LTC4006EGN-2 Linear Technology, LTC4006EGN-2 Datasheet - Page 12

• Manufacturer Part Number: LTC4006EGN-2
• Description: IC CHARGER BATTERY 4A 16-SSOP
• Manufacturer: Linear Technology

Specifications of LTC4006EGN-2

• Function: Charge Management
• Battery Type: Lithium-Ion (Li-Ion)
• Voltage - Supply: 6 V ~ 28 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 16-SSOP (0.150", 3.90mm Width)
• Output Current: 4A
• Output Voltage: 12.6V
• Operating Supply Voltage (min): 6V
• Operating Supply Voltage (max): 28V
• Operating Temp Range: -40C to 85C
• Package Type: SSOP N
• Mounting: Surface Mount
• Pin Count: 16
• Operating Temperature Classification: Industrial
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

APPLICATIO S I FOR ATIO
LTC4006
Charger Current Programming
The basic formula for charging current is:
Table 3. Recommended R
Setting the Timer Resistor
The charger termination timer is designed for a range of 1
hour to 3 hours with a ±15% uncertainty. The timer is
programmed by the resistor R
equation:
It is important to keep the parasitic capacitance on the R
pin to a minimum. The trace connecting R
be as short as possible.
CHG Status Output Pin
When the charge cycle starts, the CHG pin is pulled down
to ground by an internal N-channel MOSFET that can drive
more than 100µA. When the charge current drops to 10%
of the full-scale current (C/10), the N-channel MOSFET is
turned off and a weak 25µA current source to ground is
connected to the CHG pin. After a time out occurs, the pin
will go into a high impedance state. By using two different
value pull-up resistors, a microprocessor can detect three
states from this pin (charging, C/10 and stop charging).
See Figure 6.
Battery Detection
It is generally not good practice to connect a battery while
the charger is running. The timer is in an unknown state
and the charger could provide a large surge current into
the battery for a brief time. The circuit shown in Figure 7
keeps the charger shut down and the timer reset while a
battery is not connected.
12
t
(seconds)
I
CHARGE MAX
TIMER
I
MAX
1.0
2.0
3.0
4.0
= 10 • 2
(A)
(
)
=
27
100
R
U
SENSE
• R
R
SENSE
mV
SENSE
RT
U
0.100
0.050
0.033
0.025
• 17.5pF (Refer to Figure 5)
Resistor Values
(Ω) 1%
RT
W
using the following
T
R
to R
SENSE
0.25
0.25
0.5
0.5
U
RT
(W)
should
T
Alternatively, a normally closed switch can be used to
detect when the battery is present (see Figure 8).
BATTERY CONNECTED
SWITCH CLOSED IF
BATTERY CONNECTED
SWITCH OPEN WHEN
ADAPTER
120
200
180
160
140
100
POWER
80
60
40
20
0
100
Figure 6. Microprocessor Interface
ADAPTER
LTC4006
POWER
150
Figure 5. t
CHG
200
2
250
3.3V
Figure 7
Figure 8
470k
R
RT
300 350
200k
TIMER
(kΩ)
33k
1
3
vs R
DCIN
ACP/SHDN
400 450 500
1
3
OUT
IN
RT
LTC4006
DCIN
ACP/SHDN
V
µP
DD
4006 F05
4006 F06
LTC4006
4006 F08
4006 F07
4006fa