SP3224ECA-L - Sipex Corporation

SP3224E-SP3227E

FEATURES

■ 15kV ESD protected RS-232 I/O pins

■ Auto On-line® Plus automatic power saving mode

■ Meets true EIA/TIA-232-F standards from +3.0V to

+5.5V power supply.

■ Adheres to EIA/TIA-562 for interoperability with

EIA/TIA-232 down to a +2.7V supply voltage

■ Regulated charge pump yields stable

RS-232 outputs

■ Drop-in replacement to MAX3224, ICL3224,

MAX3225, ICL3225, MAX3226, ICL3226,

MAX3227 and ICL3227

■ SP3224E and SP3225E reduced EMI with a slew

rate controlled 250kbps data rate

■ SP3226E and SP3227E- high speed data rate of

1 Mbps.

■ Available in RoHS compliant, Lead Free

Packaging

3.0V to 5.5V RS-232 Transceivers with Auto On-Line® Plus

DESCRIPTION

TYPICAL APPLICATIONS

■ Diagnostic/Serial ports on

embedded applications

■ Handheld Test Equipment

■ PC related Peripherals and

Equipment

■ Battery Powered Equipment

■ Point-of-sale Equipment

■ Set-top Box

The SP3224E/3225E are 2-driver/2-receiver devices and the SP3226E/SP3227E are 1-

driver/1-receiver devices. All are ideal for computer peripherals, point-of-sale equipment,

consumer and embedded applications. These devices use an internal high-efﬁciency,

charge-pump power supply that requires only 0.1µF capacitors in 3.3V operation. This

charge pump and Sipex’s driver architecture allow it to deliver compliant RS-232 perfor-

mance from a single power supply ranging from +3.0V to +5.5V. At voltages between 2.7V

and 3.0V the driver outputs are compliant with RS-562 and can interface to RS-232 over

short cables.

The Auto On-line® Plus feature allows the device to automatically “wake-up” during a shut-

down state upon detecting activity and to enter a low power shutdown if idle. This power

saving feature functions without system intervention or modiﬁcations to software or driv-

ers.

SELECTION TABLE

All devices feature 3.0V to 5.5V power supply, 4 small charge pump capacitors, and 15kV ESD

protection.

Device Data Rate (bps) No. of

Drivers/Receivers

READY pin Low-Power Shutdown Package

SP3224E 250k 2/2 Yes Auto On-Line® Plus 20 SSOP/TSSOP

SP3225E 1M 2/2 Yes Auto On-Line® Plus 20 SSOP/TSSOP

SP3226E 250k 1/1 Yes Auto On-Line® Plus 16 SSOP/TSSOP

SP3227E 1M 1/1 Yes Auto On-Line® Plus 16 SSOP/TSSOP

Solvedby

SP3224E

SP3225E

READY

C1+

V+

C1-

C2+

C2-

V-

T2OUT

R2IN

R2OUT

SHUTDOWN

VCC

GND

T1OUT

R1IN

R1OUT

ONLINE

T1IN

T2IN

STATUS

ELECTRICAL SPECIFICATIONS

These are stress ratings only and functional operation of the device at

these ratings or any other above those indicated in the operation sections

of the speciﬁcations below is not implied. Exposure to absolute maximum

rating conditions for extended periods of time may affect reliability.

ABSOLUTE MAXIMUM RATINGS

Supply Voltage (Vcc).................................................-0.3V to + 6.0V

V+ (Note 1)................................................................-0.3V to + 7.0V

V- (Note 1).................................................................+0.3V to - 7.0V

|V+| + |V-| .................................................................................+13V

Input voltage at TTL input pins ............................-0.3V to Vcc+0.3V

RxIN......................................................................................... ±18V

Driver output (from Ground).................................................. ±13.2V

RxOUT, STATUS..................................................-0.3V to Vcc+0.3V

Short Circuit Duration, TxOUT to GND,. Continuous

(One output at a time maximum)

Storage Temperature...............................................-65°C to +150°C

Operating Temperature SP322XECX...........................0°C to +70°C

Operating Temperature SP322XEEX........................-40°C to +85°C

Lead Temperature (soldering, 10s)....................................... +300°C

Maximum junction temperature.....................................................150°C

Thermal Derating, Junction to Ambient

SSOP20..............................................................................θJA =83°C/W

TSSOP20.......................................................................θJA =110.7°C/W

SSOP16..............................................................................θJA =87°C/W

TSSOP16.......................................................................θJA =100.4°C/W

Note 1: V+ and V- can have maximum magnitudes of 7V, but their

absolute difference cannot exceed 13V.

