 |
|
| If you can't view the Datasheet, Please click here to try to view without PDF Reader . |
|
|
|
| If you can't view the Datasheet, Please click here to try to view without PDF Reader . |
|
|
| Datasheet File OCR Text: |
| LTC1262 12V, 30mA Flash Memory Programming Supply FEATURES s s s s s s s DESCRIPTIO Regulated 12V 5% Output Voltage No Inductors Supply Voltage Range: 4.75V to 5.5V Guaranteed 30mA Output Low Power: ICC = 500A ICC in Shutdown: 0.5A 8-Pin PDIP or SO-8 Package The LTC(R)1262 is a regulated 12V, 30mA output DC/DC converter. It is designed to provide the 12V 5% output necessary to program byte-wide flash memories. The output will provide up to 30mA from input voltages as low as 4.75V without using any inductors. Only four external capacitors are required to complete an extremely small surface mountable circuit. The TTL compatible shutdown pin can be directly connected to a microprocessor and reduces the supply current to less than 0.5A. The LTC1262 offers improved shutdown current performance and requires fewer external components than competing solutions. The LTC1262 is available in an 8-pin PDIP or SO-8 package. , LTC and LT are registered trademarks of Linear Technology Corporation. APPLICATI s s s S 12V Flash Memory Programming Supplies Compact 12V Op Amp Supplies Battery-Powered Systems TYPICAL APPLICATI 1 0.22F 2 3 0.22F 4 C1- C1+ SHDN GND LTC1262 VOUT VCC 8 7 FROM MPU FLASH MEMORY VPP 4.7F VCC LTC1262 * TA01 4.7F C2 - C2+ 6 5 SHDN 5V 5V/DIV 0V 12V VOUT 5V/DIV 5V 0V 1ms/DIV 1262 TA01a VCC 4.75V TO 5.5V U In/Out of Shutdown + UO + UO 1 LTC1262 ABSOLUTE (Note 1) AXI U RATI GS PACKAGE/ORDER I FOR ATIO TOP VIEW C1- 1 C1+ 2 C2 - Supply Voltage (VCC) ................................................ 6V Input Voltage (SHDN) ................... - 0.3V to V CC + 0.3V Output Current (IOUT) ........................................... 50mA Operating Temperature Range LTC1262C................................................ 0C to 70C LTC1262I........................................... - 40C to 85C Storage Temperature Range ................ - 65C to 150C Lead Temperature (Soldering, 10 sec)................. 300C ORDER PART NUMBER 8 7 6 5 SHDN GND VOUT VCC 3 C2 + 4 N8 PACKAGE 8-LEAD PDIP LTC1262CN8 LTC1262CS8 LTC1262IS8 S8 PART MARKING 1262 1262I S8 PACKAGE 8-LEAD PLASTIC SO TJMAX = 150C, JA = 100C/W (N8) TJMAX = 150C, JA = 150C/W (S8) Consult factory for Military grade parts. ELECTRICAL CHARACTERISTICS VCC = 4.75V to 5.5V, TA = - 40C to 85C, (Notes 2, 3), unless otherwise noted. SYMBOL VOUT ICC ISHDN fOSC PARAMETER Output Voltage Supply Current Shutdown Supply Current Oscillator Frequency Power Efficiency RSW VIH VIL VCC to VOUT Switch Impedance SHDN Input High Voltage SHDN Input Low Voltage SHDN Input Current VCC = 5V, VSHDN = 0V, 0C TA 70C VCC = 5V, VSHDN = 0V, - 40C TA 85C VCC = 5V, VSHDN = 5V C1 = C2 = 0.22F, CIN = COUT = 4.7F, (Figures 1, 2) C1 = C2 = 0.22F, CIN = COUT = 4.7F, (Figures 1, 2) CONDITIONS 0mA IOUT 30mA, VSHDN = 0V, 0C TA 70C 0mA IOUT 30mA, VSHDN = 0V, - 40C TA 85C No Load, VSHDN = 0V, 0C TA 70C No Load, VSHDN = 0V, - 40C TA 85C No Load, VSHDN = VCC VCC = 5V, IOUT = 30mA VCC = 5V, IOUT = 30mA VCC = VSHDN = 5V, IOUT = 0mA q q q q q q q q q q q q q MIN 11.4 11.2 TYP MAX 12.6 12.6 UNITS V V mA mA A kHz % 0.5 0.5 0.5 300 74 0.18 2.4 1.0 1.3 10 2 0.8 - 20 -35 - 10 -10 0.06 500 3.3 -5 -5 10 tON tOFF Turn-On Time Turn-Off Time 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 the 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. 