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LTC1323 Single 5V AppleTalk Transceiver
(R)
FEATURES
s s s
DESCRIPTIO
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Single Chip Provides Complete LocalTalk(R)/AppleTalk Port Operates From a Single 5V Supply ESD Protection to 10kV on Receiver Inputs and Driver Outputs Low Power: ICC = 2.4mA Typ Shutdown Pin Reduces ICC to 0.5A Typ Receiver Keep-Alive Function: ICC = 65A Typ Differential Driver Drives Either Differential AppleTalk or Single-Ended EIA562 Loads Drivers Maintain High Impedance in Three-State or with Power Off Thermal Shutdown Protection Drivers are Short-Circuit Protected
APPLICATI
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S
The LTC(R)1323 is a multi-protocol line transceiver designed to operate on AppleTalk or EIA562-compatible singleended networks while operating from a single 5V supply. There are two versions of the LTC1323 available: a 16-pin version designed to connect to an AppleTalk network, and a 24-pin version which also includes the additional single-ended drivers and receivers necessary to create an Apple-compatible serial port. An on-board charge pump generates a - 5V supply which can be used to power external devices. Additionally, the 24-pin LTC1323 features a micropower keep-alive mode during which one of the single-ended receivers is kept active to monitor external wake-up signals. The LTC1323 draws only 2.4mA quiescent current when active, 65A in receiver keepalive mode, and 0.5A in shutdown, making it ideal for use in battery-powered systems. The differential driver can drive either differential AppleTalk loads or conventional single-ended loads. The driver outputs three-state when disabled, during shutdown, in receiver keep-alive mode, or when the power is off. The driver outputs will maintain high impedance even with output common-mode voltages beyond the power supply rails. Both the driver outputs and receiver inputs are protected against ESD damage to 10kV.
LocalTalk Peripherals Notebook/Palmtop Computers Battery-Powered Systems
, LTC and LT are registered trademarks of Linear Technology Corporation. AppleTalk and LocalTalk are registered trademarks of Apple Computer, Inc.
TYPICAL APPLICATI
1 0.33F 2 CPEN 3 TXD 4 TXI 5 TXDEN 6 SHDN 7 RXEN 8 RXO 9 RXO 10 RXDO 11 12
LTC1323 24 CHARGE PUMP 23 22 21
DX
5V
+
0.33F
1F
5 TO 10 EMI FILTER = 1F
+
EMI FILTER
20 TXD -
DX
19 TXD + 18 TXO 17 RXI
RX
EMI FILTER EMI FILTER EMI FILTER EMI FILTER EMI FILTER EMI FILTER
LTC1323 * TA01
8 5 2
16 RXI 15 RXD - 14 RXD +
RX
RX
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5 TO 10 100pF 7 4 1 6 3
UO
UO
1
LTC1323 ABSOLUTE AXI U RATI GS
Driver Short-Circuit Duration .......................... Indefinite Operating Temperature Range .................... 0C to 70C Storage Temperature Range ................ - 65C to 150C Lead Temperature (Soldering, 10 sec)................. 300C Supply Voltage (VCC) ................................................ 7V Input Voltage Logic Inputs .............................. - 0.3V to VCC + 0.3V Receiver Inputs ................................................ 15V Driver Output Voltage (Forced) ............................. 15V
PACKAGE/ORDER I FOR ATIO
TOP VIEW C1+ 1 28 VCC 27 C2+ 26 C2 - 25 NC 24 NC 23 VEE 22 TXD- 21 TXD+ 20 TXO 19 RXI 18 RXI 17 RXD- 16 RXD+
ORDER PART NUMBER LTC1323CG
TOP VIEW C1+ 1 16 VCC 15 C2+ 14 C2 - 13 VEE 12 TXD - 11 TXD + 10 RXD - 9 RXD+
C2 - 2 CPEN 3 TXD 4 TXI 5 TXDEN 6 SHDN 7 RXEN 8 RXO 9 RXO 10 RXDO 11 NC 12 NC 13 GND 14
15 PGND
G PACKAGE 28-LEAD PLASTIC SSOP
TJMAX = 150C, JA = 96C/W
TOP VIEW C1+ 1 24 VCC 23 C2+ 22 C2 - 21 VEE 20 TXD - 19 TXD+ 18 TXO 17 RXI 16 RXI 15 RXD - 14 RXD+ 13 PGND
ORDER PART NUMBER LTC1323CSW
C1 - 2 CPEN 3 TXD 4 TXI 5 TXDEN 6 SHDN 7 RXEN 8 RXO 9 RXO 10 RXDO 11 GND 12
SW PACKAGE 24-LEAD PLASTIC SO WIDE
TJMAX = 125C, JA = 85C/W
Consult factory for Industrial and Military grade parts.
