IR3831WMTR1PBF International Rectifier, IR3831WMTR1PBF Datasheet - Page 16

• Manufacturer Part Number: IR3831WMTR1PBF
• Description: IC REG SYNC BUCK 8A 15-QFN
• Manufacturer: International Rectifier
• Series: SupIRBuck™r

Specifications of IR3831WMTR1PBF

• Applications: Converter, DDR
• Voltage - Input: 1.5 ~ 16 V
• Number Of Outputs: 1
• Voltage - Output: 0.6 ~ 14.4 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 15-PowerVQFN
• Part Status: Preferred
• Package: PQFN / 5 x 6
• Circuit: Single Output
• Iout (a): 8
• Switch Freq (khz): 250 - 1500
• Input Range (v): 1.5 - 16
• Output Range (v): 0.7 - 0.9*Vin
• Ocp Otp Uvlo Pre-bias Soft Start And: PGOOD + EN + OVD + DDR Tracking
• Server Storage: Yes
• Routers Switches: Yes
• Base Station Telecom: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: IR3831WMTR1PBFTR

Minimum on time Considerations
The minimum ON time is the shortest amount of
time for which the Control FET may be reliably
turned on, and this depends on the internal
timing delays. For the IR3831W, the typical
minimum on-time is specified as 50 ns.
Any design or application using the IR3831W
must ensure operation with a pulse width that is
higher than this minimum on-time and preferably
higher than 100 ns. This is necessary for the
circuit to operate without jitter and pulse-
skipping, which can cause high inductor current
ripple and high output voltage ripple.
In any application that uses the IR3831W, the
following condition must be satisfied:
The minimum output voltage for the IR3831W is
limited to V
Furthermore, for the IR3831W, especially for
active bus termination applications, it is strongly
recommended to use a switching frequency of
400 kHz to obtain clean and jitter free operation
in sourcing as well as sinking modes. Therefore,
the maximum input voltage that may be stepped
down to 0.6V at 400 kHz without jitter or pulse
skipping is 15 V.
Rev 14.0
∴
∴
V
∴
∴
in
t
V
out(min)
on
V
t
in
×
on
t
(min)
in
on
F
×
(min)
×
s
F
=
=
F
s
= 0.6 V.
≤
≤
V
s
F
≤
D
≤
in
V
t
s
V
≤
on
t
V
out
100
on
out
×
0.6
t
in
V
on
(min)
V
(min)
F
out
×
out
(min)
s
ns
V
F
s
=
6
×
10
6
V/s
Maximum Duty Ratio Considerations
A fixed off-time of 200 ns maximum is specified
for the IR3831W. This provides an upper limit on
the operating duty ratio at any given switching
frequency. It is clear, that higher the switching
frequency, the lower is the maximum duty ratio at
which the IR3831W can operate. To allow a
margin of 50ns, the maximum operating duty
ratio in any application using the IR3831W
should still accommodate about 250 ns off-time.
Fig 9. shows a plot of the maximum duty ratio v/s
the switching frequency, with 250 ns off-time.
Fig. 9. Maximum duty cycle v/s switching
95
90
85
80
75
70
65
60
55
250
frequency.
450
650
S w itching Frequency (kH z )
IR3831WMPbF
M a x Duty Cycle
850
1050
1250
1450
16
1650