ICL3225 Datasheet, PDF (12/18 Pages) Intersil Corporation – 1 Microamp, +3V to +5.5V, 1Mbps, RS-232 Transceivers with Enhanced Automatic Powerdown

ICL3225, ICL3245
High Data Rates
The ICL32XX maintain the RS-232 ±5V minimum transmitter
output voltages even at high data rates. Figure 12 details a
transmitter loopback test circuit, and Figure 13 illustrates the
loopback test result at 250kbps. For this test, all transmitters
were simultaneously driving RS-232 loads in parallel with
1000pF, at 250kbps. Figure 14 shows the loopback results
for a single transmitter driving 250pF and an RS-232 load at
1Mbps. The static transmitters were also loaded with an
RS-232 receiver.
V_CC
0.1µF
+
+
C1+
V_CC
V+
C₁
+
C₃
C1-
ICL32XX
+
C2+
C₂
V-
+C⁴
C2-
T_IN
T_OUT
R_OUT
R_IN
C_L
FORCEON
5K
V_CC
FORCEOFF
FIGURE 12. TRANSMITTER LOOPBACK TEST CIRCUIT
5V/DIV.
T1_IN
T1_OUT
5V/DIV.
T1_IN
T1_OUT
R1_OUT
V_CC = +3.3V
C1 - C4 = 0.1µF
0.5µs/DIV.
FIGURE 14. LOOPBACK TEST AT 1Mbps (C_L = 250pF)
Interconnection with 3V and 5V Logic
The ICL32XXE directly interfaces with 5V CMOS and TTL
logic families. Nevertheless, with the ICL32XX at 3.3V, and
the logic supply at 5V, AC, HC, and CD4000 outputs can
drive ICL32XX inputs, but ICL32XX outputs do not reach the
minimum V_IH for these logic families. See Table 4 for more
information.
TABLE 4. LOGIC FAMILY COMPATIBILITY WITH VARIOUS
SUPPLY VOLTAGES
SYSTEM
V_CC
POWER-SUPPLY SUPPLY
VOLTAGE VOLTAGE
(V)
(V)
COMPATIBILITY
3.3
3.3 Compatible with all CMOS
families.
5
5
Compatible with all TTL and
CMOS logic families.
5
3.3 Compatible with ACT and HCT
CMOS, and with TTL. ICL32XX
outputs are incompatible with AC,
HC, and CD4000 CMOS inputs.
R1_OUT
V_CC = +3.3V
C1 - C4 = 0.1µF
2µs/DIV.
FIGURE 13. LOOPBACK TEST AT 250kbps (C_L = 1000pF)
12