LTC1258-5 LTC1258CS8-5 LTC1542 LT1460 LTC1440 LTC1540 - Datasheet Archive

 

LTC1258-5 Micropower Low Dropout Reference October 1998 U DESCRIPTION FEATURES s s s s s s s s 200mV Max Dropout at 10mA Output

 

Final Electrical Specifications LTC1258-5 LTC1258-5 Micropower Low Dropout Reference October 1998 U DESCRIPTION FEATURES s s s s s s s s 200mV Max Dropout at 10mA Output Current 4µA Typical Quiescent Current 0.15% Max Initial Accuracy No Output Capacitor Required Output Sources 10mA, Sinks 2mA 40ppm/°C Max Drift Over Commercial Temp Range Load Regulation Over Temperature: 0.1mV/mA, Source up to 10mA 1.75mV/mA, Sink up to 2mA 5.2V to 12.6V Supply Voltage Range U APPLICATIONS s s s s Battery-Powered Systems Hand-Held Instruments Precision Power Supply A/D and D/A Converters The LTC®1258-5 is a micropower bandgap reference that combines high accuracy and low drift with very low supply current and small package size. The combination of ultralow quiescent current and low dropout voltage of only 200mV max makes it ideal for battery-powered equipment. This reference uses curvature compensation to obtain low temperature coefficient and trimmed thin-film resistors to achieve high output accuracy. The reference can supply up to 10mA and sink up to 2mA, making it ideal for precision regulator applications. The LTC1258-5 LTC1258-5 is stable without an output bypass capacitor, but also is stable with capacitance up to 1µF. This feature is important in critical applications where PC board space is a premium and fast settling is demanded. Series references provide power dissipation advantages over shunt references. In addition to supply current, shunt references must also idle the entire load current to operate. The LTC1258-5 LTC1258-5 is available in the 8-pin SO package. , LTC and LT are registered trademarks of Linear Technology Corporation. U TYPICAL APPLICATION Temperature Drift LTC1258-5 LTC1258-5 5.2V TO 12.6V 2 IN OUT 1 5V 0.1µF GND 4 1258-5 TA01 REFERENCE VOLTAGE CHANGE (mV) 5 4 3 2 1 0 ­1 ­2 ­3 ­4 ­5 ­40 ­20 0 20 40 60 TEMPERATURE (°C) 80 100 1258 · G01 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. 1 LTC1258-5 LTC1258-5 W U U U W W W ABSOLUTE MAXIMUM RATINGS PACKAGE/ORDER INFORMATION (Note 1) Supply Voltage . 13V Input Voltages . ­0.3V to 13V Output Voltages . ­0.3V to 13V Output Short Circuit Duration . Indefinite Operating Temperature Range . 0°C to 70°C Storage Temperature Range (Note 2) . ­65°C to 150°C Lead Temperature (Soldering, 10 sec). 300°C ORDER PART NUMBER TOP VIEW OUT 1 8 NC* IN 2 7 NC* NC* 3 6 NC* GND 4 5 NC* LTC1258CS8-5 LTC1258CS8-5 S8 PACKAGE 8-LEAD PLASTIC SO S8 PART MARKING TJMAX = 125°C, JA = 190°C/W 12585 *CONNECTED INTERNALLY. DO NOT CONNECT EXTERNAL CIRCUITRY TO THESE PINS. Consult factory for Industrial and Military grade parts. ELECTRICAL CHARACTERISTICS SYMBOL PARAMETER VIN Input Voltage Range IIN VIN = 5.2V, IOUT = 0mA, TA = 25°C unless otherwise noted. CONDITIONS MIN Input Current q TYP 4.9925 5 UNITS V 6.5 8.5 q MAX 12.6 5.2 µA µA 5.0075 V VOUT Output Voltage (Note 3) en Output Voltage Noise (Note 4) 0.1Hz f 10Hz TC Output Voltage Temp Coefficient (Note 5) TMIN TJ TMAX q 15 40 ppm/°C VOUT/VIN Line Regulation VIN = 5.2V to 12.6V q 75 150 µV/V VOUT/IOUT Load Regulation (Note 6) Sourcing 0mA to 10mA 0.1 0.2 0.3 mV/mA mV/mA 1.75 4.0 5.5 mV/mA mV/mA 40 4 60 15 mA mA 100 200 mV mV q Sinking 0mA to 2mA q ISC Short-Circuit Output Current VOUT Shorted to GND VOUT Shorted to VIN VDO Dropout Voltage (Note 7) IOUT = 0, VOUT 0.1% IOUT = 10mA, VOUT 0.1% VHYST Output Hysteresis (Note 8) T = ­40°C to 85°C T = 0°C to 70°C 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: If the part is stored outside of the specified operating temperature range, the output may shift due to hysteresis. Note 3: ESD (Electrostatic Discharge) sensitive device. Extensive use of ESD protection devices are used internal to the LTC1258-5 LTC1258-5, however, high electrostatic discharge can damage or degrade the device. Use proper ESD handling precautions. Note 4: Peak-to-peak noise is measured with a single highpass filter at 0.1Hz and 2-pole lowpass filter at 10Hz. Note 5: Temperature coefficient is measured by dividing the change in output voltage by the specified operating temperature range. 