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LT1331 3V RS562 or 5V/3V RS232 Transceiver with One Receiver Active in SHUTDOWN
FEATURES
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DESCRIPTIO
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RS232 Compatible 3V Operation 3V Logic Interface ESD Protection Over 10kV One Low Power Receiver Remains Active While in SHUTDOWN 60A Supply Current in SHUTDOWN Low Power DRIVER DISABLE Mode Uses Small Capacitors: 0.1F, 0.2F 120kBaud Operation for RL = 3k, CL = 2500pF 250kBaud Operation for RL = 3k, CL = 1000pF CMOS Comparable Low Power: 60mW Easy PC Layout: Flowthrough Architecture Rugged Bipolar Design Outputs Assume a High Impedance State When OFF or Powered Down
The LT1331 is a 3-driver, 5-receiver RS232 transceiver designed for 3V and mixed 3V/5V systems. Receivers operate from 3V logic supply VL, while the on-board charge pump and drivers operate from 5V or 3V supply VCC. The transceiver has two SHUTDOWN modes. One mode disables the drivers and the charge pump, the other shuts down all circuitry except for one low power receiver which can be used for ring detection. The VCC supply may be shut down while in ring detection mode. While shut down, the drivers and receivers assume high impedance output states. The LT1331 is fully compliant with all EIA-RS232 specifications when VCC = 5V. If VCC = 3V, output drive levels are compatible with all known interface circuits. Special bipolar construction techniques protect the drivers and receivers beyond the fault conditions stipulated for RS232. The RS232 I/O pins are resilient to multiple 10kV ESD strikes. An advanced driver output stage operates up to 120k baud while driving heavy capacitive loads.
APPLICATI
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Notebook Computers Palmtop Computers
TYPICAL APPLICATI
+
0.1F 2 x 0.1F V+ 1 2 3 4 DRIVER 1 OUT RX1 IN DRIVER 2 OUT TO LINE RX2 IN RX3 IN RX4 IN DRIVER 3 OUT RX5 IN (LOW-Q) ON/OFF 3.3V VL 5 6 7 8 9 10 11 12 13 14 LT1331 VCC = 3.3V
3.3V Operation
28 V - 27 25 24 23 22 21 20 19 0.1F 26 DRIVER 1 IN RX1 OUT DRIVER 2 IN RX2 OUT RX3 OUT RX4 OUT TO LOGIC 2 x 0.1F
DRIVER 3 IN 18 RX5 OUT (LOW-Q) 17 GND 16 DRIVER DISABLE 15 NC
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RECEIVER OUTPUT CL = 50pF
R DRIVER OUTPUT RL = 3k CL = 2500pF
RING DETECT IN CONTROLLER OR PROCESSOR SHUTDOWN CONTROL OUT
1331 TA01
INPUT
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1331 TA02
+
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1
LT1331 ABSOLUTE AXI U RATI GS
PACKAGE/ORDER I FOR ATIO
TOP VIEW V+ C1+ C1- 1 3 4 28 V - 27 C2 - 26 C2+ 25 DRIVER 1 IN 24 RX1 OUT 23 DRIVER 2 IN 22 RX2 OUT 21 RX3 OUT 20 RX4 OUT 19 DRIVER 3 IN RX5 OUT 18 (LOW-Q) 17 GND 16 DRIVER DISABLE 15 NC N PACKAGE 28-LEAD PLASTIC DIP 5V/3V VCC 2
Supply Voltage (VCC) ................................................ 6V Supply Voltage (VL) .................................................. 6V V + ........................................................................ 13.2V V - ...................................................................... -13.2V Input Voltage Driver ........................................................... V + to V - Receiver ................................................ 30V to - 30V ON/OFF ...................................... - 0.3V to VCC + 0.3V DRIVER DISABLE ...................... - 0.3V to VCC + 0.3V Output Voltage Driver ................................................... - 30V to 30V Receiver ...................................... - 0.3V to VL + 0.3V Short Circuit Duration V + ................................................................... 30 sec V - ................................................................... 30 sec Driver Output .............................................. Indefinite Receiver Output .......................................... Indefinite Operating Temperature Range LT1331C ................................................. 0C to 70C Storage Temperature Range ................ - 65C to 150C Lead Temperature (Soldering, 10 sec)................. 300C
ORDER PART NUMBER LT1331CG LT1331CN LT1331CS
DRIVER 1 OUT 5 RX1 IN 6 DRIVER 2 OUT 7 RX2 IN 8 RX3 IN 9 RX4 IN 10 DRIVER 3 OUT 11 RX5 IN (LOW-Q) 12 ON/OFF 13 3.3V VL 14 G PACKAGE 28-LEAD SSOP
S PACKAGE 28-LEAD PLASTIC SOL TJMAX = 125C, JA = 96C/ W (G) TJMAX = 125C, JA = 56C/ W (N) TJMAX = 125C, JA = 85C/ W (S)
Consult factory for Industrial and Military grade parts.