Unless otherwise noted VCC = +3.0V to +5.5V, TAMB = TMIN to TMAX,. Typical values are at TAMB = +25°C.

C1–C4 = 0.1µF tested at 3.3V ±10%. C1=0.047µF C2–C4 = 0.33µF tested at 5V ±10%.

Parameters Symb Test Conditions Min. Typ. Max. Unit

DC Characteristics

Supply Current, Auto On-Line® Plus ICC3

Receivers idle, TxIN = Vcc or GND,

ONLINE = GND, SHUTDOWN = Vcc

Note 2

1 10 µA

Supply Current, Shutdown ICC2SHUTDOWN = GND 1 10 µA

Supply Current, Active ICC1ONLINE = SHUTDOWN = Vcc, No Load 1.5 2.0 mA

Supply Current, Active ICC1ONLINE = SHUTDOWN = VCC=3.3V,

No Load 0.7 1.0 mA

Driver Input and Logic Input Pins

Logic Input

Voltage

High

VIH Vcc = 3.3V 2

VIH Vcc = 5.0V 2.4

Low VIL 0.8

Logic Threshold VT1.5

Logic Input Leakage Current IIL 0.05 ±1.0 µA

Logic Input Hysteresis VHYS 100 mV

Receiver Outputs and STATUS Output

Receiver Output Voltage Low VOL IOUT = -1.6mA 0.4 V

Receiver Output Voltage High VOH IOUT = 1mA Vcc

- 0.6 V

Note 2: Characterized, not 100% tested.

ELECTRICAL SPECIFICATIONS

Parameters Symb Test Conditions Min. Typ. Max.

Driver Outputs

Output Voltage Swing VOOutput load = 3kΩ to GND ±5.0 ±6.0 V

Output load = Open Circuit ±15.0

Short Circuit Current VOUT = 0V ±60 mA

Power-Off Impedance Vcc=V+ = V- = 0

transmitter outputs= ±2V

300 10M Ω

Output Leakage Current Vcc = 0 or 3V to 3.3V, VOUT

= ±12V, Drivers disabled

±25 µA

Receiver Inputs

Input Voltage Range -15 15 V

Input Threshold Low Vcc = 3.3V 0.6 1.2 V

Vcc = 5.0V 0.8 1.5

Input Threshold High Vcc = 3.3V 1.5 2.4 V

Vcc = 5.0V 1.8 2.4

Input Hysteresis 500 mV

Input Resistance 3 5 7 kΩ

ESD Protection

ESD Protection for R_In, T_Out pins Human Body Model ±15 kV

All Other Pins Human Body Model ±2 kV

Auto On-line® Plus (ONLINE = GND, SHUTDOWN = Vcc)

Rx Input Threshold to STATUS output high ±2.7 V

Rx Input Threshold to STATUS output low ±0.3 V

Threshold to STATUS high tSTH 0.5 µs

Threshold to STATUS low tSTL 30 µs

Rx or Tx transition to drivers enabled tONLINE Note 3 100 µs

Last Rx or Tx transition to drivers disabled tOFFLINE Note 2, 3 15 30 60 sec

Note 3: A transmitter/receiver edge is deﬁned as a transition through input logic thresholds.

Unless otherwise noted VCC = +3.0V to +5.5V, TAMB = TMIN to TMAX,. Typical values are at TAMB = +25°C.

C1–C4 = 0.1µF tested at 3.3V ±10%. C1=0.047µF C2–C4 = 0.33µF tested at 5V ±10%.

TIMING CHARACTERISTICS

Unless otherwise noted VCC = +3.0V to +5.5V, TAMB = TMIN to TMAX,. Typical values are at TAMB = +25°C. C1–C4 =