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WW
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ORDER PART NUMBER LTC1323CS
C1- 2 TXD 3 TXDEN 4 SHDN 5 RXEN 6 RXDO 7 GND 8
S PACKAGE 16-LEAD PLASTIC SO
TJMAX = 125C, JA = 85C/W
LTC1323 ELECTRICAL CHARACTERISTICS
SYMBOL Supplies ICC Normal Operation Supply Current Receiver Keep-Alive Supply Current Shutdown Supply Current VEE Negative Supply Output Voltage No Load, SHDN = 0V, CPEN = 0V, TXDEN = 0V, RXEN = 0V No Load, SHDN = 0V, CPEN = VCC, TXDEN = 0V, RXEN = 0V No Load, SHDN = VCC, CPEN = X, TXDEN = X, RXEN = 0V ILOAD 10mA (Note 4), VCC = 5V, RL = 100 (Figure 1), TXI = VCC, RTXO = 3k (Figure 5)
q q q q
VCC = 5V 10%, TA = 0C to 70C (Notes 2, 3)
MIN TYP 2.4 65 0.5 - 5.5 -5 MAX 4 100 10 - 4.5 UNITS mA A A V
PARAMETER
CONDITIONS
fOSC VOD VOD
Charge Pump Oscillator Frequency Differential Output Voltage Change in Magnitude of Differential Output Voltage Differential Common-Mode Output Voltage Single-Ended Output Voltage Common-Mode Range Short-Circuit Current Three-State Output Current No Load RL = 100 (Figure 1) RL = 100 (Figure 1)
q q
200 8 2 0.2
kHz V V
Differential Driver
Differential Driver VOC VOS VCMR ISS IOZ RL = 100 No Load RL = 3k to GND SHDN = VCC or CPEN = VCC or Power Off - 5V VO 5V SHDN = VCC or CPEN = VCC or Power Off, - 10V VO 10V No Load RL = 3k to GND SHDN = VCC or CPEN = VCC or TXDEN = VCC or Power Off - 5V VO 5V SHDN = VCC or CPEN = VCC or TXDEN = VCC or Power Off, - 10V VO 10V - 7V VIN 7V - 7V VCM 7V - 7V VCM 7V (Note 5) (Note 5) IO = - 4mA IO = 4mA - 5V VO 5V - 5V VO 5V, RXEN = VCC
q q q q q
3 4.0 3.7 10 35 120 2 500 200
V V V V mA A
Single-Ended Driver (Note 5) VOS VCMR ISS IOZ Receivers RIN Input Resistance Differential Receiver Threshold Voltage Differential Receiver Input Hysteresis Single-Ended Input, Low Voltage Single-Ended Input, High Voltage VOH VOL ISS IOZ Output High Voltage Output Low Voltage Output Short-Circuit Current Output Three-State Current
q q q q q q q q q
Single-Ended Output Voltage Common-Mode Range Short-Circuit Current Three-State Output Current
q q q q q
4.5 3.7 10 35 220 2 500 200
V V V mA A
12 - 200 70 0.8 2 3.5 0.4 7 2 85 100 200
k mV mV V V V V mA A
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LTC1323 ELECTRICAL CHARACTERISTICS
SYMBOL Logic Inputs VIH VIL IC tPLH, tPHL Input High Voltage Input Low Voltage Input Current Differential Driver Propagation Delay Differential Driver Propagation Delay with Single-Ended Load Single-Ended Driver Propagation Delay Differential Receiver Propagation Delay Single-Ended Receiver Propagation Delay Inverting Receiver Propagation Delay in Keep-Alive Mode, SHDN = 0V, CPEN = VCC tSKEW tr, tf Differential Driver Output to Output Differential Driver Rise/Fall Time Differential Driver Rise/Fall Time with Single-Ended Load Single-Ended Driver Rise/Fall Time tHDIS, tLDIS Differential Driver Output Active to Disable Any Receiver Output Active to Disable tENH, tENL Differential Driver Enable to Output Active Any Receiver, Enable to Output Active VEER Supply Rise Time from Shutdown or Receiver Keep-Alive All Logic Input Pins All Logic Input Pins All Logic Input Pins RL = 100, CL = 100pF (Figures 2, 7) RL = 3k, CL = 100pF (Figures 3, 9) RL = 3k, CL = 100pF, (Figures 5, 10) (Note 5) CL = 15pF (Figures 2, 11) CL = 15pF (Figures 6, 12) (Note 5) CL = 15pF (Figures 6, 12) (Note 5)