ELECTRICAL CHARACTERISTICS
PARAMETER Power Supply Generator V + Output V - Output Supply Current (VCC) Supply Current (VL) Supply Current When OFF (VCC) Supply Current When OFF (VL) Supply Rise Time, SHUTDOWN to Turn-On ON/OFF Pin Thresholds ON/OFF Pin Current DRIVER DISABLE Pin Thresholds DRIVER DISABLE Pin Current Oscillator Frequency CONDITIONS
(Note 1)
MIN TYP 8.6 5.5 - 7.0 - 4.8 12 12 3 2 0.1 60 3 0.2 1.4 1.4 1.4 1.4 130 MAX UNITS V V V V mA mA mA A mA A mA ms V V A V V A kHz
VCC = 5V VCC = 3.3V VCC = 5V VCC = 3.3V VCC = 5V (Note 2) VCC = 3.3V (Note 3) SHUTDOWN (Note 4) DRIVER DISABLE SHUTDOWN (Note 4) DRIVER DISABLE C1 = C2 = 0.2F, C + = C - = 0.1F Input Low Level (Device SHUTDOWN) Input High Level (Device Enabled) 0V VON/OFF 5V Input Low Level (Drivers Enabled) Input High Level (Drivers Disabled) 0V VDRIVER DISABLE 5V
q q q q q
17 17 5 50 1 100 5 0.8 80 0.8 500
q q q q q q
2.4 -15 2.4 -10
2
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W
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LT1331
ELECTRICAL CHARACTERISTICS
PARAMETER Any Driver Output Voltage Swing, Positive Output Voltage Swing, Negative Logic Input Voltage Level Logic Input Current Output Short-Circuit Current Output Leakage Current Data Rate Slew Rate Propagation Delay Any Receiver Input Voltage Thresholds Hysteresis Input Resistance Receivers 1 Through 4 Output Voltage Output Short-Circuit Current Propagation Delay Output Leakage Current Receiver 5 (Low Q-Current RX) Output Voltage Output Short-Circuit Current Propagation Delay CONDITIONS VCC = 5V, RL = 3k VCC = 3.3V, RL = 3k VCC = 5V, RL = 3k VCC = 3.3V, RL = 3k Input Low Level (VOUT = High) Input High Level (VOUT = Low) 0.8V VIN 2V VOUT = 0V SHUTDOWN VOUT = 30V (Note 4) RL = 3k, CL = 2500pF RL = 3k, CL = 1000pF RL = 3k, CL = 51pF RL = 3k, CL = 2500pF Output Transition tHL High to Low (Note 5) Output Transition t LH Low to High Input Low Threshold (VOUT = High) Input High Threshold (VOUT = Low) VIN = 10V Output Low, IOUT = - 1.6mA Output High, IOUT = 160A (VL = 3.3V) Sinking Current, VOUT = VCC Sourcing Current, VOUT = 0V Output Transition tHL High to Low (Note 6) Output Transition t LH Low to High SHUTDOWN (Note 4) 0 VOUT VCC Output Low, IOUT = - 500A Output High, IOUT = 160A (VL = 3V) Sinking Current, VOUT = VCC Sourcing Current, VOUT = 0V Output Transition tHL High to Low (Note 6) Output Transition t LH Low to High
q q q q q q q
MIN 5.0 3.7
TYP 6.5 4.0 - 6.0 - 3.3 1.4 1.4 5 17 10
MAX
UNITS V V V V V V A mA A kBaud kBaud V/s V/s s s V V V k V V mA mA ns ns A V V mA mA s s
- 5.0 - 2.7 0.8 20 100
2.0 9
q
120 250 15 6 0.6 0.5
q q q
30 1.3 1.3
0.8 0.1 3
1.3 1.7 0.4 5 0.2 2.4 - 20 20 250 350 1 0.2 2.4 -4 4 1 1
2.4 1.0 7 0.4 - 10 600 600 10 0.4 -2 3 3
2.0 10
q q q
2.0 2
