DS2711/DS2712
Loose Cell NiMH Chargers
www.maxim-ic.com
DESCRIPTION
The DS2711 and DS2712 are ideal for in-system or
stand-alone charging of 1 or 2 AA or AAA NiMH
“loose” cells. Temperature, voltage, and charge time
are monitored to provide proper fast charging control
algorithms for nickel metal hydride (NiMH) batteries.
Battery tests are included to detect defective or
inappropriate cells such as alkaline primary batteries.
The DS2711/DS2712 support series and parallel
topologies, with independent monitoring and control of
each cell. Charging of NiCd chemistry cells is also
supported.
PIN CONFIGURATION
FEATURES
Charge 1 or 2 NiMH Cells
Detect and Avoid Charging Alkaline Cells
Precharge Deeply Depleted Cells
Fast Charge NiMH with -ΔV Termination
Sensitivity of 2mV (typ)
Monitor Voltage, Temperature, and Time for
Safety and Secondary Termination
Regulate Charge Current:
Linear Control (DS2711)
Switch-Mode Control (DS2712)
Drive PMOS or PNP-Type Pass Element or
Switch, or an Optocoupler
Compatible with Popular Optocouplers and
Integrated Primary Side PWM Controllers
Small 16-Pin SO or TSSOP Package
16 SO (150 mil) / TSSOP (4.4 mm)
See Table 1 for Ordering Information.
PIN DESCRIPTION
PIN
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
NAME
CC1
CC2
LED1
V
SS
LED2
CSOUT
VN1
VN0
DMSEL
CTST
TMR
V
DD
THM1
THM2
VP1
VP2
FUNCTION
Cell 1 Charge-Control Output
Cell 2 Charge-Control Output
Cell 1 Status
Ground Reference and Chip-Supply
Return
Cell 2 Status, Mode-Select Input
Current-Sense Output
Current-Sense + Input
Current-Sense - Input
Display-Mode Select
Cell Test Threshold Set
Charge Timer Set
Chip-Supply Input (4.0V to 5.5V)
Cell 1 Thermistor Input
Cell 2 Thermistor Input
Cell 1 Positive-Terminal Sense Input
Cell 2 Positive-Terminal Sense Input
APPLICATIONS
Desktop/Stand-Alone Chargers (AAA/AA)
Digital Still Cameras
Music Players
Games
Toys
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120808
DS2711/DS2712: Loose Cell NiMH Charger
Table 1. ORDERING INFORMATION
PART
DS2711Z
DS2711Z/T&R
DS2712Z
DS2712Z/T&R
DS2711Z+
DS2711Z+T&R
DS2712Z+
DS2712Z+T&R
DS2711E+
DS2711E+T&R
DS2712E+
DS2712E+T&R
MARKING
DS2711
DS2711
DS2712
DS2712
DS2711
DS2711
DS2712
DS2712
DS2711
DS2711
DS2712
DS2712
PIN-PACKAGE
16 SO
16 SO, Tape-and-Reel
16 SO
16 SO, Tape-and-Reel
16 SO
16 SO, Tape-and-Reel
16 SO
16 SO, Tape-and-Reel
16 TSSOP
16 TSSOP, Tape-and-Reel
16 TSSOP
16 TSSOP, Tape-and-Reel
+ Denotes lead-free package.
ABSOLUTE MAXIMUM RATINGS*
Voltage on All Pins Relative to V
SS
Voltage on DMSEL
Continuous Sink Current CC1, CC2, LED1, LED2 and CSOUT
Operating Temperature Range
Storage Temperature Range
Soldering Temperature
-0.3V to +6V
V
DD
+ 0.3V
20mA
-40°C to +85°C
-55°C to +125°C
See IPC/JEDECJ-STD-020
*This is a stress rating only and functional operation of the device at these or any other conditions above those
indicated in the operation sections of this specification is not implied. Exposure to absolute maximum rating
conditions for extended periods of time may affect reliability.
RECOMMENDED DC OPERATING CONDITIONS
(4.0V
≤
V
DD
≤
5.5V; T
A
= -20°C to +70°C.)
PARAMETER
Supply Voltage
Input Voltage Range
SYMBOL
V
DD
CONDITIONS
(Note 1)
LED2, DMSEL
MIN
4.0
-0.3
TYP
MAX
5.5
+5.5
UNITS
V
V
DC ELECTRICAL CHARACTERISTICS
PARAMETER
Supply Current, V
DD
UVLO Threshold
UVLO Hysteresis
Output-Voltage Low,
CC1, CC2, LED1, LED2
Output-Voltage Low,
CSOUT
Leakage Current,
CC1, CC2, LED1, LED2,
CSOUT
Threshold Voltage,
-ΔV Termination
Mode Test Current,
DMSEL, LED2
SYMBOL
I
DD
V
UVLO
V
UHYS
V
OL1
V
OL2
I
LKG
V
-ΔV
I
MTST
(4.0V
≤
V
DD
≤
5.5V, T
A
= -20°C to +70°C, unless otherwise noted.)
CONDITIONS
Operating mode
V
DD
rising (Note 1)
V
DD
falling from above
V
UVLO
V
DD
= 5.0V,
I
OL
= 20mA (Note 1)
V
DD
= 5.0V,
I
OL
= 20mA (Note 1)
V
DD
= 5.0V,
Output inactive
After t
THO
(Notes 2, 3)
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40
1.0
0.75
-1
1.0
2.0
5
1.25
+1
3.0
15
MIN
TYP
250
3.5
MAX
500
3.9
UNITS
μA
V
mV
V
V
μA
mV
μA
DS2711/DS2712: Loose Cell NiMH Charger
PARAMETER
Duty Factor, Parallel
Precharge/Top-Off
Duty Factor, Maintenance
Charge
Cell Test Interval
Precharge Time-Out
Fast-Charge Termination
Hold-Off Period
Fast-Charge Flat Voltage
Time-Out
Charge Timer Period
Charge Timer Accuracy
Charge Timer Range
t
CTMR-RANGE
SYMBOL
CONDITIONS
CC1, CC2
CC1, CC2
t
CTST
t
PCHG
t
THO
t
FLAT
t
CTMR
V
CELL
not increasing
R
TMR
= 100kΩ
R
TMR
= 100kΩ
-5
0.5
V
CELL
< V
BAT-MIN
MIN
TYP
0.125
0.0156
31
34
4
16
2.5
+5
10
s
minutes
minutes
minutes
h
%
h
MAX
UNITS
Note 1:
Note 2:
Note 3:
Note 4:
Note 5:
Note 6:
Note 7:
Note 8:
Voltages relative to V
SS
.
I
MTST
current is applied as a source current and as a sink current within 5ms after power-up.
When operating in two-cell-series charge configuration, the DMSEL pin must have less than 50pF of external load capacitance
for proper operation. If the load capacitance is greater than 50pF, a resistor voltage divider should be used to maintain DMSEL
at V
DD
/ 2.
Specification applicable during charge cycle with T
A
= 0°C to +70°C.
V
BAT-MAX1
and V
BAT-MAX1
are generated from the same reference. Their ranges never overlap.
V
THM-MIN,
V
THM-MAX,
and V
THM-STOP
are fixed ratios of V
DD.
Their ranges never overlap.
Tested with I
CSOUT
= -1mA.
Gain tested with 1mV step with I
CSOUT
= -1mA.
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PCB Design
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