SP6680 Datasheet, PDF (8/12 Pages) Sipex Corporation – High Efficiency Buck/Boost Charge Pump Regulator

MANUFACTURER / TELEPHONE #
PART NUMBER
CAPACITANCE / MAX ESR CAPACITOR
VOLTAGE
@ 100kHz SIZE / TYPE
TDK / 847-803-6100
C2012X5R1A225K
2.2µF / 10V
0.030Ω
0805 / X5R
TDK / 847-803-6100
C3216X5R1C475K
4.7µF / 10V
0.020Ω
1206 / X5R
AVX / 843-448-9411
1206ZC225K
2.2µF / 10V
0.030Ω
1206 / X7R
Taiyo Yuden / 847-925-0888
LMK212BJ225MG
2.2µF / 10V
0.030Ω
0805 / X5R
Taiyo Yuden / 847-925-0888
LMK316BJ475ML
Figure 2. Suggested Low ESR Cermic Surface Mount Capacitors.
4.7µF / 10V
0.020Ω
1206 / X7R
Board Layout
PC board layout is an important design consideration to mitigate switching current effects. High
frequency operation makes PC layout important for minimizing ground bounc and noise. Components
should be place as close to the IC as possible with connections made through short, low impedance
traces. To maximize output ripple voltage, use a ground plane and solder the IC's GND pin directly to
the ground plane.
Output Resistance with Various Output and Pump Capacitors
From Tables 3 & 4 it can be seen that increasing output capacitance alone reduces the output resistance
more than increasing pump capacitance. This offers the advantage of increasing one capacitor versus
two capacitors in the case for the pump capacitance.
Table 3. Output Resistance vs Output Capacitance
All Ceramic Capacitors ESR < 0.05ohm
Cin, CF1, CF2 = 2.2uF, Vin = 3.85V, Iout = 5mA, CLK = 32kHz
Cout (uF)
SP6680 Rout (ohms)
0.47
57
1
28
2.2
18
4.7
13
10
11
22
10
Table 4. Output Resistance vs Pump Capacitance
All Ceramic Capacitors ESR < 0.05ohm
Cin, Cout = 2.2uF, Vin = 3.85V, Iout = 5mA, CLK = 32kHz
CF1, CF2 (uF)
SP6680 Rout (ohms)
0.47
39
1
24
2.2
18
4.7
15
10
14
22
13
Date: 5/25/04
SP6680 High Efficiency Buck/Boost Charge Pump Regulator
8
© Copyright 2004 Sipex Corporation