HIN232, HIN236, HIN237, HIN238, HIN239, HIN240, HIN241
Electrical Specifications Test Conditions: V = +5V ±10%, T = Operating Temperature Range (Continued)
CC
A
PARAMETER
TIMING CHARACTERISTICS
Baud Rate (1 Transmitter Switching)
TEST CONDITIONS
MIN
TYP
MAX
UNITS
R
= 3kΩ
120
-
-
-
kbps
ns
L
Output Enable Time, t
HIN236, HIN239, HIN240, HIN241
HIN236, HIN239, HIN240, HIN241
-
-
-
-
-
400
250
0.5
-
EN
Output Disable Time, t
-
ns
DIS
Propagation Delay, t
RS-232 to TTL
= 10pF, R = 3kΩ, T = 25 C (Note 4)
-
µs
PD
o
Instantaneous Slew Rate SR
C
30
-
V/µs
V/µs
L
L
A
Transition Region Slew Rate, SR
R = 3kΩ, C = 2500pF Measured from +3V to -3V or
3
T
L
L
-3V to +3V, 1 Transmitter Switching
TRANSMITTER OUTPUTS
Output Voltage Swing, T
OUT
Transmitter Outputs, 3kΩ to Ground
±5
300
-
±9
-
±10
V
Ω
Output Resistance, T
OUT
V
= V+ = V- = 0V, V
OUT
= ±2V
-
-
CC
RS-232 Output Short Circuit Current, I
T
shorted to GND
±10
mA
SC
OUT
NOTE:
4. Guaranteed by design.
VOLTAGE DOUBLER
+
VOLTAGE INVERTER
+
S5
S1
S3
S2
C2
C1
V+ = 2V
S6
CC
V
GND
CC
+
-
+
-
+
-
+
C4
-
C3
C2
C1
V
GND
CC
V- = -(V+)
GND
-
C1-
S4
C2
S7
S8
RC
OSCILLATOR
FIGURE 1. CHARGE PUMP
to 5.5V. The output impedance of the voltage doubler section
(V+) is approximately 200Ω, and the output impedance of the
voltage inverter section (V-) is approximately 450Ω. A typical
application uses 1µF 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.
Detailed Description
The HIN232 thru HIN241 family of RS-232
transmitters/receivers are powered by a single +5V power
supply (except HIN239), feature low power consumption, and
meet all ElA RS-232C and V.28 specifications. The circuit is
divided into three sections: The charge pump, transmitter, and
receiver.
Charge Pump
During shutdown mode (HIN236, HIN240 and HIN241),
SHUTDOWN control line set to logic “1”, the charge pump is
An equivalent circuit of the charge pump is illustrated in
Figure 1. 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 16kHz. During phase
turned off, V+ is pulled down to V , V- is pulled up to GND,
CC
and the supply current is reduced to less than 10µA. The
transmitter outputs are disabled and the receiver outputs are
placed in the high impedance state.
one of the clock, capacitor C1 is charged to V . During
CC
phase two, the voltage on C1 is added to V , producing a
CC
signal across C3 equal to twice V . During phase one, C2 is
CC
also charged to 2V , and then during phase two, it is
CC
inverted with respect to ground to produce a signal across C4
equal to -2V . The charge pump accepts input voltages up
CC
9
ISSI [ INTEGRATED SILICON SOLUTION, INC ]
