MIC94310 Evaluation Board
200mA LDO with
Ripple Blocker™ Technology
Ripple Blocker is a trademark of Micrel, Inc
MLF and MicroLeadFrame are registered trademarks of Amkor Technology, Inc.
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 ( 408) 474-1000 • http://www.micrel.com
February 2012 M9999-020912
(408) 944-0800
General Description
The MIC94310 is a 200mA Low Dropout (LDO)
regulator that provides high power supply ripple
rejection (PSRR). This is important for applications
where switching noise cannot be tolerated by sensitive
downstream circuits such as in RF applications. The
MIC94310 maintains high power supply ripple rejection
(PSRR) with input voltage operating near the output
voltage level to improve overall system efficiency.
The MIC94310 operates from an input voltage of 1.8V to
3.6V.
Datasheets and support documentation can be found on
Micrel’s web site at www.micrel.com.
Requirements
The MIC94310 evaluation board requires an input power
supply that is capable of delivering greater than 400mA
at a voltage range of 1.8V to 3.6V. The output load can
be either active or passive.
Precautions
The MIC94310 evaluation board does not have reverse
polarity protection. Applying a negative voltage to the
VIN terminal may damage the device.
Getting Started
• Connect an External Supply to VIN. Apply the
desired input voltage to the VIN and ground terminal
of the evaluation board, paying careful attention to
polarity and supply voltage (1.8V ≤ VIN ≤ 3.6V).
• Enable/Disable the MIC94310. The evaluation
board is supplied with 100kΩ pull-up resistor to VIN
for default on state. To disable the output, simply
jumper the EN terminal to ground.
• Connect the Load. Connect the load to the VOUT
terminal and the ground terminal. The load can be
either a passive (resistor) or active (electronic load).
Be sure to monitor the output voltage at the VOUT
terminal.
Ordering Information
Part Numbe
r
Description
MIC94310-GYCS EV
200mA LDO Ripple Blocker
™
CSP
Package Evaluation Board
VOUT=1.8V
MIC94310-GYMT EV
200mA LDO Ripple Blocker
™
Thin
MLF® Package Evaluation Board
VOUT=1.8V
Micrel, Inc. MIC94310 Evaluation Board
February 2012 2 M9999-020912
(408) 944-0800
Power Supply Ripple Rejection (PSRR)
Measurements
Figure 1 illustrates the frequency response of the
MIC94310.
PSRR C
OUT
= 1µF
-120
-100
-80
-60
-40
-20
0
1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 1.E+07
FREQUENCY ( Hz)
PSRR ( d B)
I
OUT
= 200mA
I
OUT
= 100mA
I
OUT
= 10mA
V
IN
= 2.5V + 40mVpp
V
OUT
= 1.8V
10 100 1K 10K 100K 1M 10M
Figure 1. MIC94310 Ripple Blocker™
Frequency Response
For high-frequency measurements (above 1MHz),
careful attention must be made to the test set-up
configuration as it is easy to introduce noise into the
grounds which will give inaccurate measurements as
shown in Figure 2.
Figure 2. High-Frequency Noise on
Measurement System
The inductance of test probes connected to the
evaluation board at higher frequencies becomes a
factor which can create a differential between the
device under test and test measurement system
grounds. Adding a low-value resistor (2Ω) in series
with the input capacitor to ground and utilizing a test
measurement system capable of making differential
measurements will help to reduce these effects.
PSRR measurements may be made using either
dedicated PSRR test equipment or with a PSRR
interface board and a network analyzer. The network
analyzer can sweep the AC frequency and perform a
comparison measurement of the amplitude on the
input and output. With this method, the network
analyzer is configured for an A/R measurement. The
difficulty arises when trying to impose the network
analyzer’s AC signal with the DC input voltage to the
MIC94310. The circuit shown in Figure 3
accomplishes this by using the MIC911 as a summing
amplifier. The summing amplifier adds the VSUPPLY
(DC voltage) and the network analyzers AC signal. As
the network analyzers source is 50Ω impedance it
may be neglected, the DC voltage seen at the non-
inverting side is half of the VSUPPLY voltage. The output
is gained up by 2 with the 1kΩ resistor divider to the
non-inverting side. This sums the AC and DC voltages
with an overall gain of 1.
Figure 3. Network Analyzer Set-Up
Micrel, Inc. MIC94310 Evaluation Board
February 2012 3 M9999-020912
(408) 944-0800
Evaluation Board Schematics
Bill of Materials
Item Part Number Manufacturer Description Qty.
C1, C2 CL10B105KA8NNNC Samsung(1) 1µF, 25V, X7R, Size 0603, ceramic capacitor 2
R1 CRCW0402100KFKEA Vishay(2) 100KΩ, 1%, 1/16W, Size 0402 resistor 1
R2 CRCW04022R00FKED Vishay(2) 2Ω, 1%, 1/16W, Size 0402 resistor 1
U1 MIC94310-xYCS Micrel, Inc.(3) 200mA LDO with Ripple Blocker™ technology 1
MIC94310-xYMT
Notes:
1. Samsung: http://www.semlcr.com.
2. Vishay: www.vishay.com.
3. Micrel, Inc:: www.micrel.com.
Micrel, Inc. MIC94310 Evaluation Board
February 2012 4 M9999-020912
(408) 944-0800
PCB Layout Recommendations (CS Package)
Top Layer
Bottom Layer
Micrel, Inc. MIC94310 Evaluation Board
February 2012 5 M9999-020912
(408) 944-0800
PCB Layout Recommendations (MT Package)
Top Layer
Bottom Layer
Micrel, Inc. MIC94310 Evaluation Board
February 2012 6 M9999-020912
(408) 944-0800
MICREL, INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131 USA
TEL +1 (408) 944-0800 FAX +1 (408) 474-1000 WEB www.micrel.com
Micrel makes no representations or warranties with respect to the accuracy or completeness of the information furnished in this data sheet. This
information is not intended as a warranty and Micrel does not assume responsibility for its use. Micrel reserves the right to change circuitry,
specifications and descriptions at any time without notice. No license, whether express, implied, arising by estoppel or otherwise, to any intellectual
property rights is granted by this document. Except as provided in Micrel’s terms and conditions of sale for such products, Micrel assumes no
liability whatsoever, and Micrel disclaims any express or implied warranty relating to the sale and/or use of Micrel products including liability or
warranties relating to fitness for a particular purpose, merchantability, or infringement of any patent, copyright or other intellectual property right.
Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a
product can reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for
surgical implant into the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significant injury
to the user. A Purchaser’s use or sale of Micrel Products for use in life support appliances, devices or systems is a Purchaser’s own risk and
Purchaser agrees to fully indemnify Micrel for any damages resulting from such use or sale.
© 2012 Micrel, Incor
p
orated.