The q denotes specifications which apply over the full operating temperature range (0C TA 70C for commercial grade). Note 1: Testing done at VCC = 5V, VL = 3.3V, and VON/OFF = 3V, unless otherwise stated. Note 2: Supply current is measured as the average over several charge pump cycles. C + = 1F, C - = 0.1F, C1 = C2 = 0.2F. All outputs are open with all driver inputs tied high. Note 3: VL supply current is measured with all receiver outputs high. Note 4: Supply current and leakage current measurements in SHUTDOWN are performed with VON/OFF 0.1V. Supply current measurements using DRIVER DISABLE are performed with VDRIVER DISABLE 3V.
Note 5: For driver delay measurements, RL = 3k and CL = 51pF. Trigger points are set between the driver's input logic threshold and the output transition to the zero crossing (t HL = 1.4V to 0V and tLH = 1.4V to 0V). Note 6: For receiver delay measurements, CL = 51pF. Trigger points are set between the receiver's input logic threshold and the output transition to standard TTL/CMOS logic threshold (t HL = 1.3V to 2.0V and t LH = 1.7V to 0.8V).
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LT1331
TYPICAL PERFOR A CE CHARACTERISTICS
Driver Short-Circuit Current
30 VCC = 5V
SHORT-CIRCUIT CURRENT (mA) DRIVER OUTPUT VOLTAGE (V)
8 OUTPUT HIGH VCC = 5V 6 5 VCC = 3.3V 4 3 RL = 3k 3 DRIVERS LOADED 50 25 75 0 TEMPERATURE (C) 100 125 7
DRIVER OUTPUT VOLTAGE (V)
25 20 ISC+ 15 10 5 0 -55 -25 ISC-
50 25 75 0 TEMPERATURE (C)
Driver Leakage in SHUTDOWN
100
16 14
LEAKAGE CURRENT (A)
10
SLEW RATE (V/s)
SLEW RATE (V/s)
1
VOUT = 30V VOUT = -30V
0.1 -55 -25
50 25 0 75 TEMPERATURE (C)
Supply Current vs Data Rate
50 RL = 3k CL = 2500pF
THRESHOLD VOLTAGE (V)
3.00 2.75
40
SUPPLY CURRENT (mA)
VCC = 5V VCC = 3.3V 3 DRIVERS
2.50 2.25 2.00 1.75 1.50 1.25 1.00 0.75 INPUT LOW INPUT HIGH
SHORT-CIRCUIT CURRENT (mA)
30
20
10 1 DRIVER 0 0 25
VCC = 3.3V
50 75 100 DATA RATE (kBAUD)
4
UW
100
1331 G01
Driver Output Voltage
-2
Driver Output Voltage
OUTPUT LOW -3 -4 -5 -6 -7 RL = 3k 3 DRIVERS LOADED 50 25 75 0 TEMPERATURE (C) 100 125 VCC = 5V VCC = 3.3V
125
2 -55 -25
-8 -55 -25
1331 G02
1331 G03
Slew Rate vs Load Capacitance
16
VCC = 5V
Slew Rate vs Load Capacitance
14 12 10 8 -SLEW 6 4 2 0 +SLEW VCC = 3.3V
12 10 8 6 +SLEW 4 2 -SLEW
100
125
0 0 1 3 4 2 LOAD CAPACITANCE (nF) 5
1331 G05
0
1
3 4 2 LOAD CAPACITANCE (nF)
5
1331 G06
1331 G04
Receiver Input Thresholds
40
VL = 3.3V
Receiver Short-Circuit Current
VL = 3.3V ISC- 30 ISC+ 20
VCC = 5V
10
125
150
0.50 -55 -25
50 25 0 75 TEMPERATURE (C)
100
125
0 -55 -25
50 0 75 25 TEMPERATURE (C)
100
125
1131 G07
1331 G08
1331 G09
LT1331
PI FU CTIO S
