Datasheet
AC1
2
BOOT1
3
BAT
4
CLMP1
5
COMM1
6
CHG
7
AD-EN
8
AD
9
AC2
19
RECT
18
BOOT2
17
CLMP2
16
COMM2
15
FOD
14
TS/
CTRL
13
ILIM
12
TERM
10
EN2
11
PGND
1
PGND
20
F1
TS/CTRL
E1
COMM2
D1
BAT
C1
BOOT2
B1
AC2
A1
PGND
F2
FOD
E2
CLMP2
D2
BAT
C2
RECT
B2
AC2
A2
PGND
D3
BAT
C3
RECT
E4
COMM1
D4
BAT
C4
BOOT1
B4
AC1
E3
CLMP1
B3
AC1
F3
AD-EN
A4
PGND
G1
ILIM
A3
PGND
G2
EN2
G3
TERM
G4
AD
F4
CHG
bq51050B
bq51051B
SLUSB42D –JULY 2012–REVISED JANUARY 2014
www.ti.com
YFP Package RHL Package
3.0mm x 1.9mm 28-Pin WCSP 4.35mm x 3.35mm 20-Pin QFN
(TOP VIEW) (TOP VIEW)
PIN FUNCTIONS
NAME WCSP QFN I/O DESCRIPTION
AC1 B3, B4 2 I
Input power from receiver coil.
AC2 B1, B2 19 I
BOOT1 C4 3 O
Bootstrap capacitors for driving the high-side FETs of the synchronous rectifier. Connect a 10nF
ceramic capacitor from BOOT1 to AC1 and from BOOT2 to AC2.
BOOT2 C1 17 O
Filter capacitor for the internal synchronous rectifier. Connect a ceramic capacitor to PGND.
RECT C2, C3 18 O
Depending on the power levels, the value may be 4.7μF to 22μF.
D1, D2,
BAT 4 O Output pin, delivers power to the battery while applying the internal charger profile.
D3, D4
Open-drain output used to communicate with primary by varying reflected impedance. Connect
through a capacitor to either AC1 or AC2 for capacitive load modulation (COMM2 must be
COMM1 E4 6 O
connected to the alternate AC1 or AC2 pin). For resistive modulation connect COMM1 and COMM2
to RECT via a single resistor; connect through separate capacitors for capacitive load modulation.
Open-drain output used to communicate with primary by varying reflected impedance. Connect
through a capacitor to either AC1 or AC2 for capacitive load modulation (COMM1 must be
COMM2 E1 15 O
connected to the alternate AC1 or AC2 pin). For resistive modulation connect COMM1 and COMM2
to RECT via a single resistor; connect through separate capacitors for capacitive load modulation.
CLMP1 E3 5 O Open drain FETs which are utilized for a non-power dissipative over-voltage AC clamp protection.
When the RECT voltage goes above 15 V, both switches will be turned on and the capacitors will
act as a low impedance to protect the IC from damage. If used, Clamp1 is required to be connected
CLMP2 E2 16 O
to AC1, and Clamp2 is required to be connected to AC2 via 0.47µF capacitors.
A1, A2,
PGND 1, 20 – Power ground
A3, A4
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