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LTC3200/LTC3200-5 Low Noise, Regulated Charge Pump DC/DC Converters
FEATURES
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DESCRIPTIO
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Low Noise Constant Frequency Operation Output Current: 100mA Available in 8-Pin MSOP (LTC3200) and Low Profile (1mm) 6-Pin ThinSOTTM (LTC3200-5) Packages 2MHz Switching Frequency Fixed 5V ± 4% Output (LTC3200-5) or ADJ VIN Range: 2.7V to 4.5V Automatic Soft-Start Reduces Inrush Current No Inductors ICC <1µA in Shutdown
The LTC®3200/LTC3200-5 are low noise, constant frequency switched capacitor voltage doublers. They produce a regulated output voltage from a 2.7V to 4.5V input with up to 100mA of output current. Low external parts count (one flying capacitor and two small bypass capacitors at VIN and VOUT) make the LTC3200/LTC3200-5 ideally suited for small, battery-powered applications. A new charge-pump architecture maintains constant switching frequency to zero load and reduces both output and input ripple. The LTC3200/LTC3200-5 have thermal shutdown capability and can survive a continuous shortcircuit from VOUT to GND. Built-in soft-start circuitry prevents excessive inrush current during start-up. High switching frequency enables the use of small ceramic capacitors. A low current shutdown feature disconnects the load from VIN and reduces quiescent current to <1µA. The LTC3200 is available in an 8-pin MSOP package and the LTC3200-5 is available in a 6-pin ThinSOT.
, LTC and LT are registered trademarks of Linear Technology Corporation. ThinSOT is a trademark of Linear Technology Corporation.
APPLICATIO S
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White LED Backlighting Li-Ion Battery Backup Supplies Local 3V to 5V Conversion Smart Card Readers PCMCIA Local 5V Supplies
TYPICAL APPLICATIO
Output Ripple Voltage vs Load Current Regulated 5V Output from a 2.7V to 4.5V Input
1µF OUTPUT RIPPLE (mVP-P)
40
VIN = 3V CFLY = 1µF TA = 25°C
30 COUT = 1µF 20
4
6
VIN 2.7V TO 4.5V 1µF
5 2 3
C+ C– LTC3200-5 VIN GND SHDN VOUT
1 1µF
VOUT = 5V ±4% IOUT UP TO 40mA, VIN ≥ 2.7V IOUT UP TO 100mA, VIN ≥ 3.1V
10
OFF ON
ALL CAPACITORS = MURATA GRM 39X5R105K6.3AJ OR TAIYO YUDEN JMK107BJ105MA
0
3200-5 TA01
0
U
COUT = 2.2µF 50 75 25 OUTPUT CURRENT (mA) 100
3200 TA02
U
U
1
LTC3200/LTC3200-5
ABSOLUTE
AXI U RATI GS
VIN to GND ...................................................– 0.3V to 6V VOUT to GND .............................................– 0.3V to 5.5V VFB, SHDN to GND ........................ – 0.3V to (VIN + 0.3V) IOUT (Note 2) ....................................................... 150mA
PACKAGE/ORDER I FOR ATIO
TOP VIEW C+ VIN C– PGND 1 2 3 4 8 7 6 5 VOUT FB SHDN SGND
ORDER PART NUMBER LTC3200EMS8 MS8 PART MARKING LTNV
VOUT 1 GND 2 SHDN 3
MS8 PACKAGE 8-LEAD PLASTIC MSOP
TJMAX = 150°C, θJA = 200°C/W
Consult factory for parts specified with wider operating temperature ranges.
The q denotes specifications which apply over the full operating temperature range. Specifications are at TA = 25°C, VIN = 3.6V, CFLY = 1µF, CIN = 1µF, COUT = 1µF unless otherwise noted.
