LTC4061 datasheet(7/20 Pages) LINER

7 / 20 page

LTC4061

4061fa

BAT (Pin 1): Charge Current Output. This pin provides

charge current to the battery and regulates the ﬁnal ﬂoat

voltage to 4.2V.

NTC (Pin 2): Input to the NTC (Negative Temperature Coef-

ﬁcient) Thermistor Temperature Monitoring Circuit. Under

normal operation, connect a thermistor from the NTC pin

to ground and a resistor of equal value from the NTC pin

to VCC. When the voltage at this pin drops below 0.35 •

VCC at hot temperatures or rises above 0.76 • VCC at cold,

charging is suspended, the internal timer is frozen and the

⎯C⎯⎯H⎯R⎯G pin output will start to pulse at 1.5Hz. Pulling this

pin below 0.016 • VCC disables the NTC feature. There is

approximately 2°C of temperature hysteresis associated

with each of the input comparators thresholds.

TIMER (Pin 3): Timer Program and Termination Select Pin.

This pin selects which method is used to terminate the

charge cycle. Connecting a capacitor, CTIMER, to ground

selects charge time termination. The charge time is set

by the following formula:

TIME HOURS

HOURS

TIME HOURS

HOURS

TIMER

()

•

.•

()

=µ

Connecting the TIMER pin to ground selects charge cur-

rent termination, while connecting the pin to VCC selects

user termination. See Applications Information for more

information on current and user termination.

ACPR (Pin 4): Open-Drain Power Supply Present Status

Output. The power supply status indicator pin has two

states: pull-down and high impedance. This output can

be used as a logic interface or as a LED driver. In the

pull-down state, an NMOS transistor capable of sinking

10mA pulls down on the ⎯⎯A⎯C⎯P⎯R pin. The state of this pin

is dependent on the value of VCC and BAT: it requires that

VCC is 190mV greater than VBAT and greater than VUVLO.

See Applications Information.

⎯C⎯H⎯R⎯G (Pin 5): Open-Drain Charge Status Output. The

charge status indicator pin has three states: pull-down,

PI FU CTIO S

pulse at 1.5Hz or 6Hz and high impedance. This output

can be used as a logic interface or as a LED driver. In the

pull-down state, an NMOS transistor capable of sinking

10mA pulls down on the ⎯C⎯H⎯R⎯G pin. The state of this pin

depends on the value of IDETECT as well as the termina-

tion method being used and the state of the NTC pin. See

Applications Information.

⎯C⎯/⎯5 (Pin 6): ⎯C⎯/⎯5 Enable Input. Used to control the amount

of current drawn from the USB port. A logic high on the

⎯C⎯/⎯5 pin sets the current limit to 100% of the current

programmed by the PROG pin. A logic low on the ⎯C⎯/⎯5 pin

sets the current limit to 20% of the current programmed

by the PROG pin. An internal 3MΩ pull-down resistor

defaults the ⎯C⎯/⎯5 pin to its low current state.

⎯E⎯N (Pin 7): Charger Enable Input. A logic high on the ⎯E⎯N pin

places the charger into shutdown mode, where the input

quiescent current is less than 50µA. A logic low on this

pin enables charging. An internal 3MΩ pull-down resistor

to ground defaults the charger to its enabled state.

IDET (Pin 8): Current Detection Threshold Program Pin.

The current detection threshold, IDETECT, is set by con-

necting a resistor, RDETECT, to ground. IDETECT is set by

the following formula:

DETECT

PROG

DET

CHG

DET

DETECT

100

•

The ⎯C⎯H⎯R⎯G pin becomes high impedance when the charge

current drops below IDETECT. IDETECT can be set to 1/10th

the programmed charge current by connecting IDET di-

rectly to PROG. If the IDET pin is not connected, the ⎯C⎯H⎯R⎯G

output remains in its pull-down state until the charge time

elapses and terminates the charge cycle. See Applications

Information.

This pin is clamped to approximately 2.4V. Driving this pin to

voltages beyond the clamp voltage should be avoided.

PROG (Pin 9): Charge Current Program and Charge Cur-

rent Monitor. The charge current is set by connecting a

LTC4061 データシート(PDF) 7 Page - Linear Technology

LTC4061 データシート(HTML) 7 Page - Linear Technology

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

データシートダウンロード