Datasheet

bq20z45
SLUS800 – MARCH 2009 .................................................................................................................................................................................................. www.ti.com
ELECTRICAL CHARACTERISTICS (continued)
over operating free-air temperature range (unless otherwise noted), T
A
= – 40 ° C to 85 ° C, V
(REG25)
= 2.41 V to 2.59 V,
V
(BAT)
= 14 V, C
(REG25)
= 1 µ F, C
(REG33)
= 2.2 µ F; typical values at T
A
= 25 ° C (unless otherwise noted)
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
Offset error
(7)
T
A
= 25 ° C to 85 ° C 10 µ V
Offset error drift 0.4 0.7 µ V/ ° C
Full-scale error
(8) (9)
± 0.35%
PPM/
Full-scale error drift 150
° C
Effective input resistance
(10)
T
A
= 25 ° C to 85 ° C 2.5 M Ω
INTERNAL TEMPERATURE SENSOR
V
(TEMP)
Temperature sensor voltage
(11)
-2.0 mV/ ° C
VOLTAGE REFERENCE
Output voltage 1.215 1.225 1.230 V
PPM/
Output voltage drift 65
° C
HIGH FREQUENCY OSCILLATOR
f
(OSC)
Operating frequency 4.194 MHz
– 3% 0.25% 3%
f
(EIO)
Frequency error
(12) (13)
T
A
= 20 ° C to 70 ° C – 2% 0.25% 2%
t
(SXO)
Start-up time
(14)
2.5 5 ms
LOW FREQUENCY OSCILLATOR
f
(LOSC)
Operating frequency 32.768 kHz
– 2.5% 0.25% 2.5%
f
(LEIO)
Frequency error
(13) (15)
T
A
= 20 ° C to 70 ° C – 1.5% 0.25% 1.5%
t
(LSXO)
Start-up time
(14)
500 µ s
(7) Post-calibration performance
(8) Reference voltage for the coulomb counter is typically V
ref
/3.969 at V
(REG25)
= 2.5 V, T
A
= 25 ° C.
(9) Uncalibrated performance. This gain error can be eliminated with external calibration.
(10) The CC input is a switched capacitor input. Since the input is switched, the effective input resistance is a measure of the average
resistance.
(11) – 53.7 LSB/ ° C
(12) The frequency error is measured from 4.194 MHz.
(13) The frequency drift is included and measured from the trimmed frequency at V
(REG25)
= 2.5V, T
A
= 25 ° C
(14) The startup time is defined as the time it takes for the oscillator output frequency to be ± 3%
(15) The frequency error is measured from 32.768 kHz.
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