SP207EEA-L Exar Corporation, SP207EEA-L Datasheet - Page 6

• Manufacturer Part Number: SP207EEA-L
• Description: IC TXRX RS232 ESD LP 24SSOP
• Manufacturer: Exar Corporation
• Type: Transceiverr

Specifications of SP207EEA-L

• Package / Case: 24-SSOP (0.200", 5.30mm Width)
• Number Of Drivers/receivers: 5/3
• Protocol: RS232
• Voltage - Supply: 4.5 V ~ 5.5 V
• Mounting Type: Surface Mount
• On Resistance (max): 7 KOhms
• Propagation Delay Time: 1.5 us
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Function: Transceiver
• Mounting Style: SMD/SMT
• Supply Current: 3 mA
• Supply Voltage (max): 6 V
• Supply Voltage (min): 5 V
• Logic Type: RS-232 Transceivers
• Number Of Circuits: 3
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

Receiver input thresholds are between .2
to .7 volts typical. This allows the receiver
to detect standard TTL or CMOS logic-level
signals as well as RS-232 signals. If a re-
ceiver input is left unconnected or un-driven,
a 5kΩ pulldown resistor to ground will commit
the receiver to a logic- output state.
Highly Efficient Charge–Pump
The onboard dual-output charge pump is
used to generate positive and negative signal
voltages for the RS-232 drivers. This enables
fully compliant RS-232 and V.28 signals from
a single power supply device.
The charge pumps use four external capaci-
tors to hold and transfer electrical charge.
The Exar–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
V
terminals of capacitors C
from V
connected to ground. C
to ground and the stored charge from C
superimposed onto C
connected to V
capacitor C
SS
charge store and double — The positive
C
CC
1
Figure . Charge Pump — Phase 
–5V
+
–
V
with their negative terminals initially
CC
= +5V
2
is now 2 x V
CC
Exar Corporation 48720 Kato Road, Fremont CA, 94538 • 50-668-707 • www.exar.com
C
the voltage potential across
2
+5V
–5V
+
–
2
– . Since C

l
+ is then connected
and C
CC
+
–
C
C
4
.
3
+
–
V
V
DD
SS
2
are charged
Storage Capacitor
Storage Capacitor
2
+ is still

– is
6
Phase 2
— V
nects the negative terminal of C
storage capacitor and the positive terminal
of C
and inverted (V - ) voltage onto C
capacitor C
for its next phase.
Phase 3
V
is identical to the first phase. The positive
terminals of capacitors C
from V
connected to ground. C
to ground and the stored charge from C
superimposed onto C
connected to V
capacitor C
Phase 4
V
the negative terminal of C
the positive terminal of C
age capacitor. This transfers the doubled
(V+) voltage onto C
C
next phase.
DD
DD

is charged from V
charge store and double —Phase three
2
SS
transfer — The fourth phase connects
Figure 3. Charge Pump — Phase 3
to ground. This transfers the doubled
C
C
CC
1
transfer and invert — Phase two con-
1
Figure 2. Charge Pump — Phase 2
–5V
+
–
+
–
V
V
with their negative terminals initially
CC
CC
= +5V
= +5V

2
charged from V
is now 2 x V
CC
C
C
2
2
the voltage potential across
+5V
–5V
–10V
+
+
–
–
4
. Meanwhile, capacitor
CC
2
– . Since C

l
+ is then connected
to prepare it for its
and C
CC
+
+
–
–
C
C
2
C
C
4
4
2
.
3
+
+
3
–
–
to the V
CC
to ground and
V
V
V
V
SP207E_00_072309
DD
SS
3
DD
SS
2
. Meanwhile,
to prepare it
are charged
Storage Capacitor
Storage Capacitor
Storage Capacitor
Storage Capacitor
2
to the V
2
+ is still
DD
stor-

– is
SS