Low-Cost Multichemistry Battery Chargers

26

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Table 2. Component List for Circuit of Figure 2

DESIGNATION

QTY

DESCRIPTION

C1

2

10µF, 50V 2220-size ceramic

capacitors

TDK C5750X7R1H106M

C4

1

22µF, 25V 2220-size ceramic

capacitor

TDK C5750X7R1E226M

C5

1

1µF, 25V X7R ceramic capacitor

(1206)

Murata GRM31MR71E105K

Taiyo Yuden TMK316BJ105KL

TDK C3216X7R1E105K

C9, C10

2

0.01µF, 16V ceramic capacitors (0402)

Murata GRP155R71E103K

Taiyo Yuden EMK105BJ103KV

TDK C1005X7R1E103K

C11, C14,

C15, C20

4

0.1µF, 25V X7R ceramic capacitors

(0603)

Murata GRM188R71E104K

TDK C1608X7R1E104K

C12, C13, C16

3

1µF, 6.3V X5R ceramic capacitors

(0603)

Murata GRM188R60J105K

Taiyo Yuden JMK107BJ105KA

TDK C1608X5R1A105K

D1 (optional)

1

10A Schottky diode (D-PAK)

Diodes, Inc. MBRD1035CTL

ON Semiconductor MBRD1035CTL

D2

1

Schottky diode

Central Semiconductor

CMPSH1–4

DESIGNATION

QTY

DESCRIPTION

D3

1

Schottky diode

Central Semiconductor CMPSH1-4

L1

1

10µH, 4.4A inductor

Sumida CDRH104R-100NC

TOKO 919AS-100M

N1

1

Dual, N-channel, 8-pin SO MOSFET

Fairchild FDS6990A or FDS6990S

P1

1

Single, P-channel, 8-pin SO MOSFET

Fairchild FDS6675

R5

1

1k

Ω ±5% resistor (0603)

R6

1

59k

Ω ±1% resistor (0603)

R7

1

19.6k

Ω ±1% resistor (0603)

R11

1

12k

Ω ±5% resistor (0603)

R12

1

15k

Ω ±5% resistor (0603)

R13

1

33

Ω ±5% resistor (0603)

R14

1

10.5k

Ω ±1% resistor (0603)

R15, R16

2

8.25k

Ω ±1% resistors (0603)

R17

1

19.1k

Ω ±1% resistor (0603)

R18

1

22k

Ω ±1% resistor (0603)

R19, R20

2

10k

Ω ±1% resistors (0603)

RS1

1

0.01

Ω ±1%, 0.5W 2010 sense resistor

Vishay Dale WSL2010 0.010 1.0%

IRC LRC-LR2010-01-R010-F

RS2

1

0.015

Ω ±1%, 0.5W 2010 sense

resistor

Vishay Dale WSL2010 0.015 1.0%

IRC LRC-LR2010-01-R015-F

U1

1

MAX1908ETI or MAX8724ETI

Chip Information

TRANSISTOR COUNT: 3772

PROCESS: BiCMOS

2) Place the IC and signal components. Keep the

main switching node (LX node) away from sensitive

analog components (current-sense traces and REF

capacitor). Important: The IC must be no further

than 10mm from the current-sense resistors.

Keep the gate-drive traces (DHI, DLO, and BST)

shorter than 20mm, and route them away from the

current-sense lines and REF. Place ceramic

bypass capacitors close to the IC. The bulk capac-

itors can be placed further away.

3) Use a single-point star ground placed directly

below the part at the backside exposed pad of the

MAX1908/MAX8724. Connect the power ground

and normal ground to this node.