Rainbow Electronics MAX3345E User Manual

Page 8

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MAX3344E/MAX3345E

±15kV ESD-Protected USB Transceivers
in UCSP with USB Detect

_______________________________________________________________________________________

The MAX3344E/MAX3345E system-side outputs are
VPI, VMI, and RCV. The MAX3344E/MAX3345E send
data through VPI, VMI, and RCV. VPI and VMI are out-
puts to the single-ended receivers and RCV is the out-
put of the differential receiver.

Output enable (

OE) controls data transmission. Drive OE

low to enable data transmission on D+ and D-. Drive

high to disable data transmission or receive data.

MODE

MODE is a control input that selects whether differential
or single-ended logic signals are recognized by the
system side of the MAX3344E/MAX3345E. Drive MODE
high to select differential mode with VPO as the positive
terminal and VMO as the negative terminal. Drive
MODE low to select single-ended mode with VPO as
the data input (Table 3).

VTRM

VTRM is the 3.3V output of the internal linear voltage
regulator. VTRM powers the internal circuitry of the USB
side of the MAX3344E/MAX3345E. Connect a 1µF (min)
low-ESR ceramic or plastic capacitor from VTRM to
GND, as close to VTRM as possible. Do not use VTRM
to power external circuitry.

Bypass V

to GND with a 1µF ceramic capacitor as

close to the device as possible. If V

drops below the

USB detect threshold, supply current drops
below 20µA avoiding excessive V

current consump-

tion, and D+/D- enter a high-impedance state allowing
other devices to drive the lines.

USB Detect

USB detect output (USB_DET) signals that V

is pre-

sent. A high at USB_DET indicates that V

is present,

while a low at USB_DET indicates that V

is not pre-

sent. The MAX3344E USB_DET threshold is between
3.6V (min) and 4V (max), while the MAX3345E USB_DET
threshold is between 1V (min) and 2.8V (max).

SUSP

Suspend (SUSP) is a control input. Force SUSP high to
place the MAX3344E/MAX3345E in a low-power state.
In this state, the quiescent supply current into V

less than 40µA and RCV goes low.

In suspend mode, VPI and VMI remain active as
receive outputs and VTRM stays on. The MAX3344E/
MAX3345E continue to receive data from the USB,
allowing the µP to sense activity on the D+/D- lines and
wake up the MAX3344E/MAX3345E.

The MAX3344E/MAX3345E can also transmit data to
D+ and D- while in suspend mode. This function is

used to signal a remote wake-up by driving a signal on
D+ and D- for a period of 1ms to 15ms. In suspend
mode, data can only be transmitted with full-speed
slope control.

Figure 1c. IEC 1000-4-2 ESD Test Model

CHARGE-CURRENT-

LIMIT RESISTOR

DISCHARGE

RESISTANCE

STORAGE
CAPACITOR

150pF

50MΩ TO 100MΩ

330Ω

HIGH-

VOLTAGE

SOURCE

DEVICE

UNDER

TEST

Figure 1b. Human Body Model Current Waveform

100%

90%

36.8%

TIME

CURRENT WAVEFORM

PEAK-TO-PEAK RINGING
(NOT DRAWN TO SCALE)

10%

AMPERES

Figure 1a. Human Body ESD Test Models