gauge solution for Li-Ion and NiMH chemistry battery
packs. A low-power, 16-bit MAXQ20 microcontroller
with generous program and data memory, combined
with an accurate measurement system for battery
current, voltage, and temperature provide the ideal
platform for customized fuel-gauge algorithms.
EEPROM data memory supports nonvolatile (NV)
in-pack storage of charge parameters, cell
characteristics, usage history, and manufacturing/lot
tracking data.
FEATURES
Accurate Current Measurement for Coulomb
Counting (Current Accumulation)
1.5% ±4µV Over ±64mV Input Range
1.5% ±267µA Over ±4.2A Range Using an
External 15m: Series Resistor
High-Resolution Current Reporting
12-Bit + Sign Average Every 0.88ms
15-Bit + Sign Average Every 2.8s
Three Voltage Measurement Sources
10-Bit Average from VIN1, VIN2–VIN1, and Vx
Inputs
Temperature Measurement
10-Bit Using On-Chip Sensor
Ratiometric Input for External Thermistor (Vx)
16-Bit MAXQ20 Low-Power Microcontroller
Efficient C-Language Programming
8k Words Total Program Memory:
4k Words EEPROM Program Memory
4k Words ROM Program Memory
64 Words Data EEPROM
256 Words Data RAM
Password-Protected Programming
On-Chip, Low Drop-Out Regulator
2.5V to 10V Operating Range
SHA-1 Hash Algorithm in ROM
19.2kbps UART Interface
Internal Oscillator: No Crystal Required
Low-Power Consumption
1.5mA CPU Mode (1MHz), 145µA ANALOG
Mode, 50µA SLEEP Mode
APPLICATIONS
Digital Video Cameras
SLR Digital Still Cameras
Subnotebook PCs and Ultra-Portable PCs
Industrial PDAs, Handheld Computers, and GPS
FUNCTIONAL DIAGRAM
ORDERING INFORMATION
PART
DS2792G+
TEMP RANGE
-20ºC to +70ºC
PIN-PACKAGE
TDFN-28
+ Denotes lead-free package.
Contact factory concerning Mask ROM devices.
Pin Configuration appears at end of data sheet.
MAXQ is a registered trademark of Maxim Integrated Products,
Inc.
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.
1 of 40
REV: 021607
DS2792 Programmable Fuel Gauge with UART Interface
ABSOLUTE MAXIMUM RATINGS
V
DD
, VIN2 to V
SS
....................................................................................................................................... -0.3V to +12V
P0.4, P0.5 to V
SS
................................................................................................................................ -0.3V to V
B
+0.3V
AV
SS
to V
SS
.............................................................................................................................................. -0.3V to +0.3V
All Other Pins to V
SS
.................................................................................................................................. -0.3V to +6V
TXD, P0.0–P0.5 Continous Sink Current ...............................................................................20mA Each, 50mA Total
Operating Temperature Range..............................................................................................................-40ºC to +85ºC
Storage Temperature Range ...............................................................................................................-55ºC to +125ºC
Soldering Temperature ................................................................................See 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 beyone 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.
RECOMMENDED DC OPERATING CHARACTERISTICS
(V
DD
= 2.5V to 10V, T
A
= -20°C to +70°C, unless otherwise noted. Typical values are at T
A
= +25°C, V
DD
= 5.0V.)
PARAMETER
Supply Voltage
Voltage Range: VIN1, TXD, RXD,
P0.0–P0.3, SNS1, SNS2
Voltage Range: P0.4–P0.5
Voltage Range: VIN2
Voltage Range: Vx
Output Voltage: V
B
V
VB
SYMBOL
V
DD
CONDITIONS
(Note 1)
(Note 1)
(Note 1)
(Note 1)
(Note 1)
V
DD
> 3.5V, I
O
= 2mA,
(Note 1)
MIN
+2.5
-0.3
-0.3
-0.3
-0.3
3.0
3.3
TYP
MAX
+10
5.5
V
B
+ 0.3
+10
V
B
+ 0.3
3.6
UNITS
V
V
V
V
V
V
ELECTRICAL CHARACTERISTICS
(V
DD
= 2.5V to 10V, T
A
= -20°C to +70°C, unless otherwise noted. Typical values are at T
A
= +25°C, V
DD
= 5.0V.)
