Time
V
O
=2.5V
-
30uS 60uS
Overshoot -
100mV
130mV
50% ~ 100%
Max Load
Settling Time
-
30uS
60uS
Overshoot -
100mV
130mV
100% ~ 50%
Max Load
Settling Time
V
O
=1.8V
- 30uS
60uS
Overshoot
-
90mV
120mV
50% ~ 100%
Max Load
Settling Time
-
30uS 60uS
Overshoot
-
90mV
120mV
100% ~ 50%
Max Load
Settling Time
V
O
=1.5V
-
30uS 60uS
Overshoot
-
90mV
120mV
50% ~ 100%
Max Load
Settling Time
-
30uS 60uS
Overshoot
-
90mV
120mV
100% ~ 50%
Max Load
Settling Time
V
O
=1.2V
-
30uS 60uS
Overshoot
-
90mV
120mV
50% ~ 100%
Max Load
Settling Time
-
30uS 60uS
Overshoot
-
90mV
120mV
100% ~ 50%
Max Load
Settling Time
V
O
=0.9V
-
30uS 60uS
Test conditions:
di/dt=0.5A/us, Vin=3.3V,
without any 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
3.3V Input
0.9V-2.5V/3A Output
General Specifications
Parameter
Min
Typ
Max
Notes
Efficiency
V
O
=2.5V
V
O
=1.8V
V
O
=1.5V
V
O
=1.2V
V
O
=0.9V
90%
86%
84%
81%
78%
93%
89%
87%
84%
81%
-
-
-
-
-
Measured at Vin=3.3V, full load and
Ta=25
C
Switching Frequency
250KHz
300KHz
340KHz
Output Trim Range (wide trim)
0
-
292%V
O
Vo=0.9V
Output Trim Range (narrow trim)
Vo=1.2V-2.5V
Vo=0.9V
90%Vo
-
-
-
110%Vo
110%Vo
MTBF
3,131,719 hours
Calculated Per Bell Core TR-332 (I
O
=
Nominal; T
a
= 25
C)
Dimensions (surface mount)
Inches (L W H)
Millimeters (L W H)
0.78 x 0.70 x 0.32
19.81 x 17.78 x 8.13
Dimensions (vertical)
Inches (L W H)
Millimeters (L W H)
0.70 x 0.308 x 0.65
17.78 x 7.82 x 16.51
Weight -
5g
-
Note
: All specifications are typical at 25
C
unless otherwise stated.
Control Specifications
Parameter
Min
Typ
Max
Notes
Remote On/Off
Signal Low (Unit Off)
-0.3V
-
0.3V
Signal High (Unit On)
1.8V
-
3.6V
Remote on/off pin open, unit on.
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
3.3V Input
0.9V-2.5V/3A Output
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 (Vnom) are shown below. The Trim Down resistor should be connected between
the Trim pin and Vout. 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.
B
V
V
A
R
adj
nom
trimdown
-
-
=
D
V
V
C
R
nom
adj
trimup
-
-
=
Vnom A B C D
Notes
0.9 2.5
N/A
N/A
3.712
1.54
Vo=0.9V when Rtrim is open
2.5
7.9117
16.14 3.712
11.5
Vo=2.505V when Rtrim is open
1.8
4.6538
20.84 3.712
16.2
Vo=1.803V when Rtrim is open
1.5
3.2633
16.14 3.712
11.5
Vo=1.503V when Rtrim is open
1.2
1.8699
11.45 3.712
6.81
Vo=1.203V when Rtrim is open
0.9
N/A
N/A
3.712
33.2
Vo=0.903V when Rtrim is open
Module
Vout
Trim
GND
Rtrimdown
Module
Vout
Trim
GND
Rtrimup
PDF 
ZIP