Rev 0; 10/08
2-Cell, Stand-Alone, Li+ Fuel-Gauge IC with
Protector and Optional SHA-1 Authentication
General Description
The DS2775–DS2778 report available capacity for
rechargeable lithium-ion (Li+) and Li+ polymer (Li-Poly)
batteries in mAh and as a percentage of full. Safe oper-
ation is ensured by the integrated Li+ protector. The
DS2776/DS2778 support SHA-1-based challenge-
response authentication in addition to all other DS2775/
DS2777 features.
Precision measurements of voltage, temperature, and
current, along with a cell characteristics table and
application parameters, are used for capacity estima-
tion calculations. The capacity registers report a con-
servative estimate of the amount of charge that can be
removed given the current temperature, discharge rate,
stored charge, and application parameters.
The DS2775–DS2778 operate from +4.0V to +9.2V for
direct integration into battery packs with two Li+ or Li-
Poly cells.
In addition to nonvolatile storage for cell compensation
and application parameters, the DS2775–DS2778 offer
16 bytes of EEPROM for use by the host system and/or
pack manufacturer to store battery lot and date tracking
information. The EEPROM can also be used for non-
volatile storage of system and/or battery usage statis-
tics. A Maxim 1-Wire
®
(DS2775/DS2776) or 2-wire
(DS2777/DS2778) interface provides serial communica-
tion to access measurement and capacity data regis-
ters, control registers, and user memory. The
DS2776/DS2778 use the SHA-1 hash algorithm in a
challenge-response pack authentication protocol for
battery-pack verification.
Features
♦
High-Side nFET Drivers and Protection Circuitry
♦
Precision Voltage, Temperature, and Current
Measurement System
♦
Cell-Capacity Estimation from Coulomb Count,
Discharge Rate, Temperature, and Cell
Characteristics
♦
Estimates Cell Aging Between Learn Cycles
♦
Uses Low-Cost Sense Resistor
♦
Allows Calibration of Gain and Temperature
Coefficient
♦
Programmable Thresholds for Overvoltage and
Overcurrent
♦
Pack Authentication Using SHA-1 Algorithm
(DS2776/DS2778)
♦
32-Byte Parameter EEPROM
♦
16-Byte User EEPROM
♦
Maxim 1-Wire Interface with 64-Bit Unique ID
(DS2775/DS2776)
♦
2-Wire Interface with 64-Bit Unique ID
(DS2777/DS2778)
♦
3mm x 5mm, 14-pin TDFN Lead-Free Package
DS2775/DS2776/DS2777/DS2778
Ordering Information
PART
DS2775G+*
DS2775G+T&R*
DS2776G+
DS776G+T&R
DS2777G+*
DS2777G+T&R*
DS2778G+
DS2778G+T&R
PIN-PACKAGE
14 TDFN-EP**
14 TDFN-EP**
14 TDFN-EP**
14 TDFN-EP**
14 TDFN-EP**
14 TDFN-EP**
14 TDFN-EP**
14 TDFN-EP**
TOP MARK
D2775
D2775
D2776
D2776
D2777
D2777
D2778
D2778
Applications
Low-Cost Notebooks
UMPCs
DSLR Cameras
Video Cameras
Commercial and Military Radios
Portable Medical Equipment
Selector Guide and Pin Configuration appear at end of data
sheet.
Note:
All devices are specified over the -20°C to +70°C oper-
ating temperature range.
+Denotes
a lead-free/RoHS-compliant package.
T&R = Tape and reel.
*Future
product—contact factory for availability.
**EP
= Exposed pad.
1-Wire is a registered trademark of Maxim Integrated Products, Inc.
________________________________________________________________
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
2-Cell, Stand-Alone, Li+ Fuel-Gauge IC with
Protector and Optional SHA-1 Authentication
DS2775/DS2776/DS2777/DS2778
ABSOLUTE MAXIMUM RATINGS
Voltage Range on PLS, CP, CC, DC Pins
Relative to V
SS
.....................................................-0.3V to +18V
Voltage Range on V
DD
, V
IN1
, V
IN2
, SRC Pins
Relative to V
SS
....................................................-0.3V to +9.2V
Voltage Range on All Other Pins Relative to V
SS
..-0.3V to +6.0V
Continuous Sink Current, PIO, DQ......................................20mA
Continuous Sink Current, CC, DC.......................................10mA
Operating Temperature Range ...........................-20°C to +70°C
Storage Temperature Range .............................-55°C to +125°C
Soldering Temperature...........................Refer to the IPC/JEDEC
J-STD-020 Specification.
