BQ24740_14 Datasheet, PDF (6/33 Pages) Texas Instruments – Host-Controlled Multi-Chemistry Battery Charger

bq24740
SLUS736C – DECEMBER 2006 – REVISED MARCH 2009............................................................................................................................................... www.ti.com
Table 1. TERMINAL FUNCTIONS – 28-PIN QFN (continued)
TERMINAL
NAME
NO.
CELLS
20
DPMDET
21
PGND
22
LODRV
23
REGN
24
PH
25
HIDRV
26
BTST
27
PVCC
28
PowerPad™
DESCRIPTION
2, 3 or 4 cells selection logic input. Logic low programs 3 cell. Logic high programs 4 cell. Floating programs 2 cell.
Dynamic power management (DPM) input current loop active, open-drain output status. Logic low indicates input
current is being limited by reducing the charge current. Connect 10-kΩ pullup resistor from DPMDET to VREF or a
different pullup-supply rail.
Power ground. Ground connection for high-current power converter node. On PCB layout, connect directly to source
of low-side power MOSFET, to ground connection of in put and output capacitors of the charger. Only connect to
AGND through the PowerPad underneath the IC.
PWM low side driver output. Connect to the gate of the low-side power MOSFET with a short trace.
PWM low side driver positive 6-V supply output. Connect a 1-µF ceramic capacitor from REGN to PGND, close to the
IC. Use for high-side driver bootstrap voltage by connecting a small-signal Schottky diode from REGN to BTST.
PWM high side driver negative supply. Connect to the phase switching node (junction of the low-side power
MOSFET drain, high-side power MOSFET source, and output inductor). Connect the 0.1-µF bootstrap capacitor from
from PH to BTST.
PWM high side driver output. Connect to the gate of the high-side power MOSFET with a short trace.
PWM high side driver positive supply. Connect a 0.1-µF bootstrap ceramic capacitor from BTST to PH. Connect a
small bootstrap Schottky diode from REGN to BTST.
IC power positive supply. Place a 0.1-µF ceramic capacitor from PVCC to PGND pin close to the IC.
Exposed pad beneath the IC. AGND and PGND star-connected only at the PowerPad plane. Always solder
PowerPad to the board, and have vias on the PowerPad plane connecting to AGND and PGND planes. It also serves
as a thermal pad to dissipate the heat.
ABSOLUTE MAXIMUM RATINGS
over operating free-air temperature range (unless otherwise noted)^{(1) (2)}
Voltage range
Maximum difference voltage
Junction temperature range
Storage temperature range
PVCC, ACP, ACN, SRP, SRN, BAT
PH
REGN, LODRV, VADJ, ACSET, SRSET, ACDET, ISYNSET, LPMD, LPREF,
CHGEN, CELLS, EXTPWR, DPMDET
VDAC
VREF
BTST, HIDRV with respect to AGND and PGND, IADAPT
ACP–ACN, SRP–SRN, AGND–PGND
VALUE
–0.3 to 30
–1 to 30
–0.3 to 7
–0.3 to 5.5
–0.3 to 3.6
–0.3 to 36
–0.5 to 0.5
–40 to 155
–55 to 155
UNIT
V
°C
(1) Stresses beyond those listed under absolute maximum ratings may cause permanent damage to the device. These are stress ratings
only, and functional operation of the device at these or any other conditions beyond those indicated under recommended operating
conditions is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
(2) All voltages are with respect to GND if not specified. Currents are positive into, negative out of the specified terminal. Consult Packaging
Section of the data book for thermal limitations and considerations of packages.
6
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