SI9137LG-T1-E3 Vishay, SI9137LG-T1-E3 Datasheet - Page 12

• Manufacturer Part Number: SI9137LG-T1-E3
• Description: IC,SMPS CONTROLLER,CURRENT-MODE,BICMOS,SSOP,28PIN,PLASTIC
• Manufacturer: Vishay

Specifications of SI9137LG-T1-E3

• Duty Cycle (max): 95 %
• Output Voltage: 3.3 V, 5 V, 5 V to ADJ V
• Output Current: 1000 mA
• Mounting Style: SMD/SMT
• Package / Case: SSOP-28
• Switching Frequency: 330 KHz
• Maximum Operating Temperature: + 90 C
• Minimum Operating Temperature: 0 C
• Synchronous Pin: No
• Topology: Boost, Buck, Flyback
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

Si9137
Vishay Siliconix
DESCRIPTION OF OPERATION
Shutdown Mode
The logic threshold for the RUN/STOP pin is 1.6 V.
voltage must be 0.8 V or less for logic low and 2.4 V or higher
for logic high.
Start-up Sequence
Start-up is controlled by RUN/STOP in conjunction with SEQ.
If SEQ is tied to GND, the 5-V SMPS output will come up first,
followed by the 3.3-V output and then the adjustable 5- to 12-V
output. If SEQ is tied to V
come up first, followed by the 5-V and then the adjustable 5- to
12-V output.
When the first SMPS output voltage is within tolerance, the
second SMPS will begin its soft-start cycle. When the second
SMPS output is within tolerance, the third SMPS will start its
soft-start cycle. When both the 3.3-V and 5-V SMPS outputs
are within tolerance and 32,000 clock cycles (typically equal to
107 ns) have elapsed since the second SMPS output went into
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DETAILED FUNCTIONAL BLOCK DIAGRAMS
RUN/STOP
SEQ
V
V
IN
L
Reference
Regulator
Linear
3.3-V
L
5-V
, then the 3.3-V SMPS output will
2.4 V
4 V
FIGURE 7. Complete Si9137 Block Diagram
Input
regulation, the RESET pin will be pulled high, signifying that all
converters are operating correctly ( see RESET Power Good
Voltage Monitor).
The Si9137 converts a 5.5-V to 30-V input voltage to five
different output voltages; two buck (step-down) high current,
PWM, switch-mode supplies of 3.3 V and 5 V, one “flyback”
PWM switch-mode supply adjustable from 5 V to 12 V, one
precision 3.3-V reference and one 5-V between low drop out
(LDO) linear regulator output. Switch-mode supply output
current capabilities depend on external components (can be
selected to exceed 10 A). In the standard application circuit
illustrated in Figure 1, each buck converter is capable of
delivering 5 A, with the flyback converter delivering 250 mA.
The recommended load current for the precision 3.3-V
reference output is less than 1 mA, and for the 5-V LDO output
is less than 30 mA. In order to maximize power efficiency of the
converter, when the 5-V buck converter output (FB5) voltage is
above 4.5-V, the internal 5-V LDO is turned off and V
supplied by the 5-V converter output.
Control
Logic
4.5 V
Adjustable
Controller
Controller
5- to 12-V
Controller
Flyback
3.3-V
Buck
Buck
5-V
S-40808—Rev. C, 26-Apr-04
Document Number: 70874
FB
CS
BST
DH
LX
DL
FB
CS
BST
DH
LX
DL
FBFY
CSP
CSN
BSTFY
DHFY
LXFY
DLFY
RESET
5
3
5
5
3
3
5
3
5
3
5
3
L
is