0.1µF tested at 3.3V ±10%. C1=0.047µF C2–C4 = 0.33µF tested at 5V ±10%

Parameters Symbol Test Conditions Min. Typ. Max. Unit

SP3224E and SP3226E

Maximum Data Rate RL = 3kΩ, CL = 1000pF. One

transmitter switching. 250 kbps

Transition -Region

Slew Rate

Measurement taken from

+3.0V to -3.0V or -3.0V to +3.0V,

TAMB = 25°C

RL = 3kΩ to 7kΩ,

CL = 150pF to 1000pF

4 30 V/µs

Receiver Propagation

Delay tRPHL , tRPLH

R_IN to R_OUT,

CL = 150pF 0.22 µs

Receiver Output

Enable Time tRZH , tRZL RL = 3kΩ, CL = 150pF 0.2 2 µs

Receiver Output

Disable Time tRHZ , tRLZ 0.2 2 µs

Receiver Skew |tPHL - tPLH| at 1.5V 200 ns

Parameters Symbol Test Conditions Min. Typ. Max. Unit

SP3225E and SP3227E

Maximum Data Rate

RL = 3kΩ, CL = 250pF. One

transmitter Switching 1000 kbps

RL = 3kΩ, CL = 1000pF. One

transmitter Switching 500 kbps

Instantaneous Slew

Rate

Measurement taken from +3.0V

to -3.0V or -3.0V to +3.0V,

TAMB=25°C 24 150 V/µs

RL = 3kΩ to 7kΩ,

CL = 150pF to 250pF

Driver Skew |tDPHL - tDPLH| at zero crossing 75 ns

Receiver Propagation

Delay tRPHL , tRPLH R_IN to R_OUT, CL = 150pF 0.20 µs

Receiver Output

Enable Time tRZH , tRZL 0.3 2 µs

Receiver Output

Disable Time tRHZ , tRLZ 0.2 2 µs

Receiver Skew |tPHL - tPLH| at 1.5V 80 ns

0 1000 2000 3000 4000 5000

Load Capacitance (pF)

Transmitter Output Slew Rate (V/us)

SRpos

SRneg

SRavg

TYPICAL PERFORMANCE CHARACTERISTICS:CURVES

SP3224E/SP3226E Transmitter Input to

Receiver Output Propagation Delay vs.

Load Capacitance

0.5

1.5

2.5

0 1000 2000 3000 4000 5000

Load Capacitance (pF)

TxIn to RxOut Propagation Delay (us)

SP3224E/SP3226E Transmitter Output

Slew Rate vs. Load Capacitance

0 1000 2000 3000 4000 5000

Load Capacitance (pF)

Transmitter Output Slew Rate (V/us)

SRpos

SRneg

SRavg

SP3224E/SP3226E Transmitter Output

Voltage vs. Load Capacitance

-6

-4

-2

0 1000 2000 3000 4000 5000

Load Capacitance (pF)

Transmitter Output Voltage (V)

V+

V-

SP3225E/SP3227E Transmitter Input to

Receiver Output Propagation Delay vs.

Load Capacitance

0.2

0.4

0.6

0.8

1.2

1.4

1.6

0 1000 2000 3000 4000 5000

Load Capacitance (pF)

TxIn to RxOut Propagation Delay (us)

SP3225E/SP3227E Transmitter Output

Slew Rate vs. Load Capacitance

SP3225E/SP3227E Transmitter Output

Voltage

-6

-4

-2

0 1000 2000 3000 4000 5000

Load Capacitance (pF)

Trasmitter Output Voltage (V)

V+

V-

TxIn to RxOut Propagation Delay (us)

Transmitter Output Slew Rate (V/us)

Transmitter Output Voltage (V)

100

150

200

250

0 500 1000 1500 2000 2500 3000 3500

Load Capacitance (pF)

Transmitter Skew (ns)

SP3224, 250kbps

SP3225, 1Mbps

0 1000 2000 3000 4000 5000

Load Capacitance (pF)

Supply Current (mA)

SP3225, 1Mbps

SP3227

SP3224, 250kbps

SP3226

Driver Skew

vs. Load Capacitance

Supply Current

vs. Load Capacitance

Transmitter Skew (ns)

Supply Current (mA)

Charge Pump Turn-on Time versus Temperature

-55 -30 -5 20 45 70 95

Temperature (C)

Charge Pump Turn-on Time (us)

Charge Pump Turn-On Time

vs. Temperature

Charge Pump Turn-On Time (us)

