Datasheet

ManualsBrandsLINEAR TECHNOLOGY ManualsPMICsPMIC - DC/DC voltage regulator Switched-capacitor voltage converter DFN 6

LTC3221/

LTC3221-3.3/LTC3221-5

3221f

LTC3221-X

OUT

3221 TA01

4.7µF

1µF

OFF ON

GND

–

SHDN

2.2µF

4,7

REGULATED 3.3V OUTPUT FROM 1.8V TO 4.4V INPUT

OUT

= 3.3V ±4%

OUT

= OmA TO 25mA; V

>1.8V

OUT

= OmA TO 60mA; V

>2V

REGULATED 5V OUTPUT FROM 2.7V TO 5.5V INPUT

OUT

= 5V ±4%

OUT

= OmA TO 25mA; V

>2.7V

OUT

= OmA TO 60mA; V

>3V

SUPPLY VOLTAGE (V)

1.5

NO-LOAD INPUT CURRENT (µA)

3.0 4.0

3221 TA01b

2.0 2.5

= –45°C

= 25°C

= 90°C

3.5

4.5

Micropower,

Regulated Charge Pump

in 2 × 2 DFN

The LTC

3221 family are micropower charge pump DC/DC

converters that produce a regulated output at up to 60mA.

The input voltage range is 1.8V to 5.5V. Extremely low

operating current (8µA typical at no load) and low external

parts count (one ﬂ ying capacitor and two small bypass

capacitors at V

and V

OUT

) make them ideally suited for

small, battery-powered applications.

The LTC3221 family includes ﬁ xed 5V and 3.3V output

versions plus an adjustable version. All parts operate

as Burst Mode

switched capacitor voltage doublers

to achieve ultralow quiescent current. The chips use a

controlled current to supply the output and will survive

a continuous short-circuit from V

OUT

to GND. The FB pin

of the adjustable LTC3221 can be used to program the

desired output voltage.

The LTC3221 family is available in a low proﬁ le (0.75mm)

2mm × 2mm 6-pin DFN package.

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

Mode is a registered trademark of Linear Technology Corporation. All other trademarks are

the property of their respective owners.

FEATURES

DESCRIPTIO

TYPICAL APPLICATIO

APPLICATIO S

■

Ultralow Power: 8µA Quiescent Current

■

Regulated Output Voltages: 3.3V ±4%, 5V ±4%, ADJ

■

Range:

1.8V to 4.4V (LTC3221-3.3)

2.7V to 5.5V (LTC3221-5)

■

Output Current: Up to 60mA

■

No Inductors Needed

■

Very Low Shutdown Current: <1µA

■

Shutdown Disconnects Load from V

■

Burst Mode Control

■

Short-Circuit Protected

■

Solution Proﬁ le < 1mm

■

Tiny 2mm × 2mm 6-Pin DFN Package

■

Low Power 2 AA Cell to 3.3V Supply

■

Memory Backup Supplies

■

Tire Pressure Sensors

■

General Purpose Low Power Li-Ion to 5V Supply

■

RF Transmitters

■

Glucose Meters

No-Load Input Current

vs Supply Voltage

Summary of content (12 pages)