q q q
VCC = 5V 10%, TA = 0C to 70C (Notes 2 and 3)
MIN 2.0 0.8 1.0 40 120 40 70 70 150 20 120 180 120 160 160 600 TYP MAX UNITS V V A ns ns ns ns ns ns
PARAMETER
CONDITIONS
Switching Characteristics
q q q q q q
RL = 100, CL = 100pF (Figures 2, 7) RL = 100, CL = 100pF (Figures 2, 7) RL = 3k, CL = 100pF (Figures 3, 9) RL = 3k, CL = 100pF (Figures 5, 10) (Note 5) CL = 15pF (Figures 4, 8) CL = 15pF (Figures 4, 13) CL = 15pF (Figures 4, 8) CL = 15pF (Figures 4, 13) C1 = C2 = 0.33F, CVEE = 1F
q q q q q q q q q
10 50 50 15 180 30 180 30 0.2
50 150 150 80 250 100 250 100
ns ns ns ns ns ns ns ns ms
The q denotes specifications which apply over the full operating temperature range. Note 1: Absolute maximum ratings are those values beyond which the life of a device may be impaired. Note 2: All currents into device pins are positive; all currents out of device pins are negative. All voltages are referenced to ground unless otherwise specified.
Note 3: All typicals are given at VCC = 5V, TA = 25C. Note 4: ILOAD is an external current being sunk into the VEE pin. Note 5: These specifications apply to the 24-pin SO Wide package only.
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LTC1323 TYPICAL PERFORMANCE CHARACTERISTICS
Charge Pump Output Voltage vs Load Current
-2.0
CHARGE PUMP OUTPUT VOLTAGE (V)
DIFFERENTIAL DRIVER OUTPUT (V)
-2.5 -3.0 -3.5 - 4.0 - 4.5 - 5.0 -5.5 - 6.0 0
3 2 1 0 -1 -2 -3 -4 -5 TA = 25C VS = 5V 50 100 200 300 500 1k 2k 3k LOAD RESISTANCE () 5k 10k
SINGLE-ENDED DRIVER OUTPUT (V)
TA = 25C VS = 5V RL(DIFF) = 100 RL(SE) = 3k TO GND VTXI = 5V
5
20 15 LOAD CURRENT (mA)
10
Supply Current vs Temperature
3.50
DIFFERENTIAL DRIVER OUTPUT (V)
SUPPLY CURRENT (mA)
3.00 2.75 2.50 2.25 2.00 1.75 1.50 -50 -25 0 50 75 25 TEMPERATURE (C) 100 125
4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0 -50 -25 50 25 0 75 TEMPERATURE (C) 100 125
SINGLE-ENDED DRIVER OUTPUT (V)
3.25
VS = 5V NO LOAD
UW
25
LTC1323 * TPC01 LTC1323 * TPC04
Differential Driver Swing vs Load Resistance
5 4 5 4 3 2 1 0 -1 -2 -3 -4 -5
Single-Ended Driver Swing vs Load Resistance
TA = 25C VS = 5V
30
50 100 200 300 500 1k 2k 3k LOAD RESISTANCE ()
5k 10k
LTC1323 * TPC02
LTC1323 * TPC03
Differential Driver Swing vs Temperature
5.0 4.5 VS = 5V RL = 100 5 4 3 2 1 0 -1 -2 -3 -4
Single-Ended Driver Swing vs Temperature
VS = 5V RL = 3k TO GND
-5 -50 -25
50 25 0 75 TEMPERATURE (C)
100
125
LTC1323 * TPC05
LTC1323 * TPC06
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LTC1323
PI FU CTIO S
LTC1323CS
C1+ 1 C1- 2 CHARGE PUMP 16 VCC 15 C2 + 14 C2 - 13 VEE
DX
TXD 3 TXDEN 4 SHDN 5 RXEN 6 RXDO 7 GND 8
RX
