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Part: ISL4270EIR-T
Category:
Analog & Mixed-Signal Processing
Description: QFN Packaged, +/-15kV Esd Protected, +3V to +5.5V, 300nA, 250kbps, RS-232 Transceivers With Enhanced Automatic Powerdown And a Separate Logic Supply
Company: Intersil Corporation
Datasheet: Download ISL4270EIR-T datasheet File size : 1127 kB
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Datasheet text preview:
®
ISL4270E
D a t a Sheet M a r c h 2003 FN6041
QFN Packaged, +/-15kV ESD Protected, +3V to +5.5V, 300nA, 250kbps, RS-232 Transceivers with Enhanced Automatic Powerdown and a Separate Logic Supply
The Intersil ISL4270E is a 3.0V to 5.5V powered RS-232 transceiver which meets ElA/TIA-232 and V.28/V.24 specifications, even at VCC = 3.0V. Additionally, it provides ±15kV ESD protection (IEC61000-4-2 Air Gap and Human Body Model) on transmitter outputs and receiver inputs (RS-232 pins). Targeted applications are PDAs, Palmtops, and notebook and laptop computers where the low operational, and even lower standby power consumption is critical. Efficient on-chip charge pumps, coupled with manual and enhanced automatic powerdown functions, reduce the standby supply current to a 300nA trickle. Tiny 5mm x 5mm Quad Flat No-Lead (QFN) packaging, and the use of small, low value capacitors ensure board space savings as well. Data rates greater than 250kbps are guaranteed at worst case load conditions. The ISL4270E features a VL pin that adjusts the logic pin output levels and input thresholds to values compatible with the VC C powering the external logic (e.g., a UART). This device includes an enhanced automatic powerdown function which powers down the on-chip power-supply and driver circuits. This occurs when all receiver and transmitter inputs detect no signal transitions for a period of 30 seconds. It power back up, automatically, whenever it senses a transition on any transmitter or receiver input. Table 1 summarizes the features of the ISL4270E, while Application Note AN9863 summarizes the features of each device comprising the 3V RS-232 family.
Features
· Available in Near Chip Scale QFN (5mmx5mm) Package · VL Supply Pin for Compatibility with Mixed Voltage Systems · ESD Protection for RS-232 I/O Pins to ±15kV (IEC61000) · Manual and Enhanced Automatic Powerdown Features · Meets EIA/TIA-232 and V.28/V.24 Specifications at 3V · On-Chip Charge Pumps Require Only Four External 0.1µF Capacitors · Receivers Stay Active in Powerdown · Very Low Supply Current . . . . . . . . . . . . . . . . . . . . 300µA · Guaranteed Minimum Data Rate . . . . . . . . . . . . . 250kbps · Wide Power Supply Range . . . . . . . Single +3V to +5.5V · Low Supply Current in Powerdown State. . . . . . . . 300nA
Applications
· Any System Requiring RS-232 Communication Ports - Battery Powered, Hand-Held, and Portable Equipment - Laptop Computers, Notebooks, Palmtops - Digital Cameras - PDA's and PDA Cradles - Cellular/Mobile Phones
Ordering Information
PART NO. ISL4270EIR ISL4270EIR-T TEMP. RANGE ( oC) -40 to 85 -40 to 85 PACKAGE 32 Ld QFN 32 Ld QFN Tape & Reel PKG. NO. L32.5x5 L32.5x5
TABLE 1. SUMMARY OF FEATURES PART NUMBER ISL4270E NO. OF NO. OF DATA RATE Rx. ENABLE Tx. Rx. (kbps) FUNCTION? 3 3 250 NO VL LOGIC SUPPLY PIN? YES MANUAL ENHANCED AUTOMATIC POWER- DOWN? POWERDOWN FUNCTION? YES YES
1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. 1-888-INTERSIL or 321-724-7143 | Intersil (and design) is a registered trademark of Intersil Americas Inc. Copyright © Intersil Americas Inc. 2003. All Rights Reserved
ISL4270E Pinout
ISL4270E (QFN) TOP VIEW
FORCEOFF
GND 26
VCC
C1+
C1-
NC
32 NC C2+ C2VT1 I N T2 I N INVALID NC 1 2 3 4 5 6 7 8 9 NC
31
30
29
28
27
NC 25 24 23 22 21 20 19 18 17 NC T1 OUT T2 OUT T3 OUT R1IN R2IN R3IN NC 16 NC
10 T3IN
V+ 11 FORCEON
12 R3OUT
13 R2OUT
14 R1OUT
15 VL
Pin Descriptions
PIN VCC V+ VGND C1+ C1C2+ C2TIN TOUT RIN ROUT VL INVALID System power supply input (3.0V to 5.5V). Internally generated positive transmitter supply (+5.5V). Internally generated negative transmitter supply (-5.5V). Ground connection. External capacitor (voltage doubler) is connected to this lead. External capacitor (voltage doubler) is connected to this lead. External capacitor (voltage inverter) is connected to this lead. External capacitor (voltage inverter) is connected to this lead. TTL/CMOS compatible transmitter Inputs. The switching point is a function of the VL voltage. ±15kV ESD Protected, RS-232 level (nominally ±5.5V) transmitter outputs. ±15kV ESD Protected, RS-232 compatible receiver inputs. TTL/CMOS level receiver outputs. Swings between GND and VL. Logic-Level Supply. All TTL/CMOS inputs and outputs are powered by this supply. Active low output that indicates if no valid RS-232 levels are present on any receiver input. Swings between GND and VL. FUNCTION
FORCEOFF Active low to shut down transmitters and on-chip power supply. This overrides any automatic circuitry and FORCEON (see Table 2). The switching point is a function of the VL voltage. FORCEON Active high input to override automatic powerdown circuitry thereby keeping transmitters active (FORCEOFF must be high). The switching point is a function of the VL voltage.
2
ISL4270E Typical Operating Circuit
+3.3V C1 0.1 µF C2 0.1 µF + 0.1µF 29 + 31 C1+
27 VCC V+ 30 + C3 0.1µF
C12 C2+ + 3 C25 T1
V-
4
C4 0.1 µF + T 1 OUT
T1IN
23
T2IN
6
T2
22
T 2 OUT
RS-232 LEVELS
T3IN TTL/CMOS LOGIC LEVELS
10
T3
21
T 3 OUT
R1OUT
14
R1 5 k
20
R1IN
R2OUT
13
R2 5 k
19
R2IN
RS-232 LEVELS
12 R3OUT
R3 5 k
18
R3IN
LOGIC VCC 0.1µF
15 + 11 28 7
VL FORCEON
VCC TO POWER CONTROL LOGIC
FORCEOFF INVALID GND 26
3
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