Datasheet

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bq20z80-V102
SLUS681B – NOVEMBER 2005 – REVISED JANUARY 2007
TERMINAL FUNCTIONS
TERMINAL
I/O
(1)
DESCRIPTION
NO. NAME
1 VIN I Voltage measurement input from the AFE
2 TS1 I 1
st
Thermistor voltage input connection to monitor temperature
3 TS2 I 2
nd
Thermistor voltage input connection to monitor temperature
4 PU O Output to pull up the PRES pin for system detection
5 PRES I Active low input to sense system insertion and typically requires additional ESD protection
6 SCLK I/OD Communication clock to the AFE
7 SAFE O Active high output to enforce additional level of safety protection; e.g., fuse blow. (Inverse of pin 12)
8 VDDD P Positive supply for digital circuitry and I/O pins
Backup power to the bq20z80 data registers during periods of low operating voltage. RBI accepts a
9 RBI P
storage capacitor or a battery input.
10 SDATA I/O Data transfer to and from the AFE
12 SAFE O Active low output to enforce additional level of safety protection; e.g., fuse blow. (Inverse of pin 7)
13 NC – Not used— leave floating
14 NC – Not used— leave floating
15 SMBC I/OD SMBus clock open-drain bidirectional pin used to clock the data transfer to and from the bq20z80
16 SMBD I/OD SMBus data open-drain bidirectional pin used to transfer address and data to and from the bq20z80
Display control for the LEDs. This pin is typically connected to bq29312A REG via a 100-k Ω resistor
17 DISP I
and a push-button switch to VSSD.
Active low input to detect secondary protector output status and allows the bq20z80 to report the
18 PFIN I
status of the 2
nd
level protection output
20 LED5 O LED5 display segment that drives an external LED depending on the firmware configuration
21 LED4 O LED4 display segment that drives an external LED depending on the firmware configuration
22 LED3 O LED3 display segment that drives an external LED depending on the firmware configuration
23 LED2 O LED2 display segment that drives an external LED depending on the firmware configuration
24 LED1 O LED1 display segment that drives an external LED depending on the firmware configuration
25 XALERT I Input from bq29312A XALERT output.
26 MRST I Master reset input that forces the device into reset when held high
Connections for a small-value sense resistor to monitor the battery charge- and discharge-current
27 SR2 IA
flow
Connections for a small-value sense resistor to monitor the battery charge- and discharge-current
28 SR1 IA
flow
31 VDDA P Positive supply for analog circuitry
Analog input connected to the external PLL filter components which are a 150-pF capacitor to V
SSA
,
32 FILT IA in parallel with a 61.9-k Ω resistor and a 2200-pF capacitor in series. Place these components as
close as possible to the bq20z80 to ensure optimal performance.
32.768-kHz crystal oscillator output pin or connected to a 100k, 50ppm or better resistor if the
33 XCK2/ROSC O
internal oscillator is used
34 XCK1/VSSA I 32.768-kHz crystal oscillator input pin or connected to VSSA if the internal oscillator is used
35 CLKOUT O 32.768-kHz output for the bq29312. This pin should be directly connected to the AFE.
36, 37 NC - Not used— leave floating
11, 19, 38 VSSD P Negative supply for digital circuitry
29, 30 VSSA P Negative supply for analog circuitry.
(1) I = Input, IA = Analog input, I/O = Input/output, I/OD = Input/Open-drain output, O = Output, OA = Analog output, P = Power
3
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