SC600
POWER MANAGEMENT
Applications Information (Cont.)
Table 2 -Ripple Performance (Cont.)
Part No.
Freq. [kHz] IOUT [mA] Output Ripple [mVp-p] Ouput Ripple [mVp-p] COUT [μF]
CBUCKET [μF]
1.5x mode
215
300
40
2x mode
50
SC600B(1) 4.5V
8
10
40
1
1
1
1
1
1
1
1
1
1
1
1
32
90
262
650
650
8
120
120
120
10
25
1
15
25
1
30
45
0.33
1
SC600D 4.0V
105
240
30
50
32
40
45
1
262
650
650
120
120
120
20
1
11
20
1
25
40
0.33
Note: (1) SC600C is very similar to SC600B.
Mode Transition Impedance
A lower value of Ro will improve efficiency, so low ESR
ceramic capacitors are required. An X7R or X5R dielec-
tric is recommended. Y5V dielectric can require 2 to 3
times the rated value of an X7R dielectric for the same
performance over the operating temperature range.
The mode transition impedance Ro refers to the output
resistance of the charge pump before a transition to a
stronger mode occurs. Ro is dependent upon the frac-
tional charge pump, switching frequency, bucket capaci-
tor value, bucket capacitor ESR, and the internal switch
resistances.
Efficiency
1
f C
Ro is proportional to,
Efficiency for the SC600 is defined as,
V
I
O
O
Ro can be measured to verify a low transition imped-
ance. Before measuring Ro, select the capacitors, set
the operating frequency and a constant load current. Find
the input voltage just before a weak to strong mode tran-
sition (i.e., 1.5x to 2x mode). Measure VIN, VOUT, and IOUT
before the transition.
η =
ꢁ
V
mode I
I
Q
ꢂ
ꢃ
IN
O
Ro will be,
ꢀ
mode VIN VOUT
Ro=
I OUT
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