ILC7082 Datasheet, PDF (10/16 Pages) Impala Linear Corporation – 150MA SOT-23 ULTRA LOW NOISE CMOS RF-LDO REGULATOR

ILC7082
Table 2. Evaluation Board Parts List For Printed Circuit Board Shown in Figure 9
Label
Part Number
Manufacturer
Description
U1
ILC7082AIM5-30
Fairchild Semiconductor
150mA RF LDO™ regulator
J1
69190-405
Berg
Connector, four position header
Cin
GRM40 Y5V 105Z16
muRata
Ceramic capacitor, 1µF, 16V, SMT ( size 0805 )
Cnoise
ECU-V1H103KBV
Panasonic
Ceramic capacitor, 0.01µF, 16V, SMT ( size 0603 )
Cout
GRM42-6X7R105K016
muRata
Ceramic capacitor, 1µF, 16V, SMT ( size 1206)
Grounding Recommendations
1. Connect C_IN between V_IN of the ILC7082 and the “GROUND PLANE”.
2. Keep the ground side of C_OUT and C_NOISE connected to the “LOCAL GROUND” and not directly to the “GROUND
PLANE”.
3. On multilayer boards use component side copper for grounding around the ILC7082 and connect back to a “GROUND
PLANE” using vias.
4. If using a DC-DC converter in your design, use a star grounding system with separate traces for the power ground and the
control signals. The star should radiate from where the power supply enters the PCB.
Layout Considerations
1. Place all RF LDO related components; ILC7082, input capacitor C_IN, noise bypass capacitor C_NOISE and output capacitor
C_OUT as close together as possible.
2. Keep the output capacitor C_OUT as close to the ILC7082 as possible with very short traces to the V_OUT and GND pins.
3. The traces for the related components; ILC7082, input capacitor C_IN, noise bypass capacitor C_NOISE and output capacitor
C_OUT can be run with minimum trace widths close to the LDO.
4. Maintain a separate “LOCAL GROUND” remote from the “GROUND PLANE” to ensure a quiet ground near the LDO.
Figure 9 shows how this circuit can be translated into a PCB layout.
10
REV. 1.6.2 11/17/04