LTC4070
6
4070fc
block DiagraM
pin FuncTions
4070 BD
3-STATE
DETECT
OSC
CLK
ADJ
1.5s
PULSED
DUTY CYCLE < 0.002%
30µs
NTCBIAS
NTC
R
NOM
10k
T
–
+
–
+
REF
–
+
EA
GND
DRV
HBO
LBO
V
CC
ADC
LTC4070
HBO (Pin 4): High Battery Monitor Output (Active High).
HBO is a CMOS output that indicates that the battery is
almost fully charged and current is being shunted away
from BAT. This pin is driven high when V
CC
rises to within
V
HBTH
of the effective float voltage. The absolute value of
this threshold depends on ADJ and NTC, both of which
affect the float voltage. HBO is driven low when V
CC
falls
by more than (V
HBTH
+ V
HBHY
) below the float voltage.
Refer to Table 1 for the effective float voltage.
GND (Pin 5, Exposed Pad Pin 9): Ground. The exposed
package pad must be connected to PCB ground for rated
thermal performance.
LBO (Pin 6): Low Battery Monitor Output (Active High).
LBO is a CMOS output that indicates when the battery
is discharged below 3.2V or rises above 3.5V. This pin
is driven high if V
CC
< V
LBTH
, and is driven low if V
CC
>
(V
LBTH
+ V
LBHY
).
DRV (Pin 7): External Drive Output. Connect to the gate of
an external PFET to increase shunt current for applications
which require more than 50mA charge current. Minimize
capacitance and leakage current on this pin. When not in
use, float DRV.
V
CC
(Pin 8): Input Supply Pin. The input supply voltage is
regulated to 4.0V, 4.1V, or 4.2V depending on the ADJ pin
state (see the ADJ pin description for more detail). This pin
can sink up to 50mA in order to keep the voltage regulation
within accuracy limits. When no battery is present, decouple
to GND with a capacitor, C
IN
, of at least 0.1µF.
