Datasheet
ISL4260E
QFN Packaged, ±15kV ESD Protected, +3V to +5.5V, 150nA, 250kbps,
RS-232 Transmitters/Receivers with Separate Logic Supply
Features
The ISL4260E contains 3.0V to 5.5V powered RS-232
transmitters/receivers that meet ElA/TIA-232 and
V.28/V.24 specifications, even at VCC = 3.0V.
Targeted applications are PDAs, Palmtops, and cell
phones where the low operational power consumption
and even lower standby power consumption is critical.
Efficient on-chip charge pumps coupled with a manual
powerdown function reduces the standby supply
current to a 150nA trickle. The 5mm x 5mm Quad Flat
No-Lead (QFN) packaging and the use of small, low
value capacitors ensure board space savings. Data
rates greater than 250kbps are ensured at worst case
load conditions.
• ESD protection for RS-232 I/O pins to ±15kV
(IEC61000)
The ISL4260E features a VL pin that adjusts the logic
pin output levels (see Pin Descriptions) and input
thresholds to values compatible with the VCC
powering the external logic (for example, a UART).
• Receiver hysteresis for improved noise immunity
The single pin powerdown function (SHDN = 0)
disables all the receiver and transmitter outputs while
shutting down the charge pump to minimize supply
current drain.
Table 1 summarizes the features of the ISL4260E.
Application Note AN9863 summarizes the features of
each device comprising the 3V RS-232 family.
Related Literature
• Available in near chip scale QFN (5mmx5mm)
package
• VL pin for compatibility with mixed voltage systems
• Single SHDN pin disables transmitters and
receivers
• Meets EIA/TIA-232 and V.28/V.24 specifications
at 3V
• On-chip charge pumps require only four external
0.1µF capacitors
• 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: 150nA
• Pb-free (RoHS compliant)
Applications
• Any system requiring RS-232 communication ports
For a full list of related documents, visit our website:
○ Battery powered, hand-held, and portable
equipment
• ISL4260E device page
○ Laptop computers, notebooks, and Palmtops
○ Digital cameras
○ PDAs and PDA cradles
○ Cellular/mobile phones
Table 1.
Summary of Features
Part Number
No. Of
Tx.
No. Of
Rx.
Data Rate
(kbps)
Rx. Enable
Function?
VL Logic
Supply Pin?
Manual
Powerdown?
Automatic Powerdown
Function?
ISL4260E
3
2
250
No
Yes
Yes
No
FN6035 Rev.3.00
May.20.19
Page 1 of 19
ISL4260E
Contents
1.
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1
1.2
1.3
1.4
2.
Typical Operating Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Ordering Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pin Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pin Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3
3
4
4
Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.1
2.2
2.3
2.4
Absolute Maximum Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Thermal Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Recommended Operating Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5
5
5
6
3.
Typical Performance Curves. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
4.
Application Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
4.1
4.1.1
4.2
4.3
4.4
4.5
4.6
4.7
4.8
4.9
4.10
4.11
4.12
5.
Charge Pump. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Charge Pump Abs Max Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Transmitters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Receivers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Low Power Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Powerdown Functionality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Software Controlled (Manual) Powerdown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
VL Logic Supply Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Capacitor Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Power Supply Decoupling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Transmitter Outputs when Exiting Powerdown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
High Data Rates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Interconnection with 3V and 5V Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10
10
11
12
12
12
12
13
13
13
13
14
14
±15kV ESD Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
5.1
5.2
5.3
5.4
Human Body Model (HBM) Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
IEC61000-4-2 Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Air-Gap Discharge Test Method. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Contact Discharge Test Method. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15
15
15
15
6.
Die Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
7.
Revision History. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
8.
Package Outline Drawing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
FN6035 Rev.3.00
May.20.19
Page 2 of 19
ISL4260E
1.
