Datasheet LTC3537 (Analog Devices) - 9
| Hersteller | Analog Devices |
| Beschreibung | 2.2 MHz, 600mA Synchronous Step-Up DC/DC Converter and 100mA LDO |
| Seiten / Seite | 22 / 9 — PIN FUNCTIONS. MODE (Pin 1):. FBB (Pin 9):. LBI (Pin 2):. FBL (Pin 10):. … |
| Dateiformat / Größe | PDF / 322 Kb |
| Dokumentensprache | Englisch |
PIN FUNCTIONS. MODE (Pin 1):. FBB (Pin 9):. LBI (Pin 2):. FBL (Pin 10):. SGND (Pin 3):. VOLDO (Pin 11):. VINB (Pin 4):. VINL (Pin 12):
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LTC3537
PIN FUNCTIONS MODE (Pin 1):
Logic Controlled Input for the Auto-Burst
FBB (Pin 9):
Feedback Input to the gm Error Amplifi er Mode Feature. of the Boost Converter. Connect resistor divider tap to this pin. The output voltage can be adjusted from 1.5V MODE = High: PWM operation with Burst Mode to 5.25V by: Operation MODE = Low: PWM operation only VOUTB = 1.21V • [1 + (R2/R1)]
LBI (Pin 2):
Low-Battery Comparator Non-Inverting Input.
FBL (Pin 10):
Feedback Input to the gm Error Amplifi er of (Comparator enabled with ENBST or ENLDO) the LDO. Connect resistor divider tap to this pin. The output voltage can be adjusted from 0.6V (typical) to 5V by:
SGND (Pin 3):
Signal Ground. Provide a short direct PCB path between GND and the (–) side of the input and output VOLDO = 0.6V • [1 + (R4/R3)] capacitors.
VOLDO (Pin 11):
LDO Regulator Output. PCB trace from
VINB (Pin 4):
Input Supply for the Step-Up Converter. VOLDO to the output fi lter capacitor (1μF minimum) should Connect a minimum of 1μF ceramic decoupling capacitor be as short and as wide as possible. from this pin to ground.
VINL (Pin 12):
Input Supply for the LDO Regulator.
PGDB (Pin 5):
Power Good Indicator for the Boost Con-
V
verter. This is an open-drain output that sinks current
OUTB (Pin 13):
Output Voltage Sense Input and Drain of the Internal Synchronous Rectifi er. PCB trace length when VOUTB is less than 94% of the programmed voltage. from VOUTB to the output fi lter capacitor (4.7μF minimum)
ENBST (Pin 6):
Logic controlled shutdown input for the should be as short and wide as possible. boost converter.
SW (Pin 14):
Switch Pin. Connect the inductor between ENBST = High: Normal operation SW and VINB. Keep these PCB trace lengths as short and ENBST = Low: Shutdown wide as possible to reduce EMI. If the inductor current falls to zero or ENBST is low, an internal anti-ringing switch is
PGDL (Pin 7):
Power Good Indicator for the LDO Regula- connected from SW to V tor. This is an open-drain output that sinks current when INB to minimize EMI. VOLDO is less than 96% of the programmed voltage.
PGND (Pin 15):
Power Ground. Provide a short direct PCB path between GND and the (–) side of the input and
ENLDO (Pin 8):
Logic Controlled Shutdown Input for the output capacitors. LDO Regulator.
LBO (Pin 16):
Low-Battery Comparator Output. (Open- ENLDO = High: Normal operation Drain) ENLDO = Low: Shutdown
GND (Exposed Pad Pin 17):
Power Ground. The Exposed Pad must be soldered to the PCB. 3537fd 9
PIN FUNCTIONS MODE (Pin 1):
Logic Controlled Input for the Auto-Burst
FBB (Pin 9):
Feedback Input to the gm Error Amplifi er Mode Feature. of the Boost Converter. Connect resistor divider tap to this pin. The output voltage can be adjusted from 1.5V MODE = High: PWM operation with Burst Mode to 5.25V by: Operation MODE = Low: PWM operation only VOUTB = 1.21V • [1 + (R2/R1)]
LBI (Pin 2):
Low-Battery Comparator Non-Inverting Input.
FBL (Pin 10):
Feedback Input to the gm Error Amplifi er of (Comparator enabled with ENBST or ENLDO) the LDO. Connect resistor divider tap to this pin. The output voltage can be adjusted from 0.6V (typical) to 5V by:
SGND (Pin 3):
Signal Ground. Provide a short direct PCB path between GND and the (–) side of the input and output VOLDO = 0.6V • [1 + (R4/R3)] capacitors.
VOLDO (Pin 11):
LDO Regulator Output. PCB trace from
VINB (Pin 4):
Input Supply for the Step-Up Converter. VOLDO to the output fi lter capacitor (1μF minimum) should Connect a minimum of 1μF ceramic decoupling capacitor be as short and as wide as possible. from this pin to ground.
VINL (Pin 12):
Input Supply for the LDO Regulator.
PGDB (Pin 5):
Power Good Indicator for the Boost Con-
V
verter. This is an open-drain output that sinks current
OUTB (Pin 13):
Output Voltage Sense Input and Drain of the Internal Synchronous Rectifi er. PCB trace length when VOUTB is less than 94% of the programmed voltage. from VOUTB to the output fi lter capacitor (4.7μF minimum)
ENBST (Pin 6):
Logic controlled shutdown input for the should be as short and wide as possible. boost converter.
SW (Pin 14):
Switch Pin. Connect the inductor between ENBST = High: Normal operation SW and VINB. Keep these PCB trace lengths as short and ENBST = Low: Shutdown wide as possible to reduce EMI. If the inductor current falls to zero or ENBST is low, an internal anti-ringing switch is
PGDL (Pin 7):
Power Good Indicator for the LDO Regula- connected from SW to V tor. This is an open-drain output that sinks current when INB to minimize EMI. VOLDO is less than 96% of the programmed voltage.
PGND (Pin 15):
Power Ground. Provide a short direct PCB path between GND and the (–) side of the input and
ENLDO (Pin 8):
Logic Controlled Shutdown Input for the output capacitors. LDO Regulator.
LBO (Pin 16):
Low-Battery Comparator Output. (Open- ENLDO = High: Normal operation Drain) ENLDO = Low: Shutdown
GND (Exposed Pad Pin 17):
Power Ground. The Exposed Pad must be soldered to the PCB. 3537fd 9