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LT1054

Switched-Capacitor Voltage

Converter with Regulator

ESCRIPTIO

■

Available in Space Saving SO-8 Package

■

Output Current: 100mA

■

Low Loss: 1.1V at 100mA

■

Operating Range: 3.5V to 15V

■

Reference and Error Amplifier for Regulation

■

External Shutdown

■

External Oscillator Synchronization

■

Can Be Paralleled

■

Pin Compatible with the LTC

1044/LTC7660

The LT

1054 is a monolithic, bipolar, switched-capacitor

voltage converter and regulator. The LT1054 provides

higher output current than previously available converters

with significantly lower voltage losses. An adaptive switch

driver scheme optimizes efficiency over a wide range of

output currents. Total voltage loss at 100mA output current

is typically 1.1V. This holds true over the full supply voltage

range of 3.5V to 15V. Quiescent current is typically 2.5mA.

The LT1054 also provides regulation, a feature not previ-

ously available in switched-capacitor voltage converters.

By adding an external resistive divider a regulated output

can be obtained. This output will be regulated against

changes in both input voltage and output current. The

LT1054 can also be shut down by grounding the feedback

pin. Supply current in shutdown is less than 100µA.

The internal oscillator of the LT1054 runs at a nominal

frequency of 25kHz. The oscillator pin can be used to adjust

the switching frequency or to externally synchronize the

LT1054.

The LT1054 is pin compatible with previous converters

such the LTC1044/LTC7660.

■

Voltage Inverter

■

Voltage Regulator

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Negative Voltage Doubler

■

Positive Voltage Doubler

, LTC and LT are registered trademarks of Linear Technology Corporation.

BLOCK DIAGRAM

OUTPUT CURRENT (mA)

VOLTAGE LOSS (V)

LT1054 • TA01

50 60 70 80 90 100

3.5V ≤ V

≤ 15V

= C

OUT

= 100µF

INDICATES GUARANTEED TEST POINT

= 125°C

= 25°C

= –55°C

REFERENCE

OSC

DRIVE DRIVE

DRIVE

OSC

CAP

–

GND

CAP

FEEDBACK/

SHUTDOWN

–

*EXTERNAL CAPACITORS

2.5V

–V

OUT

LT1054 • BD

REF

OUT

Voltage Loss

Summary of content (16 pages)

