HIN202E Intersil Corporation, HIN202E Datasheet - Page 12

• Manufacturer Part Number: HIN202E
• Description: +/-15kV/ ESD-Protected/ +5V Powered/RS-232 Transmitters/Receivers
• Manufacturer: Intersil Corporation

Test Circuits (HIN232E)
Detailed Description
The HIN2XXE family of high-speed RS-232
transmitters/receivers are powered by a single +5V power
supply, feature low power consumption, and meet all ElA
RS232C and V.28 specifications. The circuit is divided into
three sections: the charge pump, transmitter, and receiver.
Charge Pump
An equivalent circuit of the charge pump is illustrated in
Figure 3. The charge pump contains two sections: the
voltage doubler and the voltage inverter. Each section is
driven by a two phase, internally generated clock to generate
+10V and -10V. The nominal clock frequency is 125kHz.
During phase one of the clock, capacitor C1 is charged to
V
producing a signal across C3 equal to twice V
phase two, C2 is also charged to 2V
phase one, it is inverted with respect to ground to produce a
signal across C4 equal to -2V
input voltages up to 5.5V. The output impedance of the
CC
OSCILLATOR
. During phase two, the voltage on C1 is added to V
30V INPUT
3k
GND
V
0.1 F
RS-232
CC
0.1 F
OUTPUT
RC
0.1 F
C1
T2
C2
C3
0.1 F C4
FIGURE 1. GENERAL TEST CIRCUIT
+
+
-
-
+
+
-
-
S1
S3
1
2
3
4
5
6
7
8
VOLTAGE DOUBLER
C1+
V+
C1-
C2+
C2-
V-
T2
R2
OUT
IN
3-12
C1+
C1
CC
R1
R2
T1
+
-
-
GND
R1
T1
T2
V
OUT
OUT
OUT
C1
. The charge pump accepts
CC
IN
IN
IN
16
15
14
13
12
10
11
CC
S2
S4
9
, and then during
RS-232 30V INPUT
TTL/CMOS OUTPUT
TTL/CMOS INPUT
TTL/CMOS INPUT
TTL/CMOS OUTPUT
+5.5V INPUT
+4.5V TO
T1 OUTPUT
CC
3k
HIN202E thru HIN241E
. During
+
-
C3
FIGURE 3. CHARGE PUMP
V
CC
CC
,
V+ = 2V
GND
CC
voltage doubler section (V+) is approximately 200 , and the
output impedance of the voltage inverter section (V-) is
approximately 450 . A typical application uses 0.1 F
capacitors for C1-C4, however, the value is not critical.
Increasing the values of C1 and C2 will lower the output
impedance of the voltage doubler and inverter, increasing
the values of the reservoir capacitors, C3 and C4, lowers the
ripple on the V+ and V- supplies.
During shutdown mode (HIN205E, HIN206E, HIN211E,
HIN213E, HIN235E, HIN236E and HIN241E) the charge
pump is turned off, V+ is pulled down to V
to GND, and the supply current is reduced to less than 10 A.
The transmitter outputs are disabled and the receiver
outputs (except for HIN213E, R4 and R5) are placed in the
high impedance state.
Transmitters
The transmitters are TTL/CMOS compatible inverters which
translate the inputs to RS-232 outputs. The input logic
threshold is about 26% of V
S5
FIGURE 2. POWER-OFF SOURCE RESISTANCE
S7
VOLTAGE INVERTER
C2+
C2
CONFIGURATION
+
-
-
C2
R
OUT
S6
S8
V
1
2
3
4
5
6
7
8
IN
C1+
V+
C1-
C2+
C2-
V-
T2
R2
= V
= 2V
OUT
IN
CC
IN
/I
, or 1.3V for V
R1
R2
T1
T2
GND
R1
T1
T2
+
V
OUT
OUT
OUT
-
OUT
CC
T1
C4
A
IN
IN
IN
OUT
16
15
14
13
12
11
10
9
CC
GND
V
CC
, V- is pulled up
-
=
-
= 5V. A logic
(V+)