ADM3251E Data Sheet
All voltages are relative to their respective ground; all minimum/maximum specifications apply over the entire recommended operating
range; T
A
= 25°C, V
CC
= 3.3 V (dc-to-dc converter disabled), and the secondary side is powered externally by V
ISO
= 3.3 V, unless
otherwise noted.
Table 2.
Parameter Min Typ Max Unit Test Conditions/Comments
DC CHARACTERISTICS
V
CC
Operating Voltage Range 3.0 3.7 V
DC-to-DC Converter Disable Threshold, V
CC(DISABLE)
1
3.7 V
DC-to-DC Converter Disabled
V
ISO
2
3.0 5.5 V
Primary Side Supply Input Current, I
CC(DISABLE)
2.5 mA No load
Secondary Side Supply Input Current, I
ISO(DISABLE)
ISO
L
Secondary Side Supply Input Current, I
ISO(DISABLE)
L
LOGIC
Transmitter Input, T
IN
Logic Input Current, I
TIN
−10 +0.01 +10 μA
Logic Low Input Threshold, V
TINL
0.3 V
CC
V
Logic High Input Threshold, V
TINH
0.7 V
CC
V
Receiver Output, R
OUT
Logic High Output, V
ROUTH
V
CC
− 0.1 V
CC
V I
ROUTH
= −20 μA
V
CC
− 0.5 V
CC
− 0.3 V I
ROUTH
= −4 mA
ROUTL
ROUTH
0.3 0.4 I
ROUTH
= 4 mA
RS-232 V
Receiver, R
IN
EIA-232 Input Voltage Range
3
−30 +30 V
EIA-232 Input Threshold Low 0.6 1.3 V
EIA-232 Input Threshold High 1.6 2.4 V
EIA-232 Input Hysteresis 0.3 V
EIA-232 Input Resistance 3 5 7 kΩ
Transmitter, T
OUT
Output Voltage Swing (RS-232) ±5 ±5.7 V R
L
= 3 kΩ to GND
Transmitter Output Resistance
ISO
Output Short-Circuit Current (RS-232)
TIMING CHARACTERISTICS
Maximum Data Rate 460 kbps R
L
= 3 kΩ to 7 kΩ, C
L
= 50 pF to 1000 pF
Receiver Propagation Delay
t
PHL
190 ns
t
PLH
135 ns
Transmitter Propagation Delay 650 ns R
L
= 3 kΩ, C
L
= 1000 pF
Transmitter Skew 80 ns
Receiver Skew 55 ns
Transition Region Slew Rate
3
5.5 10 30 V/μs
+3 V to −3 V or −3 V to +3 V, V
CC
= 3.3 V,
R
L
= 3 kΩ, C
L
= 1000 pF, T
A
= 25°C
AC SPECIFICATIONS
Output Rise/Fall Time, t
R
/t
F
(10% to 90%) 2.3 ns C
L
= 15 pF, CMOS signal levels
Common-Mode Transient Immunity at Logic High Output
4
25 kV/μs V
CM
= 1 kV, transient magnitude = 800 V
Common-Mode Transient Immunity at Logic Low Output
4
25 kV/μs V
CM
= 1 kV, transient magnitude = 800 V
ESD PROTECTION (R
IN
AND T
OUT
PINS) ±15 kV Human body model air discharge
±8 kV Human body model contact discharge
1
Enable/disable threshold is the V
CC
voltage at which the internal dc-to-dc converter is enabled/disabled.
2
To maintain data sheet specifications, do not draw current from V
ISO
.
3
Guaranteed by design.
4
V
CM
is the maximum common-mode voltage slew rate that can be sustained while maintaining specification-compliant operation. V
CM
is the common-mode potential
difference between the logic and bus sides. The transient magnitude is the range over which the common mode is slewed. The common-mode voltage slew rates
apply to both rising and falling common-mode voltage edges.
Rev. G | Page 4 of 16