NS7520B-1-I46 Digi International, NS7520B-1-I46 Datasheet - Page 320

• Manufacturer Part Number: NS7520B-1-I46
• Description: IC ARM MICROPROCESSOR 177BGA
• Manufacturer: Digi International
• Series: NET+ARM®r

Specifications of NS7520B-1-I46

• Applications: Network Processor
• Core Processor: ARM7
• Program Memory Type: External Program Memory
• Controller Series: -
• Ram Size: External
• Interface: EBI/EMI, Ethernet, DMA, SPI, UART
• Number Of I /o: 16
• Voltage - Supply: 1.4 V ~ 3.6 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 177-LFBGA
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

SPI slave mode errata
Error in “No Connect” pin terminations
3 0 8
N S 7 5 2 0 e r r a t a
SPI slave modes are non-functional. SPI slave logic is unable to sample or drive data
on the correct clock edges. This causes byte mismatches.
Workaround
None.
Table 9: “No Connect” pins in the NS7520 Hardware Reference erroneously advises
connecting pins R13, P12, and N12 directly to V
excessive V
cause the case temperature to rise above normal, but exhibits no operational
failures.
Workaround
1
2
Note:
Correction
Refer to Table 8 in Chapter 2 of the NS7520 Hardware Reference manual.
For existing designs: Cut the pin R13, P12, and N12 traces to the V
connection. This will “float” pins R13, P12, and N12. It is advisable to modify
the PCB to add two pulldown resistors and one GND, as recommended next for
new designs.
For new designs: Add individual 15K ohm pulldowns to GND on R13 and P12. Tie
N12 to ground. (A 15K ohm pulldown is the recommended value; 10–20K ohms is
acceptable.)
On designs that have implemented 10 to 20K ohm pullups instead of
pulldowns on R13 and P12 pins or GND on N12, no action is required. This
method of termination limits the increase of V
RESET
N S 7 5 2 0 H a r d w a r e R e f e r e n c e , R e v G 9 / 2 0 0 7
CC
(333uA with 10K ohm pullup or 165 uA with 20K ohm pullup).
current, at times following
RESET
, in the range of 120 ma. This will
CC
. This can cause the NS7520 to draw
CC
current, at times following
CC
supply