ADM101E ,Craft Port Tiny RS-232 Transceiver to Portable ApplicationsSpecifications subject to change without notice.ABSOLUTE MAXIMUM RATINGS* ORDERING GUIDE(T = 25°C u ..
ADM101EARM ,Craft PortTM Tiny RS-232 Transceiver for Portable ApplicationsSpecifications subject to change without notice.ABSOLUTE MAXIMUM RATINGS* ORDERING GUIDE(T = +25
ADM101E
Craft Port Tiny RS-232 Transceiver to Portable Applications
REV.A
Craft PortTM Tiny RS-232 Transceiver for
Portable Applications
FUNCTIONAL BLOCK DIAGRAM
FEATURES
460 kbit/s Transmission Rate
Single 5 V Power Supply
Compatible with RS-232 Input/Output Levels
0.1 �F Charge Pump Capacitors
One Driver and One Receiver
On-Board DC-DC Converter�4.2 V Output Swing with 5 V Supply
Low Power BiCMOS: 500�A ICC
Ultralow Power (1 �A) Shutdown Mode
10-Lead �SOIC Package
APPLICATIONS
Mobile Telephones
Palmtop Computers
PDAs
Portable Instrumentation
GPS Receivers
GENERAL DESCRIPTIONThe ADM101E is a single channel RS-232 driver and receiver in
the Analog Devices Craft Port series, designed to operate from a
single, 5 V supply. A highly efficient charge-pump voltage inverter
generates an on-chip –5 V supply, which eliminates the need
for a negative power supply for the driver and permits RS-232
compatible output levels to be developed using charge pump
capacitors as small as 0.1 µF.
A shutdown input disables the charge pump and puts the device
into a low power shutdown mode, in which the current con-
sumption is typically less than 1 µA. The transmitter is disabled
during shutdown but the receiver remains functional.
Craft Port is a trademark of Analog Devices, Inc.
An epitaxial BiCMOS construction minimizes power consump-
tion to 3 mW and also guards against latch-up. Overvoltage
protection is provided allowing the receiver inputs to withstand
continuous voltages in excess of ±30 V. In addition, all I-O pins
have ESD protection to levels greater than 15 kV.
The ADM101E is available in a 10-lead µSOIC package, which
makes it ideal for serial communications in small, portable
applications such as palmtop computers and mobile telephones,
where a full, RS-232 serial interface is not required, but com-
pact size and low power drain are paramount.
ADM101E–SPECIFICATIONS
(VCC = 5 V � 10%, C1 = C2 = 0.1 �F. All specifications TMIN to TMAX unless
otherwise noted.)VCC Power Supply Current (Shutdown)
Input Logic Threshold High, VINH
Input Leakage Current
RS-232 Input Voltage Range
RS-232 Input Threshold Low
RS-232 Input Threshold High
RS-232 Input Hysteresis
RS-232 Input Resistance
TTL/CMOS Output Voltage Low, VOL
TTL/CMOS Output Voltage High, VOH
Propagation Delay
Instantaneous Slew Rate
Transition Region Slew Rate
Baud Rate
Output Resistance
NOTESSample tested to ensure compliance.
Specifications subject to change without notice.
ABSOLUTE MAXIMUM RATINGS*(TA = 25°C unless otherwise noted)
VCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +0.3 V to –6 V
Input Voltages
Driver Input TIN . . . . . . . . . . . . . . –0.3 V to (VCC, +0.3 V)
Receiver Input RIN . . . . . . . . . . . . . . . . . . . . . . . . . . ±30 V
Output Voltages
Driver Output TOUT . . . . . . . (VCC, +0.3 V) to (V–, –0.3 V)
Receiver Output ROUT . . . . . . . . . . –0.3 V to (VCC +0.3 V)
Short Circuit Duration
TOUT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Continuous
Power Dissipation
RM-10 (Derate 12 mW/°C above 70°C) . . . . . . . . . 1488mW
Thermal Impedance . . . . . . . . . . . . . . . . . . . . . . . . 135°C/W
Operating Temperature Range
Industrial (A Version) . . . . . . . . . . . . . . . –40°C to +85°C
Storage Temperature Range . . . . . . . . . . . . –65°C to +150°C
Lead Temperature Soldering
Vapor Phase (60 sec) . . . . . . . . . . . . . . . . . . . . . . . . 215°C
Infrared (15 sec) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220°C
ESD Rating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . >2000 V
ESD Rating (I-O Pins) . . . . . . . . . . . . . . . . . . . . . . . . .15 kV
*This is a stress rating only; functional operation of the device at these or any other
conditions above those indicated in the operation sections of this specification is
not implied. Exposure to absolute maximum rating conditions for extended
periods of time may affect reliability.