TYPICAL PERFORMANCE CHARACTERISTICS:CURVES

TYPICAL PERFORMANCE CHARACTERISTICS: SCOPE SHOTS

SP3224E/SP3226E Waveforms

for 250kbps Clock Rate, RL=3kΩ,

CL=1000pF

SP3224E/SP3226E Waveforms

for 250kbps Clock Rate, RL=3kΩ,

CL=4700pF

SP3224E/SP3226E Charge Pump

Out of Shutdown

SP3224E/SP3226E Charge Pump

Into Shutdown

SP3224E/SP3226E Charge Pump

Power On Time, Vcc=3.3V

SP3224E/SP3226E Charge Pump

Waveforms for 250kbp Clock Rate

All Charge Pump waveforms use charge pump capacitor values C1-C4 = 0.1µF

SP3224E/SP3226E C2+ Charge

Pump Waveforms, Vcc=3.3V, All

Channels switching

SP3224E/SP3226E C2+ Charge

Pump Waveforms, Vcc=5V,

All Channels switching

SP3225E/SP3227E Waveforms

for 1Mbps Clock Rate, RL=3KΩ,

CL=50pF

SP3225E/SP3227E Waveforms for

1Mbps Clock Rate, RL=3KΩ,

CL=250pF

SP3225E/SP3227E Waveforms

for 1Mbps Clock Rate, RL=3KΩ,

CL=1000pF

SP3225E/SP3227E Charge

Pump Out of Shutdown

TYPICAL PERFORMANCE CHARACTERISTICS: SCOPE SHOTS

All Charge Pump waveforms use charge pump capacitor values C1-C4 = 0.1µF

TYPICAL PERFORMANCE CHARACTERISTICS

SP3225E/SP3227E Charge Pump

Into Shutdown

SP3225E/SP3227E Charge Pump

Power On Time, Vcc=3.3V

SP3225E/SP3227E Charge Pump

Waveforms for 1Mbps Clock Rate

SP3225E/SP3227E Charge Pump

Waveforms, Vcc=3.3V, All Chan-

nel Switching

SP3225E/SP3227E Charge Pump

Waveforms, Vcc=5V, All Channel

Switching

All Charge Pump waveforms use charge pump capacitor values C1-C4 = 0.1µF

Generator

(see note B) 50Ω

SHUTDOWN

RS-232

Output

(see note A)

TEST CIRCUIT

Figure 1. Driver Slew Rate

SR= 6V

tTHL or tTLH

tTLHtTHL

-3V

VOH

VOL

Input

Output

VOLTAGE WAVEFORMS

A. CL includes probe and jig capacitance

B. The pulse generator has the following characteristics: PRR= 250kbit/s, Zo=50Ω, 50% duty cycle, tr ≤10ns, tf ≤10ns

NOTES

Generator

(see note B) 50Ω

SHUTDOWN

RS-232

Output

(see note A)

TEST CIRCUIT

Figure 2. Driver Propagation and Skew

tDPLH

tDPHL

1.5V

50% 50%

VOH

VOL

Input

Output

VOLTAGE WAVEFORMS

1.5V

Skew= ItDPHL- tDPLHI

A. CL includes probe and jig capacitance

B. The pulse generator has the following characteristics: PRR= 250kbit/s, Zo=50Ω, 50% duty cycle, tr ≤10ns, tf ≤10ns

NOTES

CHARACTERIZATION CIRCUITS AND WAVEFORMS

Generator

(see note B) 50Ω

SHUTDOWN

RS-232

Output

(see note A)

TEST CIRCUIT

NOTES A. CL includes probe and jig capacitance

B. The pulse generator has the following characteristics: PRR= 250kbit/s, Zo=50Ω, 50% duty cycle, tr ≤10ns, tf ≤10ns

Figure 3. Receiver Propagation Delay and Skew

tRPLH

tRPHL

1.5V

50% 50%

VOH

VOL

Input

Output

VOLTAGE WAVEFORMS

1.5V

3V or 0V

ONLINE

Skew= ItRPHL- tRPLHI

3V or 0V

ONLINE

3V or 0V

SHUTDOWN

50Ω

Generator

(See Note B)

(see note A)

Output

GNDVCC

TEST CIRCUIT

NOTES: A CL includes probe and jig capacitance

B. The pulse generator has the folowing characteristics Zo=50Ω, 50% duty cycle, tr ≤10ns, tf ≤10ns

C. tPLZ and tPHZ are the same as tdis

D. tPZL and tPZH are the same as ten

Figure 4. Receiver Enable and Disable Times

VOLTAGE WAVEFORMS

Input

tPHZ

1.5V 1.5V

VOH

50%

0.3V

(51 at GND)

Output

tPLZ

(51 at VCC)

Output

0.3V

50%

VOL

tPZL

(S1 at VCC)

tPZH

THEORY OF OPERATION

Description

The SP3224E and SP3225E are 2-driver/

2-receiver devices. The SP3226E and

SP3227E are 1-driver/1-receiver devices.