C1+ : C1 Positive Input. Connect a 0.33F capacitor between C1+ and C1-. C1-: C1 Negative Input. Connect a 0.33F capacitor between C1+ and C1-. CPEN: TTL Level Charge Pump Enable Input. With CPEN held low, the charge pump is enabled and the chip operates normally. When CPEN is pulled high, the charge pump is disabled as well as both drivers, the noninverting single-ended receiver, and the differential receiver. The inverting single-ended receiver (RXI) is kept alive to monitor the control line and ICC drops to 65A. To turn off the receiver and drop ICC to 0.5A, pull the SHDN pin high. TXD: Differential Driver Input (TTL compatible). TXI: Single-Ended Driver Input (TTL compatible). TXDEN: Differential Driver Output Enable (TTL compatible). A high level on this pin forces the differential driver into three-state; a low level enables the driver. This input does not affect the single-ended driver. SHDN: Shutdown Input (TTL compatible). When this pin is high, the chip is shut down. All driver and receiver outputs are three-state, the charge pump turns off, and the supply current drops to 0.5A. A low level on this pin allows normal operation.
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LTC1323CSW
C1+ 1 C1- 2 CHARGE PUMP 24 VCC 23 C2 +
LTC1323CG
C1+ 1 C1- 2 CHARGE PUMP 28 VCC 27 C2 + 26 C2 -
DX
CPEN 3 TXD 4
- + -
DX
22 C2 - 21 VEE 20 TXD
DX
CPEN 3 TXD 4
-
25 NC 24 NC
12 TXD 11 TXD
TXI 5 TXDEN 6 SHDN 7 RXEN 8
RX
TXI 5 TXDEN 6 SHDN 7 RXEN 8 RXO 9
DX
19
TXD +
23 VEE 22 TXD - 21 TXD + 20 TXO
RX
10 RXD
18 TXO 17 RXI 16 RXI
RX
9 RXD+
RXO 9 RX0 10 RXDO 11
RX
15 RXD 14 RXD
- +
RX0 10 RXDO 11 NC 12 NC 13
19 RXI 18 RXI
GND 12
13 PGND
RX
17 RXD - 16 RXD +
RX
GND 14
15 PGND
RXEN: Receiver Enable (TTL compatible). A high level on this pin disables the receivers and three-states the logic outputs; a low level allows normal operation. RXO: Inverting Single-Ended Receiver Output. Remains active in the receiver keep-alive mode. RXO: Noninverting Single-Ended Receiver Output. RXDO: Differential Receiver Output. GND: Signal Ground. Connect to PGND with 24-pin package. PGND: Power ground is connected internally to the charge pump and differential driver. Connect to the GND pin. RXD+: Differential Receiver Noninverting Input. When this pin is 200mV above RXD-, RXDO will be high; when this pin is 200mV below RXD-, RXDO will be low. RXD-: Differential Receiver Inverting Input. RXI: Noninverting Receiver Input. This input controls the RXO output. RXI: Inverting Receiver Input. This input controls the RXO output. In receiver keep-alive mode (CPEN high, SHDN low), this receiver can be used to monitor a wake-up control signal.
LTC1323
PI FU CTIO S
TXO: Single-Ended Driver Output. TXD+: Differential Driver Noninverting Output. TXD-: Differential Driver Inverting Output. VEE: Negative Supply Charge Pump Output. Requires a 1F bypass capacitor to ground. If an external load is connected to the VEE pin, the bypass capacitor value should be increased to 4.7F. C2 -: C2 Negative Input. Connect a 0.33F capacitor between C2+ and C2 -. C2+: C2 Positive Input. Connect a 0.33F capacitor between C2+ and C2-. VCC: Positive Supply Input. 4.5V VCC 5.5V. Requires a 1F bypass capacitor to ground.
