MAX3344E/MAX3345E
Detailed Description
The MAX3344E/MAX3345E are bidirectional transceivers
that convert single-ended or differential logic-level signals
to differential USB signals, and convert differential USB
signals to single-ended or differential logic-level signals.
The MAX3344E/MAX3345E are operational from V
CC
=
5.5V to V
CC
= 3V (electrical specifications are not guaran-
teed for V
CC
< 4V). Both devices include an internal
1.5kΩ pullup resistor that connects and disconnects D+
to VTRM (see the Functional Diagram).
The MAX3344E/MAX3345E are tolerant to power seq-
uencing with either V
CC
> V
L
or V
L
> V
CC
. Additionally,
the USB I/O, D+ and D-, and V
CC
are ESD protected to
±15kV. The MAX3344E/MAX3345E can receive USB
power (V
CC
) directly from the USB connection and
operate with logic supplies (V
L
) down to 1.65V, while
still meeting the USB physical layer specifications. The
MAX3344E/MAX3345E support full-speed (12Mbps)
USB specification 2.0 operation.
The MAX3344E/MAX3345E have an enumerate feature
that functions when power is applied. Driving ENUM low
disconnects the internal 1.5kΩ pullup resistor from D+
enumerating the USB. This is useful if changes in commu-
nication protocol are required while power is applied, and
while the USB cable is connected.
±15kV ESD-Protected USB Transceivers
in UCSP with USB Detect
6 _______________________________________________________________________________________
Pin Description
UCSP
O U T PU T
Output
Receiver Output. Single-ended CMOS output. RCV responds to the differential input
on D+ and D-.
2D1VPO Input Logic-Level Data Input. VPO is level translated to D+.
3C2MODE Input
Mode-Control Input. Selects differential (mode 1) or single-ended (mode 0) input for
the system side when converting logic-level signals to USB level signals. Force
MODE high to select mode 1. Force MODE low to select mode 0.
4C1VMO Input Logic-Level Data Input. VMO is level translated to D-.
5B1OE Input
Output Enable. Drive OE low to enable data transmission on D+ and D-. Drive OE
high to disable data transmission or to receive data.
6B2SUSP Input
Suspend Input. Drive SUSP low for normal operation. Drive SUSP high for low-power
state. In low-power state, RCV is low and VPI/VMI are active.
7A1VPI
Output
Logic-Level Data Output. VPI is the level-translated value of D+.
8A2VMI
Output
Logic-Level Data Output. VMI is the level-translated value of D-.
9B3ENUM Input
Enumerate. Drive ENUM high to connect the internal 1.5kΩ resistor from D+ to 3.3V.
Drive ENUM low to disconnect the internal 1.5kΩ resistor.
10 A3 V
CC
Power
USB-Side Power-Supply Input. Connect V
CC
to the incoming USB power supply.
Bypass V
CC
to GND with a 1µF ceramic capacitor.
11 A4 GND Power Ground
12 B4 D-
Input/
Output
Negative USB Differential Data Input/Output. Connect to the USB’s D- signal through
a 23.7Ω ±1% resistor.
13 C4 D+
Input/
Output
Positive USB Differential Data Input/Output. Connect to the USB’s D+ signal through
a 23.7Ω ±1% resistor.
14 D4 VTRM Power
Reg ul ated Outp ut V ol tag e. V TRM p r ovi d es a 3.3V outp ut d er i ved fr om V
C C
. Byp ass
V TRM to G N D w i th a 1µF ( m i n) l ow - E S R cap aci tor , such as cer am i c or p l asti c fi l m typ es.
15 D3 V
L
Power
S ystem - S i d e P ow er - S up p l y Inp ut. C onnect to the system ’ s l og i c- l evel p ow er sup p l y,
1.65V to 3.6V .
16 C3
USB_DET Output
USB Detector Output. A high at USB_DET signals to the ASIC that V
CC
is present. A
low at USB_DET indicates that V
CC
is not present. 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).