1.1
1. Overview
Overview
Typical Operating Circuit
+3.3V to +5V
C1
0.1µF
+
C2
0.1µF
+
T1IN
T2IN
TTL/CMOS
Logic Levels
+
0.1µF
T3IN
R1OUT
R2OUT
Logic VCC
0.1µF
29
31
2
3
27
C1+
VCC
30
V+
C1C2+
4
V-
C2-
+
T1
5
23
T2
6
22
T3
10
C4
0.1µF
T1OUT
T2OUT
21
T3OUT
R1
13
19
5kΩ
R2
12
18
5kΩ
15
+
+ C3
0.1µF
RS-232
Levels
R1IN
R2IN
VL
GND
SHDN
28
VCC
26
1.2
Ordering Information
Part Number (Notes 2, 3)
Part
Marking
Temp. Range
(°C)
Tape and Reel
(Units) (Note 1)
Package (RoHS
Compliant)
Pkg.
Dwg. #.
ISL4260EIRZ
ISL4260 EIRZ
-40 to +85
-
32 Ld QFN
L32.5x5B
ISL4260EIRZ-T
ISL4260 EIRZ
-40 to +85
6k
32 Ld QFN
L32.5x5B
Notes:
1. See TB347 for details about reel specifications.
2. These Pb-free plastic packaged products employ special Pb-free material sets; molding compounds/die attach materials and matte tin
termination finish, which is RoHS compliant and compatible with both SnPb and Pb-free soldering operations. Pb-free products are MSL
classified at Pb-free peak reflow temperatures that meet or exceed the Pb-free requirements of IPC/JEDEC J STD-020.
3. For Moisture Sensitivity Level (MSL), see the ISL4260E device page. For more information about MSL, see TB363.
FN6035 Rev.3.00
May.20.19
Page 3 of 19
ISL4260E
1.3
1. Overview
Pin Configuration
1.4
28
NC
29
GND
30
VCC
V+
31
SHDN
C1-
32
C1+
NC
32 LD QFN
Top View
27
26
25
NC
1
24
NC
C2+
2
23
T1OUT
C2-
3
22
T2OUT
V-
4
21
T3OUT
PD
19
R1IN
NC
7
18
R2IN
NC
8
17
NC
11
12
13
14
NC
10
NC
9
15
16
NC
6
VL
T2IN
R1OUT
NC
R2OUT
20
NC
5
T3IN
T1IN
Pin Descriptions
Pin
Function
VCC
System power supply input (3.0V to 5.5V).
V+
Internally generated positive transmitter supply (+5.5V).
V-
Internally generated negative transmitter supply (-5.5V).
GND
Ground connection. This is also the potential of the thermal pad (PD).
C1+
External capacitor (voltage doubler) is connected to this lead.
C1-
External capacitor (voltage doubler) is connected to this lead.
C2+
External capacitor (voltage inverter) is connected to this lead.
C2-
External capacitor (voltage inverter) is connected to this lead.
TIN
TTL/CMOS compatible transmitter Inputs. The switching point is a function of the VL voltage.
TOUT
RIN
ROUT
VL
SHDN
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 TTL/CMOS input to tri-state receiver and transmitter outputs and to shut down the onboard power supply to
place the device in low power mode. The switching point is a function of the VL voltage.
NC
No connection
PD
Exposed thermal pad. Connect to GND.
FN6035 Rev.3.00
May.20.19
Page 4 of 19
ISL4260E
2.
2. Specifications
Specifications
2.1
Absolute Maximum Ratings
Minimum
Maximum
Unit
VCC to Ground
Parameter
-0.3
6
V
VL to Ground
-0.3
7
V
V+ to Ground
-0.3
7
V
V- to Ground
+0.3
-7
V
14
V
6
V
±25
V
±13.2
V
VL + 0.3
V
V+ to VInput Voltages
TIN, SHDN
-0.3
RIN
Output Voltages
TOUT
-0.3
ROUT
Short-Circuit Duration
TOUT
ESD Rating
Continuous
-
See ESD Performance
-
CAUTION: Do not operate at or near the maximum ratings listed for extended periods of time. Exposure to such conditions can adversely
impact product reliability and result in failures not covered by warranty.
2.2
Thermal Information
Thermal Resistance (Typical)
θJA (°C/W)
θJC (°C/W)
30
2.2
32 Ld QFN Package (Notes 4, 5)
Notes:
4. θJA is measured in free air with the component mounted on a high-effective thermal conductivity test board with “direct attach” features.
