SLIN-03E1A0 BEL [Bel Fuse Inc.], SLIN-03E1A0 Datasheet - Page 18

• Manufacturer Part Number: SLIN-03E1A0
• Description: NON-ISOLATED DC/DC CONVERTERS 4.5 Vdc - 14 Vdc Input, 0.59 Vdc - 5.5 Vdc /3 A Outputs
• Manufacturer: BEL [Bel Fuse Inc.]

Output Voltage Sequencing (continued)
After applying input voltage to the module, a minimum 10msec delay is required before applying voltage on the
SEQ pin. During this time, a voltage of 50mV (± 20 mV) is maintained on the SEQ pin. This delay gives the
module enough time to complete its internal power-up soft-start cycle. During the delay time, the SEQ pin
should be held close to ground (nominally 50mV ± 20 mV). This is required to keep the internal op-amp out of
saturation thus preventing output overshoot during the start of the sequencing ramp. By selecting resistor R1
according to the following equation:
The voltage at the sequencing pin will be 50mV when the sequencing signal is at zero.
After the 10msec delay, an analog voltage is applied to the SEQ pin and the output voltage of the module will
track this voltage on a one-to-one volt bases until the output reaches the set-point voltage.
simultaneous shutdown of the modules, the SEQ pin voltage is lowered in a controlled manner. The output
voltage of the modules tracks the voltages below their set-point voltages on a one-to-one basis. A valid input
voltage must be maintained until the tracking and output voltages reach ground potential.
When using the sequencing feature to control start-up of the module, pre-bias immunity during start-up is
disabled. The pre-bias immunity feature of the module relies on the module being in the diode-mode during
start-up. When using the sequencing feature, modules goes through an internal set-up time of 10msec, and will
be in synchronous rectification mode when the voltage at the SEQ pin is applied. This will result in the module
sinking current if a pre-bias voltage is present at the output of the module. When pre-bias immunity during start-
up is required, the sequencing feature must be disabled.
feature please contact the Bel Power technical representative for additional information.
October 8, 2009
NON-ISOLATED DC/DC CONVERTERS
4.5 Vdc - 14 Vdc Input, 0.59 Vdc - 5.5 Vdc /3 A Outputs
Bel Fuse Inc. 206 Van Vorst Street, Jersey City, NJ 07302 • Tel [phone] • Fax [phone] •
Circuit showing connection of the sequencing signal to the SEQ pin
VIN+
GND
R1
SEQ
R
1
Bel Power, Inc. , a subsidiary of Bel Fuse, Inc.
=
499K
V
IN
24950
10K
−
MODULE
. 0
For additional guidelines on using the sequencing
05
+
-
OUT
ohms
www.belfuse.com
To initiate
18