Texas Instruments bq24740/1EVM, User Manual

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3 PCB Layout Guideline
4 Bill of Materials, Board Layout, and Schematics
4.1 Bill of Materials
PCB Layout Guideline
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1. It is critical that the exposed power pad on the backside of the bq24740/1 package be soldered to the
PCB ground. Ensure that sufficient thermal vias are right underneath the IC, connecting to the ground
plane on the other layers.
2. Route the control stage and the power stage separately. At each layer, the signal ground and the
power ground are connected only at the power pad.
3. AC current sense resistor must be connected to ACP and ACN with a Kelvin contact. Minimize the
area of this loop. Place the decoupling capacitors for these pins as close to the IC as possible.
4. Connect the charge current sense resistor to SRP, SRN with a Kelvin contact. Minimize the area of this
loop. Place the decoupling capacitors for these pins as close to the IC as possible.
5. Place the decoupling capacitors for PVCC, VREF, REGN underneath the IC (on the bottom layer), and
make the interconnections to the IC as short as possible.
6. Place the decoupling capacitors for BAT, IADAPT close to the corresponding IC pins, and make the
interconnections to the IC as short as possible.
7. Decoupling capacitor(s) for the charger input must be placed close to Q4 drain and Q5 source.
bq24740 bq24741 RefDes Value Description Size Part Number MFR
-001 -002
0 0 C1, C3, C11, Open Capacitor, Ceramic 0805 STD STD
C18
0 0 C12, C25 Open Capacitor, Ceramic 1206 STD STD
2 2 C13, C32 10uF Capacitor, Ceramic, 25V, 1206 STD STD
X5R, 10%
4 4 C14, C15, 10uF Capacitor, Ceramic, 25V, 1210 GRM32DR61E106K Murata
C28, C29 X5R, 10% A12L
1 1 C19 2.2uF Capacitor, Ceramic, 25V, 1210 STD STD
X5R, 10%
5 5 C2, C7, C10, 0.1uF Capacitor, Ceramic, 50V, 0805 STD STD
C16, C27 X7R, 10%
2 2 C22, C23 10nF Capacitor, Ceramic, 50V, 0603 STD STD
X7R, 10%
0 0 C24 Open Capacitor, Ceramic 1210 STD STD
0 0 C31 Open Capacitor, Ceramic 1210 STD STD
1 1 C4 1uF Capacitor, Ceramic, 25V, 0603 GRM188R61E105K muRata
X5R, 10% A12D
1 1 C5 100pF Capacitor, Ceramic, 50V, 0603 STD STD
C0G, 5%
3 3 C6, C8, C27 1uF Capacitor, Ceramic, 25V, 0805 GRM216R61E105K muRata
X5R, 10% A12D
8 8 C9, C17, 0.1uF Capacitor, Ceramic, 50V, 0603 STD STD
C20, C21, X7R, 10%
C26, C30,
C33, C34
1 1 D1 BAT54 Diode, Schottky, 200-mA, SOT23 BAT54 Vishay-Liteon
30-V
6 6 D2, D3, D4, 160-1183-1- Diode, LED, Green, 2.1-V, 0603 160-1183-1-ND Lite On
D5, D7, D8 ND 20-mA, 6-mcd
1 1 D6 160-1181-1- Diode, LED, Red, 1.8-V, 0603 160-1181-1-ND Lite On
ND 20-mA, 20-mcd
1 1 D9 MBRS130TR Diode, Schottky, 1A, 30V SMB MBRS130TR IR
1 1 J1 D120/2DS Terminal Block, 2-pin, 15-A, 0.40 x 0.35 inch D120/2DS OST
5.1mm
8 bq24740/1EVM (HPA206) For Multicell Synchronous Notebook Charger SLUU284A – June 2007 – Revised October 2008
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