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
absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(V
DD
= +4.0V to +9.2V, T
A
= -20°C to +70°C, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
SYMBOL
I
DD0
Supply Current
I
DD1
I
DD2
Temperature Accuracy
T
ERR
2.0 V
IN1
4.6, 2.0
0°C T
A
+50°C
Voltage Accuracy
2.0 V
IN1
4.6, 2.0
T
A
= 25°C
2.0
Input Resistance (V
IN1
, V
IN2
)
Current Resolution
Current Full Scale
Current Gain Error
Current Offset
Accumulated Current Offset
Time-Base Error
CP Output Voltage (V
CP
- V
SRC
)
CP Startup Time
Output High: CC, DC
Output Low: CC
Output Low: DC
DQ, PIO Voltage Range
DQ, PIO, SDA, SCL Input
Logic-High
DQ, PIO, SDA, SCL Input
Logic-Low
OVD Input Logic-High
OVD Input Logic-Low
V
IH
V
IL
V
IH
V
IL
V
BAT
- 0.2
V
SS
+ 0.2
I
LSB
I
FS
I
GERR
I
OERR
q
OERR
t
ERR
V
GS
t
SCP
V
OHCP
V
OLCC
V
OLDC
0°C
0°C
0°C
T
A
T
A
T
A
+70°C (Note 1)
+70°C (Note 1)
+50°C
-51.2
-1
-9.375
-255
-2
-3
I
OUT
= 0.9μA
CE = 0, DE = 0, C
CP
= 0.1 μF, active mode
I
OH
= 100μA (Note 2)
I
OL
= 100 μA
I
OL
= 100 μA
-0.3
1.5
0.6
V
CP
- 0.4
V
SRC
+ 0.1
V
SRC
+ 0.1
+5.5
4.4
4.7
V
IN1
4.6, 2.0
(V
IN2
- V
IN1
)
(V
IN2
– V
IN1
)
(V
IN2
- V
IN1
)
4.6,
4.6,
4.6
CONDITIONS
Sleep mode, T
A
Active mode
Active mode during SHA-1 computation
-3
-35
-22
-50
15
1.56
+51.2
+1
9.375
0
+2
+3
5
200
+50°C
Sleep mode, T
A
> +50°C
80
120
MIN
TYP
3
MAX
5
10
135
300
+3
+35
22
+50
M
μV
mV
% FS
μVh
μVh/Day
%
V
ms
V
V
V
V
V
V
V
V
mV
°C
μA
UNITS
2
_______________________________________________________________________________________
2-Cell, Stand-Alone, Li+ Fuel-Gauge IC with
Protector and Optional SHA-1 Authentication
ELECTRICAL CHARACTERISTICS (continued)
(V
DD
= +4.0V to +9.2V, T
A
= -20°C to +70°C, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
DQ, PIO, SDA Output Logic-Low
DQ, PIO Pullup Current
DQ, PIO, SDA, SCL Pulldown
Current
DQ Input Capacitance
DQ Sleep Timeout
PIO, DQ Wake Debounce
SYMBOL
V
OL
I
PU
I
PD
C
DQ
t
SLEEP
t
WDB
DQ < V
IL
Sleep mode
2
100
I
OL
= 4mA
Sleep mode, V
PIN
= (V
DD
- 0.4V)
Active mode, V
PIN
= 0.4V
30
30
100
100
50
9
CONDITIONS
MIN
TYP
MAX
0.4
200
200
UNITS
V
nA
nA
pF
s
ms
DS2775/DS2776/DS2777/DS2778
SHA-1 COMPUTATION TIMING (DS2776/DS2778 ONLY)
(V
DD
= +4.0V to +9.2V, T
A
= 0°C to +70°C, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
Computation Time
SYMBOL
t
COMP
CONDITIONS
MIN
TYP
MAX
30
UNITS
ms
ELECTRICAL CHARACTERISTICS: PROTECTION CIRCUIT
(V
DD
= +4.0V to +9.2V, T
A
= 0°C to +50°C, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
Overvoltage Detect
Charge-Enable Voltage
Undervoltage Detect
Overcurrent Detect: Charge
Overcurrent Detect: Discharge
Short-Circuit Current Detect
Overvoltage Delay
Undervoltage Delay
Overcurrent Delay
Short-Circuit Delay
Charger-Detect Hysteresis
Test Threshold
Test Current
PLS Pulldown Current
Recovery Current
SYMBOL
V
OV
V
CE
V
UV
V
COC
V
DOC
V
SC
t
OVD
t
UVD
t
OCD
t
SCD
V
CD
V
TP
I
TST
I
PPD
I
RC
V
UV
condition
COC, DOC condition
DOC condition
COC condition
Sleep mode
V
UV
condition, max: V
PLS
= 15V, V
DD
= 1.4V;
min: V
PLS
= 4.2V, V
DD
= 2V
0.4
20
-45
200
3.3
CONDITIONS
V
OV
= 1110111b
V
OV
= 1100011b
Relative to V
OV
Programmable in Control register 0x60h,
UV[1:0] = 10
OC = 11b
OC = 00b
OC = 11b
OC = 00b
SC =1b
SC = 0b
(Note 3)
(Note 3)
2.415
-60
-12.5
80
25
240
120
600
600
8
80
10
120
50
1.0
40
-60
400
8
1.2
80
-95
630
13
MIN
4.438
4.242
TYP
4.473
4.277
-100
2.450
-75
-25
100
38
300
150
2.485
-90
-38
120
50
360
180
1400
1400
12
160
MAX
4.508
4.312
UNITS
V
mV
V
mV
mV
mV
ms
ms
ms
μs
mV
V
μA
μA
mA
_______________________________________________________________________________________
3
2-Cell, Stand-Alone, Li+ Fuel-Gauge IC with
Protector and Optional SHA-1 Authentication
DS2775/DS2776/DS2777/DS2778
EEPROM RELIABILITY SPECIFICATION
(V
DD
= +4.0V to +9.2V, T
A
= -20°C to +70°C, unless otherwise noted.)