All are ideal for serial ports in embedded,

consumer, portable, or handheld applica-

tions. The transceivers meet the EIA/TIA-

232 and ITU-T V.28/V.24 communication

protocols for reliable serial communication.

The devices feature Sipex’s proprietary

and patented (U.S. 5,306,954) on-board

charge pump circuitry that generates ±5.5V

RS-232 voltage levels from a single +3.0V

to +5.5V power supply.

The SP3224E-SP3227E are ideal choic-

es for power sensitive designs. With the

Auto On-line® Plus enabled, the SP3224E-

SP3227E reduce supply current to 1µA

whenever the transceivers are in idle. In

shutdown, the internal charge pump and

the drivers will shut down. This feature al-

lows design engineers to address power

saving concerns without major design

changes.

Theory Of Operation

The SP3224E-SP3227E are made up of

four basic circuit blocks: 1. Drivers, 2. Re-

ceivers, 3. the Sipex proprietary charge

pump, and 4. Auto On-line® Plus circuitry.

Drivers

The drivers are inverting level transmit-

ters that convert TTL or CMOS logic lev-

els to 5.0V EIA/TIA-232 levels with an

inverted sense relative to the input logic

levels. Typically, the RS-232 output volt-

age swing is +5.4V with no load and +5V

minimum fully loaded. The driver outputs

are protected against inﬁnite short-circuits

to ground without degradation in reliabili-

ty. These drivers comply with the EIA-TIA-

232-F and all previous RS-232 versions.

Unused driver inputs should be connected

to GND or VCC.

The drivers can guarantee output data

rates fully loaded with 3KΩ in parallel with

1000pF (SP3224E/SP3226E), or 3KΩ in

parallel with 250pF (SP3225E/SP3227E)

ensuring compatibility with PC-to-PC com-

munication software. The slew rate of the

driver output on the SP3224E/SP3226E is

internally limited to a maximum of 30V/µs

in order to meet the EIA standards (EIA

RS-232D 2.1.7, Paragraph 5). The Slew

Rate of SP3225E/SP3227E is not limited

to enable higher speed data transfers. The

transition of the loaded output from HIGH

to LOW also meets the monotonic signal

transition requirements of the standard.

Receivers

The receivers convert EIA/TIA-232 signal

levels to TTL or CMOS logic output lev-

els. Receivers remain active during device

shutdown. Since receiver input is usually

from a transmission line where long cable

lengths and system interference can de-

grade the signal, the inputs have a typical

hysteresis margin of 500mV. This ensures

that the receiver is virtually immune to noisy

transmission lines. Should an input be left

unconnected, an internal 5KΩ pulldown re-

sistor to ground will commit the output of

the receiver to a HIGH state.

Charge Pump

The charge pump is a Sipex–patented de-

sign (US Patent #5,306,954) and uses a

unique approach compared to older less-

efﬁcient designs. The charge pump still

requires four external capacitors, but uses

a four phase voltage shifting technique to

attain symmetrical 5.5V power supplies.

The internal power supply consists of a

regulated dual charge pump that provides

output voltages 5.5V regardless of the in-

put voltage (Vcc) over the +3.0V to +5.5V

range. This is important to maintain com-

pliant RS-232 levels regardless of power

supply ﬂuctuations.

The charge pump operates in a discontinu-

ous mode using an internal oscillator. If the

output voltages are less than a magnitude

THEORY OF OPERATION

of 5.5V, the charge pump is enabled. If the

output voltages exceed a magnitude of

5.5V, the charge pump is disabled. This os-

cillator controls the four phases of the volt-

age shifting. A description of each phase

follows.

Highly Efﬁcient Charge Pump

The charge pump is used to generate posi-

tive and negative signal voltages for the

RS-232 drivers. This enables fully compli-

ant RS-232 and V.28 signals from a single

3.0 or 5.5V power supply.

The charge pumps use four external capac-

itors to hold and transfer electrical charge.

The Sipex patented design (US Patent

#5,306,954) uses a unique approach com-

pared to older less efﬁcient designs. The

pumps use a four–phase voltage shifting

technique to attain symmetrical V+ and V-

power supplies. An intelligent control oscil-

lator regulates the operation of the charge

pump to maintain the proper voltages at

maximum efﬁciency.