PAGE 1
LTC3221/ LTC3221-3.3/LTC3221-5 Micropower, Regulated Charge Pump in 2 × 2 DFN U FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ DESCRIPTIO Ultralow Power: 8µA Quiescent Current Regulated Output Voltages: 3.3V ±4%, 5V ±4%, ADJ VIN Range: 1.8V to 4.4V (LTC3221-3.3) 2.7V to 5.
PAGE 2
LTC3221/ LTC3221-3.3/LTC3221-5 U W W W ABSOLUTE AXI U RATI GS U W U PACKAGE/ORDER I FOR ATIO (Note 1) TOP VIEW VIN, ⎯S⎯H⎯D⎯N, FB ............................................. – 0.3V to 6V VOUT to GND............................................. – 0.3V to 5.5V VOUT Short-Circuit Duration ............................ Indeﬁnite Operating Temperature Range (Note 2) .. – 40°C to 85°C Storage Temperature Range.................. – 65°C to 125°C Maximum Junction Temperature ..........................
PAGE 3
LTC3221/ LTC3221-3.3/LTC3221-5 ELECTRICAL CHARACTERISTICS The ● denotes the speciﬁcations which apply over the full operating temperature range, otherwise speciﬁcations are at T = 25°C. V = 2.5V (LTC3221-3.3/LTC3221) or 3V (LTC3221-5), ⎯S⎯H⎯D⎯N = V , A IN IN CFLY = 1µF, CIN = 2.2µF, COUT = 2.2µF, unless otherwise speciﬁed. SYMBOL PARAMETER LTC3221-3.
PAGE 4
LTC3221/ LTC3221-3.3/LTC3221-5 U W TYPICAL PERFOR A CE CHARACTERISTICS 3.36 120 3.34 110 LOAD CURRENT (mA) OUTPUT VOLTAGE (V) VOUT = 3.168V TA = –45°C VIN = 3.2V 3.32 3.30 VIN = 2.5V 3.26 3.24 VIN = 1.8V 3.22 Effective Open-Loop Output Resistance vs Temperature 100 90 TA = 90°C 80 TA = 25°C 70 60 3.20 50 3.18 3.16 0 20 40 60 80 LOAD CURRENT (mA) 100 40 1.5 120 2.0 2.5 3.0 SUPPLY VOLTAGE (V) 3.
PAGE 5
LTC3221/ LTC3221-3.3/LTC3221-5 U W TYPICAL PERFOR A CE CHARACTERISTICS 120 5.10 TA = –45°C 110 5.05 VIN = 4.2V LOAD CURRENT (mA) OUTPUT VOLTAGE (V) VOUT = 4.8V Effective Open-Loop Output Resistance vs Temperature 5.00 VIN = 3.6V 4.95 VIN = 2.7V 4.90 4.85 100 TA = 90°C 90 TA = 25°C 80 70 60 50 0 20 40 60 80 LOAD CURRENT (mA) 40 2.7 120 100 3.0 3.3 3.6 3.9 SUPPLY VOLTAGE (V) 4.
PAGE 6
LTC3221/ LTC3221-3.3/LTC3221-5 U U U PI FU CTIO S C+ (Pin 1): Flying Capacitor Positive Terminal. GND (Pin 4): Ground. Should be tied to a ground plane for best performance. C– (Pin 2): Flying Capacitor Negative Terminal. ⎯ SH ⎯ D ⎯ N ⎯ (Pin 3) (LTC3221-3.3/LTC3221-5): Active Low ⎯ D ⎯ N ⎯ disables the LTC3221-3.3/ Shutdown Input. A low on S⎯ H ⎯ D ⎯ N ⎯ must not be allowed to ﬂoat. LTC3221-5. S⎯ H FB (Pin 3) (LTC3221): Feedback. The voltage on this pin is compared to the internal reference voltage (1.
PAGE 7
LTC3221/ LTC3221-3.3/LTC3221-5 U OPERATIO (Refer to Block Diagrams) The LTC3221 has a FB pin in place of the ⎯S⎯H⎯D⎯N pin. This allows the output voltage to be programmed using an external resistive divider. VOUT stays above this lower threshold for a long period of time, this result in a very low average input current. Soft-Start and Short-Circuit Protection Burst Mode Operation The LTC3221 family regulates the output voltage throughout the full 60mA load range using Burst Mode control.
PAGE 8
LTC3221/ LTC3221-3.3/LTC3221-5 U W U U APPLICATIO S I FOR ATIO depends on many factors such as the oscillator frequency (fOSC), value of the ﬂying capacitor (CFLY), the nonoverlap time, the internal switch resistances (RS) and the ESR of the external capacitors. A ﬁrst order approximation for ROL is given below: ROL ≅ 2 ∑ S = 1 TO 4 RS + 1 fOSC • C FLY EFFECTIVE OPEN-LOOP OUTPUT RESISTANCE (Ω) Typical ROL values as a function of temperature are shown in Figure 2. 15 VIN = 1.
PAGE 9
LTC3221/ LTC3221-3.3/LTC3221-5 U W U U APPLICATIO S I FOR ATIO be expressed by the following equation: ROL(MIN) ≡ 2VIN – VOUT 1 ≅ IOUT fOSC • C FLY where fOSC is the switching frequency (600kHz) and CFLY is the value of the ﬂying capacitor. The charge pump will typically be weaker than the theoretical limit due to additional switch resistance. However, for very light load applications, the above expression can be used as a guideline in determining a starting capacitor value.
PAGE 10
LTC3221/ LTC3221-3.3/LTC3221-5 U U W U APPLICATIO S I FOR ATIO If the standing current is too low, the FB pin becomes very sensitive to the switching noise and will result in errors in the programmed VOUT. The compensation capacitor (C1) helps to improve the response time of the comparator and to keep the output ripple within an acceptable range. For best results, C1 should be between 22pF to 220pF.
PAGE 11
LTC3221/ LTC3221-3.3/LTC3221-5 U PACKAGE DESCRIPTIO DC Package 6-Lead Plastic DFN (2mm × 2mm) (Reference LTC DWG # 05-08-1703) R = 0.115 TYP 0.56 ± 0.05 (2 SIDES) 0.675 ±0.05 2.50 ±0.05 1.15 ±0.05 0.61 ±0.05 (2 SIDES) PIN 1 BAR PACKAGE TOP MARK OUTLINE (SEE NOTE 6) 0.38 ± 0.05 4 2.00 ±0.10 (4 SIDES) PIN 1 CHAMFER OF EXPOSED PAD 3 0.25 ± 0.05 0.50 BSC 1.42 ±0.05 (2 SIDES) 0.200 REF RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS NOTE: 1.
PAGE 12
LTC3221/ LTC3221-3.3/LTC3221-5 RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LTC1262 12V, 30mA Flash Memory Program Supply Regulated 12V ±5% Output, IQ = 500µA LTC1514/LTC1515 Buck/Boost Charge Pumps with IQ = 60µA 50mA Output at 3.3V or 5V; 2V to 10V Input LTC1516 Micropower 5V Charge Pump IQ = 12µA, Up to 50mA Output, VIN = 2V to 5V LTC1517-5/LTC1517-3.3 Micropower 5V/3.