VCC: Power Supply for Charge Pump and Drivers. Proper circuit operation is insured for VCC = 3V to 6V. VCC = 5V operation gives full RS232 compliant performance, 3V operation results in lower driver output amplitude. The VCC pin should be decoupled with a 0.1F ceramic capacitor. VL: Power Supply for Receivers. This pin should be powered to the same voltage as the logic circuits connected to the receiver outputs, either 5V or 3V. The VL pin should be decoupled with a 0.1F ceramic capacitor. GND: Ground. ON/OFF: A TTL/CMOS Compatible Operating Mode Control. A logic low puts the device in the SHUTDOWN mode. All drivers and four of the receivers go to a high impedance state, and the VCC supply may be turned off. A logic high fully enables the transceiver. DRIVER DISABLE: A logic high shuts down the charge pump, placing all drivers in a high impedance state. All receivers remain active. Floating the pin, or driving it to a logic low, fully enables the transceiver. A low voltage on the ON/OFF pin supersedes the state of the DRIVER DISABLE control. V +: Positive Supply Output. V + 2VCC - 1.5V. This pin requires an external capacitor for charge storage, chosen to minimize ripple to acceptable levels. A minimum size of 0.1F is recommended. V -: Negative Supply Output. V - - (2VCC - 2.5V). This pin requires an external charge storage capacitor, chosen to minimize ripple on V -. A minimum value of 0.1F is recommended. C1+,C1-,C2 +,C2 -: These pins require two external capacitors C 0.2F. One from C1+ to C1-, and another from C2 + to C2 -. To maintain charge pump efficiency, the capacitor's effective series resistance should be less than 2. Low ESR tantalum capacitors work well in this application, small value ceramic capacitors may also be used with minimal reduction in charge pump compliance. DRIVER IN: RS232 Driver Inputs. Inputs are TTL/CMOS compatible. Tie unused inputs to VCC. DRIVER OUT: RS232 Driver Outputs. Outputs are in a high impedance state when in SHUTDOWN, DRIVER DISABLE, or VCC = 0V. Outputs are fully short-circuit protected from V - + 30V to V + - 30V. Although the outputs are protected, short circuits on one output can load the power supply generator and may disrupt the signal levels of the other outputs. The driver outputs are protected against ESD to 10kV for human body model discharges. Output levels of - 3.3V to 4V are achieved when the circuit is operated with VCC = 3.3V. RX IN: Receiver Inputs with 0.4V of Hysteresis for Noise Immunity. These pins accept RS232 level signals (30V) into a protected 5k terminating resistor. The receiver inputs are protected against ESD to 10kV for human body model discharges. RX OUT: Receiver Outputs. RX1 through RX4 outputs are in a high impedance state when in SHUTDOWN mode to allow data line sharing. Outputs, including LOW-Q RX OUT, are fully short-circuit protected to ground, VCC, or VL. Output voltage levels are determined by the choice of power supply VL. LOW-Q RX IN: Low Power Receiver Input. This receiver remains active in SHUTDOWN mode, consuming only 60A from supply VL. This receiver has the same input and protection characteristics as receivers RX1 through RX4. LOW-Q RX OUT: Low Power Receiver Output. This pin produces the same output levels as standard receivers, with slightly decreased speed and short-circuit current.
