LM2650EVAL/NOPB National Semiconductor, LM2650EVAL/NOPB Datasheet - Page 2

• Manufacturer Part Number: LM2650EVAL/NOPB
• Description: EVALUATION BOARD FOR LM2650X
• Manufacturer: National Semiconductor

Specifications of LM2650EVAL/NOPB

• Main Purpose: DC/DC, Step Down
• Outputs And Type: 1, Non-Isolated
• Voltage - Output: 1.5 ~ 16V
• Current - Output: 3A
• Voltage - Input: 4.5 ~ 18V
• Regulator Topology: Buck
• Board Type: Fully Populated
• Utilized Ic / Part: LM2650
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Power - Output: -
• Frequency - Switching: -
• Other names: *LM2650EVAL; *LM2650EVAL/NOPB; LM2650EVAL

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COUT1, COUT2, and COUT3
Input Filter Capacitors C1, C2,
and C6
Bootstrap Capacitor CB
Soft-start Capacitor CSS
VDD Bypass Capacitor CVDD
Input Bulk Capacitors CIN1
and CIN2
Inductor L1
Output Capacitors COUT1,
COUT2, and COUT3
Feedback Resistors R1 and
R2
Compensation Components
RC, CC, R3, and C10
Applicable Cell Stacks
C1, C2, C3, and C4
RSOA and RSOC
RSIA and RSIC
CIN1 and CIN2
Input Voltage
CVDD
Label
Output
CSS
RFA
C10
CB
CC
RC
U1
C5
C6
C9
R1
R2
R3
R4
L1
TABLE 2. Components for Two Typical 90 kHz Application Circuits
0.1 µF ceramic chip capacitor
0.1 µF ceramic chip capacitor
0.01 µF ceramic chip capacitor
0.2 µF ceramic chip capacitor
22 µF, 35V AVX TPS Series or Sprague 593D
Series tantalum chip capacitor
40 µH (See Table 3.)
220 µF, 10V AVX TPS Series or Sprague 593D
Series tantalum chip capacitor
R1 = 75 kΩ, 1%, R2 = 24.9 kΩ, 1%
RC = 37.4 kΩ, CC = 4.7 nF, R3= 3.57 kΩ,C10
= 5.6 nF
TABLE 1. A Complete List of Pads for Placing Components
#
1
4
0
1
1
1
1
1
2
3
1
1
1
1
1
1
1
1
1
2
2
8- to 12-Cell NiCd or NiMH, 3- to 4-Cell Li Ion, 8- to 11-Cell Alkaline, 6-Cell Lead Acid
For placing the LM2650.
Capacitors placed here filter high-frequency switching noise from the input power rail.
These pads should not be labeled with a C. No component is placed here. They can be
used to ground the SLEEP LOGIC input. The pad connected to the SLEEP LOGIC pin
can be used to pull the input up.
A capacitor placed here also filters high-frequency switching noise from the input power
rail but at the VIN rail, the rail used by the signal-level circuits inside the IC.
Usually no component is placed here. A capacitor might be placed here for loop
compensation purposes, but most applications don’t use it.
A capacitor is placed here for loop compensation purposes.
The bootstrap capacitor is placed here.
A capacitor is placed here for loop compensation purposes. This capacitor and an internal
6.5 kΩ resistor create an integrator pole.
The bulk input capacitors are placed here.
The output filter capacitors are placed here.
A capacitor placed here programs the soft-start interval.
A capacitor placed here bypasses the output of the VDD regulator.
The inductor is placed here.
One of the feedback resistors is placed here.
The other feedback resistor is placed here.
A resistor is placed here for loop compensation purposes.
These pads can be used to ground the SYNC input when the synchronization feature is
not being used. The pad connected to the SYNC input can be used to connect the
synchronization signal. The evaluation board has a 0Ω jumper placed here to ground the
SYNC input.
A resistor is also placed here for loop compensation purposes. This resistor and the
capacitor placed at CC create an integrator zero.
A resistor placed here adjusts the switching frequency up from the nominal 90 kHz. No
component is placed here for applications switching at 90 kHz.
Resistors placed here program the sleep-in threshold.
Resistors placed here program the sleep-out threshold.
5V, 3A Out
2
7 to 18V IN
Notes
0.1 µF ceramic chip capacitor
0.1 µF ceramic chip capacitor
0.01 µF ceramic chip capacitor
0.2 µF ceramic chip capacitor
22 µF, 35V AVX TPS Series or Sprague 593D
Series tantalum chip capacitor
33 µH (See Table 3.)
220 µF, 10V AVX TPS Series or Sprague 593D
Series tantalum chip capacitor
R1 = 41.2 kΩ, 1%, R2 = 24.9 kΩ, 1%
RC = 23.2 kΩ, CC= 8.2 nF, R3 = 2.0 kΩ, C10
= 10 nF
3.3V, 3A Out