PM6680 STMicroelectronics, PM6680 Datasheet - Page 28
![IC CTRLR DUAL STEP DOWN 32VFQFPN](/photos/7/42/74252/497-32-vfqfpn_series_sml.jpg)
PM6680
Manufacturer Part Number
PM6680
Description
IC CTRLR DUAL STEP DOWN 32VFQFPN
Manufacturer
STMicroelectronics
Datasheet
1.PM6680TR.pdf
(49 pages)
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
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
PM6680
Manufacturer:
STMicroelectronics
Quantity:
135
Company:
Part Number:
PM6680
Manufacturer:
INFIONEON
Quantity:
1
Company:
Part Number:
PM6680ATR
Manufacturer:
STMicroelectronics
Quantity:
10 000
Company:
Part Number:
PM6680TR
Manufacturer:
st
Quantity:
1 050
Device description
7.7
28/49
Where RSNS is the sensing element (R
PM6680 provides also a fixed negative peak current limit to prevent an excessive reverse
inductor current when the switching section sinks current from the load in PWM mode. This
negative current limit threshold is measured between PHASE and SGND pins, comparing
the magnitude drop on the PHASE node during the conduction time of the low side
MOSFET with an internal fixed voltage of 120 mV.
If the current is sensed on the low side MOSFET, the negative valley-current limit I
device works in PWM mode) is given by:
Equation 9
Soft start and soft end
Each switching section is enabled separately by asserting high EN1/EN2 pins respectively.
In order to realize the soft start, at the startup the overcurrent threshold is set 25 % of the
nominal value and the undervoltage protection (see related sections) is disabled. The
controller starts charging the output capacitor working in current limit. The overcurrent
threshold is increased from 25 % to 100 % of the nominal value with steps of 25 % every
700 µs (typ.). After 2.8 ms (typ.) the undervoltage protection is enabled. The soft start time is
not programmable. A minimum capacitor CINT is required to ensure a soft start without any
overshoot on the output:
Equation 10
Figure 35. Soft start waveforms
Switching output
Current limit threshold
EN1/EN2
C
INT
≥
I
NEG
DSon
I
Lvalley
4
=
6
)
120
uA
R
+
DSon
∆
mV
2
I
L
×
C
out
Time
NEG
PM6680
(if the