MAXIM DS2714 Technical data

www.maxim-ic.com

GENERAL DESCRIPTION

The DS2714 is ideal for standalone charging of 1 to 4 AA or AAA NiMH “loose” cells. NiCd cells can also be charged. 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 DS2714 supports a parallel charging topology, with independent monitoring and control of each cell.

APPLICATIONS

Desktop/Standalone Chargers (AAA/AA) Digital Still Cameras Music Players Games Toys

CHARGE TOPOLOGY

DS2714

Quad Loose Cell NiMH Charge

FEATURES

 Charges 1 to 4 NiMH Cells  Detects and Avoids Charging Alkaline Cells  Pre-Charges Deeply Depleted Cells  Fast Charges NiMH with -ΔV Termination

Sensitivity of 2mV (typ)

 Monitors Voltage, Temperature and Time for

Safety and Secondary Termination

 Works with Regulated Charge Current Source  Drives PNP Type Pass Element  Compatible with Integrated Primary-Side PWM

Controllers

 20-pin TSSOP Package

ORDERING INFORMATION

PART MARKING PIN-PACKAGE

DS2714E+ DS2714 20 TSSOP DS2714E+T&R DS2714 20 TSSOP Tape-and-Reel

+Denotes lead-free package.

PIN CONFIGURATION

Controlled

Current Source

GND

4-Cell NiMH Charger

DS2714

TSSOP

Note: Some revisions of this device may incorporate deviations from published specifications known as errata. Multiple revisions of any device may be simultaneously available through various sales channels. For information about device errata, click here: www.maxim-ic.com/errata

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REV: 080206

DS2714: Quad Loose Cell NiMH Charger

ABSOLUTE MAXIMUM RATINGS

Voltage Range on Any Pin Relative to V Voltage on DMSEL V Continuous Sink Current CC1-4, LED1-4 Operating Temperature Range -40°C to +85°C Storage Temperature Range Soldering Temperature

Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to the absolute maximum rating conditions for extended periods may affect device reliability.

-55°C to +125°C

See IPC/JEDECJ-STD-020A

-0.3V to +6V

+ 0.3V

20mA

RECOMMENDED DC OPERATING CONDITIONS

(4.0V ≤ VDD ≤ 5.5V; T

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Supply Voltage VDD (Note 1) 4.0 5.5 V Input Voltage Range LEDx, DMSEL -0.3 5.5 V

= -20°C to +70°C)

DC ELECTRICAL CHARACTERISTICS

(4.0V ≤ VDD ≤ 5.5V; TA = -20°C to +70°C. Unless otherwise noted.)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Supply Current, VDD I

Output Voltage Low, CC1-4. LED1-4 Leakage Current, CC1-4 LED1-4 Threshold Voltage,

-ΔV Termination

Mode Test Current, DMSEL I

Input Logic High, DMSEL, VIH (Note 1)

Operating mode 500 750

VDD = 5.0V,

OL1

LKG

MTST

-ΔV

= 20mA (Note 1)

VDD = 5.0V, Output inactive

After t

THO

Pulse high/low once <5ms after power-up

1.0 2.0 3.0 mV

1.0 V

-1 +1

- 5 15

0.2V

μA

Input Logic Low, DMSEL, VIL (Note 1) 0.2 V

Input Leakage Current, DMSEL

Threshold Voltage, Cell Test Accuracy Threshold Voltage, Cell Test Range Threshold Voltage, Cell Voltage Low Threshold Voltage, Cell Voltage Max1 Threshold Voltage, Cell Voltage Max2 Threshold Voltage, Thermistor

- Min Threshold Voltage, Thermistor

- Max Threshold Voltage, Thermistor

- Stop Threshold Current, TMR Pin Suspend

IL1

CTST-ACC

CTST-RANGE

BAT-LOW

BAT-MAX1

BAT-MAX2

THM-MIN

THM-MAX

THM-STOP

TMR-SUS

After power-up mode select, DMSEL = V

= 80KΩ

TMR

or VSS

-1 +1

μA

-15 15 %

32 400 mV

CC1 = CC2 = hi-Z (Note 1, 2) CC1 = CC2 = hi-Z (Note 1, 2) CC1, CC2 active (Note 1, 2)