PAGE 1
LT1054 Switched-Capacitor Voltage Converter with Regulator U DESCRIPTIO FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ The LT ®1054 is a monolithic, bipolar, switched-capacitor voltage converter and regulator. The LT1054 provides higher output current than previously available converters with significantly lower voltage losses. An adaptive switch driver scheme optimizes efficiency over a wide range of output currents. Total voltage loss at 100mA output current is typically 1.1V.
PAGE 2
LT1054 W W W AXI U U ABSOLUTE RATI GS Supply Voltage (Note 1).......................................... 16V Input Voltage Pin 1 ................................................. 0V ≤ VPIN1 ≤ V+ Pin 3 (S Package) ............................. 0V ≤ VPIN3 ≤ V+ Pin 7 ............................................. 0V ≤ VPIN7 ≤ VREF Pin 13 (S Package) ...................... 0V ≤ VPIN13 ≤ VREF Operating Temperature Range LT1054C ................................................. 0°C to 70°C LT1054I ...........
PAGE 3
LT1054 ELECTRICAL CHARACTERISTICS PARAMETER Supply Current (Note 6) CONDITIONS ILOAD = 0mA VIN = 3.
PAGE 4
LT1054 U W TYPICAL PERFOR A CE CHARACTERISTICS Average Input Current Output Voltage Loss 1.4 100 120 1.2 100 1.
PAGE 5
LT1054 U U U PIN FUNCTIONS V + (Pin 8): Input Supply. The LT1054 alternately charges CIN to the input voltage when CIN is switched in parallel with the input supply and then transfers charge to COUT when CIN is switched in parallel with COUT. Switching occurs at the oscillator frequency. During the time that CIN is charging, the peak supply current will be approximately equal to 2.2 times the output current.
PAGE 6
LT1054 U U U PIN FUNCTIONS OSC (Pin 7): Oscillator Pin. This pin can be used to raise or lower the oscillator frequency or to synchronize the device to an external clock. Internally pin 7 is connected to the oscillator timing capacitor (Ct ≈ 150pF) which is alternately charged and discharged by current sources of ±7µA so that the duty cycle is ≈50%. The LT1054 oscillator is designed to run in the frequency band where switching losses are minimized.
PAGE 7
LT1054 U U W U APPLICATIONS INFORMATION Theory of Operation REQUIV V1 To understand the theory of operation of the LT1054, a review of a basic switched-capacitor building block is helpful. In Figure 3 when the switch is in the left position, capacitor C1 will charge to voltage V1. The total charge on C1 will be q1 = C1V1. The switch then moves to the right, discharging C1 to voltage V2. After this discharge time the charge on C1 is q2 = C1V2.
PAGE 8
LT1054 U W U U APPLICATIONS INFORMATION 20k or greater because the reference output current is limited to ≈ 100µA. R2 should be chosen to be in the range of 100k to 300k. For optimum results the ratio of CIN/COUT is recommended to be 1/10. C1, required for good load regulation at light load currents, should be 0.002µF for all output voltages. A new die layout was required to fit into the physical dimensions of the S8 package.
PAGE 9
LT1054 U U W U APPLICATIONS INFORMATION P ≈ (VIN – |VOUT|)(IOUT) + (VIN)(IOUT)(0.2) where both VIN and VOUT are referred to the ground pin (pin 3) of the LT1054. For LT1054 regulator circuits, the power dissipation will be equivalent to that of a linear regulator. Due to the limited power handling capability of the LT1054 packages, the user will have to limit output current requirements or take steps to dissipate some power external to the LT1054 for large input/output differentials.
PAGE 10
LT1054 U TYPICAL APPLICATIONS N Basic Voltage Inverter Basic Voltage Inverter/Regulator + OSC CAP LT1054 GND VREF + 100µF CAP – VIN VIN FB/SHDN V + 2µF + VOUT 10µF –VOUT 100µF CAP – ) + LT1054 • TAO2 + 2µF OSC CAP + LT1054 GND VREF + )) ) |VOUT| |VOUT| R2 = +1 = +1 , 1.21V VREF R1 – 40mV 2 R1 R2 VOUT 0.
PAGE 11
LT1054 U TYPICAL APPLICATIONS N Strain Gauge Bridge Signal Conditioner VIN 3.5V TO 15V + – FB/SHDN V + OSC CAP + LT1054 GND VREF + 10µF CAP – + 100µF VOUT 10µF VIN = 3.
PAGE 12
LT1054 U TYPICAL APPLICATIONS N VIN 3.5V TO 5.5V 1 1N914 8 2 FB/SHDN V 1N914 + + + 10µF OSC CAP LT1054 GND VREF CAP – 1µF + + 5µF R1 20k VOUT R2 125k 0.002µF + R2 125k 7 LTC1044 3 6 4 5 + 1N914 1µF VOUT = 5V 3k 100µF + 20k 3.5V to 5V Regulator – VIN = 3.5V TO 5.5V VOUT = 5V IOUT(MAX) = 50mA 2N2219 1N914 LT1054 • TA10 1N5817 Regulating 200mA, 12V to – 5V Converter 5µF 12V + 10µF + ) CAP – R1 39.2k + 10µF R2 200k VOUT )) ) |VOUT| |VOUT| R2 = +1 = +1 , 1.
PAGE 13
LT1054 U TYPICAL APPLICATIONS N Positive Doubler with Regulation (5V to 8V Converter) Negative Doubler with Regulator VIN = 5V + + 100µF + 1N5817 0.03µF 5.5k 10k 2.5k 10k CAP – 5V – + OSC CAP LT1054 GND VREF + 10µF VOUT CAP – + 2µF VOUT 10µF 10k + OSC CAP + LT1054 GND VREF 1N4001 R2 1M 100µF 0.002µF 1N4001 –VOUT LT1006 VIN = 3.5V TO 15V VOUT(MAX) ≈ 2VIN + (VL + 2VDIODE) VL = LT1054 VOLTAGE LOSS ) LT1054 • TA13 0.
PAGE 14
LT1054 U PACKAGE DESCRIPTION Dimension in inches (millimeters) unless otherwise noted. J8 Package 8-Lead Ceramic DIP CORNER LEADS OPTION (4 PLCS) 0.405 (10.287) MAX 0.005 (0.127) MIN 0.023 – 0.045 (0.584 – 1.143) HALF LEAD OPTION 8 6 7 5 0.025 (0.635) RAD TYP 0.045 – 0.068 (1.143 – 1.727) FULL LEAD OPTION 0.220 – 0.310 (5.588 – 7.874) 0.300 BSC (0.762 BSC) 1 2 3 0.200 (5.080) MAX 4 0.015 – 0.060 (0.381 – 1.524) 0.008 – 0.018 (0.203 – 0.457) 0.385 ± 0.025 (9.779 ± 0.635) 0° – 15° 0.
PAGE 15
LT1054 U PACKAGE DESCRIPTION Dimension in inches (millimeters) unless otherwise noted. S8 Package 8-Lead Ceramic DIP 0.189 – 0.197* (4.801 – 5.004) 7 6 8 5 0.150 – 0.157* (3.810 – 3.988) 0.228 – 0.244 (5.791 – 6.197) 1 0.010 – 0.020 × 45° (0.254 – 0.508) 0.008 – 0.010 (0.203 – 0.254) 3 2 4 0.053 – 0.069 (1.346 – 1.752) 0.004 – 0.010 (0.101 – 0.254) 0°– 8° TYP 0.016 – 0.050 0.406 – 1.270 0.050 (1.270) BSC 0.014 – 0.019 (0.355 – 0.
PAGE 16
LT1054 U.S. Area Sales Offices NORTHEAST REGION Linear Technology Corporation 3220 Tillman Drive, Suite 120 Bensalem, PA 19020 Phone: (215) 638-9667 FAX: (215) 638-9764 Linear Technology Corporation 266 Lowell St., Suite B-8 Wilmington, MA 01887 Phone: (508) 658-3881 FAX: (508) 658-2701 SOUTHEAST REGION Linear Technology Corporation 17000 Dallas Parkway Suite 219 Dallas, TX 75248 Phone: (214) 733-3071 FAX: (214) 380-5138 SOUTHWEST REGION Linear Technology Corporation 22141 Ventura Blvd.