SYMBOL VIN VOUT ICC ISHDN VFB IFB VR η FOSC VIH VIL IIH IIL
tON
ELECTRICAL CHARACTERISTICS
PARAMETER Input Voltage Output Voltage Operating Supply Current Shutdown Current FB Voltage (LTC3200) FB Input Current (LTC3200) Output Ripple (LTC3200-5) Efficiency (LTC3200-5) Switching Frequency SHDN Input Threshold SHDN Input Threshold SHDN Input Current SHDN Input Current VOUT Turn-On Time Open-Loop Output Resistance
CONDITIONS
q
2.7V ≤ VIN ≤ 4.5V, IOUT ≤ 40mA 3.1V ≤ VIN ≤ 4.5V, IOUT ≤ 100mA IOUT = 0mA, SHDN = VIN SHDN = 0V, VOUT = 0V VFB = 1.4V VIN = 3V, IOUT = 100mA VIN = 3V, IOUT = 50mA
SHDN = VIN SHDN = 0V VIN = 3V, IOUT = 0mA, 10% to 90% VIN = 3V, IOUT = 100mA, VFB = 0V (Note 4)
ROL
Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note 2: Based on long term current density limitations.
2
U
U
W
W W U
W
(Note 1)
VOUT Short-Circuit Duration ............................. Indefinite Operating Temperature Range (Note 3) .. – 40°C to 85°C Storage Temperature Range ................. – 65°C to 150°C Lead Temperature (Soldering, 10 sec).................. 300°C
TOP VIEW 6 C+ 5 VIN 4 C–
ORDER PART NUMBER LTC3200ES6-5 S6 PART MARKING LTSH
S6 PACKAGE 6-LEAD PLASTIC SOT-23
TJMAX = 150°C, θJA = 230°C/W
MIN 2.7 4.8 4.8
q q q q q q
TYP 5 5 3.5
MAX 4.5 5.2 5.2 8 1 1.319 50
UNITS V V V mA µA V nA mVP-P % MHz
V
1.217 –50
1.268 30 80
1
q q q q
2 0.4
1.3 –1 –1 0.8 9.2 1 1
V µA µA
ms Ω
Note 3: The LTC3200E/LTC3200E-5 are guaranteed to meet performance specifications from 0°C to 70°C. Specifications over the –40°C to 85°C operating temperature range are assured by design, characterization and correlation with statistical process controls. Note 4: ROL ≡ (2 VIN – VOUT)/IOUT
LTC3200/LTC3200-5 TYPICAL PERFOR A CE CHARACTERISTICS
Output Voltage vs Supply Voltage
5.15 5.10 OUTPUT VOLTAGE (V) 5.05 5.00 TA = – 40°C 4.95 4.90 4.85 4.8 3 0 100 150 50 LOAD CURRENT (mA) 200
3200 G02
CIN = COUT = CFLY = 1µF IOUT = 20mA
OUTPUT VOLTAGE (V)
TA = 85°C TA = 25°C
5.1
SUPPLY CURRENT (mA)
2.7
3.0
3.3 3.6 3.9 SUPPLY VOLTAGE (V)
Oscillator Frequency vs Supply Voltage
3.0 2.8
OSCILLATOR FREQUENCY (MHz) 1.1 1.0
2.4 2.2 2.0 1.8 1.6 1.4 1.2 1.0 2.7 3.0 TA = – 40°C
TA = 25°C
THRESHOLD VOLTAGE (V)
2.6
TA = 25°C 0.8 0.7 0.6 0.5 2.7 3.0 3.3 3.6 3.9 SUPPLY VOLTAGE (V) 4.2 4.5
3200 G05
EFFICIENCY (%)
TA = 85°C
3.3 3.6 3.9 SUPPLY VOLTAGE (V)
OUTPUT CURRENT (mA)
U W
4.2
3200 F01
(LTC3200-5) No Load Supply Current vs Supply Voltage
6 CIN = COUT = CFLY = 1µF VSHDN = VIN TA = 25°C
Output Voltage vs Load Current
5.2 CIN = COUT = CFLY = 1µF TA = 25°C
5
5.0 VIN = 2.7V 4.9 VIN = 3.2V VIN = 3V
TA = 85°C 4 TA = – 40°C
4.5
2.7
3.0
3.3 3.6 3.9 SUPPLY VOLTAGE (V)
4.2
4.5
3200 G03
VSHDN Threshold Voltage vs Supply Voltage
100 90
Efficiency vs Load Current
CIN = COUT = CFLY = 1µF TA = 25°C VIN = 2.7V VIN = 3.2V VIN = 3.7V VIN = 4.5V 50 40 30
0.9
TA = – 40°C
80 70 60
TA = 85°C
4.2
4.5
3200 G04
1
10 LOAD CURRENT (mA)
100
3200 G06
Short Circuit Current vs Supply Voltage
250 CFLY = 1µF TA = 25°C VOUT = 0V
200
150
100
2.7
3.0
3.3 3.6 3.9 SUPPLY VOLTAGE (V)
4.2
4.5
3200 G07
3
LTC3200/LTC3200-5 TYPICAL PERFOR A CE CHARACTERISTICS
VOUT Soft-Start Ramp
VSHDN 2V/DIV
VOUT (AC COUPLED) 20mV/DIV COUT = 1µF COUT = 3.3µF
VOUT 1V/DIV
VIN = 3V
200µs/DIV
32005 G08
PIN FUNCTIONS
LTC3200/LTC3200-5
C + (Pins 1/6): Flying Capacitor Positive Terminal. VIN (Pins 2/5): Input Supply Voltage. VIN should be bypassed with a 1µF to 4.7µF low ESR ceramic capacitor. C – (Pins 3/4): Flying Capacitor Negative Terminal. GND (Pins 4,5/2): Ground. Should be tied to a ground plane for best performance. SHDN (Pins 6/3): Active Low Shutdown Input. A low on SHDN disables the LTC3200/LTC3200-5. SHDN must not be allowed to float.