(Note 1, 2, 6)

(Note 1, 2, 6) 0.30

(Note 1, 2, 6)

0.1 0.5

0.9 1.0 1.1 V

1.55 1.65 1.75 V

1.64 1.75 1.86 V

0.73

0.33

0.29

0.36 V

μA

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DS2714: Quad Loose Cell NiMH Charger

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Presence Test Current, VP1-4 I Reverse Leakage Current, VP1, VP2, VP3, VP4

10 15

PTST

VDD = 0V, VPx = 1.5V

LKGR

μA

ELECTRICAL CHARACTERISTICS: TIMING

(4.0V ≤ VDD ≤ 5.5V; TA = -20°C to +70°C. Unless otherwise noted.)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Internal Timebase Period t

Internal Timebase Accuracy

Duty Factor, Fast Charge DF1 CCx 0.234

(Note 5) 0.48 s

BASE

-10 +10 %

Duty Factor, PreCharge/Top-Off Duty Factor, Maintenance Charge

Cell Test Interval t

Pre-Charge Time-out t

Fast Charge Termination Hold-Off Period Fast Charge Flat Voltage Time-out

DF2 CCx 0.0625

DF3 CCx Note 4 0.0078

(Note 3) 31 s

CTST

PCHG

3.6 4 4.4 minutes

THO

FLAT

< V

CELL

not increasing 14.4 16 17.6 minutes

CELL

30.6 34 37.4 minutes

BAT-MIN

Charge Timer Accuracy -5 +5 %

Charge Timer Range t

CTMR-RANGE

0.5 10 h

Note 1: Voltages relative to V Note 2: Specification applicable during charge cycle with TA = 0°C to +70°C. Note 3: One time slot out of every 16 available slots gets a Cell Test. Note 4: One time slot out of every 32 available time slots gets a charge pulse.

0.48 seconds is one charge time slot. A complete cycle of 4 time slots (one charge time slot per cell) is 1.92 sec.

Note 5: Note 6: V Note 7: I

THM-MIN, VTHM-MAX, and VTHM-STOP are fixed ratios of V

MTST current is applied as a source current and as a sink current within 5ms after power-up.

Their ranges never overlap.

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DS2714: Quad Loose Cell NiMH Charger

PIN DESCRIPTION

PIN NAME FUNCTION

1 CC1 2 CC2 3 CC3

4 CC4 5 LED1 6 LED2 7 VSS 8 LED3

9 LED4 10 DMSEL 11 CTST 12 TMR 13 VDD 14 VSS 15 VP1 16 VP2 17 VP3 18 VP4 19 THM1 20 THM2

Charge Control 1. Turn on and off the charge PNP for Cell 1. Charge Control 2. Turn on and off the charge PNP for Cell 2. Charge Control 3. Turn on and off the charge PNP for Cell 3.

Charge Control 4. Turn on and off the charge PNP for Cell 4. LED 1. Open drain output for LED. Display Cell 1 status. LED 2. Open drain output for LED. Display Cell 2 status. Device Ground. Return current path for LEDx pins. Both VSS pins must be connected to ground. LED 3. Open drain output for LED. Display Cell 3 status. LED 4. Open drain output for LED. Display Cell 4 status. Display Mode Select. Select the LED blink rate. Cell Test Resistor. Cell test threshold set. Timer Resistor. Charge timer set. Power-Supply Input. Chip supply input (4.0V to 5.5V). Device Ground. Internally connected to Pin 7. Both VSS pins must be connected to ground. Voltage Sense 1. Positive terminal sense input for Cell 1. Voltage Sense 2. Positive terminal sense input for Cell 2. Voltage Sense 3. Positive terminal sense input for Cell 3. Voltage Sense 4. Positive terminal sense input for Cell 4. Thermister 1. Thermister input for Cell 1 and 2. Thermister 2. Thermister input for Cell 3 and 4.

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