MIC2174-1YMM Micrel Inc, MIC2174-1YMM Datasheet - Page 20

• Manufacturer Part Number: MIC2174-1YMM
• Description: IC BUCK SYNC ADJ 25A 10MSOP
• Manufacturer: Micrel Inc
• Series: Hyper Speed Control™r
• Type: Step-Down (Buck)r

Specifications of MIC2174-1YMM

• Internal Switch(s): No
• Synchronous Rectifier: Yes
• Number Of Outputs: 1
• Voltage - Output: 0.8 ~ 5.5 V
• Frequency - Switching: 300kHz
• Voltage - Input: 3 ~ 5.5 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 10-MSOP, Micro10™, 10-uMAX, 10-uSOP
• Power - Output: 421mW
• Primary Input Voltage: 40V
• No. Of Outputs: 2
• Output Current: 25A
• Voltage Regulator Case Style: MSOP
• No. Of Pins: 10
• Operating Temperature Range: -40°C To +125°C
• Svhc: No SVHC (15-Dec-2010)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Current - Output: -
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant
• Other names: 576-3546-5

Micrel, Inc.
Step 3. Select C
as short for a wide range of the frequencies.
Setting Output Voltage
The MIC2174/MIC2174C requires two resistors to set
the output voltage as shown in Figure 8.
The output voltage is determined by the equation:
where, V
between 3kΩ and 10kΩ. If R1 is too large, it may allow
noise to be introduced into the voltage feedback loop. If
R1 is too small, it will decrease the efficiency of the
power supply, especially at light loads.
September 2010
Figure 8. Voltage-Divider Configuration
REF
V
OUT
= 0.8V. A typical value of R1 can be
inj
=
as 100nF, which could be considered
V
REF
×
(1
+
R2
R1
)
(41)
20
Once R1 is selected, R2 can be calculated using:
In addition to the external ripple injection added at the
FB pin, internal ripple injection is added at the inverting
input of the comparator inside the MIC2174, as shown in
Figure 9. The inverting input voltage V
1.2V. For applications with high V
swing of V
the line regulation because it is reflected back as a DC
error on the FB terminal. Therefore, the maximum output
voltage of MIC2174 should be limited to 5.5V for up to
28V V
output voltage is required, use the MIC2176 instead.
HSD
and 3.6V for V
INJ
Figure 9. Internal Ripple Injection
R2
will be clamped. The clamped V
=
V
V
OUT
REF
−
HSD
×
V
R1
REF
higher than 28V. If a higher
HSD
MIC2174/MIC2174C
and high V
INJ
M9999-091310-C
is clamped to
INJ
reduces
OUT
, the
(42)