Phase 1

VSS charge store and double: The posi-

tive terminals of capacitors C1 and C2 are

charged from VCC with their negative termi-

nals initially connected to ground. C1+ is

then connected to ground and the stored

charge from C1– is superimposed onto

C2– . Since C2+ is still connected to VCC

the voltage potential across capacitor C2 is

now 2 x VCC.

Phase 2

VSS transfer and invert: Phase two con-

nects the negative terminal of C2 to the VSS

storage capacitor and the positive terminal

of C2 to ground. This transfers the doubled

and inverted (V–) voltage onto C4. Mean-

while, capacitor C1 charged from VCC to

prepare it for its next phase.

Phase 3

VDD charge store and double: Phase three

is identical to the ﬁrst phase. The posi-

tive terminals of capacitors C1 and C2 are

charged from VCC with their negative termi-

nals initially connected to ground. C1+ is

then connected to ground and the stored

charge from C1– is superimposed onto

C2–. Since C2+ is still connected to VCC

the voltage potential across capacitor C2 is

now 2 x VCC.

Phase 4

VDD transfer: The fourth phase connects

the negative terminal of C2 to ground and

the positive terminal of C2 to the VDD stor-

age capacitor. This transfers the doubled

(V+) voltage onto C3. Meanwhile, capaci-

tor C1 charged from VCC to prepare it for

its next phase.

The Sipex charge pump generates V+ and

V– independently from VCC. Hence in a no-

load condition V+ and V- will be symmetri-

cal. Older charge pump approaches gen-

erate V+ and then use part of that stored

charge to generate V-. Because of inherent

losses the magnitude of V- will be smaller

than V+ on these older designs.

Under lightly loaded conditions the intelli-

gent pump oscillator maximizes efﬁciency

by running only as needed to maintain V+

and V–. Since interface transceivers often

spend much of their time at idle this power-

efﬁcient innovation can greatly reduce total

power consumption. This improvement is

made possible by the independent phase

sequence of the Sipex charge pump

design.

The clock rate for the charge pump typi-

cally operates at greater than 70kHz allow-

ing the pump to run efﬁciently with small

0.1µF capacitors. Efﬁcient operation de-

pends on rapidly charging and discharging

C1 and C2, therefore capacitors should be

mounted close to the IC and have low ESR

(equivalent series resistance). Inexpensive

surface mount ceramic capacitors (such as

THEORY OF OPERATION

The SP3224E-SP3227E devices have the

advanced Auto On-Line® Plus feature

RS-232 signals use both positive and neg-

ative voltages of greater than ±5V magni-

tude. Receivers have nominal 5kΩ imped-

ance to ground. Even when idle, drivers

will maintain output signal voltage creating

a continuous current ﬂow. In low power,

battery operated devices this constant cur-

rent drain can decrease battery life

signiﬁcantly.

are widely used for power-supply decou-

pling) are ideal for use on the charge pump.

The charge pumps are designed to be able

to function properly with a wide range of

capacitor styles and values. If polarized ca-

pacitors are used the positive and negative

terminals should be connected as shown

on the Typical Operating Circuit.

Capacitance values may be increased if

operating at higher VCC or to provide great-

er stability as the capacitors age.

Minimum Recommended Charge Pump Capacitor Values

Input Voltage VCC Charge Pump Capacitor Value for SP32XX

3.0V to 3.6V C1-C4=0.1µF

4.5V to 5.5V C1=0.047µF, C2-C4=0.33µF

3.0V to 5.5V C1-C4=0.22µF

Charge Pump Capacitor Values

VCC

Phases 1 and 3: Store/Double.

Double charge from C1 onto C2.

C2 is now charged to -2xVcc

VCC

e+e+

VCC

Phase 2 – Vss transfer from C2 to C4.

Meanwhile C1 is charged to Vcc

Vss

transfer from C2 to C3.

Meanwhile C1 is charged to Vcc

VDD

V-

V+

V-

V+

Patented 5,306,954 (Sipex, inc.)

Phase 4 VDD

Charge Pump Phases

that saves power by turning off the charge

pumps and driver outputs when the trans-

ceiver inputs are idle for more than 30 sec-

onds. Auto On-line® Plus is equivalent to

Maxim’s “Auto Shutdown Plus” feature. It

differs from our existing Auto On-line® by

relying on signal transitions rather than

voltage levels to trigger shutdown and

wakeup.

