LTC1731-4.2 Linear Technology, LTC1731-4.2 Datasheet - Page 7

• Manufacturer Part Number: LTC1731-4.2
• Description: Lithium-Ion Linear Battery Charger Controller
• Manufacturer: Linear Technology

APPLICATIONS
constant-current only mode, the timer and voltage ampli-
fier are both disabled. An external termination method is
required to properly terminate the charge.
Stability
The charger is stable without any compensation when a
P-channel MOSFET is used as the pass transistor.
However, a 10 F capacitor is recommended at the BAT
PACKAGE
TYPICAL
(0.203 – 0.254)
**
0.008 – 0.010
*
DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH
SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE
DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD
FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE
(0.254 – 0.508)
0.010 – 0.020
(0.406 – 1.270)
0.016 – 0.050
APPLICATION
DESCRIPTION
45
U
INFORMATION
U
C
TIMER
0.1 F
0 – 8 TYP
U
R2
1k
W
U
2
3
(1.346 – 1.752)
0.053 – 0.069
(0.355 – 0.483)
0.014 – 0.019
8-Lead Plastic Small Outline (Narrow 0.150)
CHRG
TIMER
LTC1731-4.2
Dimensions in inches (millimeters) unless otherwise noted.
Linear Charger Using a PNP Transistor
TYP
GND
V
CC
4
7
SENSE
PROG
U
DRV
BAT
(LTC DWG # 05-08-1610)
8
6
1
5
S8 Package
R
19.6k
PROG
C1
1nF
pin to keep the ripple voltage low when the battery is
disconnected.
When a PNP transistor is chosen as the pass transistor, a
1000pF capacitor is required from the DRV pin to V
capacitor is needed to help stablize the voltage loop. A
10 F capacitor at the BAT pin is also recommended when
a battery is not present.
Q1
2N5087
R1
10k
(1.270)
5V TO 15V
0.050
BSC
(0.101 – 0.254)
V
0.004 – 0.010
IN
+
Q2
ZTX749
R
0.2
I
SENSE
MBRM120T3
BAT
Li-ION
CELL
= 500mA
(5.791 – 6.197)
0.228 – 0.244
1731 TA02
C3
1 F
C2
10 F
8
1
(4.801 – 5.004)
0.189 – 0.197*
7
2
LTC1731-4.2
6
3
5
4
(3.810 – 3.988)
0.150 – 0.157**
SO8 1298
CC
. This
7