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General Description

The MAX3388E/MAX3389E are 2.5V-powered EIA/TIA-

232 and V.28/V.24 communications interfaces with low

power requirements, high data-rate capabilities, and

enhanced electrostatic discharge (ESD) protection. The

MAX3388E/MAX3389E have two receivers and three

transmitters. All RS-232 inputs and outputs are protected

to ±15kV using the IEC 1000-4-2 Air-Gap Discharge

method, ±8kV using the IEC 1000-4-2 Contact Discharge

method, and ±15kV using the Human Body Model.

In addition to the traditional RS-232 I/O, these devices have

dedicated logic-level I/O pins for additional device-to-

device handshaking. During shutdown the logic-level I/O

pins are active for the MAX3389E. An internal 62Ω switch is

provided to switch power to external circuitry or modules.

A proprietary low-dropout transmitter output stage

enables RS-232 compatible performance from a +2.35V

to +3.0V supply with a dual charge pump. The charge

pump requires only four small 0.1µF capacitors for oper-

ation from a +2.5V supply. The MAX3388E/MAX3389E

are capable of running at data rates up to 460kbps while

maintaining RS-232-compatible output levels.

The MAX3388E/MAX3389E have a unique V

pin that

allows interoperation in mixed-logic voltage systems.

Both input and output logic levels are pin programma-

ble through the V

pin. The MAX3388E/MAX3389E are

available in a space-saving TSSOP package.

Features

♦ V

Pin for Compatibility with Mixed-Voltage

Systems

♦ Additional I/O for Hot-Sync Applications

♦ ±15kV ESD Protection on Rx Inputs, Tx Outputs,

LIN, and SWIN

♦ Low 300µA Supply Current

♦ Guaranteed 460kbps Data Rate

♦ 1µA Low-Power Shutdown

♦ Integrated Switch for Powering Remote Circuitry

♦ Flow-Through Pinout

♦ L

OUT

Active During Shutdown (MAX3389E)

Applications

Subnotebook/Palmtop Computers

PDAs and PDA Cradles

Cell Phone Data Cables

Battery-Powered Equipment

Hand-Held Equipment

Peripherals

MAX3388E/MAX3389E

2.5V, ±15kV ESD-Protected RS-232

Transceivers for PDAs and Cell Phones

________________________________________________________________ Maxim Integrated Products 1

SHDN

GND

T1OUTC2+

C1-

V+

C1+

TOP VIEW

T2OUT

T3OUT

R1IN

R2INT2IN

T1IN

V-

C2-

LIN

SWIN

R1OUTR2OUT

SWOUT

LOUT

T3IN

TSSOP

MAX3388E

MAX3389E

Typical Operating Circuit

19-1845; Rev 1; 9/01

Pin Configuration

Ordering Information

PART TEMP. RANGE PIN-PACKAGE

MAX3388ECUG

0°C to +70°C 24 TSSOP

MAX3388EEUG -40°C to +85°C 24 TSSOP

MAX3389ECUG

0°C to +70°C 24 TSSOP

MAX3389EEUG -40°C to +85°C 24 TSSOP

MAX3388E

MAX3389E

R2OUT12

R1OUT

R2IN

GND

RS-232

I/O

T2IN

T1IN

C2-

C2+

C1-

C1+

R1IN

T2OUT

T1OUT

V-

V+

0.1µF

BYPASS

+2.5V

T3IN

T3OUT

5kΩ

0.1µF

SHDN

SWIN

LIN

30kΩ

SWOUT

SHDN

10 LOUT

= ±15kV ESD PROTECTION

For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at

1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.

Summary of content (11 pages)