4
U W
(LTC3200-5) TA = 25°C Load Transient Response
IL 10mA TO 90mA 50mA/DIV VOUT (AC COUPLED) 50mV/DIV
Output Ripple
COUT = 10µF
VIN = 3.3V IL = 100mA
200ns/DIV
32005 G09
VIN = 3.3V COUT = 1µF
10µs/DIV
32005 G10
U
U
U
FB (Pin 7): (LTC3200 Only) Feedback Input Pin. An output divider should be connected from VOUT to FB to program the output voltage. VOUT (Pins 8/1): Regulated Output Voltage. VOUT should be bypassed with a 1µF to 4.7µF low ESR ceramic capacitor as close as possible to the pin for best performance.
LTC3200/LTC3200-5
SI PLIFIED BLOCK DIAGRA S
LTC3200
VOUT FB
8 7 2MHz OSCILLATOR
VIN
2 C–
VOUT
1 2MHz OSCILLATOR
VIN
5 C–
–
+
–
+
W
W
SOFT-START AND SWITCH CONTROL
6
SHDN
CHARGE PUMP 1 C+
3
5 SGND
4 PGND
3200 BD
LTC3200-5
SOFT-START AND SWITCH CONTROL
3
SHDN
CHARGE PUMP 6 C+
4
2 GND
3200-5 BD
5
LTC3200/LTC3200-5
OPERATIO
Operation (Refer to Simplified Block Diagrams) The LTC3200/LTC3200-5 use a switched capacitor charge pump to boost VIN to a regulated output voltage. Regulation is achieved by sensing the output voltage through an internal resistor divider (LTC3200-5) and modulating the charge pump output current based on the error signal. A 2-phase nonoverlapping clock activates the charge pump switches. The flying capacitor is charged from VIN on the first phase of the clock. On the second phase of the clock it is stacked in series with VIN and connected to VOUT. This sequence of charging and discharging the flying capacitor continues at a free running frequency of 2MHz (typ). In shutdown mode all circuitry is turned off and the LTC3200/LTC3200-5 draw only leakage current from the VIN supply. Furthermore, VOUT is disconnected from VIN. The SHDN pin is a CMOS input with a threshold voltage of approximately 0.8V. The LTC3200/LTC3200-5 is in shutdown when a logic low is applied to the SHDN pin. Since the SHDN pin is a high impedance CMOS input it should never be allowed to float. To ensure that its state is defined it must always be driven with a valid logic level. Short-Circuit/Thermal Protection The LTC3200/LTC3200-5 have built-in short-circuit current limiting as well as overtemperature protection. During short-circuit conditions, they will automatically limit their output current to approximately 225mA. At higher temperatures, or if the input voltage is high enough to cause excessive self heating on chip, thermal shutdown circuitry will shut down the charge pump once the junction temperature exceeds approximately 160°C. It will reenable the charge pump once the junction temperature drops back to approximately 155°C. The LTC3200/LTC3200-5 will cycle in and out of thermal shutdown indefinitely without latch-up or damage until the short-circuit on VOUT is removed. Shutdown Current Since the output voltage can go above the input voltage, special circuitry is required to control internal logic. Detection logic will draw an input current of 5µA when the LTC3200 is in shutdown. However, this current will be eliminated wh
