Datasheet LTC4001-1 (Analog Devices) - 5
| Manufacturer | Analog Devices |
| Description | 2A Synchronous Buck Li-Ion Charger |
| Pages / Page | 20 / 5 — TYPICAL PERFORMANCE CHARACTERISTICS. IDET Threshold vs RIDET for. CHRG … |
| File Format / Size | PDF / 236 Kb |
| Document Language | English |
TYPICAL PERFORMANCE CHARACTERISTICS. IDET Threshold vs RIDET for. CHRG Pin Temperature Fault. Soft-Start (PWM Mode)
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LTC4001-1
TYPICAL PERFORMANCE CHARACTERISTICS IDET Threshold vs RIDET for CHRG Pin Temperature Fault Soft-Start (PWM Mode) RPROG = 549Ω Behavior (Detail)
400 INPUT 350 CURRENT (IIN) 0.5A/DIV 300 0 INDUCTOR CHRG CURRENT (I 250 L) 1V/DIV 0.5A/DIV 0 200 SOFT-START VOLTAGE (V IDET (mA) SS) 150 1V/DIV 0 EN PIN (VEN) 5V/DIV 100 0 V 2ms/DIV 40011 G09 BAT = 3.5V TIME (20μs/DIV) 40011 G11 50 VIN = 5V 0300 400 500 600 700 800 900 100011001200 RIDET (Ω) 40011 G10
PIN FUNCTIONS BAT (Pin 1):
Battery Charger Output Terminal. Connect a off and a 30μA current source is connected from CHRG to 10μF ceramic chip capacitor between BAT and PGND to ground. (This signal is latched and is reset by initiating a keep the ripple voltage small. new charge cycle.) When the timer runs out or the input supply is removed, the current source will be disconnected
SENSE (Pin 2):
Internal Sense Resistor. Connect to ex- and the CHRG pin is forced to a high impedance state. A ternal inductor. temperature fault causes this pin to blink.
PGND (Pin 3):
Power Ground.
PVIN (Pin 8):
Positive Supply Voltage Input. This pin con-
GNDSENS (Pin 4):
Ground Sense. Connect this pin to the nects to the power devices inside the chip. VIN ranges negative battery terminal. GNDSENS provides a Kelvin from 4V to 5.5V for normal operation. Operation down to connection for PGND and must be connected to PGND the undervoltage lockout threshold is allowed with cur- schematically. rent limited wall adapters. Decouple with a 10μF or larger
SW (Pin 5):
Switch Node Connection. This pin connects surface mounted ceramic capacitor. to the drains of the internal main and synchronous power
VINSENSE (Pin 9):
Positive Supply Sense Input. This pin MOSFET switches. Connect to external inductor. connects to the inputs of all input comparators (UVL, VIN
EN (Pin 6):
Enable Input Pin. Pulling the EN pin high to VBAT). It also supplies power to the controller portion places the LTC4001-1 into a low power state where the of this chip. When the BATSENS pin rises to within 30mV BAT drain current drops to less than 3μA and the supply of VINSENSE, the LTC4001-1 enters sleep mode, dropping current is reduced to less than 50μA. For normal opera- IIN to 50μA. Tie this pin directly to the terminal of the PVIN tion, pull the pin low. decoupling capacitor.
CHRG (Pin 7):
Open-Drain Charge Status Output. When the
FAULT (Pin 10):
Battery Fault. This pin is a logic high if battery is being charged, CHRG is pulled low by an internal a shorted battery is detected or if a temperature fault is N-channel MOSFET. When the charge current drops below detected. A temperature fault occurs with the temperature the IDET threshold (set by the R monitor circuit enabled and the thermistor temperature is IDET programming resistor) for more than 5milliseconds, the N-channel MOSFET turns either below 0°C or above 50°C (typical). 40011fa 5
TYPICAL PERFORMANCE CHARACTERISTICS IDET Threshold vs RIDET for CHRG Pin Temperature Fault Soft-Start (PWM Mode) RPROG = 549Ω Behavior (Detail)
400 INPUT 350 CURRENT (IIN) 0.5A/DIV 300 0 INDUCTOR CHRG CURRENT (I 250 L) 1V/DIV 0.5A/DIV 0 200 SOFT-START VOLTAGE (V IDET (mA) SS) 150 1V/DIV 0 EN PIN (VEN) 5V/DIV 100 0 V 2ms/DIV 40011 G09 BAT = 3.5V TIME (20μs/DIV) 40011 G11 50 VIN = 5V 0300 400 500 600 700 800 900 100011001200 RIDET (Ω) 40011 G10
PIN FUNCTIONS BAT (Pin 1):
Battery Charger Output Terminal. Connect a off and a 30μA current source is connected from CHRG to 10μF ceramic chip capacitor between BAT and PGND to ground. (This signal is latched and is reset by initiating a keep the ripple voltage small. new charge cycle.) When the timer runs out or the input supply is removed, the current source will be disconnected
SENSE (Pin 2):
Internal Sense Resistor. Connect to ex- and the CHRG pin is forced to a high impedance state. A ternal inductor. temperature fault causes this pin to blink.
PGND (Pin 3):
Power Ground.
PVIN (Pin 8):
Positive Supply Voltage Input. This pin con-
GNDSENS (Pin 4):
Ground Sense. Connect this pin to the nects to the power devices inside the chip. VIN ranges negative battery terminal. GNDSENS provides a Kelvin from 4V to 5.5V for normal operation. Operation down to connection for PGND and must be connected to PGND the undervoltage lockout threshold is allowed with cur- schematically. rent limited wall adapters. Decouple with a 10μF or larger
SW (Pin 5):
Switch Node Connection. This pin connects surface mounted ceramic capacitor. to the drains of the internal main and synchronous power
VINSENSE (Pin 9):
Positive Supply Sense Input. This pin MOSFET switches. Connect to external inductor. connects to the inputs of all input comparators (UVL, VIN
EN (Pin 6):
Enable Input Pin. Pulling the EN pin high to VBAT). It also supplies power to the controller portion places the LTC4001-1 into a low power state where the of this chip. When the BATSENS pin rises to within 30mV BAT drain current drops to less than 3μA and the supply of VINSENSE, the LTC4001-1 enters sleep mode, dropping current is reduced to less than 50μA. For normal opera- IIN to 50μA. Tie this pin directly to the terminal of the PVIN tion, pull the pin low. decoupling capacitor.
CHRG (Pin 7):
Open-Drain Charge Status Output. When the
FAULT (Pin 10):
Battery Fault. This pin is a logic high if battery is being charged, CHRG is pulled low by an internal a shorted battery is detected or if a temperature fault is N-channel MOSFET. When the charge current drops below detected. A temperature fault occurs with the temperature the IDET threshold (set by the R monitor circuit enabled and the thermistor temperature is IDET programming resistor) for more than 5milliseconds, the N-channel MOSFET turns either below 0°C or above 50°C (typical). 40011fa 5
