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| 型号： | MAX668EUB+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 8/18页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR PWM HYBRID 10-UMAX |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 2,500 |
| PWM 型： | 电流模式，混合 |
| 输出数： | 1 |
| 频率 - 最大： | 575kHz |
| 占空比： | 94% |
| 电源电压： | 3 V ~ 28 V |
| 降压： | 无 |
| 升压： | 是 |
| 回扫： | 是 |
| 反相： | 无 |
| 倍增器： | 无 |
| 除法器： | 无 |
| Cuk： | 无 |
| 隔离： | 是 |
| 工作温度： | -40°C ~ 85°C |
| 封装/外壳： | 10-TFSOP，10-MSOP（0.118"，3.00mm 宽） |
| 包装： | 带卷 (TR) |
MAX668/MAX669
1.8V to 28V Input, PWM Step-Up
Controllers in μMAX
Pin Description
PIN
1
2
3
4
5
6
7
8
9
10
NAME
LDO
FREQ
GND
REF
FB
CS+
PGND
EXT
V CC
SYNC/
SHDN
FUNCTION
5V On-Chip Regulator Output. This regulator powers all internal circuitry including the EXT gate driver.
Bypass LDO to GND with a 1μF or greater ceramic capacitor.
Oscillator Frequency Set Input. A resistor from FREQ to GND sets the oscillator from 100kHz (R OSC =
500k ? ) to 500kHz (R OSC = 100k ? ). f OSC = 5 x 10 10 / R OSC . R OSC is still required if an external clock is used
at SYNC/ SHDN . (See SYNC/ SHDN and FREQ Inputs section.)
Analog Ground
1.25V Reference Output. REF can source 50μA. Bypass to GND with a 0.22μF ceramic capacitor.
Feedback Input. The FB threshold is 1.25V.
Positive Current-Sense Input. Connect a current-sense resistor, R CS , between CS+ and PGND.
Power Ground for EXT Gate Driver and Negative Current-Sense Input
External MOSFET Gate-Driver Output. EXT swings from LDO to PGND.
Input Supply to On-Chip LDO Regulator. V CC accepts inputs up to 28V. Bypass to GND with a 0.1μF ceramic
capacitor.
Shutdown control and Synchronization Input. There are three operating modes:
? SYNC/ SHDN low: DC-DC off.
? SYNC/ SHDN high: DC-DC on with oscillator frequency set at FREQ by R OSC .
? SYNC/ SHDN clocked: DC-DC on with operating frequency set by SYNC clock input. DC-DC conversion
cycles initiate on rising edge of input clock.
Detailed Description
The MAX668/MAX669 current-mode PWM controllers
operate in a wide range of DC-DC conversion applica-
tions, including boost, SEPIC, flyback, and isolated out-
put configurations. Optimum conversion efficiency is
maintained over a wide range of loads by employing
both PWM operation and Maxim ’s proprietary Idle
Mode control to minimize operating current at light
loads. Other features include shutdown, adjustable
internal operating frequency or synchronization to an
external clock, soft start, adjustable current limit, and a
wide (1.8V to 28V) input range.
28V. Bootstrapping is required because the MAX669
does not have undervoltage lockout, but instead drives
EXT with an open-loop, 50% duty-cycle start-up oscilla-
tor when LDO is below 2.5V. It switches to closed-loop
operation only when LDO exceeds 2.5V. If a non-boot-
strapped connection is used with the MAX669 and if
V CC (the input voltage) remains below 2.7V, the output
voltage will soar above the regulation point. Table 2
recommends the appropriate device for each biasing
option.
Table 1. MAX668/MAX669 Comparison
MAX668 vs. MAX669 Differences
Differences between the MAX668 and MAX669 relate
to their use in bootstrapped or non-bootstrapped cir-
cuits (Table 1). The MAX668 operates with inputs as
low as 3V and can be connected in either a boot-
strapped or non-bootstrapped (IC powered from input
supply or other source) configuration. When not boot-
strapped, the MAX668 has no restriction on output volt-
age. When bootstrapped, the output cannot exceed
28V.
The MAX669 is optimized for low input voltages (down
FEATURE
V CC Input
Range
Operation
Under-
voltage
Lockout
MAX668
3V to 28V
Bootstrapped or nonboot-
strapped. V CC can be con-
nected to input, output, or
other voltage source such as
a logic supply.
IC stops switching for LDO
below 2.5V.
MAX669
1.8V to 28V
Must be boot-
strapped (V CC
must be connect-
ed to boosted out-
put voltage, V OUT ).
No
to 1.8V) and requires bootstrapped operation (IC pow-
ered from V OUT ) with output voltages no greater than
8
Soft-Start
Yes
When LDO is
above 2.5V
Maxim Integrated
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX668EVKIT | 功能描述:电源管理IC开发工具 Evaluation Kit for the MAX668 MAX669 RoHS:否 制造商:Maxim Integrated 产品:Evaluation Kits 类型:Battery Management 工具用于评估:MAX17710GB 输入电压: 输出电压:1.8 V |
| MAX668EVKIT+ | 功能描述:电源管理IC开发工具 Evaluation Kit for the MAX668 MAX669 RoHS:否 制造商:Maxim Integrated 产品:Evaluation Kits 类型:Battery Management 工具用于评估:MAX17710GB 输入电压: 输出电压:1.8 V |
| MAX66901-K00# | 功能描述:射频识别变换器工具 MAX66901 RF Eval Kit RoHS:否 制造商:Olimex Ltd. 产品:RFID Readers 用于:ISO15693 |
| MAX66902-K00# | 功能描述:射频识别变换器工具 HF DEVELOPER KIT RoHS:否 制造商:Olimex Ltd. 产品:RFID Readers 用于:ISO15693 |
| MAX66903-K00 | 功能描述:射频识别变换器工具 MAX6100/20/40 Eval Kit RoHS:否 制造商:Olimex Ltd. 产品:RFID Readers 用于:ISO15693 |
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