LT3500
8
3500fc
PIN FUNCTIONS
Driving the R
T
/SYNC pin with an external clock signal
will synchronize the switch to the applied frequency.
Synchronization occurs on the rising edge of the clock
signal after the clock signal is detected. Each rising clock
edge initiates an oscillator ramp reset. A gain control loop
servos the oscillator charging current to maintain a con-
stant oscillator amplitude. Hence, the slope compensation
remains unchanged. If the clock signal is removed, the
oscillator reverts to resistor mode and reapplies the 1V
bias to the R
T
/SYNC pin after the synchronization detection
circuitry times out. The clock source impedance should
be set such that the current out of the R
T
/SYNC pin in
resistor mode generates a frequency roughly equivalent
to the synchronization frequency. Floating or holding the
R
T
/SYNC pin above 1.1V will not damage the device, but
will halt oscillation.
PG: The power good bar pin is an open-collector output 
that sinks current when the FB or LFB rises above 90%
of its nominal regulating voltage.
FB: The FB pin is the negative input to the switcher error 
ampli er. The output switches to regulate this pin to 0.8V
with respect to the exposed ground pad. Bias current
 ows out of the FB pin.
LFB: The LFB pin is the negative input to the linear error 
ampli er. The L
DRV
 pin servos to regulate this pin to 0.8V
with respect to the exposed ground pad. Bias current  ows
out of the LFB pin.
LDRV: The LDRV pin is the emitter of an internal NPN that 
can be con gured as an output of a linear regulator or as
the drive for an external NPN high current regulator. Cur-
rent  ows out of the LDRV pin when the LFB pin voltage is
below 0.8V. The LDRV pin has a typical maximum current
capability of 13mA.
BST: The BST pin provides a higher than V
IN
 base drive to
the power NPN to ensure a low switch drop. A compara-
tor to V
IN
 imposes a minimum off time on the SW pin if
the BST pin voltage drops too low. Forcing a SW off time
allows the boost capacitor to recharge.
SW: The SW pin is the emitter of the on-chip power NPN. 
At switch off, the inductor will drive this pin below ground
with a high dV/dt. An external catch diode to ground, close
to the SW pin and respective V
IN
 decoupling capacitors
ground, must be used to prevent this pin from excessive
negative voltages.
Exposed Pad: GND. The exposed pad is the only ground 
connection for the device. The exposed pad should be
soldered to a large copper area to reduce thermal resis-
tance. The GND pin also serves as small-signal ground.
For ideal operation all small-signal ground paths should
connect to the GND pin at a single point, avoiding any
high current ground returns.
NC Pins (MSE Package Only): No Connection. The NC pins 
are electrically isolated from the LT3500. The NC pins may
be connected to PCB traces to aid PCB layout.
相关PDF资料
LT3507HUHF#TRPBF IC REG QD BUCK/LINEAR 38-QFN
LT3570IFE#TRPBF IC REG BUCK/BST/LINEAR 20TSSOP
LT3645HMSE#TRPBF IC REG DL BUCK/LINEAR 12-MSOP
LT3694IFE-1#TRPBF IC REG TRPL BUCK/LINEAR 20TSSOP
LT4220IGN#TR IC CTLR HOTSWAP DUAL 16-SSOP
LT4250LCN8 IC CONTRLR HOT SWAP NEG 48V 8DIP
LT4254CGN IC CTRLR HOTSWAP POSVOLT 16SSOP
LT4256-1IS8#TRPBF IC CTRLR HOTSWAP HV LATCH 8SOIC
相关代理商/技术参数
LT3500HMSE-PBF 制造商:LINER 制造商全称:Linear Technology 功能描述:Monolithic 2A Step-Down Regulator Plus Linear Regulator/Controller
LT3500HMSE-TRPBF 制造商:LINER 制造商全称:Linear Technology 功能描述:Monolithic 2A Step-Down Regulator Plus Linear Regulator/Controller
LT3500IDD#PBF 功能描述:IC REG DL BUCK/LINEAR 12-DFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - 线性 + 切换式 系列:- 标准包装:2,500 系列:- 拓扑:降压(降压)同步(3),线性(LDO)(2) 功能:任何功能 输出数:5 频率 - 开关:300kHz 电压/电流 - 输出 1:控制器 电压/电流 - 输出 2:控制器 电压/电流 - 输出 3:控制器 带 LED 驱动器:无 带监控器:无 带序列发生器:是 电源电压:5.6 V ~ 24 V 工作温度:-40°C ~ 85°C 安装类型:* 封装/外壳:* 供应商设备封装:* 包装:*
LT3500IDD#TRPBF 功能描述:IC REG DL BUCK/LINEAR 12-DFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - 线性 + 切换式 系列:- 标准包装:2,500 系列:- 拓扑:降压(降压)同步(3),线性(LDO)(2) 功能:任何功能 输出数:5 频率 - 开关:300kHz 电压/电流 - 输出 1:控制器 电压/电流 - 输出 2:控制器 电压/电流 - 输出 3:控制器 带 LED 驱动器:无 带监控器:无 带序列发生器:是 电源电压:5.6 V ~ 24 V 工作温度:-40°C ~ 85°C 安装类型:* 封装/外壳:* 供应商设备封装:* 包装:*
LT3500IDD-PBF 制造商:LINER 制造商全称:Linear Technology 功能描述:Monolithic 2A Step-Down Regulator Plus Linear Regulator/Controller
LT3500IDD-TRPBF 制造商:LINER 制造商全称:Linear Technology 功能描述:Monolithic 2A Step-Down Regulator Plus Linear Regulator/Controller
LT3500IMSE#PBF 功能描述:IC REG DL BUCK/LINEAR 16-MSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - 线性 + 切换式 系列:- 标准包装:2,500 系列:- 拓扑:降压(降压)同步(3),线性(LDO)(2) 功能:任何功能 输出数:5 频率 - 开关:300kHz 电压/电流 - 输出 1:控制器 电压/电流 - 输出 2:控制器 电压/电流 - 输出 3:控制器 带 LED 驱动器:无 带监控器:无 带序列发生器:是 电源电压:5.6 V ~ 24 V 工作温度:-40°C ~ 85°C 安装类型:* 封装/外壳:* 供应商设备封装:* 包装:*
LT3500IMSE#TRPBF 功能描述:IC REG DL BUCK/LINEAR 16-MSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - 线性 + 切换式 系列:- 标准包装:2,500 系列:- 拓扑:降压(降压)同步(3),线性(LDO)(2) 功能:任何功能 输出数:5 频率 - 开关:300kHz 电压/电流 - 输出 1:控制器 电压/电流 - 输出 2:控制器 电压/电流 - 输出 3:控制器 带 LED 驱动器:无 带监控器:无 带序列发生器:是 电源电压:5.6 V ~ 24 V 工作温度:-40°C ~ 85°C 安装类型:* 封装/外壳:* 供应商设备封装:* 包装:*