PARAMETER
EEPROM Copy Time
EEPROM Copy Endurance
SYMBOL
t
EEC
N
EEC
T
A
= +50°C
50,000
CONDITIONS
MIN
TYP
MAX
10
UNITS
ms
Cycles
ELECTRICAL CHARACTERISTICS: 1-Wire INTERFACE, STANDARD (DS2775/DS2776 ONLY)
(V
DD
= +4.0V to +9.2V, T
A
= -20°C to +70°C.)
PARAMETER
Time Slot
Recovery Time
Write-Zero Low Time
Write-One Low Time
Read Data Valid
Reset Time High
Reset Time Low
Presence-Detect High
Presence-Detect Low
SYMBOL
t
SLOT
t
REC
t
LOW0
t
LOW1
t
RDV
t
RSTH
t
RSTL
t
PDH
t
PDL
480
480
15
60
960
60
240
CONDITIONS
MIN
60
1
60
1
120
15
15
TYP
MAX
120
UNITS
μs
μs
μs
μs
μs
μs
μs
μs
μs
ELECTRICAL CHARACTERISTICS: 1-Wire INTERFACE, OVERDRIVE (DS2775/DS2776 ONLY)
(V
DD
= +4.0V to +9.2V, T
A
= -20°C to +70°C.)
PARAMETER
Time Slot
Recovery Time
Write-Zero Low Time
Write-One Low Time
Read Data Valid
Reset Time High
Reset Time Low
Presence-Detect High
Presence-Detect Low
SYMBOL
t
SLOT
t
REC
t
LOW0
t
LOW1
t
RDV
t
RSTH
t
RSTL
t
PDH
t
PDL
48
48
2
8
80
6
24
CONDITIONS
MIN
6
1
6
1
16
2
2
TYP
MAX
16
UNITS
μs
μs
μs
μs
μs
μs
μs
μs
μs
4
_______________________________________________________________________________________
2-Cell, Stand-Alone, Li+ Fuel-Gauge IC with
Protector and Optional SHA-1 Authentication
ELECTRICAL CHARACTERISTICS: 2-WIRE INTERFACE (DS2777/DS2778 ONLY)
(V
DD
= +4.0V to +9.2V, T
A
= -20°C to +70°C.)
PARAMETER
SCL Clock Frequency
Bus-Free Time Between a STOP
and START Condition
Hold Time (Repeated) START
Condition
Low Period of SCL Clock
High Period of SCL Clock
Setup Time for a Repeated
START Condition
Data Hold Time
Data Setup Time
Rise Time of Both SDA and SCL
Signals
Fall Time of Both SDA and SCL
Signals
Setup Time for STOP Condition
Spike Pulse Widths Suppressed
by Input Filter
Capacitive Load for Each Bus
Line
SCL, SDA Input Capacitance
SYMBOL
f
SCL
t
BUF
t
HD:STA
t
LOW
t
HIGH
t
SU:STA
t
HD:DAT
t
SU:DAT
t
R
t
F
t
SU:STO
t
SP
C
B
C
BIN
(Note 8)
(Note 9)
(Notes 6, 7)
(Note 6)
(Note 5)
(Note 4)
CONDITIONS
MIN
0
1.3
0.6
1.3
0.6
0.6
0
100
20 +
0.1C
B
20 +
0.1C
B
0.6
0
50
400
60
300
300
0.9
TYP
MAX
400
UNITS
kHz
μs
μs
μs
μs
μs
μs
ns
ns
ns
μs
ns
pF
pF
DS2775/DS2776/DS2777/DS2778
Note 1:
Accumulation bias and offset bias registers set to 00h. NBEN bit set to 0.
Note 2:
Measurement made with V
SRC
= +8V, V
GS
driven with external +4.5V supply.
Note 3:
Overvoltage (OV) and undervoltage (UV) delays (t
OVD
, t
UVD
) are reduced to zero seconds if the OV or UV condition is
detected within 100ms of entering active mode.
Note 4:
Timing must be fast enough to prevent the DS2777/DS2778 from entering sleep mode due to bus low for period > t
SLEEP
.
Note 5:
f
SCL
must meet the minimum clock low time plus the rise/fall times.
Note 6:
The maximum t
HD:DAT
need only be met if the device does not stretch the low period (t
LOW
) of the SCL signal.
Note 7:
This device internally provides a hold time of at least 75ns for the SDA signal (referred to the V
IHMIN
of the SCL signal) to
bridge the undefined region of the falling edge of SCL.
Note 8:
Filters on SDA and SCL suppress noise spikes at the input buffers and delay the sampling instant.
Note 9:
C
B
is total capacitance of one bus line in pF.
_______________________________________________________________________________________
5
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