FAN5234QSCX_NL Fairchild Semiconductor, FAN5234QSCX_NL Datasheet - Page 12

• Manufacturer Part Number: FAN5234QSCX_NL
• Manufacturer: Fairchild Semiconductor

Specifications of FAN5234QSCX_NL

• Dc To Dc Converter Type: Synchronous Buck Controller/PWM DC to DC Controller
• Number Of Outputs: 1
• Pin Count: 16
• Input Voltage: 5 to 24V
• Output Voltage: 0.9 to 5.5V
• Package Type: QSOP
• Mounting: Surface Mount
• Operating Temperature Classification: Commercial
• Operating Temperature (min): -10C
• Operating Temperature (max): 85C
• Lead Free Status / Rohs Status: Compliant

PRODUCT SPECIFICATION
Table 2. BOM For 1.8V, 3.5A regulator (Figure 1)
Layout Considerations
Switching converters, even during normal operation,
produce short pulses of current which could cause substan-
tial ringing and be a source of EMI if layout constrains are
not observed.
There are two sets of critical components in a DC-DC
converter. The switching power components process large
amounts of energy at high rate and are noise generators.
The low power components responsible for bias and feed-
back functions are sensitive to noise.
A multi-layer printed circuit board is recommended.
Dedicate one solid layer for a ground plane. Dedicate
another solid layer as a power plane and break this plane
into smaller islands of common voltage levels.
Notice all the nodes that are subjected to high dV/dt voltage
swing such as SW, HDRV and LDRV, for example. All
surrounding circuitry will tend to couple the signals from
these nodes through stray capacitance. Do not oversize
copper traces connected to these nodes. Do not place traces
connected to the feedback components adjacent to these
traces. It is not recommended to use High Density
Interconnect Systems, or micro-vias on these signals.
The use of blind or buried vias should be limited to the low
current signals only. The use of normal thermal vias is left to
the discretion of the designer.
12
Description
Capacitor 68µF, Tantalum, 25V, ESR 95mΩ
Capacitor 10nF, Ceramic
Capacitor 68µF, Tantalum, 6V, ESR 1.8Ω
Capacitor 0.1µF, Ceramic
Capacitor 330µF, Tantalum, 6V, ESR 100mΩ
1.82KΩ, 1% Resistor
1.3KΩ, 1% Resistor
100KΩ, 5% Resistor
56.2KΩ, 1% Resistor
Schottky Diode; 0.5A, 20V
Inductor 8.4µH, 6A
Dual MOSFET with Schottky
PWM Controller
Qty
Keep the wiring traces from the IC to the MOSFET gate and
source as short as possible and capable of handling peak
currents of 2A. Minimize the area within the gate-source
path to reduce stray inductance and eliminate parasitic
ringing at the gate.
Locate small critical components like the soft-start capacitor
and current sense resistors as close as possible to the
respective pins of the IC.
The FAN5234 utilizes advanced packaging technologies
with lead pitches of 0.6mm. High performance analog
semiconductors utilizing narrow lead spacing may require
special considerations in PWB design and manufacturing.
It is critical to maintain proper cleanliness of the area
surrounding these devices. It is not recommended to use any
type of rosin or acid core solder, or the use of flux in either
the manufacturing or touch up process as these may
contribute to corrosion or enable electromigration and/or
eddy currents near the sensitive low current signals. When
chemicals such as these are used on or near the PWB, it is
suggested that the entire PWB be cleaned and dried
completely before applying power.
1
2
1
2
2
2
1
1
1
2
1
1
1
C2, C3
R1, R2
Ref.
C1
C4
C5
C6
R3
R4
R5
D1
Q1
U1
L1
Fairchild
Fairchild
Fairchild
Vendor
AVX
AVX
AVX
Any
Any
Any
Any
Any
TPSV686*025#095
TAJB686*006
TPSE337*006#0100
MBR0520L
FDS6986S
FAN5234
Part Number
REV. 1.0.10 5/3/04
FAN5234