19-498; Rev 1; 1/ ±15k ESD-Protected, 1Mbps, 3/5, eneral Description The are rugged, low-power, quad, RS-422/RS-485 receivers with electrostatic discharge (ESD) protection for use in harsh environments. All receiver inputs are protected to ±15k using IEC 1-4-2 Air-ap Discharge, ±8k using IEC 1-4-2 Contact Discharge, and ±15k using the Human Body Model. The MAX395 operates from a +5 supply, while the MAX396 operates from a +3.3 supply. Receiver propagation delays are guaranteed to within ±8 of a predetermined value, thereby euring device-to-device matching across production lots. Complementary enable inputs can be used to place the devices in a 1nA low-power shutdown mode in which the receiver outputs are high impedance. When active, these receivers have a fail-safe feature that guarantees a logic-high output if the input is open circuit. They also feature a quarter-unit-load input impedance that allows 128 receivers on a bus. The are pin-compatible, low-power upgrades to the industry-standard 26LS32. They are available in a space-saving QSOP package. Applicatio Telecommunicatio Equipment Rugged RS-422/RS-485/RS-423 Bus Receiver Receivers for ESD-Seitive Applicatio Level Tralators Functional Diagram CC MAX395 MAX396 Features ESD Protection: ±15k IEC 1-4-2, Air-ap Discharge ±8k IEC 1-4-2, Contact Discharge ±15k Human Body Model uaranteed Propagation-Delay Tolerance Between All ICs: ±8 (MAX395) ±1 (MAX396) Single +3 Operation (MAX396) Single +5 Operation (MAX395) 16-Pin QSOP (8-pin SO footprint) 1Mbps Data Rate Allow up to 128 Receivers on the Bus 1nA Low-Power Shutdown Mode 2.4mA Operating Supply Current Pin-Compatible Upgrades to 26LS32 Ordering Information PART MAX395CPE MAX395CSE MAX395CEE MAX395EPE MAX395ESE MAX395EEE MAX396CPE MAX396CSE MAX396CEE MAX396EPE MAX396ESE MAX396EEE TEMP. RANE C to +7 C C to +7 C C to +7 C -4 C to +85 C -4 C to +85 C -4 C to +85 C PIN-PACKAE 16 Plastic DIP 16 Narrow SO 16 QSOP 16 Plastic DIP 16 Narrow SO 16 QSOP C to +7 C 16 Plastic DIP C to +7 C C to +7 C -4 C to +85 C -4 C to +85 C -4 C to +85 C 16 Narrow SO 16 QSOP 16 Plastic DIP 16 Narrow SO 16 QSOP Pin Configuration A1 B1 Y1 TOP IEW B1 1 16 CC A2 B2 Y2 A1 Y1 2 3 15 14 B4 A4 A3 B3 A4 B4 Y3 Y4 Y2 A2 B2 ND 4 5 6 7 8 MAX395 MAX396 13 12 11 1 9 Y4 Y3 A3 B3 ND DIP/SO/QSOP Maxim Integrated Products 1 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.