ORDERING GUIDE
PIN FUNCTION DESCRIPTIONS
PIN CONFIGURATION
Typical Performance CharacteristicsTPC 1.Charge Pump Voltage vs. Current
TPC 2.IDD vs. Load Capacitance @ 460 kbps
ADM101E
LOAD CAPACITANCE – pF500
O/P
Volts
2500TPC 3.Transmitter Output Voltage vs. Load Capacitance @
460 kbps
VCC – Volts
O/P HI & LO4TPC 4.Tx Output Voltage vs. Supply
TPC 5.Slew Rate vs. Data Rate
LOAD CURRENT – mA02
OUTPUT VOLTAGE812TPC 6.Transmitter Output Voltage vs. Load Current
GENERAL DESCRIPTIONThe ADM101E is an RS-232 compatible line driver/receiver in
the Analog Devices Craft Port series, containing one driver (trans-
mitter) and one receiver. It is ideal for serial communication in
small portable devices such as mobile telephones, palmtop per-
sonal computers and personal digital assistants, where a full,
RS-232 serial interface is not required, and only Tx and Rx lines
are required for low speed communication between devices. The
ADM101E operates from a single, 5 V supply, and generates its
own, on-chip, –5 V power supply, thus removing the need for a
negative power supply for the driver.
CIRCUIT DESCRIPTIONThe internal circuitry consists of three main sections. These are:A charge pump dc-to-dc converter.5V logic to EIA-232 driver.EIA-232 to 5V logic receiver.
Charge Pump DC-DC ConverterThe dc-dc converter generates a negative supply voltage from
the 5 V supply, thus removing the need for a separate –5 V rail.
It consists of an on-chip 200 kHz oscillator, switching matrix
and two external capacitors, as shown in Figure 1.
Figure 1.Charge Pump DC–DC Converter
When S1 and S2 are closed, S3 and S4 are open, and C1
charges to +VCC. S1 and S2 are then opened, while S3 and S4
are closed to connect C1 across C2, dumping charge into C2.
Since the positive terminal of C2 is at ground, a negative voltage
will be built up on its negative terminal with each cycle of the
oscillator. This voltage depends on the current drawn from C2.
If the current is small, the voltage will be close to –VCC, but will
fall as the current drawn increases.
Charge Pump Capacitors And Supply DecouplingFor proper operation of the charge pump, the capacitors should
have an equivalent series resistance (ESR) less than 1 Ω. As the
charge pump draws current pulses from VCC, the VCC decou-
pling capacitor should also have low ESR. The VCC decoupling
capacitor and V– reservoir capacitor should also have low ESR
because they determine how effectively ESD pulses are clamped
to VCC or V– by the on-chip clamp diodes. Tantalum or mono-
lithic ceramic capacitors are suitable for these components. If
using tantalum capacitors, do not forget to observe polarity.
Transmitter (Driver) SectionThe driver converts 5V logic input levels into RS-232 compat-
ible output levels. With VCC = 5 V and driving an EIA-232 load,
the output voltage swing is typically ±4.2 V.
Receiver SectionThe receivers are inverting level-shifters that accept EIA-232
input levels and translate them into 5 V logic output levels.
The inputs have internal 5 kΩ pull-down resistors to ground and
are also protected against overvoltages of up to ±25 V. The
guaranteed switching thresholds are 0.8 V minimum and 2.8 V
maximum. An unconnected receiver input is pulled to 0 V by
the internal 5 kΩ pull-down resistor. This, therefore, results in a
Logic 1 output level for unconnected inputs or for inputs con-
nected to GND.
The receivers have Schmitt trigger input with a hysteresis level
of 0.25 V. This ensures error-free reception for both noisy
inputs and for inputs with slow transition times.
SHUTDOWN INPUTThe shutdown input allows the ADM101E to be put into an
ultralow power mode where the dc-dc converter is switched off
and the transmitter is disabled. The receiver remains active
during shutdown. Logic 0 at this input enables the ADM101E,
while a Logic 1 at this input shuts down the ADM101E.
ADM101E
OUTLINE DIMENSIONSDimensions shown in inches and (mm).
C00053–0–2/01 (rev. A)
PRINTED IN U.S.A.
10-Lead �SOIC
(RM-10)
ADM101E–Revision History
LocationPageData sheet changed from REV. 0 to REV. A.
Changes made to Outline Dimensions (RM-10) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