See TB379 and TB389.
5. For θJC, the “case temp” location is the center of the exposed metal pad on the package underside..
Parameter
Minimum
Maximum Junction Temperature
Maximum Storage Temperature Range
-65
Pb-Free Reflow Profile
2.3
Maximum
Unit
+150
°C
+150
°C
see TB493
Recommended Operating Conditions
Parameter
Temperature Range
FN6035 Rev.3.00
May.20.19
Minimum
Maximum
Unit
-40
+85
°C
Page 5 of 19
ISL4260E
2.4
2. Specifications
Electrical Specifications
Test Conditions: VCC = 3V to 5.5V, C1 - C4 = 0.1µF, VL = VCC; unless otherwise specified. Typicals are at TA = 25°C, VCC = VL = 3.3V
Parameter
Test Conditions
Temp
(°C)
Min
(Note 7)
Typ
Max
(Note 7)
Unit
DC Characteristics
Supply Current, Powerdown
SHDN = GND, all inputs at VCC or GND
25
-
0.15
1
µA
Supply Current
All outputs unloaded, SHDN = VCC, VCC = 3.15V
25
-
0.3
1
mA
TIN, SHDN
VL = 3.3V or 5V
Full
-
-
0.8
V
VL = 2.5V
Full
-
-
0.6
V
VL = 5V
Full
2.4
-
-
V
VL = 3.3V
Full
2.0
-
-
V
VL = 2.5V
Full
1.4
-
-
V
VL = 1.8V
25
-
0.9
-
V
25
-
0.5
-
V
TIN, SHDN
Full
-
±0.01
±1
µA
Output Leakage Current
VCC = 0V or 3V to 5.5V, SHDN = GND
Full
-
±0.05
±10
µA
Output Voltage Low
IOUT = 1.6mA
Full
-
-
0.4
V
Output Voltage High
IOUT = -1.0mA
Full
VL - 0.6
VL - 0.1
-
V
Full
-25
-
25
V
VL = 5.0V
25
0.8
1.5
-
V
VL = 3.3V
25
0.6
1.2
-
V
VL = 5.0V
25
-
1.8
2.4
V
VL = 3.3V
25
-
1.5
2.4
V
Input Hysteresis
25
-
0.5
-
V
Input Resistance
25
3
5
7
kΩ
Logic and Transmitter Inputs
Input Logic Threshold Low
Input Logic Threshold High
TIN, SHDN
Transmitter Input Hysteresis
Input Leakage Current
Receiver Outputs
Receiver Inputs
Input Voltage Range
Input Threshold Low
Input Threshold High
Transmitter Outputs
Output Voltage Swing
All transmitter outputs loaded with 3kΩ to ground
Full
±5.0
±5.4
-
V
Output Resistance
VCC = V+ = V- = 0V, transmitter output = ±2V
Full
300
10M
-
W
Output Short-Circuit Current
Shorted to GND
Full
-
-
±60
mA
Output Leakage Current
VOUT = ±12V, VCC = 0V or 3V to 5.5V, SHDN = GND
Full
-
-
±25
µA
Maximum Data Rate
RL = 3kΩCL = 1000pF, one transmitter switching
Full
250
500
-
kbps
Receiver Propagation Delay
Receiver input to receiver
output, CL = 150pF
tPHL
25
-
0.15
-
µs
tPLH
25
-
0.15
-
µs
Receiver Output Enable Time
25
-
200
-
ns
Receiver Output Disable Time
25
-
200
-
ns
Transmitter Output Enable Time From SHDN rising edge to TOUT = ±3.7V
25
-
100
-
µs
Transmitter Skew
tPHL - tPLH (Note 6)
25
-
100
-
ns
Receiver Skew
tPHL - tPLH
25
-
50
-
ns
Timing Characteristics
FN6035 Rev.3.00
May.20.19
Page 6 of 19
ISL4260E
2. Specifications
Test Conditions: VCC = 3V to 5.5V, C1 - C4 = 0.1µF, VL = VCC; unless otherwise specified. Typicals are at TA = 25°C, VCC = VL = 3.3V
Parameter
Transition Region Slew Rate
Temp
(°C)
Min
(Note 7)
Typ
Max
(Note 7)
Unit
CL = 150pF to 1000pF
25
6
18
30
V/µs
CL = 150pF to 2500pF
25
4
13
30
V/µs
Human Body Model
25
-
±15
-
kV
IEC61000-4-2 Air Gap Discharge
25
-
±15
-
kV
IEC61000-4-2 Contact Discharge
25
-
±8
-
kV
Test Conditions
RL = 3kΩto 7kΩ
measured from 3V to -3V
or -3V to 3V, VCC = 3.3V
ESD Performance
RS-232 Pins (TOUT, RIN)
Note:
6. Transmitter skew is measured at the transmitter zero crossing points.
7. Parameters with MIN and/or MAX limits are 100% tested at +25°C, unless otherwise specified. Temperature limits established by
characterization and are not production tested.
FN6035 Rev.3.00
May.20.19
Page 7 of 19
ISL4260E
3.
3. Typical Performance Curves
Typical Performance Curves
VCC = 3.3V, TA = 25°C
30
VOUT+
4.0
25
2.0
Slew Rate (V/µs)
Transmitter Output Voltage (V)
6.0
1 Transmitter at 250kbps
Other Transmitters at 30kbps
0
-2.0
-6.0
0
1000
2000
3000
4000
+Slew
15
-Slew
10
VOUT -
-4.0
20
5
5000
0
1000
3000
4000
5000
Figure 2. Slew Rate vs Load Capacitance
Figure 1. Transmitter Output Voltage vs Load
Capacitance
45
3.5
40
No Load
All Outputs Static
3.0
250kbps
35
Supply Current (mA)
Supply Current (mA)
2000
Load Capacitance (pF)
Load Capacitance (pF)
30
120kbps
25
20
2.5
2.0
1.5
1.0
20kbps
15
0.5
10
0
1000
2000
3000
4000
5000
Load Capacitance (pF)
Figure 3. Supply Current vs Load Capacitance When
Transmitting Data
FN6035 Rev.3.00
May.20.19
0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
Supply Voltage (V)
Figure 4. Supply Current vs Supply Voltage
Page 8 of 19
ISL4260E
3. Typical Performance Curves
VCC = 3.3V, TA = 25°C (Continued)
10m
1m
No Load
All Outputs Static
VCC = 3.3V
100µ
IL (A)
10µ
VL ≤ VCC
VL > VCC
1µ
100n
10n
1n
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
6.5
7.0
VL (V)
Figure 5. VL Supply CurrenT vs VL Voltage
FN6035 Rev.3.00
May.20.19
Page 9 of 19
ISL4260E
4.
4. Application Information
Application Information
The ISL4260E operates from a single +3V to +5.5V supply, ensures a 250kbps minimum data rate, requires only
four small external 0.1µF capacitors, features low power consumption, and meets all ElA RS-232C and V.28
specifications.
4.1
Charge Pump
The ISL4260E uses regulated on-chip dual charge pumps as voltage doublers, and voltage inverters to generate
±5.5V transmitter supplies from a VCC supply as low as 3.0V. These voltages allow the ISL4260E to maintain
RS-232 compliant output levels over the ±10% tolerance range of 3.3V powered systems. The efficient on-chip
power supplies require only four small, external 0.1µF capacitors for the voltage doubler and inverter functions
over the full VCC range; other capacitor combinations can be used as shown in Table 6 on page 13. The charge
pumps operate discontinuously (turning off as soon as the V+ and V- supplies are pumped up to the nominal
values) and provide significant power savings.
4.1.1 Charge Pump Abs Max Ratings
The ISL4270E is fully characterized for 3.0V to 3.6V operation and at critical points for 4.5V to 5.5V operation.
Furthermore, load conditions were favorable using static logic states only.