2 U k V V A A A s ms W U U WW W LTC1262 TYPICAL PERFORMANCE CHARACTERISTICS Efficiency vs Output Current 85 80 75 VCC = 5.5V 70 65 60 55 3.6 SHUTDOWN SUPPLY CURRENT (A) VCC = 4.75V VCC = 5V EFFICIENCY (%) 0 10 20 30 40 OUTPUT CURRENT (mA) Supply Current vs Supply Voltage 600 IOUT = 0 580 SUPPLY CURRENT (A) OUTPUT VOLTAGE (V) 560 540 520 TA = 25C 500 TA = 0C 480 4.5 4.75 5.0 5.25 5.5 SUPPLY VOLTAGE (V) 5.75 6.0 PI FU CTIO S C1 - (Pin 1): C1 Negative Input. Connect a 0.22F capacitor C1 between C1+ and C1 -. C1 + (Pin 2): C1 Positive Input. Connect a 0.22F capacitor C1 between C1+ and C1-. C2 - (Pin 3): C2 Negative Input. Connect a 0.22F capacitor C2 between C2 + and C2 -. C2+ (Pin 4): C2 Positive Input. Connect a 0.22F capacitor C2 between C2 + and C2 -. VCC (Pin 5): Positive Supply Input Where 4.75V VCC 5.5V. Connect a 4.7F bypass capacitor CIN to ground. VOUT (Pin 6): 12V Output. Connect a 4.7F bypass capacitor COUT to ground. When in the shutdown mode VOUT = VCC. GND (Pin 7): Ground. SHDN (Pin 8): Logic Level Shutdown Pin. Application of a logic low at SHDN pin will place the regulator in normal operation. With no external connection, or with SHDN tied to VCC, the device will be put into shutdown mode. Connect to GND for normal operation. In shutdown mode the charge pump is turned off and VOUT = VCC. UW TA = 70C Shutdown Supply Current vs Temperature VCC = 5V 3.0 2.4 1.8 1.2 0.6 0 -50 50 LTC1262 G01 -25 0 25 50 TEMPERATURE (C) 75 100 LTC1262 G02 Output Voltage vs Output Current 12.2 12.0 11.8 11.6 11.4 11.2 11.0 10.8 10.6 10.4 10.2 0 5 10 15 20 25 30 35 40 45 50 OUTPUT CURRENT (mA) 1262 G04 VCC = 4.75V VCC = 5.5V VCC = 5V LTC1262 G03 U U U 3 LTC1262 BLOCK DIAGRAM W VCC + S3A C1+ C1 C1 - S3B C2+ C2 C2 - S3D CHARGE PUMP OSCILLATOR S4B S4A D2 S3C D1 S1 SHDN VOUT R1 CIN + R2 COUT S1 AND S2 SHOWN WITH SHDN PIN LOW. S3A, S3B, S3C, S3D, S4A AND S4B SHOWN WITH OSCILLATOR OUTPUT LOW AND VDIV < VBGAP - VHYST. COMPARATOR HYSTERISIS IS VHYST. TI I G DIAGRA S 1 t OFF VOUT 5.1V t ON 11.4V VOUT C1 0.22F VCC VCC C2 0.22F 3 4 C2 - C2+ VOUT VCC 6 5 VSHDN 1.4V 1.4V 0V LTC1262 * F01 VCC 4.75V TO 5V Figure 1. LTC1262 Timing Diagram Figure 2. LTC1262 Timing Circuit 4 + + - VBGAP BANDGAP REFERENCE VDIV R3 + S2 GND LTC1262 * BD W UW C1- C1+ SHDN GND LTC1262 8 7 VSHUTDOWN 2 COUT 4.7F CIN 4.7F VOUT LTC1262 * F02 LTC1262 APPLICATIONS INFORMATION Operation The LTC1262 uses a charge pump tripler to generate 12V from a VCC of 5V. The charge pump operates when clocked by a 300kHz oscillator. When the oscillator output is low, C1 and C2 are connected between VCC and GND, charging them to VCC. When the oscillator output goes high, C1 and C2 are stacked in series with the bottom plate of C1 pulled to