TEST CIRCUITS
TXD + R VOD R TXD -
LTC1323 * F01
LTC1323 * F02
VOC
Figure 1
VCC
500 OUTPUT CL
LTC1323 * F04
Figure 4
SWITCHI G WAVEFOR S
3V TXD 0V tPLH VO -VO TXD - VO TXD + tSKEW tSKEW
LTC1323 * F07
1.5V
W
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TXI
RXD+ TXD - RL
CL CL
RXD+ RXD -
RXDO 15pF
TXI
TXD + TXD - RL CL
LTC1323 * F03
RL
CL
Figure 2
Figure 3
S1
TXI
TXO CL RL
RXI
RXO CL
RXI
RXO CL
S2
LTC1323 * F05
LTC1323 * F06
Figure 5
Figure 6
f = 1MHz: tr 10ns: tf 10ns
1.5V tPHL
90% 50% 10% tr
VDIFF = V(TXD +) - V(TXD - ) 1/2 VO
90% 50% 10% tf
Figure 7. Differential Driver
7
LTC1323
SWITCHI G WAVEFOR S
3V TXDEN 0V tZL 5V TXD+, TXD - VOL tZH VOH TXD , TXD
- +
1.5V
0V
LTC1323 * F08
Figure 8. Differential Driver Enable and Disable
3V TXD 0V tPHL VOH TXD - VOL VOH TXD + VOL 0V 10% 1.5V
Figure 9. Differential Driver With Single-Ended Load
3V TXI 0V tPHL VOH TXO VOL 90% 1.5V
V OD2 (RXD ) - (RXD ) -VOD2 tPLH VOH RXDO VOL
+ -
0V
8
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f = 1MHz: tr 10ns: tf 10ns
1.5V tLZ
2.3V OUTPUT NORMALLY LOW OUTPUT NORMALLY HIGH 2.3V tHZ 0.5V 0.5V
f = 1MHz: tr 10ns: tf 10ns
1.5V tPLH
0V
0V
90%
90% 0V 10%
tr
tf
LTC1323 * F09
f = 1MHz: tr 10ns: tf 10ns
1.5V tPLH 90%
0V 10% tr
0V 10% tr
LTC1323 * F10
Figure 10. Single-Ended Driver
f = 1MHz: tr 10ns: tf 10ns
0V tPHL 1.5V
1.5V
LTC1323 * F11
Figure 11. Differential Receiver
LTC1323
SWITCHI G WAVEFOR S
VIH RXI, RXI VIL tPHL VOH RXI VOL VIH RXI V
LTC1323 * F12
3V RXEN 0V tZL 5V RXO, RXO, RXDO VOL tZH VOH RXO, RXO, RXDO 0V
LTC1323 * F13
APPLICATIO S I FOR ATIO
Functional Description
The "serial port" on the back of an Apple-compatible computer or peripheral is a fairly versatile "multi-protocol" connector. It must be able to connect to a wide bandwidth LAN (an AppleTalk/LocalTalk network), which requires a high speed differential transceiver to meet the AppleTalk specification, and it must also be able to connect directly to a printer or modem through a short RS232 style link. The LTC1323 is designed to provide all the functions necessary to implement such a port on a single chip. Two versions of the LTC1323 are available: a 16-pin SO version which provides the minimum solution for interfacing to an AppleTalk network in a smaller package, and a larger 24-pin SO Wide version which additionally includes all the handshaking lines required to implement a complete AppleTalk/ modem/printer serial port. All LTC1323s run from a single 5V power supply while providing true single-ended compatibility, and include a 0.5A low power shutdown mode
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W
1.5V
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UU
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f = 1MHz: tr 10ns: tf 10ns
1.5V tPLH 2.4V
0.8V
1.5V
1.5V
Figure 12. Single-Ended Receiver
1.5V
f = 1MHz: tr 10ns: tf 10ns
1.5V tLZ
2.3V OUTPUT NORMALLY LOW OUTPUT NORMALLY HIGH 2.3V tHZ 0.5V 0.5V
Figure 13. Receiver Enable and Disable
to improve lifetime in battery-powered devices. The 24pin SO Wide version also includes a receiver keep-alive mode for monitoring external signals while drawing 65A typically. The LTC1323 includes an RS422-compatible differential driver/receiver pair for data transmission, with the driver specified to drive 2V into the 100 primary of a typical LocalTalk interface transformer/RFI interference network. Either output of the differential RS422 driver can also act as an single-ended driver, allowing the LTC1323 to communicate over a standard serial connection. The 24-pin SO Wide LTC1323 also includes an extra single ended only driver and two extra RS232-compatible single-ended receivers for handshaking lines. All versions include an onboard charge pump to provide a regulated - 5V supply required for the single-ended drivers. The charge pump can also provide up to 10mA of external load current to power other circuitry.
