LTC4053-4.2_15 Datasheet, PDF (14/16 Pages) Linear Technology – USB Compatible Lithium-Ion Battery Charger with Thermal Regulation

LTC4053-4.2
APPLICATIO S I FOR ATIO
PROG pin. With no additional capacitance on the PROG
pin, stability is acceptable with program resistor values as
high as 50k. However, additional capacitance on this node
reduces the maximum allowed program resistor. The pole
frequency at the PROG pin should be kept above 500kHz.
Therefore, if the PROG pin is loaded with a capacitance, C,
the following equation should be used to calculate the
maximum resistance value for R_PROG:
R_PROG < 1/(6.283 • 5 × 10⁵ • C)
Average, rather than instantaneous, battery current may
be of interest to the user. For example, if a switching power
supply operating in low-current mode is connected in
parallel with the battery the average current being pulled
out of the BAT pin is typically of more interest than the
instantaneous current pulses. In such a case, a simple RC
filter can be used on the PROG pin to measure the average
battery current as shown in Figure 5. A 10k resistor is
added between the PROG pin and the filter capacitor and
monitoring circuit to ensure stability.
LTC4053
7
10k
PROG
GND
5
R_PROG C_FILTER
CHARGE
CURRENT
MONITOR
CIRCUITRY
4053 F05
Figure 5. Isolating Capacitive Load on PROG Pin and Filtering
PACKAGE DESCRIPTIO
DD Package
10-Lead Plastic DFN (3mm × 3mm)
(Reference LTC DWG # 05-08-1698)
0.675 ±0.05
R = 0.115
TYP
6
0.38 ± 0.10
10
3.50 ±0.05
1.65 ±0.05
2.15 ±0.05 (2 SIDES)
PIN 1
PACKAGE TOP MARK
OUTLINE (SEE NOTE 6)
0.25 ± 0.05
0.50
BSC
2.38 ±0.05
(2 SIDES)
0.200 REF
RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS
NOTE:
1. DRAWING TO BE MADE A JEDEC PACKAGE OUTLINE M0-229 VARIATION OF (WEED-2).
CHECK THE LTC WEBSITE DATA SHEET FOR CURRENT STATUS OF VARIATION ASSIGNMENT
2. DRAWING NOT TO SCALE
3. ALL DIMENSIONS ARE IN MILLIMETERS
3.00 ±0.10 1.65 ± 0.10
(4 SIDES) (2 SIDES)
0.75 ±0.05
0.00 – 0.05
(DD10) DFN 1103
5
1
0.25 ± 0.05
0.50 BSC
2.38 ±0.10
(2 SIDES)
BOTTOM VIEW—EXPOSED PAD
4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE
MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE
5. EXPOSED PAD SHALL BE SOLDER PLATED
6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE
TOP AND BOTTOM OF PACKAGE
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