The specified maximum values for V+ and V- are +7V and -7V, respectively. These limits apply for VCC values set
to 3.0V and 3.6V (see Table 2). For VCC values set to 4.5V and 5.5V, the maximum values for V+ and
V- can approach +9V and -7V, respectively (Table 3 on page 11). The breakdown characteristics for V+ and Vwere measured with ±13V.
Table 2.
V+ and V- Values for VCC = 3.0V to 3.6V
C1 (μF)
C2, C3, C4 (μF)
Load
T1IN
(Logic State)
0.1
0.1
Open
H
3kΩ // 1000pF
0.047
0.33
Open
3kΩ // 1000pF
1
1
Open
3kΩ // 1000pF
FN6035 Rev.3.00
May.20.19
V+ (V)
V- (V)
VCC = 3.0V
VCC = 3.6V
VCC = 3.0V
VCC = 3.6V
5.80
6.56
-5.60
-5.88
L
5.80
6.56
-5.60
-5.88
2.4kbps
5.80
6.56
-5.60
-5.88
H
5.88
6.60
-5.56
-5.92
L
5.76
6.36
-5.56
-5.76
2.4kbps
6.00
6.64
-5.64
-5.96
H
5.68
6.00
-5.60
-5.60
L
5.68
6.00
-5.60
-5.60
2.4kbps
5.68
6.00
-5.60
-5.60
H
5.76
6.08
-5.64
-5.64
L
5.68
6.04
-5.60
-5.60
2.4kbps
5.84
6.16
-5.64
-5.72
H
5.88
6.24
-5.60
-5.60
L
5.88
6.28
-5.60
-5.64
2.4kbps
5.80
6.20
-5.60
-5.60
H
5.88
6.44
-5.64
-5.72
L
5.88
6.04
-5.64
-5.64
2.4kbps
5.92
6.40
-5.64
-5.64
Page 10 of 19
ISL4260E
4. Application Information
Table 3.
V+ and V- Values for VCC = 4.5V to 5.5V
C1 (μF)
C2, C3, C4 (μF)
Load
T1IN
(Logic State)
0.1
0.1
Open
H
7.44
8.48
-6.16
-6.40
L
7.44
8.48
-6.16
-6.44
2.4kbps
7.44
8.48
-6.17
-6.44
H
7.76
8.88
-6.36
-6.72
3kΩ // 1000pF
0.047
0.33
Open
3kΩ // 1000pF
1
1
Open
3kΩ // 1000pF
V+ (V)
VCC = 4.5V
V- (V)
VCC = 5.5V
VCC = 4.5V
VCC = 5.5V
L
7.08
8.00
-5.76
-5.76
2.4kbps
7.76
8.84
-6.40
-6.64
H
6.44
6.88
-5.80
-5.88
L
6.48
6.88
-5.84
-5.88
2.4kbps
6.44
6.88
-5.80
-5.88
H
6.64
7.28
-5.92
-6.04
L
6.24
6.60
-5.52
-5.52
2.4kbps
6.72
7.16
-5.92
-5.96
H
6.84
7.60
-5.76
-5.76
L
6.88
7.60
-5.76
-5.76
2.4kbps
6.92
7.56
-5.72
-5.76
H
7.28
8.16
-5.80
-5.92
L
6.44
6.84
-5.64
-6.84
2.4kbps
7.08
7.76
-5.80
-5.80
The resulting new maximum voltages at V+ and V- are listed in Table 4.
Table 4.
4.2
New Measured Withstanding Voltages
V+, V- to Ground
±13V
V+ to V-
20V
Transmitters
The transmitters are proprietary, low dropout, inverting drivers that translate TTL/CMOS inputs to EIA/TIA-232
output levels. These transmitters are coupled with the on-chip ±5.5V supplies to deliver true RS-232 levels across
a wide range of single supply system voltages.
All transmitter outputs disable and assume a high impedance state when the device enters the powerdown mode
(see Table 5). The outputs can be driven to ±12V when disabled.
All devices guarantee a 250kbps data rate for full load conditions (3kΩ and 1000pF), VCC ≥ 3.0V, with one
transmitter operating at full speed. Under more typical conditions of VCC ≥ 3.3V, RL = 3kΩ, and CL = 250pF, one
transmitter easily operates at 1.25Mbps.