ABSOLUTE MAXIMUM RATINS Supply oltage ( CC )...7 Control Input oltage (, )...-.3 to ( CC +.3) Receiver Input oltage (A_, B_)...±25 Receiver Output oltage (Y_)...-.3 to ( CC +.3) Continuous Power Dissipation (T A = +7 C) 16-Pin Plastic DIP (derate 1.5mW/ C above +7 C).762mW 16-Pin SO (derate 8.7mW/ C above +7 C)...696mW 16-Pin QSOP (derate 8.3mW/ C above +7 C)...667mW Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditio beyond those indicated in the operational sectio of the specificatio is not implied. Exposure to absolute maximum rating conditio for extended periods may affect device reliability. DC ELECTRICAL CHARACTERISTICS MAX395 Operating Temperature Ranges MAX39_C... C to +7 C MAX39_E...-4 C to +85 C Storage Temperature Range...-65 C to +16 C Lead Temperature (soldering, 1s)...+3 C ( CC = 5 ±5%, T A = T MIN to T MAX, unless otherwise noted. Typical values are at T A = +25 C.) (Note 1) PARAMETER Receiver Differential Input Threshold Receiver Input Hysteresis Enable Input Current (, ) Enable Input High oltage (, ) Enable Input Low oltage (, ) Receiver Output High oltage SYMBOL TH -7 CM 12 CM = Receiver Input Current (A_, B_) I IN CC = or 5.25 IH IL OH CONDITIONS I OUT = -4mA, ID = 2m, = CC or = ND, Figure 1 IN = 12 IN = -7 MIN TYP MAX -2 2 2. CC - 1.5 45 25-2 ±1.8 UNITS m m Receiver Output Low oltage OL I OUT = 4mA, ID = -2m, = CC or = ND, Figure 1.4 Three-State Current at Receiver Output I OZR OUT CC, = ND and = CC ±1 Output Short-Circuit Current I OSR OUT CC, = CC or = ND ±7 ±75 ma Receiver Input Resistance R IN -7 CM 12 48 kω Supply Current I CC No load, = CC or = ND = ND and = CC 2.4 3.5.1 1 ma ESD Protection (Note 2) Human Body Model IEC1-4-2 (Air-ap Discharge) IEC1-4-2 (Contact Discharge) ±15 ±15 k ±8 2
SWITCHIN CHARACTERISTICS MAX395 ( CC = 5 ±5%, T A = T MIN to T MAX, unless otherwise noted. Typical values are at T A = +25 C.) PARAMETER SYMBOL CONDITIONS Input-to-Output Propagation Delay Device-to-Device Propagation- Delay Matching Propagation-Delay Skew (t PLH - t PHL ) Output Enable Time to Low Level t PLH, t PHL t SK t ZL CC = 5 ±5%, T A = T MIN to T MAX T A = +85 C CC = 5.25 T A = +25 C ID = 3, T A = -4 C Figure 2 T A = +85 C CC = 4.75 T A = +25 C T A = -4 C ID = 3, Figure 2, matched conditio MIN TYP MAX 65 98 78 86 94 71 79 87 65 73 81 82 9 98 74 82 9 68 76 84 16-4 ±1 6 8 UNITS Output Enable Time to High Level t ZH 6 8 Output Disable Time from Low Level t LZ 6 1 Output Disable Time from High Level t HZ 6 1 Maximum Data Rate f MAX 1 Mbps DC ELECTRICAL CHARACTERISTICS MAX396 ( CC = 3. to 3.6, T A = T MIN to T MAX, unless otherwise noted. Typical values are at CC = 3.3, T A = +25 C.) (Note 1) PARAMETER Receiver Differential Input Threshold Receiver Input Hysteresis Enable Input Current (, ) Enable Input High oltage (, ) Enable Input Low oltage (, ) Receiver Output High oltage SYMBOL TH IH -7 CM 12 CM = Receiver Input Current (A_, B_) I IN CC = or 3.6 IL OH CONDITIONS I OUT = -1.5mA, ID = 2m, = CC or = ND, Figure 1 IN = 12 IN = -7 MIN TYP MAX -2 2 45 25-2 ±1 2..8 CC -.4 UNITS m m Receiver Output Low oltage OL I OUT = 2.5mA, ID = -2m, = CC or = ND, Figure 1.4 Three-State Current at Receiver Output I OZR OUT CC, = ND and = CC ±1 Output Short-Circuit Current I OSR OUT CC, = CC or = ND ±4 ±6 ma Receiver Input Resistance R IN -7 CM 12 48 kω 3