VCC. The top plate of C2 is switched to charge COUT and VOUT rises. VOUT is regulated to within 5% of 12V by an oscillator pulse gating scheme. A resistor divider senses VOUT. When the output of the divider (VDIV) is less than the output of a bandgap (VBGAP) by the hysteresis voltage (VHYST) of the comparator, oscillator pulses are applied to the charge pump to raise VOUT. When VDIV is above VBGAP by VHYST, the oscillator pulses are prevented from clocking the charge pump. VOUT drops until VDIV is below VBGAP by VHYST again. The gates of all internal switches are driven between VOUT and GND. An internal diode ensures that the LTC1262 will start up under load by charging COUT to one diode drop below VCC. To reduce supply current the LTC1262 may be put into shutdown mode by floating the SHDN pin or taking it to VCC. In this mode the bandgap, comparator, oscillator and resistor divider are switched off to reduce supply current to typically 0.5A. At the same time an internal switch shorts VOUT to VCC; VOUT takes 3.3ms to reach 5.1V (see tOFF in Figure 1). When the SHDN pin is low, the LTC1262 exits shutdown and the charge pump operates to raise VOUT to 12V. VOUT takes 500s to reach the lower regulation limit of 11.4V (see tON in Figure 1). Choice of Capacitors The LTC1262 is tested with the capacitors shown in Figure 2. C1 and C2 are 0.22F ceramic capacitors and CIN and COUT are 4.7F tantalum capacitors. Refer to Table 1 if other choices are desired. Table 1. Recommended Capacitor Types and Values CAPACITOR C1, C2 COUT CIN CERAMIC 0.22F to 1F 2F (Min) 1F (Min) TANTALUM Not Recommended 4.7F (Min) 4.7F (Min) ALUMINUM Not Recommended 10F (Min) 10F (Min) U W U U C1 and C2 should be ceramic capacitors with values in the range of 0.22F to 1F. Higher values provide better load regulation. Tantalum capacitors are not recommended as the higher ESR of these capacitors degrades performance when the load current is above 25mA with VCC = 4.75V. CIN and COUT can be ceramic, tantalum or electrolytic capacitors. The ESR of COUT introduces steps in the VOUT waveform whenever the charge pump charges COUT. This tends to increase VOUT ripple. Ceramic or tantalum capacitors are recommended for COUT if minimum ripple is desired. The LTC1262 does not require a 0.1F capacitor between VCC and VOUT for stability. Maximum Load Current The LTC1262 will source up to 50mA continuously without any damage to itself. Do not short the VOUT pin to ground. If the VOUT pin is shorted to ground, irreversible damage to the device will result. 5 LTC1262 TYPICAL APPLICATI 1 C7 0.22F 2 3 C8 0.22F 4 C1- C1+ C2 - C2+ VCC 5 U1 LTC1148-3.3 3 C6 10F 25V SHUTDOWN Q2 VN7002 1 R2 100 C3 1000pF R3 100 + 10 6 4 11 VIN SHDN ITH CT SGND PDRIVE 8 SENSE + 7 SENSE - NDRIVE PGND 14 12 R1 510 C1 3300pF C2 150pF R6 TM 22k Burst Mode DEFEAT; USE IF REQUIRED 6 + UO 5V to 3.3V/10A Converter SHDN GND VOUT 8 7 6 C9 1F U2 LTC1262 Q1 TP0610 Q3 Si9410 Q4 Si9410 L2 3H/10A + + + R4 0.01 2W VIN 5V C4 220F 8V x3 PANASONIC ECGCOKB220R VOUT 3.3V 10A + Q5 Si9410 D1 MBRS120T3 + C5 330F 6.3V x2 OS-CON LTC1262 * TA02 Burst Mode is a trademark of