The transmitter input threshold is set by the voltage applied to the VL pin. Transmitter inputs float if they are
unconnected (there are no pull-up resistors), and may cause ICC increases. Connect unused inputs to GND for
the best performance.
Table 5.
Powerdown Truth Table
SHDN Input
Transmitter Outputs
Receiver Outputs
L
High-Z
High-Z
Manual Powerdown
H
Active
Active
Normal Operation
FN6035 Rev.3.00
May.20.19
Mode Of Operation
Page 11 of 19
ISL4260E
4.3
4. Application Information
Receivers
The ISL4260E contains standard inverting receivers that convert RS-232 signals to CMOS output levels and
accept inputs up to ±25V while presenting the required 3kΩ to 7kΩ input impedance (see Figure 6 on page 12)
even if the power is off (VCC = 0V). The receivers’ Schmitt trigger input stage uses hysteresis to increase noise
immunity and decrease errors due to slow input signal transitions. Receiver outputs swing from GND to VL, and
tristate in powerdown.
VL
RXOUT
RXIN
-25V ≤ VRIN ≤ +25V
GND ≤ VROUT ≤ VL
5kΩ
GND
Figure 6. Receiver Connections
4.4
Low Power Operation
The ISL4260E requires a nominal supply current of 0.3mA, even at VCC = 5.5V during normal operation (not in
powerdown mode). This supply current is considerably less than the 11mA current required by comparable
5V RS-232 devices, which allows you to reduce system power by replacing the old style device with the ISL4260E
in new designs.
4.5
Powerdown Functionality
The already low current requirement drops significantly when the device enters powerdown mode. In powerdown,
supply current drops to 150nA because the on-chip charge pump turns off (V+ collapses to VCC, V- collapses to
GND), and the transmitter and receiver outputs tri-state. This micro-power mode makes the ISL4260E ideal for
battery powered and portable applications.
4.6
Software Controlled (Manual) Powerdown
The ISL4260E can be forced into its low power, standby state with a simple shutdown (SHDN) pin (see Figure 7).
Driving SHDN high enables normal operation. Driving SHDN low forces the IC into its powerdown state. The time
required to exit powerdown and resume transmission is less than 100µs. Connect SHDN to VCC if the powerdown
function is not needed.
SHDN
Power
Management
Logic
I/O Chip
Power Supply
VL
ISL4260E
VCC
CPU
I/O
UART
Figure 7. Connections for Manual Powerdown
FN6035 Rev.3.00
May.20.19
Page 12 of 19
ISL4260E
4.7
4. Application Information
VL Logic Supply Input
Unlike other RS-232 interface devices where the CMOS outputs swing between 0 and VCC, the ISL4260E
features a separate logic supply input (VL; 1.8V to 5V, regardless of VCC) that sets VOH for the receiver outputs.
Connecting VL to a host logic supply lower than VCC prevents the ISL4260E outputs from forward biasing the
input diodes of a logic device powered by that lower supply. Connecting VL to a logic supply greater than VCC
ensures that the receiver output levels are compatible even with the CMOS input VIH of AC, HC, and CD4000
devices. Note: The VL supply current increases to 100µA with VL = 5V and VCC = 3.3V (see Figure 5). VL also
powers the transmitter and logic inputs and sets their switching thresholds to levels compatible with the logic
supply. The VLseparate logic supply pin allows a great deal of flexibility in interfacing to systems with different
logic supplies. If logic translation is not required, connect VL to the ISL4260E VCC.
4.8
Capacitor Selection
The ISL4260E charge pumps require only 0.1µF capacitors for the full operational voltage range. Table 6 lists
other acceptable capacitor values for various supply voltage ranges. Do not use values smaller than those listed
in Table 6. Increasing the capacitor values (by a factor of 2) reduces ripple on the transmitter outputs and slightly
reduces power consumption.
Table 6.