DC ELECTRICAL CHARACTERISTICS MAX396 (continued) ( CC = 3. to 3.6, T A = T MIN to T MAX, unless otherwise noted. Typical values are at CC = 3.3, T A = +25 C.) (Note 1) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS Supply Current I CC No load, = CC or = ND 2.4 4. ma = ND and = CC.1 1 Human Body Model ±15 ESD Protection (Note 2) IEC1-4-2 (Air-ap Discharge) ±15 k IEC1-4-2 (Contact Discharge) ±8 SWITCHIN CHARACTERISTICS MAX396 ( CC = 3. to 3.6, T A = T MIN to T MAX, unless otherwise noted. Typical values are at T A = +25 C.) PARAMETER Input-to-Output Propagation Delay Device-to-Device Propagation- Delay Matching SYMBOL t PLH, t PHL CONDITIONS CC = 3. to 3.6, T A = T MIN to T MAX T A = +85 C CC = 3.6 T A = +25 C ID = 3, T A = -4 C Figure 2 T A = +85 C CC = 3. T A = +25 C T A = -4 C ID = 3, Figure 2, matched conditio MIN TYP MAX 69 123 88 98 18 78 88 98 69 79 89 13 113 123 91 11 111 82 92 12 2 UNITS Propagation-Delay Skew (t PLH - t PHL ) t SK -2 ±1 Output Enable Time to Low Level t ZL 6 1 Output Enable Time to High Level t ZH 6 1 Output Disable Time from Low Level t LZ 8 18 Output Disable Time from High Level t HZ 8 18 Maximum Data Rate f MAX 1 Mbps Note 1: All currents into the device are positive; all currents out of the device are negative. All voltages are referred to device ground, unless otherwise noted. Note 2: Receiver inputs (A_, B_). 4
Typical Operating Characteristics ( CC = 5 for MAX395, CC = 3.3 for MAX396, T A = +25 C, unless otherwise noted.) OUTPUT CURRENT (ma) -5-4 -3-2 -1 OUTPUT CURRENT vs. OUTPUT LOW OLTAE MAX396 MAX395 1 2 3 4 5 OUTPUT LOW OLTAE () MAX395-1 OUTPUT CURRENT (ma) 3 25 2 15 1 5 OUTPUT CURRENT vs. OUTPUT HIH OLTAE MAX396 MAX395 1 2 3 4 5 OUTPUT HIH OLTAE () MAX395-2 OUTPUT LOW OLTAE () 1..9.8.7.6.5.4.3.2.1 I OUT = 8mA OUTPUT LOW OLTAE vs. TEMPERATURE MAX396-4 -15 1 35 6 85 TEMPERATURE ( C) MAX395 MAX395-3 OUTPUT HIH OLTAE () 5 4 3 2 1 OUTPUT HIH OLTAE vs. TEMPERATURE MAX396 MAX395 MAX395-4 SUPPLY CURRENT (ma) 3. 2.8 2.6 2.4 2.2 SUPPLY CURRENT vs. TEMPERATURE MAX395-5 SHUTDOWN SUPPLY CURRENT (na) 2 15 1 5 SHUTDOWN SUPPLY CURRENT vs. TEMPERATURE MAX396 MAX395 MAX395-6 I OUT = -8mA -4-15 1 35 6 85 TEMPERATURE ( C) 2. -4-15 1 35 6 85 TEMPERATURE ( C) -4-15 1 35 6 85 TEMPERATURE ( C) PROPAATION DELAY () 12 11 1 9 8 MAX395 PROPAATION DELAY vs. TEMPERATURE ID = 3 C L = 15pF MAX395-7 PROPAATION DELAY () 14 13 12 11 1 9 MAX396 PROPAATION DELAY vs. TEMPERATURE ID = 3 C L = 15pF MAX395-8 7-4 -15 1 35 6 85 TEMPERATURE ( C) 8-4 -15 1 35 6 85 TEMPERATURE ( C) 5
Typical Operating Characteristics (continued) ( CC = 5 for MAX395, CC = 3.3 for MAX396, T A = +25 C, unless otherwise noted.) MAX395 Y OLTAE MAX396 Y OLTAE OLTAE SHUTDOWN TIMIN TIME (2/div) CIRCUIT OF FIURE 3, S1 OPEN, S2 CLOSED, S3 = 1 MAX395 TOC9 5/div 2/div 2/div _ Pin Description PIN NAME FUNCTION 1 B1 Inverting Receiver Input 2 A1 Noninverting Receiver Input 3 Y1 4 8 ND round Receiver Output. Enabled when = high OR = low. Y1 will be logic high if A1 > B1 by 2m, and low if A1 < B1 by 2m. It will be logic high if A1 and B1 remain floating. Otherwise, the state is undetermined. Y1 goes high impedance when the = low and = high. Receiver Output Enable High. A logic high on this input enables all receivers. When taken low and is high, all receivers are shut down, and the outputs go high impedance. 