LM9833CCVJD/NOPB National Semiconductor, LM9833CCVJD/NOPB Datasheet - Page 35

• Manufacturer Part Number: LM9833CCVJD/NOPB
• Description: IC USB IMAGE SCAN 48BIT 100-TOFP
• Manufacturer: National Semiconductor

Specifications of LM9833CCVJD/NOPB

• Number Of Bits: 16
• Number Of Channels: 3
• Voltage - Supply, Analog: 5V
• Voltage - Supply, Digital: 4.5 V ~ 5.5 V
• Package / Case: 100-TQFP, 100-VQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Power (watts): -
• Other names: *LM9833CCVJD; *LM9833CCVJD/NOPB; LM9833CCVJD

Applications Information
12.3 Steps to Reverse Register Increased
To improve performance with some mechanical designs, the
number of bits in register 50 was increased from 6 to 8 bits. This
allows the scanner to reverse up to 255 steps when pausing due
to a buffer full condition.
12.4 - Acceleration Profile Modified
The highest setting of the Acceleration Profile (bits 2-7 of register
51) has been modified to give the motor more time during the
acceleration/deceleration phases. In the LM9831, a setting of 3
for the “stopped” time, “25%” time, and “50%” time caused the
state machine to spend 3 full steps in that state. In the LM9833, a
setting of 3 will cause the state machine to spend 8 full steps in
that state.
12.5 1 Channel Color Mode
When using the LM9831 in 1 Channel Color Mode with the hold
current timeout set to 0, the LM9831 would sometimes skip a line
during a pause/resume cycle. This problem has been fixed in the
LM9833.
12.6 DRAM Control Signals
The RD, WR, CAS, and RAS pins are now tri-stated when the
LM9833 is in Suspend Mode. In a USB bus-powered application
where the DRAM is powered down in suspend mode but the
LM9833’s VDRAM supply still has power, this change prevents
the RD, WR, CAS, and RAS pins from potentially forward biasing
the input protection diodes of the external DRAM which could
cause the current drawn from the USB’s power source to exceed
the 2.5mA maximum allowable current draw when in suspend
mode.
12.7 Start of Scan Reset
In the LM9831, the value in register 01 is not reset (and therefore
not accurate) until the first line of the image has been scanned.
The LM9833 resets this counter as soon as a scan is initiated, so
the value in register 01 is always valid.
12.8 Power-On Reset (POR)
The LM9831 has a power-on reset circuit that causes the chip to
be reset during power-up when the analog power supply (V
passes 2V. If V
the LM9831 to be reset and start trying to load data from the
external EEPROM before the external was EEPROM became
active, which could cause the LM9831 to think there was no
external EEPROM attached.
The LM9833 has a power-on reset threshold to 3V, to reduce the
chance of this occurring. Additionally, the input to the POR comes
from V
when in Suspend mode, allowing more flexibility in USB bus-pow-
ered designs.
12.9 Remote Wakeup
The LM9833 supports enabling and disabling remote wakeup
through the LM9833 minidriver software.
D
, not V
A
A
. This allows the V
ramped very slowly (2V/ms), this could cause
A
supply to be switched off
(Continued)
A
)
35
12.10 Reduced Current Consumption
The LM9833 includes 4 current settings (100%, 80%, 70%, and
50%) to control the current consumed by the analog supply (V
The LM9833 is tested and guaranteed at the 100% setting, which
is the same as the LM9831’s analog section. For USB bus-pow-
ered settings, To reduce the current consumption (for bus-pow-
ered applications) set this register to one of the 3 other settings.
The performance of the analog section (INL, DNL, and noise) will
degrade at the lower settings, but this may not be noticeable in
the final image, particularly with CIS sensors where the noise and
non-linearities of the sensor may be far greater than that of the
LM9833’s analog front end.
12.11 Motor Phase Swap
Bit 5 has been added to register 45 to “swap” the A and B stepper
motor phases. This will reverse the stepper motor’s direction of
movement. This can be used to make the scanner scan in the
opposite (or both) directions, provides an alternative means of
sensing the home position by scanning towards home until a pat-
tern on the calibration strip (instead of an optical sensor) is
detected, and also provides a software fix for a motor that hap-
pens to be wired backwards. Note that this only works in fullstep
mode.
12.12 ITA Output on LAMP
The LM9833 adds 1 bit (register 29 bit 2) that, when set, will out-
put the ITA (Integration Time Adjust) phase on the LAMP
pin. This signal can potentially be used to turn off the illumination
source during the ITA’s long integration time period.
12.13 Faster Fullstep Movement
In Fullstep Mode, the LM9831 and LM9833 normally move the
motor with the motor winding current set to 0.35V/R
(0.5V/R
ment). The problem is that the ideal R
ping was too small for fullstepping, and vice-versa. So if the
scanner needed to use both modes (fullstepping for high speed
movement and low resolution scans, microstepping for high reso-
lution scans), there wasn’t a sense resistor value that worked well
for both.
The LM9833 improves this situation by adding this function: if the
Kickstart Steps value (register 55 bits 0-2) is set to 0, the LM9833
will set the winding current to 0.5V/R
ment. This provides more current to the stepper motor in fullstep
mode, while allowing the sense resistor to be at a value optimized
for microstepping.
12.14 Fullstepping Fastfeed, Microstepping Scan
The LM9833 adds 1 bit (register 45 bit 6) that, when set, makes
the scanner automatically use fullstep mode for fastfeeding at the
start of scan, then switch to microstepping when scan begins.
12.15 Device and Vendor IDs for USB Interface
The LM9833’s internal (default) ROM is programmed for a Ven-
dor ID of 0x0400 and Device ID of 0x1002. The Vendor String is
“National Semiconductor” and the Device String is “LM9833 48
Bit Scanner”.
SENSE
during the Kickstart period at the start of move-
B
SENSE
SENSE
for all fullstep move-
value for microstep-
www.national.com
B
output
SENSE
A
).