2 µVp-p 40 20 2 q q 200 50 ppm ppm Note 6: Load regulation is measured on a pulse basis from no load to the specified load current. Output changes due to die temperature change must be taken into account separately. Note 7: Dropout voltage is (VIN ­ VOUT) when VOUT falls to 0.1% below its nominal value at VIN = VOUT + 0.5V. Note 8: Hysteresis in output voltage is created by package stress that differs depending on whether the IC was previously at a higher or lower temperature. Output voltage is always measured at 25°C, but the IC is cycled to 85°C or ­40°C before successive measurements. Hysteresis is roughly proportional to the square of the temperature change. Hysteresis is not normally a problem for operational temperature excursions where the instrument might be stored at high or low temperature. LTC1258-5 LTC1258-5 U U U PIN FUNCTIONS OUT (Pin 1): Reference Output. The output can source up to 10mA and sink up to 2mA. Stable with output bypass capacitor ranges from 0µF to 1µF. NC (Pins 3, 5, 6, 7, 8): No Connection. Connected internally for post package trim. These pins should be left unconnected. IN (Pin 2): Positive Supply. Bypass with a 0.1µF capacitor is recommended if the output loading changes. (VOUT + 0.2V) VIN 12.6V. GND (Pin 4): Negative Supply or Ground Connection. W BLOCK DIAGRAM 2 IN + OUT 1 ­ 2.424V R1 R2 GND 4 1258-5 · BD U W U U APPLICATIONS INFORMATION Longer Battery Life Series references have an advantage over shunt style references. To operate, shunt references require a resistor between the power supply and the output. This resistor must be chosen to supply the maximum current that is demanded by the circuit being regulated. When the circuit being controlled is not operating at this maximum current, the shunt reference must always sink this current, resulting in high power dissipation and short battery life. The LTC1258-5 LTC1258-5 series low dropout reference does not require a current setting resistor and can operate with any supply voltage from (VOUT + 0.2V) to 12.6V. When the circuitry being regulated does not demand current, the LTC1258-5 LTC1258-5 reduces its dissipation and battery life is extended. If the reference is not delivering load current it dissipates only 24µW on a 6V supply, yet the same connection can deliver 10mA of load current when demanded. 1mA IOUT 0mA 1mA IOUT 0mA VOUT 100mV/DIV VOUT 100mV/DIV 0.5ms/DIV 10ms/DIV Figure 1. Reference Output Load Transient Response 3 LTC1258-5 LTC1258-5 U U W U APPLICATIONS INFORMATION The LTC1258-5 LTC1258-5 is designed to be stable with or without capacitive loads. With no capacitive load, the reference is ideal for fast settling applications, or where PC board space is a premium. In applications with significant output loading changes, an output bypass capacitor of up to 1µF can be used to improve the output transient response. Figure 1 shows the response of the reference to a 1mA to 0µA load step with a 1µF output capacitor. If more than 1µF of output capacitance is required, a resistor in series with the capacitor is recommended to reduce the output ringing. Figure 2 shows the resistor and capacitor values required to achieve critical damping. Internal P-Channel Pass Transistor The LTC1258-5 LTC1258-5 consumes only 4µA of quiescent current under light and heavy loads as well as in dropout; whereas, PNP based references waste considerable amounts of current when the pass transistor is saturated. In addition, the LTC1258-5 LTC1258-5 provides a lower dropout voltage (200mV max) than PNP based references. 10k RESISTOR VALUE () Output Bypass Capacitor 1k 100 10 The LTC1258-5 LTC1258-5 features an internal P-channel MOSFET pass transistor. This provides several advantages over similar designs using a PNP bipolar pass transistor. 1 10 100 OUTPUT CAPACITOR VALUE (µF) 1k 1258 · G02 Figure 2. Damping Resistance vs Output Capacitor Value U TYPICAL APPLICATIONS Micropower Low Dropout Negative Reference 2 1 Supply Splitter 0.2V VCC 6.5V LTC1258-5 LTC1258-5 IN LTC1258-5 LTC1258-5 VCC = 10V 2 IN OUT 0.1µF OUT 1 5V VIRTUAL GROUND 0.1µF GND 2 ­ 1/2 LTC1542 LTC1542 3 0.1µF 8 1 GND 4 4 VOUT = ­ 5V 1258-5 TA04 + 4 VSS = ­ 6V 1258-5 TA03 RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LT 1634 Micropower Precision Shunt Voltage Reference 0.05% Max, 25ppm/°C Max Drift, 1.25V, 2.5V, 4.096V and 5V Outputs LT1460 LT1460 Micropower Series Reference 0.075% Max, 10ppm/°C Max Drift, 2.5V, 5V and 10V Outputs LTC1440 LTC1440 Micropower Comparator with Reference 3.7µA Max ICC, 1% 1.182V Reference, Adjustable Hysteresis LTC1540 LTC1540 Nanopower Comparator with Reference 600nA Max ICC, 2% 1.182V Reference, Adjustable Hysteresis ® 4 Linear Technology Corporation 12585i LT/TP 1098 4K · PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408)432-1900 q FAX: (408) 434-0507 q www.linear-tech.com © LINEAR TECHNOLOGY CORPORATION 1998