MAX3421EEHJ+T Maxim Integrated Products, MAX3421EEHJ+T Datasheet - Page 24

• Manufacturer Part Number: MAX3421EEHJ+T
• Description: IC USB PERIPH/HOST CNTRL 32TQFP
• Manufacturer: Maxim Integrated Products

Specifications of MAX3421EEHJ+T

• Controller Type: USB Peripheral Controller
• Interface: USB/Serial
• Voltage - Supply: 3 V ~ 3.6 V
• Current - Supply: 15mA
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 32-TQFP, 32-VQFP
• For Use With: MAX3421EVKIT-1+ - EVAL KIT FOR MAX3421E
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

USB Peripheral/Host Controller
with SPI Interface
Figure 19. MAX3421E in a Bus-Powered Peripheral Application
C
C
Drive level: 200µW
Series resonance resistance: 60Ω (max)
Note: Series resonance resistance is the resistance
observed when the resonator is in the series resonant
condition. This is a parameter often stated by quartz crys-
tal vendors and is called R1. When a resonator is used in
the parallel resonant mode with an external load capaci-
tance, as is the case with the MAX3421E oscillator circuit,
the effective resistance is sometimes stated. This effec-
tive resistance at the loaded frequency of oscillation is:
For typical C
tance can be greater than R1 by a factor of 2.
Figure 19 depicts the MAX3421E in a peripheral device
that is powered by V
geous because it requires no external power supply.
V
regulator to power the MAX3421E. This diagram
24
BUS
LOAD
O
: 7pF (max)
MAX3421E in a Bus-Powered Peripheral
______________________________________________________________________________________
is specified from 4.75V to 5.25V, requiring a 3.3V
: 18pF (max)
CONNECTOR
O
R1 x ( 1 + (C
USB "B"
and C
BUS
LOAD
V
GND
BUS
. This configuration is advanta-
4.7μF
D+
D-
O
values, the effective resis-
/ C
REGULATOR
MAX6349TL
LOAD
3.3V
GPI
33Ω
33Ω
))
2
Application
CERAMIC
1.0μF
RES
D+
D-
VBCOMP
V
CC
V
GND
L
0.1μF
MAX3421E
assumes that the microprocessor is powered by 3.3V
as well, so the V
connected to V
pose inputs/outputs) are referenced to 3.3V.
USB is a hot-plug system (V
device is plugged in), so it is good design practice to
use a power-on reset circuit to provide a clean reset to
the system when the device is plugged in. The
MAX6349TL serves as an excellent USB regulator,
since it has very low quiescent current and a POR cir-
cuit built in.
Because this design is bus powered, it is not necessary
to test for the presence of V
voltage-detection input, VBCOMP, makes an excellent
general-purpose input. The VBCOMP input has two inter-
rupts associated with it, VBUSIRQ and NOVBUSIRQ.
These interrupts can detect both edges of any transitions
on the VBCOMP input.
The configuration in Figure 19 shows the SPI interface
using the maximum number of SPI interface pins. The
data pins, MOSI and MISO, are separate, and the
MAX3421E supplies an interrupt signal through the INT
output pin to the µP to notify the µP when its attention
is required.
GPIN GPOUT
8
C
XI
XI
12MHz
CC
8
GPIO
L
XO
. Therefore, the GPIOs (general-pur-
pin (logic-level reference voltage) is
MOSI
MISO
SCLK
C
INT
XO
SS
BUS
BUS
. In this case, the bus
is powered when the
μP