Electronic Components Datasheet Search
Selected language     English  ▼
Advanced Search

              



Part Name


UT3223_17 Datasheet(PDF) 6 Page - Unisonic Technologies

Part No. UT3223_17
Description  DRIVERS/RECEIVERS
Download  9 Pages
Scroll/Zoom Zoom In 100% Zoom Out
Maker  UTC [Unisonic Technologies]
Homepage  http://www.utc-ic.com
Logo 

   
 6 page
background image
UT3223
Preliminary
CMOS IC
UNISONICTECHNOLOGIESCO.,LTD
6 of 9
www.unisonic.com.tw
QW-R502-A91.e
DETAILED DESCRIPTION
Charge-Pump Voltage Converter
The UTC UT3223 consists of a regulated dual charge pumps that provide output voltages of +5.5V and -5.5V,
regardless of the input voltage (VCC) changing from +3.0V to +5.5V.
The charge pumps operate in a discontinuous mode: if the output voltages are less than 5.5V, the charge pumps
are enabled; if the output voltages exceed 5.5V, the charge pumps are disabled.
Each charge pump requires a flying capacitor (C1, C2) and a reservoir capacitor (C3, C4) to generate the V+ and
V- supplies, refer to application circuit.
RS-232 Transmitters
UTC UT3223’s transmitters are inverting level translators that convert CMOS-logic levels to 5.0V EIA/TIA-232
levels. They guarantee a 250kbps data rate with worst-case loads of 3kΩ in parallel with 1000pF, providing
compatibility with PC-to-PC communication software.
Transmitters can be paralleled to drive multiple receivers or mouse. When FORCEOFF is driven to ground, or
shutdown circuitry senses invalid voltage levels at all receiver inputs, the transmitters are disabled and the outputs
are forced into a high-impedance state.
RS-232 Receivers
The UTC UT3223’s receivers convert RS-232 signals to CMOS-logic output levels. All receivers have one
inverting three-state output. In shutdown or in autoshutdown, the UT3223’s receivers are active. Drive EN high to
place the receiver in a high-impedance state.
Table 1. EN Control Truth Table
EN
R_OUT
0
Active
1
High-Z
Shutdown Function
A 1µA supply current is achieved with shutdown feature, which operates when FORCEON is low and
FORCEOFF is high. When the UTC UT3223 senses no valid signal levels on all receiver inputs for 30µs, the
on-board power supply and drivers are shut off, reducing supply current to 1µA. This occurs if the RS-232 cable is
disconnected or the connected peripheral transmitters are turned off. The system turns on again when a valid level is
applied to any RS-232 receiver input. As a result, the system saves power without changes to the existing BIOS or
operating system. INVALID indicates the receiver inputs’ condition, when using shutdown function, the INVALID
output is high when the device is on and low when the device is shut down.
Table 2. Shutdown Logic Control Truth Table
OPERATION STATUS
FORCEOFF
INPUT
FORCEON
INPUT
INVALID
OUTPUT
T_OUT
Normal Operation (Forced On)
H
H
X
Active
Normal Operation (AutoShutdown)
H
L
H
Active
Normal Operation (AutoShutdown)
H
L
L
High-Z
Shutdown (Forced Off)
L
X
X
High-Z




Html Pages

1  2  3  4  5  6  7  8  9 


Datasheet Download




Link URL

Does ALLDATASHEET help your business so far?  [ DONATE ]  

About Alldatasheet   |   Advertisement   |   Contact us   |   Privacy Policy   |   Bookmark   |   Link Exchange   |   Manufacturer List
All Rights Reserved© Alldatasheet.com


Mirror Sites
English : Alldatasheet.com  , Alldatasheet.net  |   Chinese : Alldatasheetcn.com  |   German : Alldatasheetde.com  |   Japanese : Alldatasheet.jp  |   Russian : Alldatasheetru.com
Korean : Alldatasheet.co.kr   |   Spanish : Alldatasheet.es  |   French : Alldatasheet.fr  |   Italian : Alldatasheetit.com  |   Portuguese : Alldatasheetpt.com  |   Polish : Alldatasheet.pl