Datasheet LTC1735 (Analog Devices) - 7
| Manufacturer | Analog Devices |
| Description | High Efficiency Synchronous Step-Down Switching Regulator |
| Pages / Page | 32 / 7 — TYPICAL PERFOR A CE CHARACTERISTICS. VOUT(RIPPLE). (Burst Mode … |
| File Format / Size | PDF / 415 Kb |
| Document Language | English |
TYPICAL PERFOR A CE CHARACTERISTICS. VOUT(RIPPLE). (Burst Mode Operation). Load Step (Burst Mode Operation)
Model Line for this Datasheet
- LTC1735CF#PBF LTC1735CF#PBF LTC1735CF#TRPBF LTC1735CF#TRPBF LTC1735CGN#PBF LTC1735CGN#PBF LTC1735CGN#TRPBF LTC1735CGN#TRPBF LTC1735CS#PBF LTC1735CS#PBF LTC1735CS#TRPBF LTC1735CS#TRPBF LTC1735EGN#PBF LTC1735EGN#PBF LTC1735EGN#TRPBF LTC1735EGN#TRPBF LTC1735IF#PBF LTC1735IF#PBF LTC1735IF#TRPBF LTC1735IF#TRPBF LTC1735IGN#PBF LTC1735IGN#PBF LTC1735IGN#TRPBF LTC1735IGN#TRPBF LTC1735IS#PBF LTC1735IS#PBF LTC1735IS#TRPBF LTC1735IS#TRPBF
Text Version of Document
LTC1735
W U TYPICAL PERFOR A CE CHARACTERISTICS VOUT(RIPPLE) (Burst Mode Operation) Load Step (Burst Mode Operation) Load Step (Continuous Mode)
I FIGURE 1 FIGURE 1 FIGURE 1 LOAD = 1.5A V V OUT OUT 20mV/DIV 50mV/DIV VOUT 50mV/DIV I I L L 5A/DIV 5A/DIV IL 5A/DIV 1735 G27 1735 G26 1735 G25 FCB = 5V 5µs/DIV 10mA TO 10µs/DIV 0A TO 10µs/DIV VIN = 15V 9A LOAD STEP 9A LOAD STEP VOUT = 1.6V FCB = 5V FCB = 0V V V IN = 15V IN = 15V V V OUT = 1.6V OUT = 1.6V
VOUT(RIPPLE) Start-Up VOUT(RIPPLE) (Synchronized) (Burst Mode Operation)
V I FIGURE 1 FIGURE 1 LOAD = 10mA ILOAD = 50mA OUT 1V/DIV VOUT VOUT 10mV/DIV 20mV/DIV VRUN/SS 5V/DIV IL IL 5A/DIV 5A/DIV IL 5A/DIV V 1735 G22 1735 G23 1735 G24 IN = 15V 5ms/DIV EXT SYNC f = fO 10µs/DIV FCB = 5V 50µs/DIV VOUT = 1.6V VIN = 15V VIN = 15V RLOAD = 0.16Ω VOUT = 1.6V VOUT = 1.6V
U U U PI FU CTIO S COSC:
External capacitor COSC from this pin to ground sets
FCB:
Forced Continuous/Synchronization Input. Tie this the operating frequency. pin to ground for continuous synchronous operation, to a
RUN/SS:
Combination of Soft-Start and Run Control In- resistive divider from the secondary output when using a puts. A capacitor to ground at this pin sets the ramp time secondary winding or to INTVCC to enable Burst Mode to full output current. The time is approximately 1.25s/µF. operation at low load currents. Clocking this pin with a Forcing this pin below 1.5V causes the device to shut signal above 1.5VP–P disables Burst Mode operation but down. (See Applications Information section for quiescent allows cycle-skipping at low load currents and synchro- current note.) In shutdown all functions, including INTV nizes the internal oscillator with the external clock.
The
CC, are disabled. Latchoff overcurrent protection is also in-
FCB pin must not be driven when the device is shut down
voked via this pin as described in the Applications Infor-
(RUN/SS pin low).
mation section.
SGND:
Small-Signal Ground. All small-signal components
I
such as COSC, CSS, the feedback divider plus the loop com-
TH:
Error Amplifier Compensation Point. The current comparator threshold increases with this control voltage. pensation resistor and capacitor(s) should single-point tie Nominal voltage range for this pin is 0V to 2.4V. to this pin. This pin should, in turn, connect to PGND. 1735fc 7
W U TYPICAL PERFOR A CE CHARACTERISTICS VOUT(RIPPLE) (Burst Mode Operation) Load Step (Burst Mode Operation) Load Step (Continuous Mode)
I FIGURE 1 FIGURE 1 FIGURE 1 LOAD = 1.5A V V OUT OUT 20mV/DIV 50mV/DIV VOUT 50mV/DIV I I L L 5A/DIV 5A/DIV IL 5A/DIV 1735 G27 1735 G26 1735 G25 FCB = 5V 5µs/DIV 10mA TO 10µs/DIV 0A TO 10µs/DIV VIN = 15V 9A LOAD STEP 9A LOAD STEP VOUT = 1.6V FCB = 5V FCB = 0V V V IN = 15V IN = 15V V V OUT = 1.6V OUT = 1.6V
VOUT(RIPPLE) Start-Up VOUT(RIPPLE) (Synchronized) (Burst Mode Operation)
V I FIGURE 1 FIGURE 1 LOAD = 10mA ILOAD = 50mA OUT 1V/DIV VOUT VOUT 10mV/DIV 20mV/DIV VRUN/SS 5V/DIV IL IL 5A/DIV 5A/DIV IL 5A/DIV V 1735 G22 1735 G23 1735 G24 IN = 15V 5ms/DIV EXT SYNC f = fO 10µs/DIV FCB = 5V 50µs/DIV VOUT = 1.6V VIN = 15V VIN = 15V RLOAD = 0.16Ω VOUT = 1.6V VOUT = 1.6V
U U U PI FU CTIO S COSC:
External capacitor COSC from this pin to ground sets
FCB:
Forced Continuous/Synchronization Input. Tie this the operating frequency. pin to ground for continuous synchronous operation, to a
RUN/SS:
Combination of Soft-Start and Run Control In- resistive divider from the secondary output when using a puts. A capacitor to ground at this pin sets the ramp time secondary winding or to INTVCC to enable Burst Mode to full output current. The time is approximately 1.25s/µF. operation at low load currents. Clocking this pin with a Forcing this pin below 1.5V causes the device to shut signal above 1.5VP–P disables Burst Mode operation but down. (See Applications Information section for quiescent allows cycle-skipping at low load currents and synchro- current note.) In shutdown all functions, including INTV nizes the internal oscillator with the external clock.
The
CC, are disabled. Latchoff overcurrent protection is also in-
FCB pin must not be driven when the device is shut down
voked via this pin as described in the Applications Infor-
(RUN/SS pin low).
mation section.
SGND:
Small-Signal Ground. All small-signal components
I
such as COSC, CSS, the feedback divider plus the loop com-
TH:
Error Amplifier Compensation Point. The current comparator threshold increases with this control voltage. pensation resistor and capacitor(s) should single-point tie Nominal voltage range for this pin is 0V to 2.4V. to this pin. This pin should, in turn, connect to PGND. 1735fc 7
