LTC6802IG-1#PBF Linear Technology, LTC6802IG-1#PBF Datasheet - Page 34

• Manufacturer Part Number: LTC6802IG-1#PBF
• Description: IC MONITOR BATT STACK MC 44-SSOP
• Manufacturer: Linear Technology

Specifications of LTC6802IG-1#PBF

• Function: Battery Monitor
• Battery Type: Lithium-Ion (Li-Ion)
• Voltage - Supply: 4 V ~ 50 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 44-SOP (0.200", 5.30mm Width)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

APPLICATIONS INFORMATION
LTC6802-1
PCB LAYOUT CONSIDERATIONS
The V
capacitor for best performance.
The LTC6802-1 is capable of operation with as much as
60V between V
layout to maintain physical separation of traces at different
potentials. The pinout of the LTC6802-1 was chosen to
facilitate this physical separation. Figure 20 shows the DC
voltage on each pin with respect to V
battery cells are connected to the LTC6802-1. There is no
more then 5.5V between any two adjacent pins. The pack-
age body is used to separate the highest voltage (43.5V)
from the lowest voltage (0V).
34
REG
Figure 20. Typical Pin Voltages for 12 3.6V Cells
and V
42.5V
42.5V
42.5V
43.2V
43.2V
43.2V
39.6V
39.6V
32.4V
32.4V
28.8V
28.8V
25.2V
25.2V
21.6V
21.6V
14.4V
14.4V
36V
36V
18V
18V
+
REF
and V
CSBO
SDOI
SCKO
V
C12
S12
C11
S11
C10
S10
C9
S9
C8
S8
C7
S7
C6
S6
C5
S5
C4
S4
pins should be bypassed with a 1μF
+
–
. Care should be taken on the PCB
LTC6802-1
V
V
V
GPIO2
GPIO1
WDTB
TEMP2
TEMP1
MODE
MMB
V
CSBI
SCKI
V
68021 F20
SDO
TOS
REG
SDI
REF
NC
S1
C1
S2
C2
S3
C3
V
−
–
0V TO 5.5V
0V TO 5.5V
0V TO 5.5V
0V TO 5.5V
0V TO 5.5V
0V TO 5.5V
0V TO 5.5V
0V TO 5.5V
0V TO 5.5V
0V TO 5.5V
5.5V
3.1V
1.5V
1.5V
0V
0V
3.6V
3.6V
7.2V
7.2V
10.8V
10.8V
when twelve 3.6V
ADVANTAGES OF DELTA-SIGMA ADCS
The LTC6802-1 employs a delta sigma analog to digital
converter for voltage measurement. The architecture of
delta sigma converters can vary considerably, but the
common characteristic is that the input is sampled many
times over the course of a conversion and then filtered or
averaged to produce the digital output code. In contrast,
a SAR converter takes a single snapshot of the input
voltage and then performs the conversion on this single
sample. For measurements in a noisy environment, a
delta sigma converter provides distinct advantages over
a SAR converter.
While SAR converters can have high sample rates, the full-
power bandwidth of a SAR converter is often greater than
1MHz, which means the converter is sensitive to noise out
to this frequency. And many SAR converters have much
higher bandwidths – up to 50MHz and beyond. It is pos-
sible to filter the input, but if the converter is multiplexed
to measure several input channels a separate filter will be
required for each channel. A low frequency filter cannot
reside between a multiplexer and an ADC and achieve a
high scan rate across multiple channels. Another conse-
quence of filtering a SAR ADC is that any noise reduction
gained by filtering the input cancels the benefit of having
a high sample rate in the first place, since the filter will
take many conversion cycles to settle.
For a given sample rate, a delta sigma converter can
achieve excellent noise rejection while settling completely
in a single conversion – something that a filtered SAR con-
verter cannot do. Noise rejection is particularly important
in high voltage switching controllers, where switching
noise will invariably be present in the measured voltage.
Other advantages of delta sigma converters are that they
are inherently monotonic, meaning they have no missing
codes, and they have excellent DC specifications.
68021fa