PAGE 1
9-1845; Rev 1; 9/01 2.
PAGE 2
MAX3388E/MAX3389E 2.5V, ±15kV ESD-Protected RS-232 Transceivers for PDAs and Cell Phones ABSOLUTE MAXIMUM RATINGS VCC to GND ..............................................................-0.3V to +6V VL to GND...................................................-0.3V to (VCC + 0.3V) V+ to GND ................................................................-0.3V to +7V V- to GND .................................................................+0.3V to -7V V+ +V-(Note 1) .....................................
PAGE 3
2.5V, ±15kV ESD-Protected RS-232 Transceivers for PDAs and Cell Phones (VCC = VL = +2.35V to +3.0V, C1–C4 = 0.1µF, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = VL = +2.5V, TA = +25°C.) PARAMETER SYMBOL CONDITIONS MIN TYP VT_OUT = ±12V, transmitters disabled, VCC = 0 or +2.5V Output Leakage Current MAX UNITS ±25 µA HANDSHAKING I/O (LIN, LOUT) Input Voltage Range 0 Input Threshold Low LIN, VL = +2.5V, TA = +25°C Input Threshold High LIN, VL = +2.5V, TA = +25°C 0.
PAGE 4
Typical Operating Characteristics (VCC = VL = +2.5V, TA = +25°C, unless otherwise noted.) TRANSMITTER OUTPUT VOLTAGE vs. LOAD CAPACITANCE SLEW RATE vs. LOAD CAPACITANCE MAX3386E toc02 MAX3388E toc01 16 14 2.5 12 SLEW RATE (V/µs) OUTPUT VOLTAGE (V) 5.0 DATA RATE = 460kbps LOAD = 3kΩ IN PARALLEL 0 -2.5 SLEW RATE 10 SLEW RATE + 8 6 4 2 -5.0 0 1000 2000 3000 4000 5000 0 2000 3000 4000 LOAD CAPACITANCE (pF) TRANSMITTER OUTPUT VOLTAGE vs. DATA RATE SUPPLY CURRENT vs.
PAGE 5
2.5V, ±15kV ESD-Protected RS-232 Transceivers for PDAs and Cell Phones PIN NAME 1 C1+ 2 V+ +4.2V Supply Generated by the Charge Pump 3 C1- Negative Terminal of the Voltage-Doubler Charge-Pump Capacitor 4 C2+ Positive Terminal of the Inverting Charge-Pump Capacitor 5 C2- Negative Terminal of the Inverting Charge-Pump Capacitor 6 V- 7, 8, 9 T1IN, T2IN, T3IN FUNCTION Positive Terminal of the Voltage-Doubler Charge-Pump Capacitor -4.
PAGE 6
MAX3388E/MAX3389E 2.5V, ±15kV ESD-Protected RS-232 Transceivers for PDAs and Cell Phones Table 1. Shutdown Logic Truth Table SHDN TRANSMITTER OUTPUTS RECEIVER OUTPUTS CHARGE PUMP SWITCH L High-Z High-Z Inactive H Active Active Active POWERMANAGEMENT UNIT OR KEYBOARD CONTROLLER LOUT MAX3389E Open MAX3388E High-Z Closed LIN LIN LIN 5V/div SHDN T1 I/O CHIP POWER SUPPLY VL 2V/div MAX3388E MAX3389E T2 VCC = +2.5V C1–C4 = 0.
PAGE 7
2.5V, ±15kV ESD-Protected RS-232 Transceivers for PDAs and Cell Phones VL Logic Supply Input Unlike other RS-232 interface devices where the receiver outputs swing between 0 and V CC, the MAX3388E/ MAX3389E feature a separate logic supply input (VL) that sets VOH for the receiver outputs and sets thresholds for the transmitter inputs. This feature allows a great deal of flexibility in interfacing to many different types of systems with different logic levels. Connect this input to the host logic supply (1.
PAGE 8
RC 50MΩ to 100MΩ RD 330Ω CHARGE-CURRENT LIMIT RESISTOR DISCHARGE RESISTANCE HIGHVOLTAGE DC SOURCE Cs 150pF The Air-Gap test involves approaching the device with a charged probe. The contact discharge method connects the probe to the device before the probe is energized. Machine Model The Machine Model for ESD tests all pins using a 200pF storage capacitor and zero discharge resistance.
PAGE 9
2.5V, ±15kV ESD-Protected RS-232 Transceivers for PDAs and Cell Phones VCC 0.1µF VCC C1+ C1 C1- Power Switch The MAX3388E/MAX3389E contain an internal switch for powering external circuitry. This can be used to power hot-sync circuitry or other low-power circuitry. The switch on- resistance is typically 62Ω. The SWIN side of the switch is ESD protected to ±15kV. MAX3388E/MAX3389E High Data Rates The MAX3388E/MAX3389E maintain RS-232-compatible transmitter output voltages even at high data rates.
PAGE 10
MAX3388E/MAX3389E 2.5V, ±15kV ESD-Protected RS-232 Transceivers for PDAs and Cell Phones T1IN 2V/div T1OUT 5V/div the phone. The receiver outputs will sink to zero for low outputs, but will not exceed VL for logic highs. The input logic levels for the transmitters are also altered, scaled by the magnitude of the VL input. The devices will work with VL as low as 1.8V. This is useful with cell phones and other power-efficient devices with core logic voltage levels that go as low as 1.8V.
PAGE 11
2.5V, ±15kV ESD-Protected RS-232 Transceivers for PDAs and Cell Phones TSSOP.EPS Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.