LTC4006EGN-2 Linear Technology, LTC4006EGN-2 Datasheet - Page 16

• 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
you, then simply set R9 = R
If you are using a thermistor that doesn’t have a 1:7 HIGH/
LOW ratio, or you wish to set the HIGH/LOW limits to
different temperatures, then the more generic network in
Figure 11 should work.
Once the thermistor, R
thermistor value is known at the temperature limits, then
resistors R9 and R9A are given by:
For NTC thermistors:
For PTC thermistors:
Example #1: 10kΩ NTC with custom limits
Example #2: 100kΩ NTC
Example #3: 22kΩ PTC
16
R9 = 6 R
R9A = 6 R
where R
R9 = 6 R
R9A = 6 R
where R
TLOW = 0°C, THIGH = 50°C
R
R
R
R9 = 24.55k → 24.3k (nearest 1% value)
R9A = 99.6k → 100k (nearest 1% value)
TLOW = 5°C, THIGH = 50°C
R
R
R
R9 = 226.9k → 226k (nearest 1% value)
R9A = 1.365M → 1.37M (nearest 1% value)
TLOW = 0°C, THIGH = 50°C
TH
TH(LOW)
TH(HIGH)
TH
TH(LOW)
TH(HIGH)
= 10k at 25°C,
= 100k at 25°C,
Figure 10. Voltage Divider Thermistor Network
TH(LOW)
TH(HIGH)
TH(LOW)
TH(LOW)
TH(LOW)
= 32.582k at 0°C
= 272.05k at 5°C
TH(LOW)
= 3.635k at 50°C
= 33.195k at 50°C
LTC4006
NTC
> 7 • R
U
> 7R
• R
• R
• R
• R
6
TH(HIGH)
TH(HIGH)
TH(HIGH)
TH(HIGH)
TH
TH(LOW)
U
R9
TH(HIGH)
, has been selected and the
TH(LOW)
/(R
/(R
/(R
/(R
C7
TH(LOW)
TH(LOW)
TH(HIGH)
TH(HIGH)
W
4006 F10
R
TH
– 7 • R
– R
– 7 • R
– R
TH(HIGH)
TH(LOW)
U
TH(HIGH)
TH(LOW)
)
)
)
)
Sizing the Thermistor Hold Capacitor
During the hold interval, C7 must hold the voltage across
the thermistor relatively constant to avoid false readings.
A reasonable amount of ripple on NTC during the hold
interval is about 10mV to 15mV. Therefore, the value of C7
is given by:
Example:
Disabling the Thermistor Function
If the thermistor is not needed, connecting a resistor
between DCIN and NTC will disable it. The resistor should
be sized to provide at least 10µA with the minimum voltage
applied to DCIN and 10V at NTC. Do not exceed 30µA into
NTC. Generally, a 301k resistor will work for DCIN less
than 15V. A 499k resistor is recommended for DCIN
between 15V and 24V.
Optional Simple Battery Discharge Path Circuit
It is NOT recommended that one permit battery current to
flow backwards through R
TGATE MOSFET internal diode to reach V
MOSFET is off when V
tional high efficiency discharge path for the battery such that
V
Normally when V
OUT
R
R
R
R9 = 43.9k → 44.2k (nearest 1% value)
R9A = 154k
C7 = t
R9 = 24.3k
R
C7 = 0.57µF → 0.56µF (nearest value)
TH
TH(LOW)
TH(HIGH)
RT
power comes from lossless “diode or” of V
= 10 • R
= 309k (~2 hour timer)
= 22k at 25°C,
HOLD
Figure 11. General Thermistor Network
= 6.53k at 0°C
LTC4006
= 61.4k at 50°C
RT
/(R9/7 • –ln(1 – 8 • 15mV/4.5V))
NTC
• 17.5pF/(R9/7 • – ln(1 – 8 • 15mV/4.5V)
IN
> V
6
BAT
IN
R9
< V
, P-channel MOSFET Q1B V
SENSE
BAT
C7
. Figure 12 shows an op-
, inductor and out the
R9A
OUT
4006 F11
R
TH
. The TGATE
IN
and V
GS
4006fa
BAT
=
.