Required Capacitor Values
VCC (V)
C1 (µF)
C2, C3, C4 (µF)
3.0 to 3.6
0.1
0.1
4.5 to 5.5
0.047
0.33
3.0 to 5.5
0.22
1
When using minimum required capacitor values, make sure that capacitor values do not degrade excessively with
temperature. If in doubt, use capacitors with a larger nominal value. The capacitor’s equivalent series resistance
(ESR) usually rises at low temperatures and it influences the amount of ripple on V+ and V-.
4.9
Power Supply Decoupling
In most circumstances a 0.1µF bypass capacitor is adequate. In applications that are particularly sensitive to
power supply noise, decouple VCC to ground with a capacitor of the same value as the charge-pump capacitor C1.
Connect the bypass capacitor as close as possible to the IC.
4.10
Transmitter Outputs when Exiting Powerdown
Figure 8 shows the response of two transmitter outputs when exiting powerdown mode. As the two transmitter
outputs activate, they properly go to opposite RS-232 levels with no glitching, ringing, or undesirable transients.
Each transmitter is loaded with 3kΩin parallel with 2500pF. Note: The transmitters enable only when the
magnitude of the supplies exceeds approximately 3V.
5V/Div
SHDN
T1
2V/Div
T2
VCC = +3.3V
C1 - C4 = 0.1µF
Time (20µs/Div)
Figure 8. Transmitter Outputs When Exiting Powerdown
FN6035 Rev.3.00
May.20.19
Page 13 of 19
ISL4260E
4.11
4. Application Information
High Data Rates
The ISL4260E maintains the RS-232 ±5V minimum transmitter output voltages even at high data rates. Figure 9
shows a transmitter loopback test circuit, and Figure 10 shows the loopback test result at 120kbps. For this test,
all transmitters were simultaneously driving RS-232 loads in parallel with 1000pF at 120kbps. Figure 11 shows the
loopback results for a single transmitter driving 1000pF and an RS-232 load at 250kbps. The static transmitters
were also loaded with an RS-232 receiver.
VCC
+
0.1µF
+
C1
C1+
VCC
VL
V+
C1+
C2
ISL4260E
V-
C2+
C2TIN
+
C3
C4
+
TOUT
1000pF
RIN
ROUT
5k
VCC
SHDN
Figure 9. Transmitter Loopback Test Circuit
5V/Div
5V/Div
T1IN
T1IN
T1OUT
T1OUT
R1OUT
R1OUT
VCC = +3.3V
C1 - C4 = 0.1µF
VCC = +3.3V
C1 - C4 = 0.1µF
5µs/Div
Figure 10. Loopback Test at 120kbps
4.12
2µs/Div
Figure 11. Loopback Test at 250kbps
Interconnection with 3V and 5V Logic
Standard 3.3V powered RS-232 devices interface well with 3V and 5V powered TTL compatible logic families
(such as ACT and HCT), but the logic outputs (for example, ROUTS) fail to reach the VIH level of 5V powered
CMOS families like HC, AC, and CD4000. The ISL4260E VL supply pin solves this problem. By connecting VL to
the same supply (1.8V to 5V) powering the logic device, the ISL4260E logic outputs swing from GND to the logic
VCC.
FN6035 Rev.3.00
May.20.19
Page 14 of 19
ISL4260E
5.
5. ±15kV ESD Protection
±15kV ESD Protection
All pins on the 3V interface devices include ESD protection structures, but the ISL4260E incorporates advanced
structures that allow the RS-232 pins (transmitter outputs and receiver inputs) to survive ESD events up to ±15kV.
The RS-232 pins are particularly vulnerable to ESD damage because they typically connect to an exposed port on
the exterior of the finished product. Touching the port pins or connecting a cable can cause an ESD event that
might destroy unprotected ICs. The ESD structures protect the device whether or not it is powered up, protect
without allowing any latchup mechanism to activate, and do not interfere with RS-232 signals as large as ±25V.
5.1
Human Body Model (HBM) Testing
The Human Body Model (HBM) test method emulates the ESD event delivered to an IC during human handling.
The tester delivers the charge through a 1.5kΩ current limiting resistor, so the test is less severe than the
IEC61000 test, which uses a 330Ω limiting resistor. The HBM method determines an IC’s ability to withstand the
ESD transients typically present during handling and manufacturing. Due to the random nature of these events,
each pin is tested with respect to all other pins. The RS-232 pins on “E” family devices can withstand HBM ESD
events to ±15kV.