PARAMETER
SYMBOL
I
SLEEP
I
SUSP
Supply Current
I
ANALOG
I
CPU
Power-On Reset Threshold
Brownout Threshold
Regulator Drop-Out
Current Measurement Input
Range
Current Measurement Resolution
Current Measurement Gain Error
Current Measurement Offset Error
Accumulated Current Range
Accumulated Current Resolution
Accumulated Current Offset
Temperature Measurement
Range
Temperature Measurement LSb
Temperature Measrement Error
V
RESET
V
BO
V
DO:VB
I
FS
I
LSB
I
GERR
I
OERR
q
FS
q
LSB
q
CA
T
FS
T
LSB
T
ERR
OBEN = 1
OBEN = 1,
R
SNS
= 0.015
0 C T
A
+50 C
o
o
CONDITIONS
SLEEP mode
(Note 2)
SUSPEND mode
(Note 3)
ANALOG mode
(Note 4)
CPU mode
(Note 5)
(Note 10)
V
DD
= 2.5V,
I
VB
= 2.0mA, (Note 6)
V
IS1
–V
IS2
MIN
TYP
25
25
110
0.8
MAX
50
50
145
1.5
2.2
2.4
0.15
UNITS
PA
PA
PA
mA
V
V
V
mV
PV/R
SNS
% Full
Scale
PV/R
SNS
mVh/R
SNS
PVh/R
SNS
PVh/Day
mAh/Day
o
o
1.0
2.0
1.6
2.2
-64
15.625
-0.5
-1
-7.8
-204.8
6.25
-94
-6.3
-40
0.125
-3
+64
+0.5
+1
+7.8
+204.8
0
0
+85
+3
C
C
C
o
2 of 40
DS2792 Programmable Fuel Gauge with UART Interface
PARAMETER
VIN1 Input Range (VIN1–V
SS
)
VIN1 LSb
VIN2 Input Range (VIN2–VIN1)
VIN2 LSb
VIN1, VIN2 Gain Error
VIN1, VIN2 Offset
Vx Input Range (Vx–V
SS
)
Vx LSb
Vx Error
VIN1, VIN2, Vx
Input Resistance
Current Measurement Sample
Frequency
Analog System Clock Frequency
SYMBOL
V
FS1
V
LSB1
V
FS2
V
LSB2
V
GERR
V
OERR
V
FSX
V
LSBX
V
ERRX
R
IN
f
SAMPLE
f
OSCA
V
DD
> 2.7V, T
A
= +25
o
C
Analog System Clock Error
f
ERR:OSCA
V
DD
> 2.7V,
0
o
C T
A
+50
o
C
-0.7
-2
-5
CPU System Clock Startup Time
CPU System Clock Frequency
CPU System Clock Error
Suspend Period Error
Filter Resistors
IS1 to SNS1, IS2 to SNS2
Input Logic High: RXD
Input Logic Low: RXD
Input Logic High: P0.0–P0.5
Input Logic Low: P0.0–P0.5
Output Logic Low: TXD, P0.X
P0.0–P0.3
Weak Pullup Current
Output Logic High: P0.4–P0.5
RXD, TXD Pulldown Current
RXD, TXD Pullup Current
RXD, TXD Capacitance
RXD Pulse Rejection
P0.0–P0.5 Pulse Rejection
t
SU:OSCI
f
OSCI
f
ERR:OSCI
t
ERR:SUS
R
KS
V
IH:RXD
V
IL:RXD
V
IH:P0
V
IL:P0
V
OL
I
PU:P0
V
OH
I
PD:UART
V
PU:UART
C
UART
t
SP:UART
t
SP:P0
Rising and falling edges
(Note 9)
Rising and falling edges
(Note 1)
(Note 1)
(Note 1)
(Note 1)
IOL = 4mA (Note 1)
V
PIN
= V
IH
,
V
DD
> 2.7V
Bits PPU:0,1,2,3 set
I
PIN
= 1mA
Bits PPU:4,5 set
V
PIN
= V
IL
,
Bits PPU:6,7 clear
V
PIN
= V
IL
,
Bits PPU:6,7 set
OSCA active
From SLEEP,
OSCA inactive
OSCA inactive
OSCA active
OSCA inactive
OSCA active
1
700
1000
14 x f
OSCA
-20
f
ERR:OSCA
-30
7
1.5
0.6
0.7 x V
B
0.3 x V
B
0.4
0.15
V
B
- 0.4
0.3
0.3
1.2
1.2
50
50
10
3
3
22.0
10
+30
13
+20
PS
kHz
kHz
%
%
k
V
V
V
V
V
PA
V
PA
PA
pF
ns
ns
(Note 8)
CONDITIONS
(Notes 1, 7)
(Notes 1, 7)
MIN
0
4.88
0
4.88
-1
-1
0
V
B
/1024
-1
15
1456
69.9
+0.7
+2
+5
%
+1
+1
+1
V
B
4.99
TYP
MAX
4.99
UNITS
V
mV
V
mV
%
LSb
V
—
% Full
Scale
M
Hz
kHz
(Note 1)
EEPROM RELIABILITY SPECIFICATION
(V
DD
= 2.5V to 10V, T
A
= -20°C to +70°C, unless otherwise noted. Typical values are at T
A
= +25°C, V
DD
= 5.0V.)
