MIC2164-3YMM Micrel Inc, MIC2164-3YMM Datasheet - Page 21

• Manufacturer Part Number: MIC2164-3YMM
• Description: IC PWM BUCK CNTLLR 10MSOP
• Manufacturer: Micrel Inc
• Series: Hyper Speed Control™r
• Type: Step-Down (Buck)r

Specifications of MIC2164-3YMM

• Internal Switch(s): No
• Synchronous Rectifier: Yes
• Number Of Outputs: 1
• Voltage - Output: 0.8 ~ 5.5 V
• Frequency - Switching: 1MHz
• 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
• Voltage - Supply: 3 V ~ 28 V
• Frequency-max: 1.25MHz
• Duty Cycle: 66%
• Pwm Type: Controller
• Buck: Yes
• Boost: No
• Flyback: No
• Inverting: No
• Doubler: No
• Divider: No
• Cuk: No
• Isolated: No
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 576-3544-5

Micrel, Inc.
Setting Output Voltage
The MIC2164/-2/-3 requires two resistors to set the
output voltage, as shown in Figure 6:
The output voltage is determined by the equation:
where V
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. Once R1 is selected, R2 can be
calculated using:
September 2010
REF
Figure 6. Voltage-Divider Configuration
= 0.8V. A typical value of R1 can be between
R2
V
OUT
=
V
=
OUT
V
V
REF
REF
−
×
V
×
R1
REF
(1
+
R2
R1
)
(34)
(33)
21
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 MIC2164/-2/-3, as
shown in Figure 7. The inverting input voltage V
clamped to 1.2V. As V
will be clamped. The clamped V
regulation because it is reflected back as a DC error on
the FB terminal. Therefore, the maximum output voltage
of the MIC2164/-2/-3 should be limited to 5.5V to avoid
this problem. If a higher output voltage is required, use
the MIC2176 instead.
Figure 7. Internal Ripple Injection
OUT
is increased, the swing of V
INJ
MIC2164/-2/-3/C
reduces the line
M9999-091310-D
INJ
INJ
is