DS2762AE+ Maxim Integrated Products, DS2762AE+ Datasheet - Page 11

• Manufacturer Part Number: DS2762AE+
• Description: IC MON BATT LI-ION HP 16-TSSOP
• Manufacturer: Maxim Integrated Products

Specifications of DS2762AE+

• Function: Battery Monitor
• Battery Type: Lithium-Ion (Li-Ion)
• Voltage - Supply: 2.5 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 16-TSSOP
• Operating Supply Voltage: 2.5 V to 5.5 V
• Supply Current: 60 uA
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Charge Safety Timers: Yes
• Mounting Style: SMD/SMT
• Temperature Monitoring: Yes
• Output Voltage: 4.275 V
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

CURRENT MEASUREMENT
In active mode, the DS2762 continually measures the current flow into and out of the battery by measuring the
voltage drop across a current-sense resistor. The DS2762 is available in two configurations: 1) internal 25mW
current-sense resistor and 2) external user-selectable sense resistor. In either configuration, the DS2762 considers
the voltage difference between pins IS1 and IS2 (V
resistor. A positive V
indicates current is flowing out of the battery (discharging).
V
every 88ms with an average of 128 readings. Currents outside the register range are reported at the range limit.
Figure 4 shows the format of the current register.
For the internal sense resistor configuration, the DS2762 maintains the current register in units of amps, with a
resolution of 0.625mA and full-scale range of no less than ±1.9A (see Note 7 on I
DS2762 automatically compensates for internal sense resistor process variations and temperature effects when
reporting current.
For the external sense resistor configuration, the DS2762 writes the measured V
with a 15.625mV resolution and a full-scale ±64mV range.
Figure 4. Current Register Format
CURRENT ACCUMULATOR
The current accumulator facilitates remaining capacity estimation by tracking the net current flow into and out of the
battery. Current flow into the battery increments the current accumulator while current flow out of the battery
decrements it. Data is maintained in the current accumulator in two’s-complement format. Figure 5 shows the
format of the current accumulator.
When the internal sense resistor is used, the DS2762 maintains the current accumulator in units of amp-hours, with
a 0.25mAhrs resolution and full-scale ±8.2Ahrs range. When using an external sense resistor, the DS2762
maintains the current accumulator in units of volt-hours, with a 6.25mVhrs resolution and a full-scale ±205mVhrs
range.
The current accumulator is a read/write register that can be altered by the host system as needed.
Figure 5.
IS
is measured with a signed resolution of 12 bits. The current register is updated in two’s-complement format
MSb
MSb
S
S
Current Accumulator Format
2
2
11
14
IS
2
2
MSB—Address 0E
MSB—Address 10
10
13
value indicates current is flowing into the battery (charging), while a negative V
2
2
12
9
2
2
11
8
2
2
10
7
2
2
6
9
LSb
LSb
2
2
IS
5
8
11 of 25
= V
IS1
- V
MSb
MSb
2
2
IS2
4
7
) to be the filtered voltage drop across the sense
2
2
3
6
Units: 0.25mAhrs for Internal Sense Resistor
Units: 0.625mA for Internal Sense Resistor
2
2
LSB—Address 0F
LSB—Address 11
6.25mVhrs for External Sense Resistor
2
5
15.625mV for External Sense Resistor
2
2
1
4
IS
voltage to the current register,
FS
2
2
0
3
spec for more details). The
2
X
2
2
X
1
LSb
LSb
2
X
0
IS
value