Micrel MIC2169A Quick Start Manual

General Description

The MIC2169A is a high-efficiency, simple to use 500kHz
PWM synchronous buck control IC housed in a small
MSOP-10 package. The MIC2169A allows compact DC-to-
DC solutions with a minimal external component count and
cost. The output voltage can be precisely regulated down
to 0.8V. The adaptive all N-Channel MOSFET drive
scheme allows efficiencies over 95% across a wide load
range.
Note: This evaluation board is for 3A applications. A 7A
output evaluation board is also available. The literature for
the 7A evaluation can be found in the MIC2169A data
sheet.
Data sheets and support documentation can be found on
Micrel's web site at: www.micrel.com.

Requirements

The MIC2169A evaluation board requires an input power
source that is able to deliver greater than 3A at 12V.

Precautions

The evaluation board does not have reverse polarity
protection. Applying a negative voltage to the V
terminal may damage the device.
The MIC2169A evaluation board is tailored for a 5V to 12V
input voltage range. The input voltage range should not
exceed 14.5V on the input.

Getting Started

1. Connect an external supply to the VIN. Apply
desired input voltage to the V
(J2) terminals of the evaluation board, paying
careful attention to polarity and supply voltage
(5V≤V ≤12V). An ammeter may be placed
IN
between the input supply and the V
the evaluation board. Ensure that the supply
voltage is monitored at the V
ammeter and/or power lead resistance can reduce
the voltage supplied to the input.
2. Enabling the MIC2169A. The MIC2169A is
enabled as soon as a power supply with a voltage
in the range of 3V to 14.5V is connected across
the V (J1) and GND (J2) terminals.
IN
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (
May 2007

Adjusting Output Voltage

The output voltage on the MIC2169A evaluation board is
adjustable. The output voltage is controlled by the
feedback resistors (R1 and R2) and can be calculated as
follows:
The evaluation board is initially adjusted to 1.5V, but can
easily be modified by removing R3 and replacing it with the
value that yields the desired output voltage. The R2
resistor is recommended for a 3kΩ to 10kΩ resistor range.
Ensure the output voltage selected does not exceed 5V,
since the tantalum output capacitor has a 6.3V voltage
rating.
capacitors should never exceed 80% of their rated voltage
value. When output voltages greater than 5V are desired,
the output capacitor should be replaced with one where
the output voltage is less than 80% of the output capacitor
(J1)
IN
voltage rating (tantalum capacitors).

Ordering Information

(J1) and ground
IN
terminal to
IN
terminal. The
IN
1
MIC2169A Evaluation Board
500kHz MSOP-10 Synchronous
Step-Down Controller
⎛
R
=
⎜
0 8 .
V V
OUT
⎝
R
⎛
⎜
= Ω
3 10
R k
⎜
⎝ V
OUT
Typically the
Part Number
MIC2169AYMM
MIC2169A Tiny3A EV
408
) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
⎞
2
+
⎟
1
3 ⎠
⎞
0 8 .
V
⎟
⎟
−
0 8 .
V ⎠
working voltage for
Description Package
IC 10-Pin MSOP
Evaluation Board 10-Pin MSOP
M9999-053107-A
tantalum