Auto On-Line® Plus automatically puts the

device into a standby mode where it draws

only 1µA typical. When the device detects

activity on either the receiver or driver in-

puts it will automatically awake and activate

to allow serial communication. Both the

wakeup and shutdown happen automati-

cally, without any user intervention, special

drivers, or software modiﬁcations.

Wakeup and shutdown can be exter-

nally controlled by the ONLINE and

SHUTDOWN pins. When ONLINE is driv-

en to logic LOW, the Auto On-line® Plus

function is active. Driving SHUTDOWN to

+0.3V

R_IN

-0.3V

30µs

timer STATUS

INVALID ASSERTED IF ALL RECEIVER INPUTS ARE

BETWEEN +0.3V AND -0.3V FOR AT LEAST 30µS

T_IN

R_IN EDGE

DETECT

EDGE

DETECT SHUTDOWN

ONLINE

30s

timer

Figure 3a.STATUS Functional Diagram STATUS low Figure 3c. Auto On-line® Plus Logic

+2.7V

R_IN

-2.7V

30µs

timer STATUS

INVALID DEASSERTED IF ALL RECEIVER INPUTS ARE

BETWEEN +2.7V AND -2.7V FOR AT LEAST 30µS

Figure 3b. STATUS Functional Diagram, STATUS high.

SHUTDOWN

ONLINE

AUTO ONLINE

POWERDOWN

POWERDOWN IS ONLY A INTERNAL SIGNAL. IT

CONTROLS THE OPERATIONAL STATUS TO THE

TRANSMITTERS AND THE POWER SUPPLIES.

Figure 3d. Powerdown Logic

AUTO ONLINE

logic LOW forces the device into shutdown

state regardless of input activity or the sta-

tus of the ONLINE pin.

The STATUS output determines whether a

valid RS-232 signal voltage is present on

the inputs. The STATUS pin goes to a logic

LOW when the receiver input signal levels

collapse near reference ground. This may

occur when the RS-232 cable is discon-

nected or the RS-232 drivers of the con-

nected peripheral are turned off.

STATUS may be used to indicate DTR or a

Ring Indicator signal or to determine wheth-

er a live RS232 driver or cable is connect-

ed. By connecting the STATUS output to

ONLINE input, the SP3224E-SP3227E will

shut down when no valid signal level and

no input transitions are detected, and wake

up on a valid signal level or signal edge. If it

detects no signal transitions with the past 30

seconds, the device will go into low power

mode. By connecting the STATUS output to

both the ONLINE input and SHUTDOWN

input pins, the device enters into shutdown

when not receiving a valid RS-232 signal voltage

input.

When the SP3224E-SP3227E devices are

THEORY OF OPERATION

life significantly.

Receiver

5kΩ

Auto On-Line (existing) Device enters low-power mode if receiver inputs see less than valid +/- 3V.

STATUS (or INVALID) signal output indicates if valid signal voltage is at

receivers.

Auto On-Line Plus (new) Device enters low-power mode if driver inputs or receiver inputs see no

transitions for 30 seconds. Return to full power mode upon any transition on

any driver input or receiver input

Shutdown occurs even if data cable is connected to an active driver, as long

as all inputs remain unchanged

STATUS (or INVALID) signal functions as before. Indicates if valid signal

voltage is present. But has no effect on shutdown

For SP3224E the EN input is replaced with a READY output. READY drives

high when charge pump achieves greater than -4V Vss (V-). Indicates “ready

to transmit.”

shut down, the charge pumps are turned off.

V+ charge pump output decays to VCC,the

V- output decays to GND. The decay time

will depend on the size of capacitors used

for the charge pump. Once in shutdown, the

time required to exit the shutdown state and

have valid V+ and V- levels is typically 50µs.

When the SP3224E-SP3227E drivers and

internal charge pump are disabled, the sup-

ply current is reduced to 1µA.

