DS2715Z+ Maxim Integrated Products, DS2715Z+ Datasheet - Page 12

• Manufacturer Part Number: DS2715Z+
• Description: IC NIMH CHARGER 16-SOIC
• Manufacturer: Maxim Integrated Products

Specifications of DS2715Z+

• Function: Charge Management
• Battery Type: Nickel Metal Hydride (NiMH)
• Voltage - Supply: 4.5 V ~ 16 V
• Operating Temperature: -20°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 16-SOIC (0.154", 3.90mm Width)
• Operating Supply Voltage: 16.5 V
• Supply Current: 1.3 mA
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 20 C
• Charge Safety Timers: Yes
• Mounting Style: SMD/SMT
• Temperature Monitoring: Yes
• Uvlo Start Threshold: 3.9 V
• Uvlo Stop Threshold: 35 mV
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

TEMPERATURE SENSE
Accurate temperature sensing is needed to determine end of charge by dT/dt and to detect over temperature fault
conditions. Connecting an external 10k NTC thermistor between THM and V
Div and THM allows the DS2715 to sense temperature. To sense the temperature of the cell pack, locate the
thermistor close to the body of a cell, preferably in the middle of the cell pack. Several recommended 10k
thermistors are shown in Table 3.
Min, Max Temperature Compare
The voltage thresholds of the THM input (V
temperature is between 0C and 45C when using the recommended 10k bias resistor and 10k thermistor
circuit. If pre-charging is in progress, and the voltage on THM reaches V
condition is generated. If the voltage on THM reaches V
stops and the DS2715 enters the DONE state. FAST_CHARGE will complete normally and TOPOFF will begin if
the voltage change on THM exceeds the equivalent T
Table 3. THM THRESHOLDS
Used with a 10k resistor, the Semitec 103AT-2 provides about 0.9% full scale per degree sensitivity. This linearity
is shown in the curve in Figure 4. The left axis is the ratio of the sensed voltage to the divider’s input voltage
(V
Figure 4. RATIO OF THM PIN TO CBIAS PIN OVER TEMPERATURE
Cbias
THRESHOLD
).
STOP
THM
MAX
MIN
0.75
0.70
0.65
0.60
0.55
0.50
0.45
0.40
0.35
0.30
0
OF V
RATIO
0.73
0.33
0.29
CBIAS
THERMISTOR
RESISTANCE
10
27.04k
4.925k
4.085k
()
THM-MIN
Divider Output
Degrees Centigrade
, V
20
TERM
12 of 17
THM-MAX
103AT-2
Semitec
ºC per minute (dT/dt Detect specification).
45C
50C
THM-STOP
0C
) are set to allow charging to start if the thermistor
during FAST-CHARGE or TOPOFF, charging
30
TEMPERATURE (C)
THM-STOP
SS
, and a 10k bias resistor between
197-103LAG-A01
173-103LAF-301
, pre-charging stops and a fault
40
Fenwal
42C
47C
4C
50