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LT1331
APPLICATI
S I FOR ATIO
Power Saving Operational Modes The LT1331 has both SHUTDOWN and DRIVER DISABLE operating modes. These operating modes can optimize power consumption based upon applications needs. The SHUTDOWN control turns off all circuitry except for Low-Q RX5. RX5 operates entirely from the VL power supply, so the power consumption from VCC drops to zero. The VCC power supply may be turned off while in SHUTDOWN, which may allow greater power savings in some systems. When RX5 detects a signal, this information can be used to wake up the system for full operation. If more than one line must be monitored, the DRIVER DISABLE mode provides a power efficient operating option. The DRIVER DISABLE mode turns off the charge pumps and RS232 drivers, but keeps all five receivers active. Power consumption in DRIVER DISABLE mode is 3mA from VL and less than 100A from VCC.
Table 1. Commonly Used RS232 Interface Circuit Receiver Thresholds
MANUFACTURER Linear Technology PART NUMBER LT1080 LT1137A LT1330 LT1281 All Others SN75189 SN75189A MAX232 SN75C185 MAX232A MAX241 SP232 SP301 MC1489 MC1489A DS1489 DS14C89A COMPATIBLE INPUT LOW THRESHOLD MIN TYP MAX 0.8 1.3 - 0.8 1.3 - 0.8 1.3 - 0.8 1.3 - 0.65 0.65 0.8 0.65 0.8 0.6 0.8 0.75 0.75 0.75 0.75 0.5 1.0 1.0 1.2 1.0 1.3 1.2 1.2 - - 0.8 1.0 - 1.25 1.25 - 1.25 - - - 1.35 1.25 1.25 1.25 1.9 INPUT HIGH THRESHOLD MIN TYP MAX - 1.7 2.4 - 1.7 2.4 - 1.7 2.4 - 1.7 2.4 0.9 1.55 - 1.6 - - - 1.75 1.0 1.75 1.0 1.3 1.3 1.9 1.7 2.1 1.8 1.5 1.7 - - 1.95 1.25 - 1.6 2.25 2.4 2.55 2.4 2.4 2.4 2.5 1.5 2.25 1.5 2.7
Texas Instruments
Maxim Sipex Motorola National
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Mixed 5V/3V Operation When operated with VCC = 5V and VL = 3.3V supplies, the RS232 drivers meet or exceed all RS232 or V.28 communication interface standards. Data rates up to 120k baud are supported, and all standard RS232 compatible mice may be driven by the LT1331. 3V Operation VCC = 3.3V operation of the LT1331 results in lower driver output swing than with VCC = 5V. The driver output swing, when operated with VCC = 3.3V, is guaranteed to be at least -2.7V to 3.7V, with typical swing being -3.3V to 4V. This insures compatibility with all commonly used RS232 and RS562 interface circuits. Table 1 summarizes the receiver input threshold specifications for RS232 circuits from many manufacturers.
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LT1331
TYPICAL APPLICATI
+
0.1F 2 x 0.1F
V+
1 2 3 4 5 6 7 8 9 10 11 12 13 14 LT1331
25 24 23 22 21 20 19
DRIVER 1 IN RX1 OUT DRIVER 2 IN RX2 OUT RX3 OUT RX4 OUT
INPUT DRIVER OUTPUT RL = 3k CL = 2500pF
DRIVER 1 OUT RX1 IN DRIVER 2 OUT TO LINE RX2 IN RX3 IN RX4 IN DRIVER 3 OUT RX5 IN (LOW-Q) ON/OFF VL = 3.3V
DRIVER 3 IN 18 RX5 OUT (LOW-Q) 17 GND 16 DRIVER DISABLE 15 NC
1331 TA03
ESD PROTECTIO
0.2F 4 DRIVER 1 OUT RX1 IN RS232 LINE PINS PROTECTED TO 10kV DRIVER 2 OUT RX2 IN RX3 IN RX4 IN DRIVER 3 OUT RX5 IN (LOW-Q) ON/OFF 3.3V 5 6 7 8 9 10 11 12 13 14 0.1F
25 24 23 22 21 20 19 18 17 16 15
DRIVER 1 IN RX1 OUT DRIVER 2 IN RX2 OUT RX3 OUT RX4 OUT DRIVER 3 IN RX5 OUT (LOW-Q) GND DRIVER DISABLE NC
1331 ESD TC
+
Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
+
0.1F
0.1F
+
3
LT1331
26
7
+
The RS232 line inputs of the LT1331 have on-chip protection from ESD transients up to 10kV. The protection structures act to divert the static discharge safely to system ground. In order for the ESD protection to function effectively, the power supply and ground pins of the LT1331 must be connected to ground through low impedances. The power supply decoupling capacitors and charge pump storage capacitors provide this low impedance in normal application of the circuit. The only constraint is that low ESR capacitors must be used for bypassing and charge storage. ESD testing must be done with pins VCC, VL, V +, V - and GND shorted to ground or connected with low ESR capacitors.
