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LTC4008 Datasheet, PDF (4/24 Pages) Linear Technology – 4A, High Efficiency, Multi-Chemistry Battery Charger
◁
LTC4008
ELECTRICAL CHARACTERISTICS The ● denotes specifications which apply over the full operating
temperature range (Note 4), otherwise specifications are at TA = 25°C. VDCIN = 20V, VBAT = 12V unless otherwise noted.
SYMBOL PARAMETER
Oscillator
fOSC
Regulator Switching Frequency
fMIN
Regulator Switching Frequency in Drop Out
DCMAX Regulator Maximum Duty Cycle
Gate Drivers (TGATE, BGATE)
TGTR
TGTF
VTGATE High (VCLP – VTGATE)
VBGATE High
VTGATE Low (VCLP – VTGATE)
VBGATE Low
TGATE Transition Time
TGATE Rise Time
TGATE Fall Time
BGTR
BGTF
BGATE Transition Time
BGATE Rise Time
BGATE Fall Time
VTGATE at Shutdown (VCLP – VTGATE)
VBGATE at Shutdown
CONDITIONS
Duty Cycle ≥ 98%
VCSP = VBAT
ITGATE = –1mA
CLOAD = 3000pF
CLOAD = 3000pF
IBGATE = 1mA
CLOAD = 3000pF, 10% to 90%
CLOAD = 3000pF, 10% to 90%
CLOAD = 3000pF, 10% to 90%
CLOAD = 3000pF, 10% to 90%
ITGATE = –1µA, DCIN = 0V, CLP = 12V
IBGATE = 1µA, DCIN = 0V, CLP = 12V
MIN TYP MAX UNITS
255
300
345
kHz
20
25
kHz
98
99
%
50
mV
5.6
10
V
5.6
10
V
50
mV
50
110
ns
50
100
ns
40
90
ns
40
80
ns
100
mV
100
mV
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2: See Test Circuit.
Note 3: Does not include tolerance of current sense resistor or current
programming resistor.
Note 4: The LTC4008E is guaranteed to meet performance specifications
from 0°C to 70°C. Specifications over the –40°C to 85°C operating
temperature range are assured by design, characterization and correlation
with statistical process controls.
Note 5: Voltage accuracy includes BATMON error and voltage reference
error. Does not include error of external resistor divider.
TYPICAL PERFOR A CE CHARACTERISTICS (TA = 25°C unless otherwise noted)
INFET Response Time to
Reverse Current
Vgs = 0
Vgs OF PFET (2V/DIV)
Vs OF PFET (5V/DIV)
Vs = 0V
Id (REVERSE) OF
PFET (5A/DIV)
Id = 0A
1.25µs/DIV
TEST PERFORMED ON DEMOBOARD
VIN = 15VDC
CHARGER = ON
VCHARGE = 12.6V
INFET = 1/2 Si4925DY
ICHARGE = <10mA
4008 G01
4
VFB vs DCIN
0.05
0
–0.05
–0.10
–0.15
–0.20
6
11
16
21
26
DCIN (V)
4008 G02
BATMON Offset
0.02
BATMON LOAD = 100kΩ
0
–0.02
–0.04
–0.06
–0.08
–0.10
3
DCIN = 15V
DCIN = 20V
DCIN = 24V
8
13
18
23
BATTERY VOLTAGE (V)
4008 G03
4008fa
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