5 Y2 Receiver Output. Same functionality as Y1. 6 A2 Noninverting Receiver Input 7 B2 Inverting Receiver Input 9 B3 Inverting Receiver Input 1 A3 Noninverting Receiver Input 11 Y3 Receiver Output. Same functionality as Y1. 12 Receiver Output Enable Low. A logic low on this pin enables all receivers. When = high and = low, all receivers are shut down, and the outputs go high impedance. 13 Y4 Receiver Output. Same functionality as Y1. 14 A4 Noninverting Receiver Input 15 B4 Inverting Receiver Input 16 CC Positive Supply 6
ID R OL Figure 1. Receiver OH and OL I OL (+) OH IOH (-) IN 1.5 OUT t PLH ID = 3 ID = CC or = ND R 1.5 OUT C L 15pF t PHL 1.5 (MAX396) 1.5 2. (MAX395) 2. 3. CC (MAX396) (MAX395) Figure 2. Receiver Propagation Delay CC +1-1 S3 ID R C L 15pF 1k S1 S2 CC 3 3 1.5 1.5 t ZH t HZ t LZ t ZL OUT.25 1.5 OH OUT 1.5 CC OL S1 OPEN S2 CLOSED S3 = 1.25 S1 CLOSED S2 OPEN S3 = -1. Receiver Enable and Disable Times 7
Detailed Description ±15k ESD Protection As with all Maxim devices, ESD-protection structures are incorporated on all pi to protect agait electrostatic discharges (ESD) encountered during handling and assembly. The receiver inputs have extra protection agait static electricity found in normal operation. Maxim s engineers developed stateof-the-art structures to protect these pi agait ±15k ESD, without damage. After an ESD event, the MAX395/ MAX396 continue working without latchup. ESD protection can be tested in several ways. The receiver inputs are characterized for protection to the following: 1) ±15k using the Human Body Model 2) ±8k using the Contact-Discharge Method specified in IEC 1-4-2 (formerly IEC 81-2) 3) ±15k using the Air-ap Method specified in IEC 1-4-2 (formerly IEC 81-2) ESD Test Conditio ESD performance depends on a number of conditio. Contact Maxim for a reliability report that documents test setup, methodology, and results. Human Body Model Figure 4a shows the Human Body Model, and Figure 4b shows the current waveform it generates when discharged into a low impedance. This model coists of a 1pF capacitor charged to the ESD voltage of interest, which is then discharged into the device through a 1.5kΩ resistor. IEC 1-4-2 Since January 1996, all equipment manufactured and/or sold in the European community has been required to meet the stringent IEC 1-4-2 specification. The IEC 1-4-2 standard covers ESD testing and performance of finished equipment; it does not specifically refer to integrated circuits. The help you design equipment that meets Level 4 (the highest level) of IEC 1-4-2, without additional ESD-protection components. The main difference between tests done using the Human Body Model and IEC 1-4-2 is higher peak current in IEC 1-4-2. Because series resistance is lower in the IEC 1-4-2 ESD test model (Figure 5a), the ESD-withstand voltage measured to this standard is generally lower than that measured using the Human Body Model. Figure 5b shows the current waveform for the ±8k IEC 1-4-2 Level 4 ESD Contact-Discharge test. The Air-ap test involves approaching the device with a charge probe. The Contact-Discharge method connects the probe to the device before the probe is energized. Machine Model The Machine Model for ESD testing uses a 2pF storage capacitor and zero-discharge