SPI-8001TW-TL ALLEGRO [Allegro MicroSystems], SPI-8001TW-TL Datasheet - Page 6

• Manufacturer Part Number: SPI-8001TW-TL
• Description: Dual 1.5 A, DC/DC Step-Down Converter
• Manufacturer: ALLEGRO [Allegro MicroSystems]

Input Capacitors (C1 and C6). Capacitors with low
impedance for high-frequency ripple current must be used.
Output Capacitors (C2, C3, C7, and C8). Capacitors
with low impedance for high-frequency ripple current must
be used. Especially when the C2 and C3 impedance is
high, the switching waveform may not be normal at low
temperatures. Film or tantalum capacitors for C2 and C3
may cause abnormal oscillations.
Catch Diodes (D1 and D2). Diode D1 and D2 must be
Schottky diodes. Other diode types will result in increased
forward voltage spikes, reverse current flow, increased IC
power dissipation during the off period, and possible
destruction of the IC.
Choke Coils (L1 and L2). If the winding resistance of
the choke coil is too high, the circuit efficiency will de-
crease. As the overcurrent protection start current is
approximately 2 A, attention must be paid to the heating of
the coil by magnetic saturation due to overload. To reduce
the output ripple, the inductor may be increased at the
expense of excessive board area and cost.
6
SPI-8001TW
Dual 1.5 A, DC/DC
Step-Down Converter
APPLICATIONS INFORMATION
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036
Output Voltage Adjustable Resistors (R1, R2, R3,
and R4). The output voltages are adjusted by R1 and R3.
1000
Soft-Start Capcitors (C4 and C5). Soft start for each
converter channel is enabled by connecting a capacitor
between terminal 6 and/or 11 and ground. The channel
may be turned off by decreasing the terminal 6 and/or 11
voltage below 0.5 V with either an npn small-signal transis-
tor or the output of open-collector TTL. If both a large
soft-start capacitor and on/off control are desired, collector
current limiting (R5 and R6) must be used to prevent
transistor damage. No external voltage can be applied to
terminal 6 or 11.
for R2 and R4 is recommended.
R1 = (V
R3 = (V
C1
C2, C3
C4, C5
C6, C7, C8
R5, R6
L1, L2
D1, D2
O1
O2
Typical Application
– V
– V
ref
ref
)/(V
)/(V
ref
ref
220 µF/63 V
470 µF/25 V
1 µF
0.1 µF
1 k
47 µH
Sanken SFPB-66
/R2)
/R4)