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LTC1323
APPLICATIO S I FOR ATIO
Driving Differential AppleTalk or Single-Ended Loads The differential driver is able to drive either an AppleTalk load or a single-ended load such as a printer or modem. With a differential AppleTalk load, TXD+ and TXD - will typically swing between 1.2V and 3.5V (Figure 14a). With a single-ended 3k load such as a printer, either TXD+ or TXD - will meet the single-ended voltage swing requirement of 3.7V (Figure 14b). An automatic switching circuit prevents the differential driver from overloading the charge pump if the outputs are shorted to ground while driving single-ended signals. This allows the second single-ended driver to continue to operate normally when the first is shorted, and allows external circuitry attached to the charge pump output to continue to operate even if there are faults at the driver outputs.
VCC = 5V
+
1F
24 12 LTC1323 13 VCC EXTERNAL CHIP GND VEE IVEE 4.7F -5.5V VEE -4.5V IVEE 10mA
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LTC1323 * F15
Figure 14
Thermal Shutdown Protection The LTC1323 includes a thermal shutdown circuit which protects against prolonged shorts at the driver outputs. If a driver output is shorted to another output or to the power supply, the current will be initially limited to a maximum of 500mA. When the die temperature rises above 150C, the thermal shutdown circuit disables the driver outputs. When the die cools to about 130C, the outputs are reenabled. If the short still exists, the part will heat again and the cycle will repeat. This oscillation occurs at about 10Hz and prevents the part from being damaged by excessive power dissipation. When the short is removed, the part will return to normal operation.
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Power Shutdown The power shutdown feature of the LTC1323 is designed for battery-powered systems. When SHDN is forced high the part enters shutdown mode. In shutdown the supply current typically drops from 2.4mA to 0.5A , the charge pump turns off, and the driver and receiver outputs are three-stated. Receiver Keep-Alive Mode (24-Pin SO Wide Only) The 24-pin SO Wide version of the LTC1323 also features a power saving receiver keep-alive mode. When CPEN is pulled high the charge pump is turned off and the outputs of both drivers, the noninverting single-ended receiver and the differential receiver are forced into three-state. The inverting single-ended receiver (RXI) is kept alive with ICC dropping to 65A and the receiver delay time increasing to a maximum of 400ns. The receiver can then be used to monitor a wake-up control signal. Charge Pump Capacitors and Supply Bypassing The LTC1323 requires two external 0.33F capacitors for the charge pump to operate: one from C1+ to C1- and one from C2 + to C2 -. These capacitors should be low ESR types and should be mounted as close as possible to the LTC1323. Monolithic ceramic capacitors work well in this application. Do not use capacitors greater than 2F at the charge pump pins or internal peak currents can rise to destructive levels. The LTC1323 also requires that both VCC and VEE be well bypassed to ensure proper charge pump operation and prevent data errors. A 1F capacitor from VCC to ground is adequate. A 1F capacitor is required from VEE to ground and should be increased to 4.7F if an external load is connected to the VEE pin. Ceramic or tantalum capacitors are adequate for power supply bypassing; aluminum electrolytic capacitors should only be used if their ESR is low enough for proper charge pump operation. Inadequate bypass or charge pump capacitors will cause the charge pump output to go out of regulation prematurely, degrading the output swing at the SINGLEENDED driver outputs.
C1
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LTC1323
APPLICATIO S I FOR ATIO
Driving an External Load from VEE An external load may be connected between ground and the VEE pin as shown in Figure 15. The LTC1323 VEE pin will sink up to a maximum of 10mA while maintaining the pin voltage between - 4.5V and - 5.5V. If an external load is connected, the VEE bypass capacitor should be increased to 4.7F. Both LTC1323 and the external chip should have separate VCC bypass capacitors but can share the VEE capacitor. EMI Filter Most LocalTalk applications use an electromagnetic interference (EMI) filter consisting of a resistor-capacitor T network between each driver and receiver and the connector. Unfortunately, the resistors significantly attenuate the drivers output signals before they reach the cable. Because
VCC = 5V
+
1F
24 12 LTC1323 13 VCC EXTERNAL CHIP GND VEE IVEE 4.7F -5.5V VEE -4.5V IVEE 10mA
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LTC1323 * F15
Figure 15
TYPICAL APPLICATIONS N
Typical LocalTalk Connection
5V
0.33F
LTC1323CS DATA IN TX ENABLE SHDN RX ENABLE DATA OUT 3 4 5 6 7
RX
12
TX
100pF
11 100pF 10 9 100pF 100pF
LTC1323 * TA02
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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.
