PM6680 STMicroelectronics, PM6680 Datasheet - Page 34

• Manufacturer Part Number: PM6680
• Description: IC CTRLR DUAL STEP DOWN 32VFQFPN
• Manufacturer: STMicroelectronics

Specifications of PM6680

• Applications: Controller, Notebook Power System
• Voltage - Input: 6 ~ 28 V
• Number Of Outputs: 2
• Voltage - Output: 0.9 ~ 5.5 V
• Operating Temperature: 0°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 32-VFQFN, 32-VFQFPN
• Output Voltage: 5 V, 0.9 V to 5.5 V, 0.9 V to 3.3 V
• Output Current: 0.33 A
• Input Voltage: 5.5 V to 28 V
• Mounting Style: SMD/SMT
• Maximum Operating Temperature: + 125 C
• Minimum Operating Temperature: - 10 C
• For Use With: 497-6379 - BOARD EVALUATION FOR PM6680A497-6378 - BOARD EVALUATION FOR PM6680497-6425 - BOARD EVAL BASED ON PM6680A
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Device description
Table 11.
7.13.4
34/49
Manufacturer
PANASONIC
SANYO
Output capacitor manufacturer
Input capacitors selection
In a buck topology converter the current that flows into the input capacitor is a pulsed current
with zero average value. The input RMS current of the two switching sections can be roughly
estimated as follows:
Equation 17
Where D
sections.
Input capacitor should be chosen with an RMS rated current higher than the maximum RMS
current given by both sections.
Tantalum capacitors are good in term of low ESR and small size, but they occasionally can
burn out if subjected to very high current during the charge. Ceramic capacitors have
usually a higher RMS current rating with smaller size and they remain the best choice.
Below there is a list of some ceramic capacitor manufacturers.
Table 12.
TAYIO YUDEN
TAYIO YUDEN
Manufacturer
POSCAP TPB,TPD, TPE
1
TDK
SPCAP UD, UE
, D
2
Input capacitor manufacturer
Series
are the duty cycles and I1, I2 are the maximum load currents of the two
I
CinRMS
UMK325BJ106KM-T
C3225X5R1E106M
GMK325BJ106MN
=
Series
Capacitor value (uF)
D
1
100 to 470
100 to 470
×
I
2
1
×
1 (
−
D
1
Capacitor value (uF)
)
+
D
2
×
Rated voltage (V)
I
2
2
10
10
10
×
2.5 to 6.3
1 (
2 to 6.3
−
D
2
)
Rated voltage (V)
ESR max (mΩ)
12 to 65
7 to 18
50
35
25
PM6680