SP207EEA-L Exar Corporation, SP207EEA-L Datasheet - Page 7

• 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

The Exar charge-pump generates V+ and V -
independently from V
condition V+ and V - will be symmetrical.
Older charge pump approaches generate
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 intelligent
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 Exar charge-pump design.
The clock rate for the charge pump typically
operates at greater than 5kHz, allowing
the pump to run efficiently with small 0.1µF
capacitors. Efficient operation depends on
rapidly charging and discharging C
C
close to the IC and have low ESR (equivalent
series resistance). Low cost surface mount
ceramic capacitors (such as are widely used
for power-supply decoupling) are ideal for
use on the charge pump.
However the charge pumps are designed
to be able to function properly with a wide
range of capacitor styles and values. If
polarized capacitors are used, the positive
and negative terminals should be connected
as shown.
2
, therefore capacitors should be mounted
Figure 4. Charge Pump — Phase 4
C
1
+
–
V
CC
= +5V
Exar Corporation 48720 Kato Road, Fremont CA, 94538 • 50-668-707 • www.exar.com
C
2
+10V
+
–
CC
. Hence in a no–load
+
–
C
C
4
3
+
–
V
V
DD
SS
Storage Capacitor
Storage Capacitor

and
7
Voltage potential across any of the capaci-
tors will never exceed 2 x V
capacitors with working v
0V rating may be used with a nominal V
supply. C
than V
adequate. The reference terminal of the
V
V
minimum 6V working voltage is required.
Higher working voltages and/or capacitance
values may be advised if operating at higher
V
capacitors age.
Figure 5. Typical waveforms seen on ca-
pacitor C2 when all drivers are at maximum
load.
a) C
b) C
DD
CC
CC
2
2
or ground, but if connected to ground a
+
capacitor may be connected either to
–
or to provide greater stability as the
+10V
gND
–10V
gND
CC
, so a working voltage of 6.3V is

will never see a potential greater
oltages
CC
SP207E_00_072309
. Therefore
as low as
CC