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the LTC1323 uses a single supply differential driver, the resistor values should be reduced to 5 to 10 to guarantee adequate voltage swing on the cable (Figure 16a). In most applications, removing the resistors completely does not cause an increase in EMI as long as a shielded connector and cable are used (Figure 16b). With the resistors removed the only DC load is the primary resistance of the LocalTalk transformer. This will increase the DC standby current when the driver outputs are active, but does not adversely affect the drivers because they can handle a direct indefinite short circuits without damage. Transformer primary resistance should be above 15 to keep the LTC1323 operating normally and prevent it from entering thermal shutdown. For maximum swing and EMI immunity, a ferrite bead and capacitor T network can be used (Figure 16c).
5 TO 10 5 TO 10 100pF 100pF FERRITE BEAD FERRITE BEAD 100pF
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C1
(a)
(b)
(c)
LTC1323 * F16
Figure 16. EMI Filters
+
+
1F 16 1 2 CHARGE PUMP 15 14 13 0.33F 1F LocalTalk TRANSFORMER 120
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LTC1323
PACKAGE DESCRIPTION
0.205 - 0.212** (5.20 - 5.38)
0 - 8 0.301 - 0.311 (7.65 - 7.90) 0.002 - 0.008 (0.05 - 0.21)
0.005 - 0.009 (0.13 - 0.22)
0.010 - 0.015 *DIMENSIONS DO NOT INCLUDE MOLD FLASH. MOLD FLASH (0.25 - 0.38) SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE **DIMENSIONS DO NOT INCLUDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE
0.022 - 0.037 (0.55 - 0.95)
0.0256 (0.65) BSC
0.010 - 0.020 x 45 (0.254 - 0.508) 0.008 - 0.010 (0.203 - 0.254) 0 - 8 TYP
0.053 - 0.069 (1.346 - 1.752)
0.016 - 0.050 0.406 - 1.270
0.014 - 0.019 (0.355 - 0.483)
*DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE **DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE
0.291 - 0.299** (7.391 - 7.595) 0.010 - 0.029 x 45 (0.254 - 0.737) 0.093 - 0.104 (2.362 - 2.642) 0.037 - 0.045 (0.940 - 1.143) 24 23 22 21
0 - 8 TYP
0.009 - 0.013 (0.229 - 0.330)
0.014 - 0.019 0.016 - 0.050 (0.356 - 0.482) (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. *DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE **DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE
NOTE 1
0.050 (1.270) TYP
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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 Plastic SSOP (0.209)
(LTC DWG # 05-08-1640)
0.397 - 0.407* (10.07 - 10.33) 28 27 26 25 24 23 22 21 20 19 18 17 16 15
0.068 - 0.078 (1.73 - 1.99)
1 2 3 4 5 6 7 8 9 10 11 12 13 14
G28 SSOP 0694
S Package 16-Lead Plastic Small Outline (Narrow 0.150)
(LTC DWG # 05-08-1610)
0.386 - 0.394* (9.804 - 10.008) 0.004 - 0.010 (0.101 - 0.254) 16 15 14 13 12 11 10 9
0.050 (1.270) TYP
0.228 - 0.244 (5.791 - 6.197)
0.150 - 0.157** (3.810 - 3.988)
S16 0695
1
2
3
4
5
6
7
8
SW Package 24-Lead Plastic Small Outline (Wide 0.300)
(LTC DWG # 05-08-1620)
0.598 - 0.614* (15.190 - 15.600) 20 19 18 17 16 15 14 13
NOTE 1 0.004 - 0.012 (0.102 - 0.305)
0.394 - 0.419 (10.007 - 10.643)
1
2
3
4
5
6
7
8
9
10
11
12
S24 (WIDE) 0695
LT/GP 1194 10K * PRINTED IN USA
(c) LINEAR TECHNOLOGY CORPORATION 1994

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