SP6121CN-L Datasheet, PDF (36/42 Pages) Sipex Corporation – Low Voltage, Synchronous Step Down PWM Controller

respectively), and the current set resistor (R₂), are discussed in detail in the SP6121
data sheet.
USING THE DEMO BOARD
To use the Demo Board, connect the input voltage, V_IN to pins 7 and 8 and a ground,
GND, to pins 5 and 6. Connect the load to pins 1, 2, 3, and 4. Pin 9 provides a logic
level “power good” signal and Pin 10 is used for trimming the output voltage.
When measuring efficiency, care must be taken to keep leads between measuring
devices, the power supply (V_IN) and the demo board as short as possible and the
measurement probes should be connected to pins 4 (V_OUT) and 7 (V_IN).
The SP708 power management controller IC (U₂) on the demo board is used to
generate a Power Good signal. On this demo board, when the voltage on the pin 6 (PFI)
of U2 is 1.25V or less, U2’s pin 7 (PFO) goes LOW. Pin 6 can be connected directly, or
through a resistor divider, to V_OUT or V_IN.
DEMO BOARD CHARACTERISTICS
96
94
92
90
88
86
84
82
80
78
0
1
2
3
4
5
6
I load (A)
FIGURE 4. EFFICIENCY vs. I load. Vout=2,5V
0.02
0
-0.02 ³
4
5
6
-0.04
-0.06
-0.08
-0.1
-0.12
-0.14
Vin (V)
C6=47uF, 3.3/2.5V
C6=47uF,5.0/1.9V
C6=330uF,3.3/2.5V
C6=330uF,5.0/1.9V
7
8
9
10
I load=5.0A
I load=3.0A
FIGURE 5. Line Regulation. Vout=2.5V
Rev 7/25/01
4