Operating Mode ONLINE SHDN |RIN| >

±2.7V

Idle Inputs

(RxIN &

TxIN)

TxOUT RxOUT

Forced Shutdown X 0 X X Hi-Z Active

Forced On-Line 1 1 X X Active Active

Auto On-Line Plus

(Wake when active)

0 1 X Active Active Active

Auto On Line Plus

(Off-Line when idle)

0 1 X Idle > 30s Hi-Z Active

Auto On-Line Plus

(Wake on cable)

STATUS 1 Yes X Active Active

Auto On-Line Plus

(Wake when active)

STATUS 1 No Active Active Active

Auto On-Line Plus

(Off-Line when idle)

STATUS 1 No Idle > 30s Hi-Z Active

Auto On-Line

(Wake on cable)

STATUS STATUS Yes X Active Active

Auto On-Line

(Auto Shutoff)

STATUS STATUS No X Hi-Z Active

Auto On-line® Plus Truth Table

THEORY OF OPERATION

Comparison of Auto On-line® Features

THEORY OF OPERATION

RECEIVER

INPUTS

INVALID

REGION

}

TRANSMITTER

INPUTS

TRANSMITTER

OUTPUTS

STATUS

OUTPUT

Vcc

V+

Vcc

V-

tTSTL tSTH tOFFLINE

tONLINE

tOFFLINE tONLINE

Auto On-Line® Plus Timing Diagram

tSTL (=30µs typ.)

tSTH (=0.4µs typ.)

tOFFLINE (=30s typ.)

tONLINE (=100µs typ.)

TYPICAL OPERATING CIRCUIT

+3.3V

C5 0.1uF

2C1+

0.1uF 4

0.1uF

C1-

C2+

C2-

T1IN

12 T2IN

TTL/CMOS

INPUTS

15 R1OUT

10 R2OUT

TTL/CMOS

OUTPUTS

1READY

ONLINE

GND SHUTDOWN 20 VCC

STATUS 11

5kΩ

R2IN 9

5kΩRS-232

INPUTS

R1IN 16

T2OUT

T1OUT

RS-232

OUTPUTS

0.1uF

V+

V-

Vcc

SP3224E

SP3225E

+3.3V

C5 0.1uF

0.1uF

1READY

ONLINE

GND SHUTDOWN

STATUS

VCC

5kΩ

R1IN 8

T1OUT 13

V- 7

0.1uF

V+

0.1uF

Vcc

R1OUT

T1IN

C2-

C2+

C1-

C1+

SP3226E

SP3227E

TTL/CMOS

INPUT/OUTPUT

RS-232

OUTPUT + INPUT

PINOUT DIAGRAMS

SP3224E

SP3225E

READY

C1+

V+

C1-

C2+

C2-

V-

T2OUT

R2IN

R2OUT

SHUTDOWN

VCC

GND

T1OUT

R1IN

R1OUT

ONLINE

T1IN

T2IN

STATUS

SP3226E

SP3227E

READY

C1+

V+

C1-

C2+

C2-

V-

R1IN

SHUTDOWN

VCC

GND

T1OUT

R1OUT

ONLINE

T1IN

STATUS

Sipex Corporation reserves the right to make changes to any products described herein. Sipex does not assume any liability arising out of the applica-

tion or use of any product or circuit described herein; neither does it convey any license under its patent rights nor the rights of others.

Sipex Corporation

Headquarters and

Sales Ofﬁce

233 South Hillview Drive

Milpitas, CA 95035

TEL: (408) 934-7500

FAX: (408) 935-7600

ORDERING INFORMATION

Part number Temperature range Package Type

SP3224ECA-L From 0°C to +70°C Lead Free 20 pin SSOP

SP3224ECY-L From 0°C to +70°C Lead Free 20 pin TSSOP

SP3224EEA-L From -40°C to +85°C Lead Free 20 pin SSOP

SP3224EEY-L From -40°C to +85°C Lead Free 20 pin TSSOP

SP3225ECA-L From 0°C to +70°C Lead Free 20 pin SSOP

SP3225ECY-L From 0°C to +70°C Lead Free 20 pin TSSOP

SP3225EEA-L From -40°C to +85°C Lead Free 20 pin SSOP

SP3225EEY-L From -40°C to +85°C Lead Free 20 pin TSSOP

SP3226ECA-L From 0°C to +70°C Lead Free 16 pin SSOP

SP3226ECY-L From 0°C to +70°C Lead Free 16 PIN SSOP

SP3226EEA-L From -40°C to +85°C Lead Free 16 pin SSOP

SP3226EEY-L From -40°C to +85°C Lead Free 16 PIN TSSOP

SP3227ECA-L From 0°C to +70°C Lead Free 16 PIN SSOP

SP3227ECY-L From 0°C to +70°C Lead Free 16 PIN TSSOP

SP3227EEA-L From -40°C to +85°C Lead Free 16 PIN SSOP

SP3227EEY-L From -40°C to +85°C Lead Free 16 PIN TSSOP

Available in Tape on Reel