+
+
26
2 x 0.1F
TO LOGIC
+
VCC = 5V
UO
Mixed 5V/3V Supply Operation
28 V - 27 0.1F
RECEIVER OUTPUT CL = 50pF
1331 TA04
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ESD Test Circuit
V+ 1 2 28 V - 27 0.1F 0.2F
+
+
5V VCC
LT1331
PACKAGE DESCRIPTIO
0.205 - 0.212* (5.20 - 5.38)
0 - 8 0.005 - 0.009 (0.13 - 0.22) 0.022 - 0.037 (0.55 - 0.95) 0.0256 (0.65) BSC 0.010 - 0.015 (0.25 - 0.38) *THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.006 INCH (0.15mm). 0.045 (1.14) 0.002 - 0.008 (0.05 - 0.21)
1 2 3 4 5 6 7 8 9 10 11 12 13 14
0.600 - 0.625 (15.240 - 15.875)
0.130 0.005 (3.302 0.127) 0.015 (0.381) MIN
0.045 - 0.065 (1.143 - 1.651)
0.009 - 0.015 (0.229 - 0.381)
(
+0.025 0.625 -0.015
+0.635 15.87 -0.381
)
0.125 (3.175) MIN
0.035 - 0.080 (0.889 - 2.032) 0.100 0.010 (2.540 0.254)
0.005 (0.127) RAD MIN
0.291 - 0.299 (7.391 - 7.595) (NOTE 2)
0.093 - 0.104 0.010 - 0.029 x 45 (2.362 - 2.642) (0.254 - 0.737) 0 - 8 TYP 0.050 (1.270) TYP
0.009 - 0.013 (0.229 - 0.330) NOTE 1 0.016 - 0.050 (0.406 - 1.270)
NOTE: 1. PIN 1 IDENT, NOTCH ON TOP AND CAVITIES ON THE BOTTOM OF PACKAGES ARE THE MANUFACTURING OPTIONS. THE PART MAY BE SUPPLIED WITH OR WITHOUT ANY OF THE OPTIONS. 2. THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.006 INCH (0.15mm).
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Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7487
(408) 432-1900 q FAX: (408) 434-0507 q TELEX: 499-3977
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Dimensions in inches (millimeters) unless otherwise noted.
G Package 28-Lead SSOP
0.397 - 0.407* (10.07 - 10.33) 0.068 - 0.078 (1.73 - 1.99)
28 27 26 25 24 23 22 21 20 19 18 17 16 15
0.301 - 0.311 (7.65 - 7.90)
0.045 (1.14)
N Package 28-Lead Plastic DIP
0.070 (1.778) TYP 28 27 26 25 24 23 1.455 (36.957) MAX 22 21 20 19 18 17 16 15
0.505 - 0.560 (12.827 - 14.224) 0.018 0.003 (0.457 0.076)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
S Package 28-Lead SOL
0.697 - 0.712 (17.70 - 18.08) (NOTE 2) 28 27 26 25 24 23 22 21 20 19 18 17 16 15
0.037 - 0.045 (0.940 - 1.143)
0.014 - 0.019 (0.356 - 0.482)
0.004 - 0.012 (0.102 - 0.305)
NOTE 1
0.394 - 0.419 (10.007 - 10.643)
1
2
3
4
5
6
7
8
9 10 11 12 13 14
LT/GP 0693 10K REV 0
(c) LINEAR TECHNOLOGY CORPORATION 1993

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