resistance. It mimics the stress caused by handling during manufacturing and assembly. Of course, all pi (not just RS-485 inputs) require this protection during manufacturing. Therefore, the Machine Model is less relevant to the I/O ports than are the Human Body Model and IEC 1-4-2. Low-Power Shutdown Mode Table 1 shows the functionality of the enable inputs. The enter shutdown when is low and is high. In shutdown, all outputs go high impedance and the devices typically draw less than 1nA. The devices exit shutdown by taking high or low. The typical shutdown exit time is 6. Table 1. Function Table (A - B) OUTPUT Y DEICE MODE 1 X 2m 1 On 1 X -2m On 1 X Open 1 On X 2m 1 On X -2m On X Open 1 On 1 X High-Z Shutdown X = don t care, High-Z = high impedance 8
HIH- OLTAE DC SOURCE R C 1M CHARE-CURRENT LIMIT RESISTOR Cs 1pF R D 1.5k DISCHARE RESISTANCE STORAE CAPACITOR Figure 4a. Human Body ESD Test Model DEICE UNDER TEST AMPERES I P 1% 9% 36.8% 1% t RL Figure 4b. Human Body Model Current Waveform Ir TIME t DL CURRENT WAEFORM PEAK-TO-PEAK RININ (NOT DRAWN TO SCALE) HIH- OLTAE DC SOURCE R C 5M to 1M CHARE-CURRENT LIMIT RESISTOR Cs 15pF R D 33Ω DISCHARE RESISTANCE STORAE CAPACITOR DEICE UNDER TEST IPEAK I 1% 9% 1% t r =.7 to 1 3 6 t Figure 5a. IEC 1-4-2 ESD Test Model Figure 5b. IEC 1-4-2 ESD-enerator Current Waveform 9
Applicatio Information Propagation-Delay Matching The exhibit propagation delays that are closely matched from one device to another, even between devices from different production lots. This feature allows multiple data lines to receive data and clock signals with minimal skewing with respect to each other. The MAX395 receiver propagation delays are trimmed to a predetermined value ±8, while the MAX396 delays are trimmed to a predetermined value ±1. 128 Receivers on the Bus The standard RS-485 input impedance is 12kΩ (oneunit load). The standard RS-485 tramitter can drive 32 unit loads. The present a 1/4- unit-load input impedance (48kΩ), which allows up to 128 receivers on a bus. Any combination of these RS- 485 receivers with a total of 32 unit loads can be connected to the same bus. Fail-Safe Implementation The receiver inputs guarantee a logic high output when the inputs are open circuit (no termination resistor used). This occurs when the tramitter is removed from the bus or when all tramitter outputs are high impedance. However, when the line is terminated and the tramitters are disabled, the differential voltage between the A and B inputs falls below the ±2m RS-485 seitivity threshold. Coequently, the outputs become undefined. To maintain a failsafe receiver output while using a terminating resistor, input A must be biased at least 2m above input B. The resistor-divider network shown in Figure 6 is recommended. 1k 15Ω 1k CC Figure 6. External Fail-Safe Implementation TRANSISTOR COUNT: 676 A B MAX395 MAX396 Chip Information 1
Package Information QSOP.EPS 11
SOICN.EPS Package Information (continued) PDIPN.EPS Maxim cannot assume respoibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licees are implied. Maxim reserves the right to change the circuitry and specificatio without notice at any time. 12 Maxim Integrated Products, 12 San abriel Drive, Sunnyvale, CA 9486 48-737-76 2 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.