5.2
IEC61000-4-2 Testing
The IEC61000 test method applies to finished equipment, rather than to an individual IC. Therefore, the pins most
likely to suffer an ESD event are those that are exposed to the outside world (the RS-232 pins in this case), and
the IC is tested in its typical application configuration (power applied) rather than testing each pin-to-pin
combination. The lower current limiting resistor coupled with the larger charge storage capacitor yields a test that
is much more severe than the HBM test. The extra ESD protection built into this device’s RS-232 pins allows the
design of equipment meeting level 4 criteria without the need for additional board level protection on the RS-232
port.
5.3
Air-Gap Discharge Test Method
For this test method, a charged probe tip moves toward the IC pin until the voltage arcs to it. The current
waveform delivered to the IC pin depends on factors such as approach speed, humidity, and temperature, so it is
difficult to obtain repeatable results. The “E” device RS-232 pins withstand ±15kV air-gap discharges.
5.4
Contact Discharge Test Method
During the contact discharge test, the probe contacts the tested pin before the probe tip is energized and
eliminates the variables associated with the air-gap discharge. The result is a more repeatable and predictable
test, but equipment limits prevent testing devices at voltages higher than ±8kV. All “E” family devices survive ±8kV
contact discharges on the RS-232 pins.
FN6035 Rev.3.00
May.20.19
Page 15 of 19
ISL4260E
6.
6. Die Characteristics
Die Characteristics
Substrate and QFN Thermal Pad Potential (Powered Up)
GND
Transistor Count
422
Process
Si Gate CMOS
FN6035 Rev.3.00
May.20.19
Page 16 of 19
ISL4260E
7.
7. Revision History
Revision History
Rev.
Date
3.00
May.20.19
FN6035 Rev.3.00
May.20.19
Description
Added related literature section on page 1.
Updated ordering information table on page 2.
Changed Note 1 and added Note 3.
Added ISL4260EIRZ-T.
Added tape and reel information and notes 1, 2, and 3.
Added Charge Pump Abs Max Ratings section starting on page 10.
Applied new template.
Added revision history.
Updated disclaimer.
Page 17 of 19
ISL4260E
8.
8. Package Outline Drawing
Package Outline Drawing
For the most recent package outline drawing, see L32.5x5B.
L32.5x5B
32 LEAD QUAD FLAT NO-LEAD PLASTIC PACKAGE
Rev 3, 5/10
4X 3.5
5.00
28X 0.50
A
B
6
PIN 1
INDEX AREA
6
PIN #1 INDEX AREA
32
25
1
5.00
24
3 .30 ± 0 . 15
17
(4X)
8
0.15
9
16
+ 0.07
32X 0.40 ± 0.10
TOP VIEW
0.10 M C A B
4 32X 0.23 - 0.05
BOTTOM VIEW
SEE DETAIL "X"
0.10 C
0 . 90 ± 0.1
C
BASE PLANE
SEATING PLANE
0.08 C
( 4. 80 TYP )
(
( 28X 0 . 5 )
SIDE VIEW
3. 30 )
(32X 0 . 23 )
C
0 . 2 REF
5
( 32X 0 . 60)
0 . 00 MIN.
0 . 05 MAX.
DETAIL "X"
TYPICAL RECOMMENDED LAND PATTERN
NOTES:
1. Dimensions are in millimeters.
Dimensions in ( ) for Reference Only.
2. Dimensioning and tolerancing conform to AMSE Y14.5m-1994.
3. Unless otherwise specified, tolerance : Decimal ± 0.05
4. Dimension applies to the metallized terminal and is measured
between 0.15mm and 0.30mm from the terminal tip.
5. Tiebar shown (if present) is a non-functional feature.
6. The configuration of the pin #1 identifier is optional, but must be
located within the zone indicated. The pin #1 identifier may be
either a mold or mark feature.
FN6035 Rev.3.00
May.20.19
Page 18 of 19
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