DRV8808 Datasheet, PDF (21/38 Pages) Texas Instruments – COMBINATION MOTOR DRIVER WITH DC-DC CONVERTER

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3.3V
NC
DRV8808
SLVS857A – DECEMBER 2009 – REVISED AUGUST 2011
LDO_IN
LDO _OUT
LDO _FB
LDO Regulator
FB _ B
Figure 9. Unused LDO Recommended Connections
For proper termination, it is recommended that, if left unused, the LDO terminals be connected in the following
fashion:
1. LDO IN must be powered by an input voltage greater than 1 V.
2. LDO OUT must be left disconnected.
LDO Feed Back must be connected to the DC/DC Converter Channel B Feed Back terminal.
Table 9. CSELECT for Start-Up ^{(1) (2) (3)}
CSELECT
Gnd
Pull down (by external 200 kΩ)
OPEN
PIN VOLTAGE
0 V to 0.3 V
1.3 V to 2.0 V
3.0 V to 3.3 V
DCDC_A
OFF
OFF
OFF
DCDC_B
OFF
ON
ON
DCDC_C
OFF
OFF
ON
(1) The CSELECT pin is connected to internal 3.3-V supply through 200-kΩ resister.
(2) This CSELECT pin control is valid after the PowerON Reset is initiated. Once the Setup Register is set, the dc-dc control follows the bits
7 to 9 on the Setup Register, bank 0, until the next PowerON Reset event occurred.
(3) For OPEN case, B starts up 1st and C follows after 10-ms delay.
SETUP REGISTER BANK 0, BIT 7
0
0
1
1
Table 10. Regulator A Control
A_CONT
0
1
0
1
DCDC_A
ON
OFF
OFF
OFF
nReset: Input for System Reset
nReset pin assertion stops all the dc-dc converters and H-bridges. It also resets all the register contents to
default values. After deassertion of input, device follows the initial start-up sequence. The CSELECT state is
captured after the nReset deassertion (L > H).
The input is pulled up to internal 3.3 V by a 200-kΩ resistor. When the pin is H or left open, the reset function is
released. Also it has deglitch filter of 2.5 μs to 7.5 μs.
Copyright © 2009–2011, Texas Instruments Incorporated
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