Linear Technology Corporation. LTC1262 PACKAGE DESCRIPTION 0.300 - 0.325 (7.620 - 8.255) 0.009 - 0.015 (0.229 - 0.381) ( +0.035 0.325 -0.015 8.255 +0.889 -0.381 ) *THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.010 INCH (0.254mm) 0.010 - 0.020 x 45 (0.254 - 0.508) 0.008 - 0.010 (0.203 - 0.254) 0- 8 TYP 0.016 - 0.050 0.406 - 1.270 *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 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. U Dimensions in inches (millimeters) unless otherwise noted. N8 Package 8-Lead PDIP (Narrow 0.300) (LTC DWG # 05-08-1510) 0.400* (10.160) MAX 8 7 6 5 0.255 0.015* (6.477 0.381) 1 2 3 4 0.130 0.005 (3.302 0.127) 0.045 - 0.065 (1.143 - 1.651) 0.065 (1.651) TYP 0.125 (3.175) 0.020 MIN (0.508) MIN 0.018 0.003 (0.457 0.076) N8 1197 0.100 0.010 (2.540 0.254) S8 Package 8-Lead Plastic Small Outline (Narrow 0.150) (LTC DWG # 05-08-1610) 0.189 - 0.197* (4.801 - 5.004) 8 7 6 5 0.228 - 0.244 (5.791 - 6.197) 0.150 - 0.157** (3.810 - 3.988) 1 0.053 - 0.069 (1.346 - 1.752) 2 3 4 0.004 - 0.010 (0.101 - 0.254) 0.014 - 0.019 (0.355 - 0.483) 0.050 (1.270) TYP SO8 0996 7 LTC1262 TYPICAL APPLICATI Paralleling Devices 1 0.22F 2 3 0.22F 4 C1 + C1- SHDN GND LTC1262 VOUT VCC 8 7 OUTPUT VOLTAGE (V) C2 - C2+ 6 5 1 0.22F 2 3 0.22F 4 C1- C1+ SHDN GND LTC1262 VOUT VCC 8 7 6 5 C2 - C2+ NOTE: KEEP DEVICES CLOSE TOGETHER OR USE SEPARATE 4.7F TANTALUM CAPACITORS IF THIS IS NOT POSSBILE. LTC1262 * TA03 RELATED PARTS PART NUMBER LT1106* LT1109-12 LT1109A-12 LT1301 LT1309 DESCRIPTION Micropower Step-Up DC/DC Converter for PCMCIA Card Flash Memory Micropower Low Cost DC/DC Converter Adjustable and Fixed 12V Micropower DC/DC Converter Flash Memory VPP Generator Adjustable and Fixed 12V Micropower High Efficiency 5V/12V Step-Up DC/DC Converter for Flash Memory 500kHz Micropower DC/DC Converter for Flash Memory COMMENTS PCMCIA Card Power Control, 9A ISHDN, Small SMT Components, Requires External Inductor Three-Lead Z Package, Requires External Inductor Requires External Inductor 7A ISHDN, SMT Inductor and Capacitors Small SMT Inductor and Capacitors, 6A ISHDN * See also LT1312/LT1313 PCMCIA VPP drivers/regulators, LT1314/LT1315 PCMCIA switch matrix and the LTC1470/LTC1471/LTC1472 Protected VCC and VPP switching matrices 8 Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417q (408)432-1900 FAX: (408) 434-0507q TELEX: 499-3977 q www.linear-tech.com + + UO Output Voltage vs Output Current for Two Paralleled Devices 12.4 12.2 12.0 VCC = 5V TIE TO VCC OR FLOAT TO SHUTDOWN BOTH DEVICES 10F 12V OUTPUT 10F 11.8 11.6 11.4 11.2 11.0 10.8 10.6 10.4 0 10 20 30 40 50 60 70 80 90 100 OUTPUT CURRENT (mA) 1262 TA04 VCC = 5.5V VCC = 4.75V VCC 4.75V TO 5.5V SEE FIGURE AT LEFT. LT/TP 0298 REV A 2K * PRINTED IN USA (c) LINEAR TECHNOLOGY CORPORATION 1994 |
Price & Availability of LTC1262
 |
|
|
|
|
All Rights Reserved © IC-ON-LINE 2003 - 2022 |
| [Add Bookmark] [Contact Us] [Link exchange] [Privacy policy] |
|
Mirror Sites : [www.datasheet.hk]
[www.maxim4u.com] [www.ic-on-line.cn]
[www.ic-on-line.com] [www.ic-on-line.net]
[www.alldatasheet.com.cn]
[www.gdcy.com]
[www.gdcy.net] |