Datasheet

LTC4090/LTC4090-5
26
4090fc
Figure 12. 800kHz Switching Frequency
HVIN
HVEN
IN
HPWR
V
C
SUSP
TIMER
CLPROG
PROG
R
T
PG
SYNC
SW
HIGH
(7.5V TO 36V)
VOLTAGE
INPUT
L1
6.8μH
4090 F12
LTC4090
BOOST
HVOUT
HVPR
OUT
GATE
BAT
VNTC
NTC
CHRG
C1
1μF
50V
1206
0.1μF
2.1k
1%
71.5k
1%
40.2k
1%
59k
1%
680Ω
0.47μF
16V
D1
C3
22μF
6.3V
1206
4.7μF
6.3V
270pF
Li-Ion
BATTERY
680Ω
D: DIODES INC. B360A
L: SUMIDA CDR6D28MN-GR5
Q1, Q2: SILICONIX Si2333DS
1k
10k
1%
Q1
Q2
10kT
LOAD
+
USB
4.7μF
6.3V
HVIN
BOOST
IN
SW
4.7μF
4.7μF
Q1
4.7μF
1μF
TIMER CLPROG
LTC4090
GND PROG
HVOUT
HVPR
OUT
BAT
0.1μF330pF
71.5k2.1k
L: SUMIDA CDRH8D28/HP-100
* USE SCHOTTKY DIODE RATED AT V
R
> 45V
USB
HIGH (7.5V TO 36V)
TRANSIENT TO 60V*
V
C
R
T
88.7k35k
Li-Ion BATTERY
+
1k
L
10μH
LOAD
4090 TAO3
0.47μF
HVIN
BOOST
IN
SW
4.7μF
22μF
Q1
4.7μF
1μF
TIMER CLPROG
LTC4090
GND PROG
HVOUT
HVPR
OUT
BAT
0.1μF330pF
71.5k2.1k
L: SUMIDA CDRH4D22/HP-2R2
USB
HIGH (7.5V TO 16V)
VOLTAGE INPUT
V
C
R
T
11.5k30k
Li-Ion BATTERY
+
1k
LOAD
4090 TAO4
L
2.2μH
0.47μF
Figure 13. 400kHz Switching Frequency Figure 14. 2MHz Switching Frequency
IN and HVIN Bypass Capacitor
Many types of capacitors can be used for input bypassing;
however, caution must be exercised when using multilayer
ceramic capacitors. Because of the self-resonant and high
Q characteristics of some types of ceramic capacitors,
high voltage transients can be generated under some
start-up conditions, such as from connecting the charger
input to a hot power source. For more information, refer
to Application Note 88.
Battery Charger Stability Considerations
The constant-voltage mode feedback loop is stable without
any compensation when a battery is connected with low
impedance leads. Excessive lead length, however, may add
enough series inductance to require a bypass capacitor
of at least 1μF from BAT to GND. Furthermore, a 4.7μF
capacitor with a 0.2Ω to 1Ω series resistor to GND is
recommended at the BAT pin to keep ripple voltage low
when the battery is disconnected.
APPLICATIONS INFORMATION
TYPICAL APPLICATIONS