PARAMETER
EEPROM Copy Time
EEPROM Copy Endurance
SYMBOL
t
EEC
N
EEC
T
A
= +50°C
50,000
CONDITIONS
MIN
TYP
10
MAX
15
UNITS
ms
Cycles
3 of 40
DS2792 Programmable Fuel Gauge with UART Interface
ELECTRICAL CHARACTERISTICS: JTAG INTERFACE
(V
DD
= 2.5V to 10V, T
A
= -20°C to +70°C, unless otherwise noted. Typical values are at T
A
= +25°C, V
DD
= 5.0V.)
(See Figure 1.)
PARAMETER
JTAG Logic Reference
TCK High Time
TCK Low Time
TCK Low to TDO Output
TMS, TDI Input Setup to TCK
High
TMS, TDI Input Hold after TCK
High
Note 1:
Note 2:
Note 3:
Note 4:
Note 5:
Note 6:
Note 7:
Note 8:
Note 9:
Note 10:
SYMBOL
V
REF
t
TH
t
TL
t
TLQ
t
DVTH
t
THDX
CONDITIONS
(Note 1)
MIN
TYP
V
B
÷ 2
MAX
UNITS
V
µs
µs
4.0
4.0
1.0
1.0
4.0
µs
µs
µs
All voltages referenced to V
SS
.
Internal voltage regulator remains active in SLEEP mode. RAM and registers are powered to maintain contents. RXD and
internal interrupts can be armed by firmware.
Internal voltage regulator and suspend timer are active in SUSPEND mode. RAM and registers are powered to maintain
contents.
Internal voltage regulator and ADC are active in ANALOG mode. RAM and registers are powered to maintain contents. ADC data
is collected and updated to registers including current accumulation to ACR register.
MAXQ core fetches and executes instructions in CPU mode.
Parameters guaranteed by design.
Voltage A/D readings saturate at 4.85V.
f
OSCA
= 48 × f
SAMPLE
.
The filter on RXD suppresses noise spikes at the input buffers and delays the sampling instant.
V
RESET
and V
BO
will never overlap.
Figure 1. JTAG Timing Diagram
4 of 40
DS2792 Programmable Fuel Gauge with UART Interface
PIN DESCRIPTION
PIN
1, 7–10,
21, 25,
26, 28
2
3
4
5
6
11
12
13
14
15
16
17
18
19
20
22
23
24
27
—
NAME
N.C.
VIN2
VIN1
Vx
TXD
RXD
P0.0
P0.1
SNS2
IS2
IS1
SNS1
AV
SS
V
SS
P0.2
P0.3
P0.4
P0.5
V
B
V
DD
PAD
No Connection
Battery Voltage Sense Input 2.
Voltage measurement on VIN2 is
relative to VIN1.
Battery Voltage Sense Input 1.
Voltage measurement on VIN1 is
relative to AV
SS
.
Auxiliary ADC Input.
Voltage measured ratiometrically with respect
to V
B
pin voltage or absolutely with respect to internal reference.
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